Volatile organic compound emissions in relation to plant carbon fixation and the terrestrial carbon budget - Kesselmeier, Jürgen; Ciccioli, Paolo; Kuhn, Uwe; Stefani, Paolo; Biesenthal, Thomas; Rottenberger, Stefanie; Wolf, Annette; Vitullo, Marina; Valentini, Ricardo; Nobre, Antonio; Kabat, Pavel; Andreae, Meinrat O. (Global Biogeochemical Cycles, 2002)
A substantial amount of carbon is emitted by terrestrial vegetation as biogenic volatile organic compounds (VOC), which contributes to the oxidative capacity of the atmosphere, to particle production and to the carbon cycle. With regard to the carbon budget of the terrestrial biosphere, a release of these carbon compounds is regarded as a loss of photosynthetically fixed carbon. The significance of this loss for the regional and global carbon cycles is controversial. We estimate the amount of VOC carbon emitted in relation to the CO2 taken up, based on our own enclosure and micrometeorological flux measurements of VOC emissions and CO2 exchange within the Mediterranean area and the tropical rainforest in Amazonia and on literature data. While VOC flux estimates are small in relation to net primary productivity and gross primary productivity, the amount of carbon lost as VOC emissions can be highly significant relative to net ecosystem productivity. In fact, VOC losses are of the same order of magnitude as net biome productivity. Although we must assume that large amounts of these reemissions are recycled within the biosphere, a substantial part can be assumed to be lost into longer-lived oxidation products that are lost from the terrestrial biosphere by transport. However, our current knowledge does not allow a reliable estimation of this carbon loss.
Keywords: carbon cycle; volatile organic compounds (VOC)

Análisis de la variabilidad de adn de cloroplastos en Quercus ilex L., Q. suber L. Y Q. coccifera L.. - COLLADA, C.; JIMÉNEZ, P.; Gil, L. (III Congreso Forestal Español, 2001)
Chloroplast (Cp) and mitochondrial (mt) DNA variation have been studied by PCR-RFLP in 14 location (13 with Q. suber, 12 with Q. ilex and 6 with Q. coccifera) along the natural distribution area of these species in the Iberian Peninsula. Five chloroplast DNA primers pairs and one mitochondrial DNA primer pair have been used, each one in combination with a restriction enzyme. 29 different haplotypes have been detected, In the case of Q. suber a characteristic haplotype, very divergent of the remaining ones has been described. Usually, species don’t share haplotypes within the same populations. The distribution of haplotypes suggests a geographical structuring. The levels of genetic differentiation are similar to those obtained in oaks.hS is significantly higher in Q. ilex (hS=0,262). Differentiation coefficients (Gst) are similar in the three species and indicate a high typical structuring of maternal markers.
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español pub-location: Granada
Keywords: chloroplast DNA; differentiation; geographic distribution; Haplotypes; phylogeny; Quercus

Aplicación de los diagramas bioclimáticos a la provincia de lérida: determinación de los parametros bioclimáticos para las masas de QUERCUS ILEX BALLOTA Y QUERCUS FAGINEA - Rovirola, D.; Alcazar, J.; Peman, J. (III Congreso Forestal Español Congreso, 2001)
The present work tries to characterize the different bulks of Quercus ilex and Q. .faginea that are distributed all over the province of Lérida through the utilization of the Diagramas bioclimáticos. Results are intended to give criteria for the utilization of these species in reforestation projects.
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español Congreso issue: 1987 pub-location: Granada
Keywords: diagramas bioclimáticos; forestation; Quercus faginea; Quercus ilex ballota

ASPECTOS METODOLÓGICOS DE LA ORDENACIÓN DE ENCINARES EN SIERRA MORENA OCCIDENTAL - DOMINGO, J. M.; MARÍN, F. J. (III Congreso Forestal Español, 2001)
This paper presents the analysis of three Management Projects made up for Mediterranean Forest Management Units, mainly composed by evergreen oaks (Quercus ilex ssp. rotundifolia) stands with a low tree density, which are called dehesas. The dehesa is mainly used as range land and normally presents hilly landforms, acidic soils non suitable for agriculture, a temperate-warm climate, and trees covering at least 10% of the surface. It is a man made system which needs work in order to maintain its balance, but it is also a traditional landscape giving highly valued productions. Therefore we must try to find management solutions to preserve an enhance the dehesa systems; one of the greatest problems, tree preservation and renewal is presented here.
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español pub-location: Granada
Keywords: Dehesa; evergreen oak; Mediterranean forest management

Caracterización de las poblaciones de Fusarium Link de suelos de dehesas de Badajoz - Rodríguez-Molina, M. C.; TORRES-VILA, L. M.; TELLO MARQUINA, J. C.; BLANCO SANTOS, A.; PALO NÚÑEZ, E. J.; Marquina, J. C. Tello (Boletín de Sanidad Vegetal Plagas, 2001)
La dehesa ocupa en Extremadura una superficie aproximada de 1.800.000 ha y constituye un ecosistema único en el que se combina la producción agro-silvo-pastoraí. Aunque la dehesa está sometida a la acción antrópica, normalmente ésta no provoca la misma perturbación que en las zonas de cultivo agrícola. Sin embargo se desconoce si la micoflora de sus suelos es similar a la de los suelos de áreas no cultivadas o a los de zonas agrícolas. La caracterización de las poblaciones de Fusarium de los suelos de 18 dehesas de Badajoz con arbolado de encina efectuada en este estudio indica que el gé- nero se encuentra ampliamente distribuido en estos suelos. Además de ser detectada su presencia en todos los suelos muestreados, las densidades de población fueron elevadas en general. Las especies aisladas fueron F. oxysporum, F. roseum y F. solani, con un pre- dominio claro de F. oxysporum seguida por F. roseum. Los resultados obtenidos indican que los Fusaria son pobladores naturales de los suelos de dehesa de Badajoz.
Keywords: Dehesa; densidad de población; fusarium; suelo

Catkin frost damage in Mediterranean cork-oak (Quercus suber L.). - García-mozo, Herminia; Hidalgo, Pablo J.; Galán, Carmen; Gómez-Casero, Maria Teresa; Domínguez, Eugenio (Israel Journal of Plant Sciences, 2001)
During a period of study of floral phenology and pollen production in the cork-oak, Quercus suber L. (199799), an interruption of catkin development was detected in spring 1998. The cause might have been a sharp drop in minimum temperatures during that period, which coincided with the initial stages of microsporogenesis. Results show that environmental temperatures close to 0 ºC halted microsporogenesis and catkinelongation, resulting in their complete death. No fruits were observed in the affected zone, as a possible consequence of the lack of pollen. Phenological, histological, andaerobiological data are analyzed as a whole in order to gain a better understanding of the phenomenon. Cold spells during flowering may be one of the factors influencing the high interannual variability of acorn production in Quercus species. [ABSTRACT FROM AUTHOR]
Keywords: CATKIN-bearing plants; Cork oak; flowers; Fruit; Phenology; PLANT spores; POLLEN (citation)

Characterization of the responses of cork oak (Quercus suber) to iron deficiency - Gogorcena, Yolanda; Molias, Nuria; Larbi, Ajmi; Abadía, Javier; Abadía, Anunciación (Tree Physiology, 2001)
We studied responses of cork oak (Quercus suber L.) to iron (Fe) deficiency by comparing seedlings grown hydroponically in nutrient solution with and without Fe. Seedlings grown without Fe developed some responses typical of the Strategy I group of Fe-efficient plants, including two- and fourfold increases in plasma membrane ferric chelate reductase activity of root tips after 2 and 4 weeks of culture in the absence of Fe, respectively. Moreover, seedlings grown hydroponically for 2 weeks without Fe caused marked decreases in the pH of the nutrient solution, indicating that root plasma membrane ATPase activity was induced by Fe deficiency. Iron deficiency also caused marked decreases in leaf chlorophyll and carotenoid concentrations, and chlorophyll concentrations were decreased more than carotenoid concentrations. Iron deficiency resulted in an 8% decrease in the dark-adapted efficiency of photosystem II and a 43% decrease in efficiency of photosystem II at steady-state photosynthesis. No major root morphological changes were observed in seedlings grown without Fe, although seedlings grown in Fe-deficient nutrient solution had light-colored roots in contrast to the dark brown color of control roots.
10.1093/treephys/21.18.133510.1093/treephys/21.18.1335
Keywords: Fe deficiency; ferric chelate reductase; plant nutrition; rhizosphere acidification.

Comportement physiologique des glands de chêne liège (Quercus suber L.) durant leur conservation et variabilité inter-individus producteurs - Merouani, Hachemi; Branco, Carmen; Almeida, Maria Helena; Pereira, João S. (Ann. For. Sci., 2001)
The mature acorns were harvested on twelve selected trees from a cork oak population in Southern Portugal (Herdade da Palma). After drying, the seed lots were stored on three types bags (polyethylene with 30 mm and 50 mm thick and plastic mesh), for six months at 0 oC. At the time of natural dissemination, the acorns from the majority of the trees from the same population were under the same state of morphological and physiological maturity. The moisture content was about 44-47% and a germination rate above 92% . At this time, the germination was very slow because of the existent embryonic dormancy that seems to be dependent on the individual trees. During the storage, germination rate is improved. This might be explained by the breaking dormancy during storage. The mean germination time was on an average 10 days for fresh seeds and decreased to about 4 days after 6 months storage. A relationship between viability and seed moisture content was observed. The Mean Germination Time of dried seed and stored seed for 4 months in plastic mesh bag increased to about 13 days. The germination capacity was strongly decreased when the seed moisture content was below 30%
Keywords: electrolyte leakage; germination; Moisture content; Quercus suber; seed; storage

A dendroclimatological approach to diameter growth in adult cork-oak trees under production - Costa, A.; Pereira, H.; Oliveira, A. (Trees, 2001)
The diameter growth of mature cork oaks under cork production in southwestern Portugal was studied during a 9-year cork-production cycle in relation to fluctuations in precipitation and temperature, and to drought indices combining the two variables. A dendroclimatological approach was applied to the series of 8 complete years contained in the cork-production cycle and growth effects were removed by standardization and calculation of annual growth indices. The most important factor positively influencing diameter growth was cumulative precipitation in the growing season (January–June) and in the previous autumn and winter (October/November of the previous year–June). The monthly temperature is a less influential factor, negatively correlated with diameter growth in high summer drought (August) and positively correlated at the beginning of physiological activity (March).
Keywords: climatic fluctuations; dendroclimatology; diameter growth; Mediterranean climate; Quercus suber L.

DETERMINACIÓN DE ROTACIONES ÓPTIMAS EN LA APLICACIÓN DE RESALVEOS DE CONVERSIÓN A MONTE ALTO EN TALLARES DE ENCINA Y DE QUEJIGO EN LA ZONA CENTRAL DE LA PENÍNSULA IBÉRICA. - BRAVO, J. A.; SÁNCHEZ, I.; SERRADA, R. (III Congreso Forestal Español, 2001)
Conversion thinning seems to be a good option for most of the coppicce forests of holm oak and gall oak, where the lack of management is causing severe problems. Intensity and rotation of thinning are the two main parameters to be studied. This paper deals with the second one. Six coppicce forests of holm oak and two for gall oak in the Guadalajara province where selected. Those stands had been thinned in a known date, and have been compared with near control stands, which have not been thinned in the past. Diameter growth after thinning has been studied throught rings count and ring width measurement in both kind of stands. 129 trees of holm oak and 79 trees of gall oak have been studied. The main conclusions are the evidence of a significant growth of diameter in holm oaks that is present 11 years after the thinning, while in gall oak results are not so clear. In gall oak just one site showed a positive answer to thinning, that was present until 17 years after. K.W.:
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español issue: 1 pub-location: Granada
Keywords: conversion thinning; coppicce forest; gall oak; Growth; Holm oak; rotation

Differential success in northwards range expansion between ecotypes of the marble gallwasp Andricus kollari: a tale of two lifecycles - Stone, G.; Atkinson, R.; Rokas, A.; Csoka, G.; Nieves-Aldrey, J. L.; Csoka, G.; Nieves-Aldrey, J. L. (MOLECULAR ECOLOGY, 2001)
The Marble gallwasp Andricus kollari has a native range divided into two geographically separated lifecycles. In Eastern Europe and Turkey, the lifecycle involves a sexual generation on Turkey oak, Quercus cerris, while in Iberia and North Africa the sexual generation host is cork oak, Q. suber. Over the last 500 years, A. kollari has expanded its range into northern Europe, following human planting of Q. cem's from Italy and the Balkans. We ask: (i) what is the genetic relationship between eastern and western distributions of Andricus kollari? Can we determine which lifecycle is ancestral, and how long ago they diverged? (ii) To what extent have eastern and western native ranges contributed to northwards range expansion? (iii) Is there any evidence for hybridization between the two life cycle types? We present analyses of allozyme data for 13 polymorphic loci and of sequence variation for a 433 bp fragment of the mitochondrial cytochrome b gene. These show: (i) that four haplotype lineages (one in Spain, two in Hungary/Italy and one in Turkey) diverged more or less simultaneously between 1 and 2 million years ago, suggesting the existence of at least four refuges through recent ice age cycles. Our data cannot resolve which lifecycle type is ancestral. (ii) Populations north of putative refuges are divided into two sets. Populations in south-west France are allied to Spain, while ail remaining populations in northern Europe have been colonized from Italy and the Balkans. (iii) The transition from one race to another in south-west France is marked by abrupt transitions in the frequency of refuge-specific private alleles and corresponds closely to the northern limit of the distribution of cork oak. Although hybrids were detected in north-west France, none were detected where the two lifecycles meet in south-western France. The biology of oak gallwasps predicts that any hybrid zone will be narrow and limited to regions where Q. cem's and Q. suber meet. Our data suggest that eastern and western A. kollari are effectively separate species.
From Duplicate 2 (Differential success in northwards range expansion between ecotypes of the marble gallwasp Andricus kollari: a tale of two lifecycles - Stone, G; Atkinson, R; Rokas, A; Csoka, G; Nieves-Aldrey, J L)From Duplicate 2 (Differential success in northwards range expansion between ecotypes of the marble gallwasp Andricus kollari: a tale of two lifecycles - Stone, G; Atkinson, R; Rokas, A; Csoka, G; Nieves-Aldrey, J L)The following values have no corresponding Zotero field: pub-location: COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA publisher: WILEY-BLACKWELL accession-num: 11298986
Keywords: Alleles; Andricus; Animals; Base Sequence; Cellulose Acetate; Cytochrome b Group; Cytochrome b Group: chemistry; Cytochrome b Group: genetics; DNA; Electrophoresis; Environment; EUROPE; Evolution; Female; gallwasp; Genetic Variation; Genetic Variation: physiology; glacial refugia; host race; Hymenoptera; Hymenoptera: genetics; Hymenoptera: growth & development; Hymenoptera: physiology; invasion; Life Cycle Stages; Mitochondrial; Mitochondrial: chemistry; Mitochondrial: isolation & purification; Molecular; Molecular Sequence Data; Parthenogenesis; phylogeny; Polymerase Chain Reaction; range expansion; Sequence Alignment; Sequence Analysis

EARLY CHECKING OF GENETIC STABILITY OF CORK OAK SOMATIC EMBRYOS BY AFLP ANALYSIS. - Hornero, J.; Martinez, I.; Celestino, C.; Gallego, F. J.; Torres, V.; Toribio, M. (International Journal of Plant Sciences, 2001)
Early checking of the genetic stability, of tissue culture-derived plants is necessary to obtain all the potential benefits of clonal forestry. Previous work in Quercus suber L. using random amplified polymorphic DNA (RAPD) markers showed no genetic variation among somatic embryos within embryogenic lines of zygotic origin. Genetic fingerprinting based on amplified fragment length polymorphisms (AFLP) allows the direct analysis of variation at the entire DNA level by generating more reproducible markers than RAPDs. To confirm the absence of genetic variation within six embryogenic lines of zygotic origin, six primer pairs were selected out of 48 combinations of primers for revealing up to 512 AFLP markers, 301 of them (58.8%) being polymorphic. The mean number of markers per genotype was 375. Again differences were recorded among embryogenic lines, even between those that arose from half-sib zygotic embryos, but no variation was observed among somatic embryos within embryogenic lines. To check variation in embryogenic lines raised from non-embryonic tissues, somatic embryogenesis was induced in expanding leaves collected from sprouts originating in three mature cork oak. DNA was extracted from leaves and from somatic embryos derived from each tree, and three primer pairs showed 165, 110, and 108 markers per genotype/tree, respectively. In one tree, AFLP patterns generated from leaves and somatic embryos were identical, but variation was detected in samples from the other two trees. Although the level of genetic variation detected in these lines (5.6% and 7.3% of polymorphism, respectively) is lower than that recorded for half sibs of cork oak (25%–31%), its influence on phenotypic variation needs further assessment. [ABSTRACT FROM AUTHOR]
Keywords: AFLP; Cork oak; DNA markers; in vitro culture; Quercus suber; somaclonal variation; Somatic embryogenesis

Efecto de la inoculación de cuatro bacterias promotoras del crecimiento vegetal sobre parámetros biométricos aéreos de plántulas de QUERCUS ILEX SSP.BALLOTA B. - Ramos, B.; Lucas García, J. A.; Santamaría, C.; Camacho, M.; Daza, A.; García, J. A. Lucas (III Congreso Forestal Español Congreso, 2001)
In the present work has studied the effect of four plant growth-promoting rhizobacteria (PGPRs) on growth of holm-oak plants (Quercus ilex ssp. ballota) in nursery before transplanting. The four strains assayed show in vitro metabolic capacities related with their action PGPR. All strains were able to increase significantly some parameters studied (high, diameter neck and dry weight). However, in the first sampling time (T1) only the strains Aur 6 and Aur 9 increased the high of the plants. In the last sampling time (T3) all strains increased the high, only Aur 6 increased the diameter neck and Cell 3, Aur 6 and Aur 9 increased the dry weight. It is important to point out that Aur 6 and Aur 9 increased the high and also the dry weight, this show that these strains enhance the general metabolism of the plants and also enhance the nutritional capacity and as a result the plants are more robust and with a better adaptative capacity.
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español Congreso issue: 1 pub-location: Granada
Keywords: adaptative capacity; colonization; PGPR; Quercus ilex ssp. ballota

Efecto de las inyecciones de fosfonato potásico en tronco de encina (QUERCUS ILEX SUBSP. BALLOTA) SOBRE EL CRECIMIENTO DE RAMILLAS Y LA FRUCTIFICACIÓN. - CORDÓN, S.; BRAVO, V.; Tapias, R.; Lopez, G.; SÁNCHEZ, I. (III Congreso Forestal Español, 2001)
The present communication intends to see the answer of the oaks (Quercus ilex subsp. ballota) treateds using antifungal materials (potassium phosphonate) injections to the trunk. In the first year, has been measured the growth of the buds and the production of acorns of three treated oaks and other three not treated, in one property of the Western Andévalo (Andalusia, Huelva).
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español pub-location: Granada
Keywords: Andévalo; Huelva; Quercus ilex; trunk injections

The effect of cork removal on the radial growth and phenology of young cork oak trees - Fialho, C.; Lopes, F.; Pereira, H. (Forest Ecology and Management, 2001)
The effect of the removal of cork was studied in 11-years old cork oak trees (Quercus suber L.), growing in favorable conditions, in relation to phenology and radial growth during two years. Longevity of leaves was 14±15 months (1996, 1998) and 10 months (1997). Bud burst started in mid-February and leaf ¯ushing in April, extending until June. Neither a distinct two-period ¯ushing nor an autumn bud burst or leaf ¯ushing were observed. Radial growth started in mid-April and continued until the end of November, with the maximum growth in June and July. In trees with the removal of cork, leaf abscission occurred a little earlier and new branches had on average 23% fewer new leaves. The radial growth of the trees and its general seasonal pattern were not affected by cork removal in the year of removal or in the year after. The only observation was a shift of the maximum radial growth rate from June to July for the trees where cork had been removed
Keywords: cork removal; cork-oak; Phenology; Quercus suber; Radial growth

Effects of acorn storage duration and parental tree on emergence and physiological status of Cork oak (Quercus suber L.) seedlings - Merouani, Hachemi; Branco, Carmen; Almeida, Maria Helena; Pereira, João S. (Ann. For. Sci., 2001)
This study was conducted to evaluate how parental trees and seed storage duration influenced subsequent seedling physiological status and growth. Seedling emergence rate was higher than 90% independently of the duration of seed storage or parental trees. Seed storage shortened significantly the time and increased the uniformity of seedling emergence. Consequently, the delayed seedling emergence from fresh seeds could be explained by epicotyl dormancy. Seed size varied with parental tree. Seedling growth rate was greatly affected by seed size, independently of storage treatment. Seedlings originating from large seeds (> 5 g) had the fastest growth rates and seedlings from the smallest seeds (< 4 g) had the slowest. Final shoot height, however, depended on the duration of seed storage. The seed size and the duration of storage had a great effect on the initial rate of leaf production, but did not affect the final number of leaves. Leaf chlorophyll concentration was reduced as the duration of seed storage increased but was independent of parental tree (i.e., seed size). Seedling biomass was positively related to seed size. The duration of seed storage reduced the shoot/root ratio, but no significant effect was observed among parental trees. The shoot/root value of seedlings from stored seed was about 1.5 and the one of seedlings from fresh seed was about 2.
Keywords: Quercus suber; root radio; Seed size; seed storage; seedling growth; shoot

Estado hídrico y demanda de fotosintesis de Quercus ilex, Quercus faginea y Pinus halepensis MICORRIZADOS ARTIFICIALMENTE CON Tuber melanosporum EN VIVERO - DOMÍNGUEZ, J. A.; R. PLANELLES; RODRÍGUEZ BARREAL, J. A.; SAÍZ DE OMEÑACA, J. A.; ZAZO, J.; TEYSSIERE, M.; MARTINEZ, G.; PINAZO, O. (III Congreso Forestal Español Congreso, 2001)
We have been carried out a periodic control in Quercus ilex, Quercus faginea and Pinus halepensis inoculated with Tuber melanosporum Vitt. during the first year of growth in nursery with a water-non stressed régime; in all the species, the minimum water potential and transpiration rate didn't reflect any differences for the treatment, but in some cases, the photosynthesis rate was major in inoculated seedlings. K.W.:
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español Congreso pub-location: Granada
Keywords: ectomycorrhiza; photosynthesis; Pinus halepensis; Quercus faginea; Quercus ilex; Tuber

Estudio de la influencia de la fertilizacion nitrogenada y la iluminacion sobre atributos morfologicos y fisiologicos de brinzales de Q.suber L. CULTIVADO EN VIVERO. RESULTADOS DEL 1er. AÑO EN CAMPO - Martínez Romero, G.; Planelles González, R.; Zazo Muncharaz, J.; Bela Quero, D.; Vivar Sanz, A.; López Arias, M. (III Congreso Forestal Español Congreso, 2001)
This essay studies the influence of fertilization and illumination of Q.suber L. in container seedlings. Plants were tested in three diferents levels of fertilization (control substrate, fertilizated substrate and fertilizated substrate plus nitrogen supplied) with two of illumination (full light conditions and a reduction of 50% illumination). After the first year in nursery, plants was installed in survey parcels, where growing measures and survival rates were studied
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español Congreso pub-location: Granada
Keywords: Cork oak; fertilization; ilumination; Quercus suber L.

Etiología de las podredumbres radicales de plántulas de QUERCUS SPP. Y PINUS HALEPENSIS EN VIVEROS FORESTALES DE ANDALUCÍA - Andicoberry, S.; LORA, F.; SÁNCHEZ, E.; Trapero, A. (III Congreso Forestal Español, 2001)
A disease surey carried out during 1998-99 showed that holm oak (Quercus ilex) and Aleppo pine (Pinus halepensis) seedlings were affected by damping-off and root rot in three forest nurseries in Andalucía, southern Spain. A similar problem was detected affecting four species of Quercus (Q. coccinea, Q. faginea, Q. ilex, and Q. suber) in a forest nursery in 2000. Three species of Phytophthora (P. cinnamomi, P. cryptogea, and P. drechsleri) were isolated from holm oak feeder roots, and P. drechsleri was isolated from feeder roots of Aleppo pine in the first survey in 1998-99. In the second survey, Cylindrocarpon didymum was isolated from the feeder roots of the four Quercus spp. essayed, and C. destructans was isolated only from Q. faginea. Pathogenicity tests were conducted using 1 year-old healthy plants of cork oak, holm oak and Aleppo pine. Isolates of the three Phytophthora species were pathogenic to the three host species, inducing root rot and plant death. Holm oak was the most susceptible host and P. cinnamomi was the most virulent species. Isolates of Cylindrocarpon were pathogenic to cork oak and holm oak causing root rot, yellowing, defoliation, and plant death.
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español pub-location: Granada
Keywords: Cylindrocarpon; Phytophthora; Quercus coccinea; Quercus faginea; Quercus ilex; Quercus suber

Evolução da paisagem de montado no Alentejo interior ao longo do século XX: dinâmica e incidências ambientais - Ferreira, D. Brum (Finisterra: Revista portuguesa de geografia, 2001)
EVOLUTION OF THE MONTADO LANDSCAPE IN THE INNER ALENTEJO DURING THE 20TH CENTURY. DYNAMICS AND ENVIRONMENTAL CONSEQUENCES – This paper presents the general context within which the montado landscape changed in the inner Alentejo during the 20th century as well as some of the environmental consequences, such as soil degradation and modification of the local climate. In large areas nowadays abandoned, the landscape dynamics depends more on environmental limitations created by soil degradation that on purely socio-economical factors.
Keywords: agricultural system; Agroforestry; climate modification; land use history; montado landscape; soil erosion

Factors affecting bird communities in fragments of secondary pine forests in the north-western Mediterranean basin - Brotons, L.; Herrando, S. (ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY, 2001)
We assessed the influence of size, extent of isolation and vegetation structure of secondary forest fragments on the richness and species composition of breeding bird communities in a sample of pine forest fragments surrounded by an agricultural matrix in the north-western Mediterranean basin. Fragment size was the main predictor of bird's occurrence, since it accounted for 70 % of the model variation. Isolation was also a valuable predictor of species occurrence, especially for forest specialists. Finally, subarboreal vegetation such as holm oak and a well-developed tree layer of large pines favoured forest species occurrence. Therefore, in spite of the long history of human impact, forest birds in Mediterranean mosaics are sensitive to both habitat loss and isolation of remnant patches in a similar manner to the patterns found in other temperate fragmented landscapes where human impact is more recent. (C) 2001 Editions scientifiques et medicales Elsevier SAS.
The following values have no corresponding Zotero field: pub-location: 23 RUE LINOIS, 75015 PARIS, FRANCE publisher: GAUTHIER-VILLARS/EDITIONS ELSEVIER
Keywords: birds; fragmentation; isolation; Mediterranean mosaics; vegetation structure

Fine-root longevity of Quercus ilex - López, B.; Sabate, S.; Gracia, C. A. (New Phytologist, 2001)
* • Fine-root longevity and phenology were studied in a Quercus ilex (holm oak) forest in Prades (NE Spain). Differences were investigated among roots that had appeared in different seasons and at different depth intervals, differentiating between white and brown roots. * • Using minirhizotrons installed in March 1994, 1211 roots were monitored every 3 wk from June 1994 to March 1997. * • Mean and median fine-root longevity were 125 ± 4 d and 67 d, respectively. Longevity of summer and winter roots was greater than that of spring and autumn roots. Although roots appeared and disappeared throughout the year, the rate of appearance was greatest in spring. Maximum longevity occurred at a soil depth of 20–30 cm. Differences among 10-cm depth intervals were due to the number of days that roots were brown, since roots remained white for a similar number of days, independent of soil depth. * • Temperate soil temperatures and lignotubers permitted the appearance of roots throughout the year. Holm oak fine roots might be more efficient during the first 50 d of their life before the white roots become less efficient brown roots.
The following values have no corresponding Zotero field: publisher: Blackwell Science Ltd
Keywords: Fine root longevity; Holm oak; minirhizotron; Quercus ilex; vertical longevity pattern

Flammability assessment of Mediterranean forest fuels - Dimitrakopoulos, A. P.; Papaioannou, K. K. (Fire Technology, 2001)
The time-to-ignition of variousdominant Mediterranean forest fuelswasmeasured during laboratory tests, in order to develop a relative ﬂammability classiﬁcation and determine the moisture of extinction of these fuels. The tests were performed with an ignition apparatusmanufactured according to the ISO standards(ISO 5657-1986E) and under a wide gradient of fuel moisture contents, ranging from air-dry to fresh foliage. Moisture content was the single most signiﬁcant factor that affected fuel ﬂammability. Regression modelswere developed between the time-to-ignition and the moisture content valuesof all the fuels tested, and subsequently, were used for the relative ﬂammability ranking of these fuels. Fuel moisture of extinction was assessed to have a threshold value ranging from 40% to more than 140% o.d.w. for the species tested. The ﬂammability ranking of natural fuels can be useful in fuel hazard assessment and ﬁre danger rating, thus facilitating the judicial ﬁre management planning in wildlandsand at the rural-urban interface.
Keywords: flammability; ignitability; Mediterranean; natural fuels; wildland fires

The foraging ecology of red deer (Cervus elaphus) in a Mediterranean environment: is a larger body size advantageous? - Bugalho, M. N.; Milne, J. a; Racey, P. a (Journal of Zoology, 2001)
In Mediterranean environments browse is expected to be a major component of the diet of red deer Cervus elaphus during the summer when most grasses senesce. In this study the hypothesis is tested that, if browse is an essential food resource at this time, the sex with the larger body size may have a greater physical ability to reach the tree canopy and include a higher proportion of browse in its diet. The organic matter digestibility (OMD) and composition of the diet of a population of red deer males and females were measured between July and September, in 1996 and 1997, in an area of Portugal with a Mediterranean type of climate, using the n-alkane technique. Direct observations of animals browsing on tree canopies and shrubs were made also during the same period. The OMD of the diet was signi®cantly different between sexes and between years and was higher in males than females both in 1996 (means sem for males and females, 0.65 and 0.58 0.026, respectively) and 1997 (means for males and females, 0.59 and 0.48 0.045, respectively). The proportion of cork oak Quercus suber in the diet was also signi®cantly different between sexes and between years, with males having a higher proportion of cork oak in their diets in 1996 (males and females, 0.30 and 0.16 0.037, respectively) and 1997 (males and females, 0.41 and 0.23 0.064, respectively). A signi®cantly lower proportion of the herbage layer was found in the diet of males in 1996 (males and females, 0.46 and 0.64 0.048) but not in 1997. The number of observations of males browsing on tree canopies was signi®cantly higher than females. It is concluded that there are differences between sexes in the composition and quality of the diet and that a larger body size may confer advantages in situations where browse is an essential food resource.
Keywords: body-size; browse; cervus elaphus; diet composition; Mediterranean

Forecasted stability of Mediterranean evergreen species considering global changes - GRATANI, L.; Bombelli, A. (GLOBAL CHANGE AND PROTECTED AREAS, 2001)
Plant communities of the Mediterranean climate Regions are exposed tohigh temperatures, high radiation and water stress during summer, they are dominated by evergreen sclerophyllous species and drought semi deciduous species. To define the adaptive strategies, anatomical and morphological leaf traits of Quercus ilex L., Phillyrea latifolia L. (typical evergreen sclerophyllous species) and Cistus incanus L., (a drought semi deciduous species), growing in the Mediterranean maquis along Pome's coast line (Italy) were analysed. The typical evergreen sclerophyllous species have long leaf life span (from 1 to 4 years), steeper leaf inclination (average 56 degrees), higher specific leaf mass (average 21.3 mg cm(-2)) and the highest leaf thickness (average 324 mum). The semi deciduous species have a lower leaf life span (from 4 to 8 months), a lower leaf inclination (44 degrees +/- 13 degrees), a lower specific leaf mass (14.7 +/-1.5 mg cm(-2)) and a lower leaf thickness (244 +/- 15 mum). The more xeromorphyc species (Q. ilex and P. latifolia) may be at a competitive advantage considering the forecasted air temperature increase in the Mediterranean basin. Increasing drought stress may in fact determine a shortening of leaf life span that may prove to be critical for C. incanus. Knowledge of plant response to stress factors is important in the perspective of climatic changes.
Meeting on Global Change and Protected Areas, LAQUILA, ITALY, SEP, 1999Meeting on Global Change and Protected Areas, LAQUILA, ITALY, SEP, 1999The following values have no corresponding Zotero field: periodical: GLOBAL CHANGE AND PROTECTED AREAS pub-location: PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS
Keywords: Q. ilex; P. latifolia; C. incanus; leaf life span

Frequent cytoplasmic exchanges between oak species that are not closely related: Quercus suber and Q. ilex in Morocco - Belahbib, N.; Pemonge, M.-H. H.; Ouassou, A.; Sbay, H.; Kremer, A.; Petit, R. J. (Molecular Ecology, 2001)
Chloroplast (cp) and mitochondrial (mt) DNA variation were studied in 97 populations of cork oak (Quercus suber) in Morocco; in 31 of these populations, holm oak (Quercus ilex), a clearly distinct species, also occurred and was compared with Q. suber. Three cpDNA and one mtDNA primer pairs were used in the survey, each in combination with one restriction enzyme. Six haplotypes belonging to two very divergent lineages were detected; one lineage predominates in each species, and is probably ancestral, as inferred from comparisons with other oak species. In the mixed-species populations, cytoplasmic genomes were frequently shared across species, as indicated by an introgression ratio of 0.63. This index is a new measure of the propensity of species to share locally genetic markers, varying from zero (complete differentiation) to one (no differentiation). By contrast, more closely related deciduous oak species (Q. robur, Q. petraea and Q. pubescens) have introgression ratios varying from 0.82 to 0.97. The introgression events appear to have been more frequent in the direction Q. ilex (female) × Q. suber (male), a finding which seems attributable to the flowering phenology of these two species. This asymmetry may have favoured immigration of Q. suber beyond its main range, in regions already colonized by Q. ilex. There, rare hybridization and further introgression through long distance pollen flow have established populations that are morphologically indistinguishable from Q. suber but that have cytoplasmic genomes originating from the local Q. ilex populations.
The following values have no corresponding Zotero field: publisher: Blackwell Science Ltd accession-num: 11555243
Keywords: Chloroplast; Chloroplast: genetics; cpDNA; DNA; Evolution; Genetic; Genetic Markers; Genetic Variation; Genetic: genetics; geographical structure; Haplotypes; Hybridization; introgression; Mitochondrial; Mitochondrial: genetics; Models; Molecular; Morocco; mtDNA; PCR–RFLP; Quercus; Quercus: genetics; Trees; Trees: genetics

Identificação e Quantificação por DAD-HPLC, da Fracção Fenólica Contida em Folhas de Quercus suber L. - Evaristo, Isabel Maria; Leitão, Maria Cecília (Silva Lusitana, 2001)
In this study, an analytical method has been developed for the determination of phenolic compounds since they are related with disease and pests plant resistance mechanisms. The components of the hydrolysed extract (gallic acid, ellagic acid, catechin, epicatechin, caffeic acid, p-coumaric acid and ferulic acid) have been resolved and identified by DAD-HPLC based on their retention times and spectral data. For quantifications, the external standard method was used.
The following values have no corresponding Zotero field: publisher: scielopt
Keywords: avoir un rôle important; caffeic acid; car ces; catechin; dans la présente étude; défense des; des feuilles de chêne; détermination des composés phénoliques; ferulic acid; gallic acid; liège; méthode analytique pour la; on a developpé une; p-coumaric acid; Quercus Suber L; résumé; substances sont susceptibles d; sur les mécanismes de

Identification of an endophytic Nodulisporium sp from Quercus ilex in central Spain as the anamorph of Biscogniauxia mediterranea by rDNA sequence analysis and effect of different ecological factors on distribution of the fungus - Collado, J.; Platas, G.; Pelaez, F. (MYCOLOGIA, 2001)
A study of fungal endophytes from aerial parts of Quercus ilex ssp. ballota was carried out on 32 specimens sampled at three forests in Central Spain. Trunk bark, fresh leaves, and healthy and decaying twigs were surveyed. A Nodulisporium sp. was frequently recorded among the isolates. Sequence analysis of the internal transcribed spacer (ITS) region of the rDNA (including the 5.8S rRNA gene) was used for the identification of this fungus. The comparison and phylogenetic analysis of the sequences from several representatives of this endophytic species and a group of xylariaceous fungi with Nodulisporium-like anamorphs revealed that the endophytic Nodulisporium sp. was conspecific with the phytopathogenic species Biscogniauxia mediterranea (equivalent to Hypoxylon mediterraneum). Significant differences were found between the isolation frequencies of the fungus, relative to the geographical origin of the samples. Also, the fungus was more frequent on samples collected in the autumn, as compared to those collected in the spring. The greatest degree of colonization was observed in twigs, while in leaves the fungus was present in significantly lower amounts. The relative frequency of this species in bark increased in the higher parts of the trunk. Tissue preference analysis revealed that this fungal species is exclusively located in bark, being absent from xylem of living twigs. The relative abundance of the fungus in decaying twigs was remarkably higher than in healthy twigs.
The following values have no corresponding Zotero field: pub-location: PUBLICATIONS DEPT, BRONX, NY 10458 USA publisher: NEW YORK BOTANICAL GARDEN
Keywords: Distribution patterns; fungal endophytes; Hypoxylon mediterraneum; ITS sequences; Periconiella-like; Xylariaceae

Inflación del capital natural de la dehesa: hipótesis sobre la naturaleza caótica de la seca de los Quercus DENTRO DEL PROCESO DE LA SENESCENCIA FOLIAR - CUEVAS, S.; Torres, E.; VÁZQUEZ, F. Mª; López Arias, M.; HERNÁNDEZ, A. (III Congreso Forestal Español Congreso, 2001)
“Dehesa” is a gap forest yielding as an ecological-economic system (money-borrowed), poor soils (money-lender) upheld during optimal stopping millenia. Have supported multiple antropogenic nutrition disturbances during chaotic and resource routine affecting oak root uptake. Shoot nutrient odyssey is represented by cobweb model as price (nitrogen) evolution working by-product quantity (biomass). This trial evaluates cork oak (Quercus suber L.) and holm oak (Quercus rotundifolia Lam.) harvest basic sustainability (HBS) or nitrogen leaf redemption, southern Extremadura situated, evaluating ecological economic orientor for ecosystem. Defective HBS management hypothesis is expound in the absence of forest management, leading to sickly phenomenon on forest health as oak decline. Parallelly, HBS is proposed as an cork quality indirect index. Leaf senescence fork leads to physiological imbalance and, in some final cases, whole canopy defoliation (tie break). K.W.: Cobweb model, Oak decline, Renewal, Optimal stopping Dehesa, Nitrogen.
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español Congreso pub-location: Granada
Keywords: Cobweb model; nitrogen; Oak decline; Optimal stopping Dehesa; Renewal

INFLUENCIA DE LA "MANCHA AMARILLA" SOBRE LA COMPOSICIÓN QUÍMICA DEL CORCHO Y LA PRESENCIA DE TCA - García Vallejo, M. C.; Varea, S.; Cadahia, E.; Fernández de Simón, B. (III Congreso Forestal Español, 2001)
The anomaly of cork known as "yellow stain" has been considered as the main responsible for the presence, in some cork stoppers, of 2,4,6-trichloroanisole (TCA), compound that confers the "cork taint" to wine. In this Communication, a comparative study on the chemical composition of cork (suberin, waxes, polyphenols, holocellulose and lignin) and on the presence of chloroanisoles and chlorophenols is carried out with samples of healthy cork and cork affected with that anomaly. The cork with "yellow stain" differed from the healthy cork because of the presence of TCA and the low content of tannins.
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español issue: 1995 pub-location: Granada
Keywords: chemical composition; Cork; yellow stain

Influencia del clima en el crecimiento longitudinal y radial de Q. ilex ssp. ballota L. y Q. faginea Lam. EN EL SISTEMA IBERICO ARAGONES - Corcuera, L.; Camarero, J. J.; GIL-PELEGRÍN, E. (III Congreso Forestal Español, 2001)
Climate influence (precipitation and temperature) on primary growth (annual growth length) and secondary growth (ring width and ring surface) of Quercus ilex ssp. ballota L. (evergreen and diffuse-porous species) and Q. faginea Lam. (decidious and ring-porous species) is studied. Samples were taken from a coppice in Sierra de Santa Cruz, Cubel, Zaragoza. Both species show lesser longitudinal and radial growth in drought years. A positive and significant relationship between precipitation and secondary growth and a negative and significant relationship between high summer temperatures and secondary growth were observed. Primary and secondary growth in 1993 and previous years mirror foliage desiccation of Q. ilex in 1993.
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español issue: 1 pub-location: Granada
Keywords: climate; primary growth; Q. faginea; Q. ilex ssp. ballota; secondary growth

Internal remobilization of carbohydrates, lipids, nitrogen and phosphorus in the Mediterranean evergreen oak Quercus ilex - Cherbuy, Bénédicte; Joffre, Richard; Gillon, Dominique; Rambal, Serge (Tree Physiology, 2001)
Remobilization of internal resources is an important mechanism enabling plants to be partly independent of external nutrient availability. We assessed resource remobilization during the growing period in woody and foliar tissues of leafy branches of mature evergreen Mediterranean oak (Quercus ilex L.) at three field sites. We compared nonstructural carbohydrates, lipids, nitrogen and phosphorus pools in leaves and stems before bud burst (March) and at the end of the growing period (July). We also experimentally defoliated leafy branches to determine the storage function of old leaves. Changes in pools of carbon compounds in leaves and stems during spring and in response to defoliation indicated that foliar and woody tissues could provide carbon to support shoot growth. Independently of stem age, soluble sugar and lipid pools decreased significantly during spring. Changes in leaf pools between March and July involved all compounds measured except starch and were accompanied by a 5%; decrease in mean leaf biomass. During the same period, 15%; of the nitrogen and 25%; of the phosphorus were removed from leaves. In contrast, woody tissues did not remobilize nitrogen or phosphorus. Our results support earlier hypotheses that leaves of evergreen species have a primary role in resource remobilization.
10.1093/treephys/21.1.910.1093/treephys/21.1.9
Keywords: defoliation; Growth; nutrient storage; resource remobilization

Isolation and functional analysis of a cDNA encoding a myrcene synthase from holm oak (Quercus ilex L.) - Fischbach, Robert J.; Zimmer, Wolfgang; Schnitzler, Jörg-Peter (European Journal of Biochemistry, 2001)
An 859-bp cDNA segment of a terpene synthase gene was amplified by PCR from the evergreen sclerophyllous holm oak (Quercus ilex L.) using heterologous primers for conserved regions of terpene synthase genes (TPS) in dicotyledonous plants. Based on the sequence of this segment, homologous primers were designed for amplification by RACE-PCR of a cDNA segment carrying the monoterpene synthase gene myrS. The gene encodes a protein of 597 amino acids including an N-terminal putative plastid transit peptide. The gene without the segment encoding the transit peptide was cloned by PCR into a bacterial expression vector. Expression in Escherichia coli yielded an active monoterpene synthase, which converted geranyl diphosphate (GDP) predominantly into the acyclic monoterpene myrcene and to a very small extent into cyclic monoterpenes. Sequence comparison with previously cloned monoterpene synthases revealed that the myrcene synthase from Q. ilex belongs to the TPSb subfamily.
The following values have no corresponding Zotero field: publisher: Blackwell Science Ltd
Keywords: functional expression; geranyl diphosphate; monoterpene synthases; myrcene synthase; Quercus ilex

Land use, biodiversity conservation, and rural development in the dehesas of Cuatro Lugares, Spain - Plieninger, T.; Wilbrand, C. (Agroforestry Systems, 2001)
Dehesas are an agrosilvopastoral system that has enhanced the maintenance of an extraordinarily high biodiversity. The traditional use is characterized by mixed livestock raising at low stocking densities, employment of hardy regional breeds and an elaborated maintenance and exploitation of holm oaks. Livestock production has traditionally been accompanied by arable systems with long rotations and closed nutrient cycles without external inputs of fodder, fertilizers and agro-chemicals. Modern trends are a specialization toward lamb and beef production and the employment of intensive techniques like freerange grazing at high stocking levels or crossbreeding with high-performance breeds. A model income statement shows that livestock create an income of 49.91 US$ per ewe per year on an average basis. The central problem for the continuity of the dehesas is the gradual decay of the tree canopy. Intensification of agricultural production and the abandonment of traditional grazing practices additionally threaten biodiversity within the dehesas. The authors suggest the foundation of a biosphere reserve in Cuatro Lugares as a framework for a sustainable development of the dehesas.
Keywords: economic output; Grazing; livestock; Mediterranean; pastoralism; Quercus ilex; rangeland

Leaves of Quercus ilex L. as biomonitors of PAHs in the air of Naples (Italy) - Alfani, Anna; Maisto, Giulia; Vittoria Prati, Maria; Baldantoni, Daniela (Atmospheric Environment, 2001)
Polycyclic aromatic hydrocarbons (PAHs)were determined by the GC-MS chromatography in the leaves of Quercus ilex L., an evergreen Mediterranean oak, to monitor the degree of pollution in the urban area of Naples compared to remote areas. Leaf samples were collected in July 1998 from four urban parks, six roadsides and two sites in remote areas. The total PAH contents in Q. ilex leaves ranged from 106.6 in a control site to 4607.5 ng/g d.w. along a road with a high tra$c #ow. The mean concentration factors (urban/control)were 3.8 for the parks and 15 for the roads. The contribution of carcinogenic PAHs (benz[a]anthracene, benzo[b]#uoranthene, benzo[k]#uoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, indeno[1,2,3-c,d]pyrene)was higher in urban area and di!ered according to the site, ranging from 6.7% to 21.3%. The total PAH burden in control sites was dominated by the low molecular weight PAHs, whilst along the urban roads #uoranthene, pyrene and benz[a]anthracene among the measured PAHs showed the highest values. PAHs were positively correlated (P(0.01)to trace metals measured in a previous study.
Keywords: biomonitoring; leaves; polycyclic aromatic hydrocarbons; Quercus ilex L; rural and urban areas

Leeuwenhoek's observations on the anatomy of bark - Baas, P. (HOLZFORSCHUNG, 2001)
Leeuwenhoek's letter to the Royal Society of 27 March 1705, dealing with the anatomy of bark of cherry, birch, cinnamon, lime and cork oak is reviewed. It contains many detailed observations and illustrations of, i.a., ray dilatation, various types of phloem sclerenchyma, and annual rings in cork. This is another example of Leeuwenhoek's importance as an early plant anatomist.
The following values have no corresponding Zotero field: pub-location: GENTHINER STRASSE 13, D-10785 BERLIN, GERMANY publisher: WALTER DE GRUYTER & CO
Keywords: biohistory; Cork; fibres; phloem; sclereids

Mediterranean natural forest living at elevated carbon dioxide: soil biological properties and plant biomass growth - Moscatelli, M. C.; Fonck, M.; De Angelis, P.; Larbi, H.; Macuz, A.; Rambelli, A.; Grego, S. (Soil Use and Management, 2001)
Abstract. Biomass productivity and soil microbial responses to long-term CO2 enrichment have been investigated in a Mediterranean natural forest ecosystem. Several biochemical parameters have been measured on soil samples taken from six open top chambers (OTCs), enclosing clumps of natural Mediterranean woody vegetation including: Quercus ilex L., Phillyrea angustifolia L., Pistacia lentiscus L. and Myrtus communis L. The CO2 concentration of the air inside the OTCs was either ambient or ambient plus 350 μmol mol–1 (c. 710 ppm as mean daily value). Microbial C biomass, microbial respiration, dehydrogenase, β-glucosidase, acid phosphatase and protease activities, inorganic N and soluble P, were tested in order to evaluate soil microbial size and activity. Statistically correlated seasonal patterns have been identified in some biochemical parameters in response to climatic conditions, soil nutritional status and the physiology of the vegetative cover. In situ soil respiration and above- and below-ground productivity were also measured. Microbial responses to CO2 enrichment were observed only at the beginning of the study and a general progressive reduction of the CO2 effect was recorded as monitoring continued. These results are in agreement with data from literature regarding similar studies on natural complex communities.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Carbon dioxide; Forests; Mediterranean Region; microbial activities; roots; Soil; Soil enzymes

Metropolitan area of Rome: an integrated vegetation study by remote sensing and field data - Giannini, M.; Anselmi, S.; Melini, S.; Allegrini, A.; Manes, F. (Remote Sensing and Data Fusion over Urban Areas, IEEE/ISPRS Joint Workshop 2001, 2001)
The objective of this work is to assess the impact of environmental stresses, both natural (water stress, due to summer dryness typical of the Mediterranean climate) and anthropogenic (atmospheric pollution), on the vegetation in sites of great naturalistic value and under strong anthropic pressure in the Rome metropolitan area. The species <e1>Q</e1>uercus ilex L<e1>.</e1> (holm oak), an evergreen oak, has been studied through ecophysiological measurements performed in the field and Landsat TM images relating to the Rome metropolitan area. The results obtained show a greater degree of structural and functional alteration in individual holm oaks within the urban area compared with those in the protected areas outside of the central zone. In particular, in 1993 the main stress factor for vegetation is attributable to climatic conditions, whereas in 1998 ozone atmospheric concentration caused an evident alteration of the parameters studied
The following values have no corresponding Zotero field: periodical: Remote Sensing and Data Fusion over Urban Areas, IEEE/ISPRS Joint Workshop 2001
Keywords: Environmental stresses; metropolitan area; multiscale approach; Vegetation

Photosynthesis, Soluble and Structural Carbon Compounds in Two Mediterranean Oak Species (Quercus pubescens and Q. ilex) after Lifetime Growth at Naturally Elevated CO2 Concentrations - Blaschke, L.; Schulte, M.; Raschi, A.; Slee, N.; Rennenberg, H.; Polle, A. (Plant Biology, 2001)
Abstract: To study physiological responses of mature forest trees to elevated CO2 after lifetime growth under elevated atmospheric CO2 concentrations (pCO2), photosynthesis, Rubisco content, foliar concentrations of soluble sugars and starch, sugar concentrations in transport tissues (phloem and xylem), structural biomass, and lignin in leaves and branches were investigated in 30- to 50-year-old Quercus pubescens and Q. ilex trees grown at two naturally elevated CO2 springs in Italy. Ribulose-1,5-bisphosphate carboxylase/oxygenase content was decreased in Q. pubescens grown under elevated CO2 concentrations, but not in Q. ilex. Photosynthesis was consistently higher in Q. pubescens grown at elevated CO2 as compared with “control” sites, whereas the response in Q. ilex was less pronounced. Stomatal conductance was lower in both species leading to decreased transpiration and increased instantaneous water use efficiency in Q. pubescens. Overall mean sugar + starch concentrations of the leaves were not affected by elevated pCO2, but phloem exudates contained higher concentrations of soluble sugars. This finding suggests increased transport to sinks. Qualitative changes in major carbon-bearing compounds, such as structural biomass and lignins, were only found in bark but not in other tissues. These results support the concept that the maintenance of increased rates of photosynthesis after long-term acclimation to elevated pCO2 provides a means of optimization of water relations under arid climatic conditions but does not cause an increase in aboveground carbon sequestration per unit of tissue in Mediterranean oak species.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Carbohydrate; climate change; Elevated CO2; Lignin; photosynthesis; Rubisco

Possibilité de contrôle automatique de la qualité du liège par vision artificielle - Benkirane, Hatim; Benslimane, Rachid; Hachmi, M'Hamed; Sesbou, Ahmed (Ann. For. Sci., 2001)
The quality control often requires some visual inspection systems for defects detection in industrial production. In such application, those systems offer more reliability and lower processing time than a human operator. So this paper aims to introduce an automatic procedure to quality control of cork bits used for quality estimation of cork stacks, which is based on digital image analysis techniques. This procedure tries to quantify defects density of cork bit and to classify them in different quality classes. Experimental results are presented in order to evaluate the performance of the proposed automatic procedure.
Keywords: Classification; cork quality control; defect quantification; digital image; visual system

Predicting heating values of lignocellulosics and carbonaceous materials from proximate analysis - Cordero, T.; Marquez, F.; Rodriguez-Mirasol, J.; Rodriguez, J. J. (Fuel, 2001)
A simple equation based on proxymate analysis (volatile matter and fixed carbon contents) is presented which allows calculation of the higher heating value of lignocellulosic as well as the charcoals resulting from their carbonization. The equation has been tested with different lignocellulosic wastes and chars obtained from carbobization at different temperatures. Derivations from the experimental heating values fall in most cases below 2%. A comparison is presented with some equationsfrom the literature based on proximate, ultimate and chemical analysis data. As a general conclusion the equation proposed in this paper leads to comparableand in many cases more accurate predictions of heating valus and has the advantage of being applicable to a wide range of carbonaceous materials, requiring only a simple, rapid and cheap proximate analysis of the samples
Keywords: charcoal; heating value calculation; lignocellulosics

Propagação Vegetativa por Estacaria do Sobreiro (Quercus suber L.) - Cordeiro, Sonia; Moreira, Carmen; Ferreira, R. P.; Carvalho, J. P. F.; Pinto, T. M. S.; Pereira, J. M. G. Torres (Silva Lusitana, 2001)
The PAMAF-IED 8110 (1997-2000) project, was used to verify the rhizogenic capacity of Quercus suber, throughout the study of rhizogenic behaviour of different kinds of propagule considering several rooting factors. Due to the preliminary state of statistical data analysis, these conclusions are at an early stage, consisting only in first indications to a later definition of the best combination of "propagule x rooting factors"
The following values have no corresponding Zotero field: publisher: scielopt
Keywords: propagule; Quercus Suber L; rooting factors

REFORESTACIÓN DE TIERRAS AGRARIAS CON ENCINA Y COSCOJA. UN CASO EN TOLEDO - BARREDA, A.; SOBRINI, I. (III Congreso Forestal Español Congreso, 2001)
The Holm Oak (Quercus ilex) and the Kermes Oak (Quercus coccifera), both together, are being used successfuly in the dry Spain in the afforestations made under the Afforestation of Agricultural Land European Program, since 1993. We study a 1998/1999 afforestation of a farm in Toledo, in two pieces of 50 ha. each, until that moment dedicated to dry farming grain crops. The slopeswere between 0 and 10%, with sandy soils. All the farm presents high density of small game species. The results obtained, with less than 8% faults after two years, under conditions of little rain in 1998/99, and very dry summer in 2000, answer for the afforestation method employed, and permit us recomend it for other farms.
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español Congreso pub-location: Granada
Keywords: Agricultural land; dry regions; Holm oak; Kermes Oak

Relaciones hídricas en procedencias de QUERCUS SUBER L. - Castro, L.; Aranda, I.; Gil, L.; Pardos, J. A. (III Congreso Forestal Español Congreso, 2001)
Response to drought was studied in 5 provenances of cork oak, which are representative of the ecogeographic range of the species. The variation of several water parameters was analysed in 2000 from the beginning of the summer to the first rainy period. Predawn water potential (ψama) was measured on 5 dates on 6 plants per provenance. On the same plants, pressure-volume curves were carried out on twigs from the spring flushing. Several parameters related to responses to drought were estimated: osmotic potential at full turgor (ψπ 100) and at the loss turgor point (ψπ 0), relative water content at zero turgor (CHR0) and elastic modulus at maximum turgor (εmax). Afterwards osmotic and elastic adjustments were evaluated, and the response to drought was separated of the influence of other factor such as phenology. When the water parameters were analysed, there were not significant differences among provenances, meanwhile the differences among dates were highly significant. A decrease in ψπ 100 and an increase of tissue rigidity (εmax) were observed during the period of water stress. The response to drought overlapped with variations due to ontogenic factors.
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español Congreso
Keywords: Cork oak; osmotic adjustment; pressure-volume curves; water potential

Response to fire of a predominantly transient seed bank in a Mediterranean weedy pasture (eastern-central Spain) - FERRANDIS, Pablo; HERRANZ, José M.; MARTÍNEZ-SÁNCHEZ, Juan J. (Ecoscience, 2001)
L'impact du feu sur la viabilité du réservoir total de graines du sol dans un pâturage méditérranéen, dominé par des herbes provenant de terrains arables, de même que sur son rétablissement pendant la première année après-feu, a été étudié. Des échantillons de sol ont été prélevés séparément en tranches de 0-2 cm et de 2-5 cm d'épaisseur, et leur contenu en graines a été évalué par la méthode d'émergence des plantules. De plus, des dénombrements de plantules émergentes ont été effectués sur le terrain au cours du printemps suivant le feu. L'analyse d'échantillons provenant d'un site non brûlé a révélé que les plantes annuelles (83 % des espèces, 86 % des graines) et les mauvaises herbes (50 % des espèces, 30 % des graines) étaient une composante majeure du réservoir de graines. Le réservoir de graines de la majorité des espèces (85 %) s'est accumulé dans la couche superficielle du sol, indiquant sa nature transitoire. Le feu a fortement réduit la densité et la richesse en espèces du réservoir de graines, tel qu'attendu pour une réserve de graines principalement transitoire d'une communauté qui n'a pas été exposée à un régime de feux récurrent au cours de son histoire évolutive. Une augmentation de la densité et de la richesse spécifique du réservoir de graines a été observée un an après le feu notamment dans les couches supérieures du sol. Le rétablissement s'est déroulé de deux façons : i) par une production de graines in situ à partir de graines ayant survécu au feu et germé et ii) par une invasion de graines disséminées par le vent provenant de la végétation adjacente non brûlée. La première a été réalisée par des espèces à graines relativement grosses selon une dispersion à faible distance. La seconde a été réalisée par des espèces anémochores et/ou à petites graines. Nous en concluons que l'habileté des communautés de mauvaises herbes de répondre au feu est basée sur la nature colonisatrice et envahissante des espèces. Les conséquences possibles pour l'utilisation du feu dans l'aménagement de telles communautés sont discutées
Keywords: disturbance history; Quercus faginea "dehesa"; seed bank recovery; seed invasion; weeds

The role of landscape structure in species richness distribution of birds, amphibians, reptiles and lepidopterans in Mediterranean landscapes - Atauri, J. A.; Lucio, J. V. De (Landscape ecology, 2001)
The parameters referring to landscape structure are essential in any evaluation for conservation because of the relationship that exists between the landscape structure and the ecological processes. This paper presents a study of the relationships between landscape structure and species diversity distribution (estimated in terms of richness of birds, amphibians, reptiles and butterﬂies) in the region of Madrid, Spain. The results show that the response of species richness to landscape heterogeneity varies depending on the group of species considered. For birds and lepidopterans, the most important factor affecting the distribution of richness of species is landscape heterogeneity, while other factors, such as the speciﬁc composition of land use, play a secondary role at this scale. On the other hand, richness of amphibians and reptiles is more closely related to the abundance of certain land-use types. The study highlights the importance of heterogeneity in Mediterranean landscapes as a criterion for landscape planning and for deﬁnition of management directives in order to maintain biodiversity
Keywords: diversity distribution; landscape ecology; landscape heterogeneity; species richness distribution

Selección de rodales selectos de alcornoque (Quercus suber) EN ANDALUCÍA Angel - Carrasco, Angel; Campayo, Pablo; Sanchez, Mª Felisa (III Congreso Forestal Español, 2001)
La Consejería de Medio Ambiente de la Junta de Andalucía, a través de la empresa pública EGMASA, como medio propio, ha desarrollado una metodología para evaluar la selección de rodales selectos de alcornoque (Quercus suber) en Andalucía. En primer lugar se consideran unos requisitos o criterios generales que debe cumplir una masa de alcornocal para poder optar a formar parte de la relación de rodales selectos. Los parámetros considerados son: Calidad productiva, Aislamiento, Pureza, Número de pies por hectárea y Estado sanitario, es decir, aquellos que mayor influencia genética van a tener sobre la calidad de las nuevas plantas de alcornoque. En segundo lugar, se hace una valoración de cada rodal. Para ello, se han definido unos índices de tal forma que el valor suma de estos sirve para diferenciar como mejores aquellos de mayor puntuación. Los índices definidos son: Indice de Calidad de Corcho, Índice Morfológico e Índice sanitario. La sumaserá el valor definitivo por el que se evalúa el rodal, considerándose como rodales selectos aquellos que superen el valor medio de cada Región de Procedencia
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español pub-location: Granada
Keywords: Andalucía; calidad; Quercus suber; selecto

Structure and floristic diversity in permanent monitoring plots in forest ecosystems of Tuscany - Chiarucci, A.; Dominicis, V. De; Wilson, J. B. (Forest Ecology and Management, 2001)
The sampling method is described which is used for the sampling of plant species richness and cover in a monitoring project on forest ecosystems in Tuscany (named MONITO). Species richness is sampled through a nested plot design, with plot size ranging from 1 to 2500 m 2 , whereas species abundance is estimated in 100 m 2 plots. This sampling design is simple to install and to manage through time. Species diversity can be monitored not just at one single spatial scale but at many scales, and species±area relations can also be calculated. The analyses of the data that were collected produced the ®rst available data on species richness in relation to plot size for Tuscan forest ecosystems, indeed for any Italian forests. The Arrhenius Power function and the General Root models showed the best ®t. Turkey oak (Quercus cerris) woods located on slightly acidic soil were found to be the forest ecosystems with the highest species richness, con®rming and quantifying well-established ¯oristic- phytosociological knowledge. Habitat heterogeneity, measured by plot ¯oristic resemblance, showed how the Turkey oak woods were the most heterogeneous at the smaller spatial scales, but not at larger ones
Keywords: forest ecosystem monitoring; habitat-heterogeneity; Permanent plots; species; species diversity; species-area relations

Thermogravimetric analysis of Mediterranean plant species - a. P. Dimitrakopoulos (Journal of Analytical and Applied Pyrolysis, 2001)
Twelve dominant Mediterranean plant species were subjected to thermogravimetric analysis (TGA) in air medium, in order to study their thermal degradation process and assess their potential combustibility as natural fuels. Statistically signiﬁcant differences were observed among the values of the pyrolytic parameters of the species analyzed. The mean volatilization rate values resulted in meaningful ranking of the species into vegetation types of similar combustibility, as veriﬁed by observations during actual wildﬁres. The use of TGA as a method for assessing the combustibility of individual plant species seems justiﬁed
Keywords: combustibility; lignocellulosic materials; Mediterranean; natural fuels; pyrolysis; thermogravimetric analysis; wildland fires

Tipología de sistemas adehesados* - Escribano, M.; Rodríguez de Ledesma, A.; Mesías, F. J.; Pulido, F. (Archivos de Zootecnia, 2001)
This work analyzes a a group of livestock farms in semiarid grazing areas in Spain. The surface sample studied adds up to 80.000 hectares. The results are expressed according to the livestock prevalence of the farms. INTRODUCCIÓN

Towards the dehesa total income accounting: theory and operative Monfragüe study cases - Campos, P.; Rodriguez, Y.; Caparros, A. (Investigación Agraria: Sistemas y Recursos Forestales, 2001)
There has been, from the beginning of the 1970s, a controversial debate on the income measurement of natural resource exploitation and sustainability both commercial and environmental of their economic resources. Treeless pastures and woodlands have been the focus of less research than has timber forestland. Up to today, institutional timber forestland accounting proposals have not integrated non-excludable and other non-market benefits into total income measurement of forestland. This paper shows a complete accounting system that can incorporate any economic benefit and cost that could accrue from active and passive uses of forestland, whether or not the economic effects are the result of on-site and off-site land uses. An application to the Spanish dehesas at Monfragüe area gives a tentative total income measurement under this new accounting proposal. The dehesa woodland study represents one of the most complex forestland uses system.
Keywords: Commercial income; Dehesa; Environmental income; Forestland accounting; Total income

UTILIZACION DE ESPECIES AUTOCTONAS PARA RECUPERACION DE SUELOS DEGRADADOS ENMENDADOS CON LODOS RESIDUALES - GASCÓ, G.; ALONSO, J.; MARTINEZ IÑIGO, M. J.; LOBO, M. C. (III Congreso Forestal Español, 2001)
The objective of this study was to analyse if composted sewage sludges could be used to amend degraded soils. Two different treatments were applied to Nerium oleander L. and Quercus ilex L (120 Tons/Ha. y 60 Tons/Ha) in a greenhouse with controled conditions. Both heavy metals and nutrients soil contents were analysed to study the influence of the compost in soil properties. Moreover, the effect of the residue in physiological and nutritive plants properties were evaluated.
The following values have no corresponding Zotero field: periodical: III Congreso Forestal Español pub-location: Granada
Keywords: composted sewage sludge; degraded soils; Heavy metals; Nerium oleander L.; Quercus ilex L.

Variation in cork production of the cork oak between two consecutive cork harvests - Costa, A.; Oliveira, A. C. (Forestry, 2001)
The variation in the cork produced by individual trees (Quercus suber L.) in three distinct locations, Mora, Alcácer do Sal and Benavente, is characterized by measurements made during two consecutive harvests of cork in the same trees. Particular emphasis is given to the variability in the weight of cork produced by individual trees and its mean caliper for the two strippings in each region. A good linear correlation between the tree circumference after the first stripping and the weight of the cork produced 9 years later as well as a poor linear correlation between the first variable and the caliper of the cork produced 9 years later is reported. A cork oak diameter curve is presented for each region, considering their two radial growths: the wood growth, which is cumulative, and the cork growth, which is the 9‐year growth.
10.1093/forestry/74.4.33710.1093/forestry/74.4.337
Keywords: Cork Production; Growth (PG); stripping; variability

The aero-aquatic Helicodendron microsporum n. sp from Mallorca, Spain - Abdullah, S. K.; Cano, J.; Descals, E.; Guarro, J. (MYCOLOGICAL RESEARCH, 2000)
A new aero-aquatic helicosporous hyphomycete, Helicodendron microsporum, is described and illustrated from decaying leaves submerged in a small artificial pond surrounded by Quercus ilex and Pinus halepensis in Mallorca, Spain. It is characterized by branched conidiophores with chains of hyaline conidia eventually forming white clusters which do not break up even at maturity. It also has small conidia (8-10 mu m diam.) consisting of a 2-2.5 mu m thick filament which coils 1.5-2 times counter-clockwise. The main characters of the species are compared with 14 similar hyalosporous Helicodendron species.
APSAPSThe following values have no corresponding Zotero field: pub-location: 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA publisher: CAMBRIDGE UNIV PRESS
Keywords: deaying leaves; hyphomycete; Pinus halepensis; Quercus ilex; Spain

Annual variations of phenoloxidase activities in an evergreen oak litter: influence of certain biotic and abiotic factors - Criquet, S.; Farnet, A. M.; Tagger, S.; Petit, J. Le (Soil Biology and Biochemistry, 2000)
This study concerns ligninolysis phenomena occurring over 13 months in forest litter. Evergreen oak (Quercus ilex L.) litter was taken as a model because Quercus ilex L. is the most abundant tree species in forests of the French Mediterranean area. Several biotic and abiotic factors potentially involved in transformations of polyphenolic compounds, were measured between October 1997 and October 1998. These factors were: global fungal micro¯ora, the fungi producing phenoloxidases (PO+ ), the activities of several phenoloxidases, hydrosoluble phenols, and temperature, humidity and pH of the litter. Results showed that the annual dynamics of fungi and phenoloxidase activities appear to be seasonal, i.e. that these biotic factors such as, were optimal in autumn. A multiple regression analysis showed that there was no correlation between biotic factors such as, fungal populations and phenoloxidase activity and abiotic factors such as, temperature, humidity and pH. Laccases were the preponderant phenoloxidase activities during the year, while those of Mn-peroxidases only appeared in the autumn of 1997. Other phenoloxidases, lignin-peroxidases and tyrosinases were never detected. Interactions between laccases and humic substances were also investigated. Adsorption of laccases on humic substances leads to a shift in the optimal temperature activity of these enzymes from 50 to 308C. Activities of laccases also shifted towards more acidic values when laccases were not adsorbed on humic substances. Nevertheless, the optimal pH was the same (5.7) whether laccases were adsorbed or not to humic substances. Electrophoresis analysis showed little variations in the number of phenoloxidase isoenzymes. Indeed, laccases showed three isoenzymes during the year (Rf 0.23, 0.34 and 0.43). Only one isoform of Mn-peroxidase, with an Rf 0.21, was detected in the litter
Keywords: fungi; humic substances; laccase; litter; peroxidase

Biochemical and molecular characterization of a laccase from Marasmius quercophilus - Dedeyan, B.; Klonowska, A.; Tagger, S.; Tron, T.; Iacazio, G.; Gil, G.; Le petit, J. (APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 2000)
The basidiomycete Marasmius quercophilus is commonly found during autumn on the decaying litter of the evergreen oak (Quercus ilex L.), a plant characteristic of Mediterranean forest. This white-rot fungus colonizes the leaf surface with rhizomorphs, causing a total bleaching of the leaf. In synthetic liquid media, this white-rot fungus has strong laccase activity. From a three-step chromatographic procedure, we purified a major isoform to homogeneity, The gene encodes a monomeric glycoprotein of approximately 63 kDa, with a 3.6 isoelectric point, that contains 12% carbohydrate, Spectroscopic analysis of the purified enzyme (UV/visible and electron paramagnetic resonance, atomic absorption) confirmed that it belongs to the ``blue copper oxidase{''} family. With syringaldazine as the substrate, the enzyme's pH optimum was 4.5, the optimal temperature was 75 degrees C, and the K-m was 7.1 mu M. The structural gene, lac1, was cloned and sequenced. This gene encodes a 517-amino-acid protein 99% identical to a laccase produced by PM1, an unidentified basidiomycete previously isolated from wastewater from a paper factory in Spain. This similarity may be explained by the ecological distribution of the evergreen oak in Mediterranean forest.
Keys: APSKeys: APSThe following values have no corresponding Zotero field: pub-location: 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA publisher: AMER SOC MICROBIOLOGY
Keywords: Basidiomycete; litter; Marasmius quercophilus; mediterranean forest; Quercus ilex L.; structural genes

Caractérisation de la croissance et de la qualité du liège dans une région de production - Ferreira, Alexandra; Lopes, Fernando; Pereira, Helena (Ann. For. Sci., 2000)
Cork growth and quality were characterised in 5 cork oak stands within the production area of the Sado basin (Alcácer do Sal, Portugal) based on a field sampling on 40 trees/stand. Cork thickness was on average 33.8 mm, with 75% of the samples in the commercial classes above 27 mm suitable for production of stoppers. Porosity measured by image analysis was 4.6% on average. Between tree and between stand variability of cork quality was large. The annual average cork growth for a production cycle with 8 complete growth years was 4.1 mm, being highest during the years following cork extraction and decreasing during the cycle. For this region, a production cycle of 9 years is adequate for raw-material industrial requirements. The results show the importance of between tree variability in growth and especially in quality.
Keywords: Cork; Growth; Porosity; Quality; variability

Characterization of cork growth and quality in one region of production. - Ferreira, A.; Lopes, F.; Pereira, H. (ANNALS OF FOREST SCIENCE, 2000)
Cork growth and quality were characterised in 5 cork oak stands within the production area of the Sado basin (Alcacer do Sal, Portugal) based on a field sampling on 40 trees/stand. Cork thickness was on average 33.8 mm, with 75% of the samples in the commercial classes above 27 mm suitable for production of stoppers. Porosity measured by image analysis was 4.6% on average. Between toe and between stand variability of cork quality was large. The annual average cork growth for a production cycle with 8 complete growth years was 4.1 mm, being highest during the years following cork extraction and decreasing during the cycle. For this region, a production cycle of 9 years is adequate for raw-material industrial requirements. The results show the importance of between tree variability in growth and especially in quality.
The following values have no corresponding Zotero field: pub-location: 23 RUE LINOIS, 75724 PARIS CEDEX 15, FRANCE publisher: EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER
Keywords: Cork; Growth; Porosity; Quality; variability

Comparative stem-growth rates of Mediterranean trees under background and naturally enhanced ambient CO2 concentrations - Tognetti, Roberto; Cherubini, Paolo; INNES, JOHN L. (New Phytologist, 2000)
Ring widths of five Mediterranean forest tree species (Arbutus unedo, Fraxinus ornus, Quercus cerris, Quercus ilex and Quercus pubescens) growing close to a natural source of CO2 in Tuscany, Italy and at a nearby control site were compared. At the CO2-enriched site, trees have been growing for decades under elevated CO2 concentrations. They originated from parent trees that also grew under elevated CO2 in natural conditions, and they have been continuously exposed to elevated CO2 throughout their growth. Tree-ring series from each of the species were prepared. Assigning calendar dates to rings was difficult but possible, and ring-width series were built for all species. The ring-width data were analysed using a two-sided t-test to assess if there was a difference between the radial growth at the CO2-enriched site and the control site. The cumulative basal area at the same cambial age at both sites was also compared using a Wilcoxon test. Radial growth of trees at the CO2-enriched site was not significantly different from growth at the control site. For each species, year by year, radial growth at the CO2-enriched site was tested against the control site and significant differences were found in only a few years; these differences were not synchronous with extreme climatic events. The expected increase in above-ground productivity, as one of the ecosystem responses to increasing CO2 during drought stress, was not observed in this Mediterranean woody plant community, despite being water-limited. Other resource limitations, such as low nutrient availability (common in the Mediterranean region), may have counteracted the positive effect of elevated CO2 under drought stress, or trees may have acclimated to the high CO2.
The following values have no corresponding Zotero field: publisher: Cambridge University Press
Keywords: Arbutus unedo (strawberry tree); Carbon Sequestration; Dendroecology; Mediterranean trees; natural CO2 springs; Quercus ilex (holm oak); tree rings; water stress

Conservation strategy of a nature reserve in Mediterranean ecosystems: the effects of protection from grazing on biodiversity - Verdú, J. R.; Crespo, M. B.; Galante, Eduardo (Biodiversity and Conservation, 2000)
Protection of natural areas has caused the elimination of traditional grazing activity on many occasions. As a result, in Mediterranean ecosystems a loss of biodiversity is usually related to a decrease of grassland and grassland–bush mosaic areas. In order to establish relationships between land use and the relative importance of each type of habitat in terms of species richness and endemicity, the Font Roja Natural Park in Alicante Province (SE Iberian Peninsula) was studied. Four sites were selected representing the four different existing habitats: a wooded area (holm-oak forest), a dense shrubland, a dense grassland, and a grassland–shrubland mosaic area. In each site, the species composition of vegetation and dung beetle fauna were analysed. The results showed that the highest diversity and endemicity, for plants and beetles, were concentrated in the dense grasslands and the grassland–shrubland mosaic. Thus, controlled grazing activity of sheep and goats which maintained a diverse variegated landscape would favour the historical sustenance of the biodiversity of Mediterranean ecosystems, as that would allow a remarkable diversity of habitats with higher conservation levels of existing species richness and endemicity. Therefore, we propose a reintroduction of traditional grazing of sheep and goats throughout ecological, cultural and economical measures, which would include guidelines and regulations, set out to boost an integrated rural policy.
Keywords: dung beetles; endemicity; impact; management; vascular plants

Constraints and trade-offs in Mediterranean plant communities: The case of holm oak-Aleppo pine forests - Zavala, M. A.; Espelta, J. M.; Retana, J. (The Botanical Review, 2000)
In this paper we review those aspects that are relevant to the development of a mechanistic ecological theory to account for the structure and dynamics of Mediterranean forests, focus- ing our attention on mixed forests of holm oak (Quercus ilex L.), a shade-tolerant, slow- growing species that resprouts vigorously after disturbance, and Aleppo pine (Pinus halepen- sis M.), a fast-growing, nonresprouting, shade-intolerant species. The main objectives of this report are: to introduce some of the primary features of these forests, showing their structural complexity and historical peculiarities; to show that much of this complexity can be concep- tually reduced to two main factors of variation, soil-moisture gradients and a complex inter- action of historical management and disturbance regimes; and to contrast the unique features of Mediterranean systems with other communities that have inspired generalization in ecol- ogy. Plants in Mediterranean-climate regions must face several environmental constraints dur- ing their life cycle: water limitation, competition for light, and a complex set of disturbance regimes, mainly fire, herbivory, and human exploitation. The response of co-occurring spe- cies to a given set of environmental constraints depends on a combination of physiological and morphological traits. In holm oak-Aleppo pine forests, the lower limit of distribution along a soil-moisture gradient appears to be controlled by dry-season water stress on seedling performance, and the upper limit seems to be controlled by shade tolerance relative to com- petitors. The processes that generate and maintain these patterns are related to the responses of the two species to the water and light environments that result from interacting gradients of disturbance and resource availability. The dynamics of mixed holm oak-Aleppo pine forests may be represented along two major environmental axes: water availability and light intensity; namely, time since last disturbance. At the regional scale, the presence of holm oak and Aleppo pine is expected to be driven mainly by the precipitation regime, with the proportion of Aleppo pine in- creasing toward the driest border and with holm oak being the dominant species in areas with higher precipitation. Changes of dominance of holm oak and Aleppo pine also re- spond to water availability at the local scale. In this case, variations between species de- pend on different factors in a complex way, because reduced soil-moisture levels may re- sult either from low precipitation or from topography and edaphic features. The dynamics of holm oak-Aleppo pine forests are also determined by temporal changes in canopy clo- sure; that is, forest recovery after disturbance. In this case, the proportion of Aleppo pine would increase in recently disturbed stands (i.e., with high light intensity reaching the for- est floor), whereas regeneration of holm oak would be dominant under partially closed canopies. Theories of forest dynamics developed in humid regions may apply only poorly to Medi- terranean plant communities, where vegetation change is qualitatively or quantitatively dif- ferent. Thus, succession in temperate forests appears to be driven by differences in light availability and shade tolerance; but in Mediterranean plant communities, water limitation is of greater importance for the distribution of forest species. In Mediterranean landscapes the interaction of life-history strategies with changing environments is difficult to infer from observational and experimental studies. A mechanistic approach, in which competi- tion or plant performance is measured as a function of resource availability, seems more feasible. The idea should be to develop multispeeies models calibrated specifically for Mediterranean forests in a combined program of modeling, field research, and experimenta- tion.
Keywords: Aleppo pine; disturbance regimes; forest dynamics; holm oak (voyant); light intensity; mediterranean plant-communities; Water availability

Contribution to the karyomorphology of some species of the genus Quercus - D'Emerico, S.; Paciolla, C.; Tommasi, F. (SILVAE GENETICA, 2000)
In order to contribute to the knowledge of the taxonomic relationships between some species of the Quercus genus, the karyomorphology of 4 species (Quercus ilex L., Q, suber L., Q. robur L, and Q. pubescens WILLD.) was carried out. The somatic chromosome number 2n=24 was found in all taxa examined. An evident differentiation in karyotype structure of Q. ilex compared to other previous studied species has been found. Quercus suber, Q. robur and Q. pubescens possess moderately asymmetrical karyotypes. Q. suber differs from other species of the subgenus Cerris on the basis of karyological data showing similarities with Q, robur and Q. pubescens.
The following values have no corresponding Zotero field: pub-location: FINKENHOFSTRASSE 21, W-6000 FRANKFURT, GERMANY publisher: SAUERLANDERS VERLAG
Keywords: B. pubescens; karyotype; Q. robur; Q. suber; Quercus ilex

Cork - Gil, Luis; Moiteiro, Cristina (Ullmann's Encyclopedia of Industrial Chemistry, 2000)
The article contains sections titled: 1.Introduction1.1.Definition and Origin1.2.History1.3.Morphology1.3.1.Microscopic Aspects1.3.2.Macroscopic Aspects1.4.Chemical Composition1.4.1.Suberin1.4.2.Lignin1.4.3.Polysaccharides1.4.4.Waxes1.4.5.Tannins1.4.6.Other Components1.5.Physical and Mechanical Properties2.Cork Extraction3.Production of Cork Based Products3.1.Disks and Cork Stoppers3.2.Granulates and Broken3.3.Composition Cork3.3.1.Floor and Wall Coverings3.3.2.Agglomerated Disks and Cork Stoppers3.3.3.Corkrubber3.4.Insulation Corkboard3.5.Other Specific Products4.Uses4.1.Stoppers4.2.Civil Construction4.3.Industrial Applications4.4.Automotive Industry4.5.Other Specific Uses5.Quality and Standardization5.1.Standardization and Testing5.2.Quality in Cork Production6.Economic Aspects6.1.Forestall Production6.2.Personnel and Companies6.3.Consumption of Products and Markets6.4.Producers7.Environmental and Toxicological Aspects7.1.Industrial Wastes7.2.Recycling and Treatments7.3.Emissions8.Legal Aspects
The following values have no corresponding Zotero field: periodical: Ullmann's Encyclopedia of Industrial Chemistry electronic-resource-num: 10.1002/14356007.f07_f01
Keywords: composition (voyant); Cork; insulation; products; stoppers

Cork suberin as an additive in offset lithographic printing inks - Cordeiro, N.; Blayo, A.; Belgacem, N. M.; Gandini, A.; Pascoal Neto, C.; LeNest, J.-F. (Industrial Crops and Products, 2000)
Suberin oligomers, isolated from cork (Quercus suber L.), were used as additives in ‘Waterless’ and vegetable-oil ink formulations, in the range of 2–10% w:w. The rheological behaviour of the suberin oligomers as well as of the inks, with and without suberin, were investigated as a function of temperature. It was shown that the addition of suberin induces a decrease of viscosity of both inks. The tack of pristine inks, suberin oligomers and their mixtures were determined at different temperatures: the variation of this parameter as a function of time provided information about the drying kinetics of these formulations. The tack of the ‘Waterless’ ink was found to increase with the introduction of suberin, whereas that of vegetable-oil based counterparts decreased. All the trends observed were interpreted in terms of the differences in composition between the two types of inks. Preliminary printing tests were carried out with the various suberin-containing inks
Keywords: Additive; Quercus suber L.; rheological properties; suberin; Tack; Vegetable oil-based ink; Viscosity; Waterless ink

Crystallization and preliminary x-ray diffraction analysis of beta-cinnamomin, an elicitin secreted by the phytopathogenic fungus Phytophthora cinnamomin. - Archer, M.; Rodrigues, M. L.; Aurélio, M.; Biemans, R.; Cravador, A.; Carrondo, M. a (Acta crystallographica. Section D, Biological crystallography, 2000)
Cinnamomin (CIN) belongs to a family of 10 kDa proteins designated as elicitins. Some of these proteins induce a hypersensitive response in diverse plant species, leading to resistance against fungal and bacterial plant pathogens. CIN was crystallized by the vapour-diffusion method using either ammonium sulfate or polyethyleneglycol (PEG) as precipitants in solutions buffered at around pH 7. These crystals are isomorphous and belong to the triclinic space group, with unit-cell parameters a = 31.69, b = 36. 99, c = 44.09 A, alpha = 76.86, beta = 84.41, gamma = 80.26 degrees. A frozen crystal diffracted X-rays beyond 1.45 A resolution on a synchrotron-radiation source.
The following values have no corresponding Zotero field: accession-num: 10713528
Keywords: Beta-cinnamomin; Elicitins; Phytopathogenic fungi

Effect of polyethylene glycol on in vitro degradability of nitrogen and microbial protein synthesis from tannin-rich browse and herbaceous legumes - Getachew, G.; Makkar, H. P. S.; Becker, K. (BRITISH JOURNAL OF NUTRITION, 2000)
Determination of microbial degradability of N is important in formulating a sound supplementation strategy for efficient utilisation of basal as well as supplementary diet components. In vitro degradability of N (IVDN) from tannin-containing browses (Acacia cyanophylla, Acacia albida, Acioa barteri and Quercus ilex) and two herbaceous legumes (Desmodium intortum andDesmodium uncinatum) was determined using the in vitro gas-production method coupled with NH3-N measurement in the presence and absence of a tannin-binding agent (polyethylene glycol (PEG), molecular mass 6000). Addition of PEG to tannin-containing feeds significantly (P < 0.05) increased in vitro gas and short-chain fatty acid (SCFA) production, and IVDN. The use of PEG as a tannin-binding agent increased IVDN from 28 to 59, 32 to 72, 19 to 40, 32 to 73, 40 to 80, and 26 to 77 % in A. cyanophylla, A. albida, A. barteri, D. intortum, D. uncinatum and Q. ilexrespectively. There was significant correlation between total phenolic compounds (total phenol, TP; total tannin, TT) in leguminous forages and percentage increase in IVDN on addition of PEG (P < 0.05; R-2 0.70 and 0.82 for TP and TT respectively). The difference in IVDN observed in the absence and presence of PEG indicates the amount of protein protected from degradation in the rumen by tannins. When measured after 24 h incubation, tannin-containing feeds incubated in absence of PEG resulted in higher microbial protein synthesis than in the presence of PEG. Addition of PEG significantly (P < 0.05) reduced the efficiency of microbial protein synthesis expressed as mu mol purine/mmol SCFA.
The following values have no corresponding Zotero field: pub-location: C/O PUBLISHING DIVISION, WALLINGFORD OX10 8DE, OXON, ENGLAND publisher: C A B INTERNATIONAL
Keywords: microbial protein synthesis; Polyethylene glycol; protein degradability; Tannins

Ericoid mycorrhizal fungi are common root associates of a Mediterranean ectomycorrhizal plant (Quercus ilex) - Bergero, R.; Perotto, S.; Girlanda, M.; Vidano, G.; Luppi, a M. (Molecular Ecology, 2000)
Mycorrhiza samples of neighbouring Quercus ilex and Erica arborea plants collected in a postcutting habitat were processed to see whether plants differing in mycorrhizal status harbour the same root endophytes. Three experiments were performed in parallel: (i) isolation, identification and molecular characterization of fungi from surface-sterilized roots of both plant species; (ii) re-inoculation of fungal isolates on axenic E. arborea and Q. ilex seedlings; (iii) direct inoculation of field-collected Q. ilex ectomycorrhizas onto E. arborea seedlings. About 70 and 150 fungal isolates were obtained from roots of Q. ilex and E. arborea, respectively. Among them, Oidiodendron species and five cultural morphotypes of sterile isolates formed typical ericoid mycorrhizas on E. arborea in vitro. Fungi with such mycorrhizal ability were derived from both host plants. Isolates belonging to one of these morphotypes (sd9) also exhibited an unusual pattern of colonization, with an additional extracellular hyphal net. Ericoid mycorrhizas were also readily obtained by direct inoculation of E. arborea seedlings with Q. ilex ectomycorrhizal tips. Polymerase chain–restriction fragment length polymorphism and random amplified polymorphic DNA analyses of the shared sterile morphotypes demonstrate, in the case of sd9, the occurrence of the same genet on the two host plants. These results indicate that ericoid mycorrhizal fungi associate with ectomycorrhizal roots, and the ecological significance of this finding is discussed.
The following values have no corresponding Zotero field: publisher: Blackwell Science Ltd accession-num: 11050558
Keywords: DNA; ectomycorrhizas; Erica arborea; ericoid fungi; fungi; Fungi: genetics; Fungi: isolation & purification; Fungi: physiology; Genetic; Mediterranean ecosystem; Mediterranean Region; Molecular Sequence Data; Plant Diseases; Plant Diseases: microbiology; Plant Roots; Plant Roots: microbiology; Polymorphism; Quercus ilex; Restriction Fragment Length; Ribosomal Spacer; Trees; Trees: microbiology

Estimating species-based community integrity under global warming, with special reference to the western Mediterranean region - Box, E. O.; Choi, J. N. (PHYTOCOENOLOGIA, 2000)
Climate-based estimates of the fitness of the main structural elementsof several western Mediterranean plant communities were used to estimate potential community integrity and its consequent vulnerability under a global-change scenario involving warming but no net drying. Results for a simple Quercus ilex community suggest expansion northward and inland under warming but with significant loss of area currently covered by the community. The data for estimating such changes in potential community integrity and areal coverage can be readily obtained from climatic envelope models. Mapping can be done by interpolation or by pixel-based GIS methods.
The following values have no corresponding Zotero field: pub-location: JOHANNESSTR 3A, D-70176 STUTTGART, GERMANY publisher: GEBRUDER BORNTRAEGER
Keywords: climatic envelope; community integrity; global war

Factors affecting the distribution of Red-legged Partridges Alectoris rufa in an agricultural landscape of southern Portugal - Borralho, R.; Stoate, C.; Araújo, M. (Bird Study, 2000)
The main factors affecting the spring distribution of Red-legged Partridges Alectoris rufa were evaluated in a 1550-km2 landscape of southern Portugal, where different arable systems and hunting regimes were implemented. Partridge surveys were performed in April 1995 along 90, 250-m transects. Partridge locations and a number of environmental variables were incorporated and manipulated in a vector-based GIS. A multivariate logistic model of partridge detection was fitted using forward stepwise selection, and was validated using a jack-knife approach. The probability of detecting Red-legged Partridges within the landscape was positively affected by game management, structural diversity of cover, proportion of olive tree groves and wheat fields along the transects. Conservation implications of the results and research priorities are discussed.
doi: 10.1080/00063650009461190doi: 10.1080/00063650009461190The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: agricultural landscape; distribution (voyant); game management; Red-legged partridge

Floristic relationship between scrubland and grassland patches in the Mediterranean landscape of the Iberian Peninsula - Ramirez-Sanz, L.; Casado, M. A.; Miguel, J. M. De (Plant Ecology, 2000)
In the rural Mediterranean landscape, mosaics of patches of sclerophyllous scrubland and semi-natural grasslands are frequent. The plant communities of these patches, which are physiognomically easy to recognise, are very heterogeneous. The objective of this paper is to determine whether the patches of scrub-grassland represent an integrated response unit of the vegetation with regard to the physical environment (climatic, geographical and edaphic factors) and human use, or whether, on the contrary, this is an independent response. In order to do this a total of 50 sampling sites where scrubland and grassland patches were in contact were studied along a 370 km E-W mesoclimatic gradient from central Spain to Portugal (Iberian Peninsula). Two distinct zones, the east and the west halves of the study area, were identiﬁed according to the plant communities. Within each of these zones, each type of patch responded to the previously mentioned factors, differentially and independently. This determined a general lack of inter-community association or ﬂoristic correlation between scrub and grassland plant communities in contact. The spatial association is a random process probably related to the particular human management realised on every scrubland and grassland patch. The scrub–grassland pattern, which is characteristic of the Mediterranean landscape, does not represent an integrated response unit of the vegetation to a given environment, but rather the sum of the independent responses to the environment of the two patches in contact.
Keywords: environmental gradient; inter-community association; mediterranean scrubland; rural landscape; spatial association; therophyte grasslands

Forests of the Mediterranean region: gaps in knowledge and research needs - Scarascia-Mugnozza, Giseppe; Oswald, Helfried; Piussi, Pietro; Radoglou, Kalliopi (Forest Ecology and Management, 2000)
Mediterranean forests are characterised by a remarkable set of features that make them naturally and aesthetically attractive, on the one hand, but also quite fragile, on the other, therefore calling for careful strategies for their conservation and management. An exceptionally large variation of environmental conditions characterises the Mediterranean countries, where the environment can limit forest growth and succession but can also give rise, more often than it is supposed, to lush, mesic forest ecosystems, similar to those of central Europe. Moreover, Mediterranean forests contain an ample, plant and animal biological diversity, exempli®ed by the large number of tree species as compared to Nordic forests, and by their relatively high genetic variability due to the survival of many conifer and broadleaf species in southern European refuges, during the glacial periods. Another peculiar aspect of this region is the long-lasting manipulation of trees, forests and landscapes, since ancient times, with the diffusion all over the Mediterranean basin of such species as Pinus pinea, Cupressus sempervirens, Castanea sativa, and Quercus suber. The harsh and unpredictable climate, the dif®cult socio-economic conditions and the history of over-exploitation of the Mediterranean forests require that a scienti®cally sound conservation strategy and a locally-tailored sustainable management should be implemented. In particular, the need for identifying those silvicultural and management strategies appropriate for southern European forests should be stressed. Obviously, this consideration will have important effects on the de®nition of criteria for sustainability and eco-certi®cation. Also, social issues should be considered key factors for effective forest conservation in the Mediterranean region, otherwise it will be impossible to control forest ®res and landscape degradation. Based on these considerations a number of research priorities are discussed, with special consideration to possible impacts that global change may have on Mediterranean forest ecosystems.
Keywords: Biodiversity; forest ecosystems; Mediterranean Region; silviculture; sustainable management

Fumigation with exogenous monoterpenes of a non-isoprenoid-emitting oak (Quercus suber): monoterpene acquisition, translocation, and effect on the photosynthetic properties at high temperatures - Delfine, Sebastiano; Csiky, Olav; Seufert, Guenther; Loreto, Francesco (New Phytologist, 2000)
We tested if fumigation with exogenous monoterpenes might induce thermotolerance in leaves of an oak species (Quercus suber) which does not form and emit isoprenoids. To understand if exogenous monoterpene fumigation results in internal accumulation of monoterpenes, a physical method of monoterpene extraction was used. The internal content of monoterpenes increased in concert with increasing fumigation doses. This unambiguously demonstrated acquisition of exogenous monoterpenes. We exposed fumigated Q. suber leaves to two cycles of increasing temperatures from 35 to 55°C at 5°C steps. When leaves were exposed to a low dose of exogenous monoterpenes, yielding an internal content similar to that endogenously formed in the leaves of the monoterpene- emitter Q. ilex, no clear improvement in thermotolerance was found. When leaves were exposed to a high dose of exogenous monoterpenes, yielding an internal content of about ®ve fold the endogenous pool of Q. ilex, but comparable with the expected content following stress-induced stomatal closure, photosynthesis inhibition at high temperatures was attenuated. This eﬀect was observed only at temperatures !45°C during the ®rst cycle, but at all temperatures between 35 and 55°C when plants were exposed to two cycles of high temperatures. Monoterpenes were still found in the leaves of Q. suber 12 h after ending the fumigation. Monoterpenes were also found in non-fumigated leaves distant up to 45 cm from the fumigated leaves. If monoterpenes make the photosynthetic apparatus more resistant to high temperatures, the eﬀect might not be limited to the fumigated leaves and might be persistent after fumigation.
Keywords: isoprenoid emission; Monoterpenes; photosynthesis; Quercus suber; thermotolerance

Grazing alone is not enough to maintain landscape diversity in the Montseny Biosphere Reserve - Bartolomé, J.; Franch, J. (Agriculture, Ecosystems & Environment, 2000)
Conservative land-use over the past few decades has converted the Montseny Biosphere Reserve (Spain) from the original open, patchy landscape to almost continuous woodland. Small ruminant grazing is virtually the only major remaining utilisation activity yet little is known about its role in the changing vegetation of the Reserve. This study was undertaken to determine the effects of current grazing practice on its main vegetation components. Three ﬂocks, composed of sheep and goats, that graze yearlong on three separate ranges in the Reserve were selected for study. The ranges represent the wooded slopes and the shrubby upland (altiplano) in the area. Biomass consumption by the ﬂocks was estimated by calculation of normative requirements for observed production and the botanical composition of the livestock diets over a whole annual cycle was determined by micro-histological analysis of the faeces. Production of herbaceous vegetation was determined by clipping sample quadrats, the production of the woody vegetation was derived from previous work in the Reserve. It was found that grazing removed a very small proportion of the dominant Holm oak (Quercus ilex) on the slopes, and a moderate fraction of the shrubby and herbaceous vegetation on the altiplano. Only the heath tree (Erica arborea), an edible shrub in the woodlands, was relatively heavily grazed. It is concluded that grazing alone is not enough to maintain the open, diverse landscape with its many natural values. As in other northern Mediterranean countries, under-utilisation of these woodlands is becoming a serious problem that is also increasing the ﬁre hazard. Maintaining landscape diversity in the region is a complex challenge that land managers should recognise
Keywords: calluna vulgaris; Erica arborea; mediterranean rangeland; Quercus ilex; small ruminants

Haploid origin of cork oak anther embryos detected by enzyme and RAPD gene markers. - Bueno, M. A.; Agundez, M. D. (International Journal of Plant Sciences, 2000)
Examines the haploid origin of cork oak anther embryos using enzyme and RAPD gene marker analysis. Exploration of the gene coding of shikimate dehydrogenase; Factor influencing the non-identification of another genotypes by isozyme analysis; Implication of detected banding patterns for the existence of multiple microspore origins.
Keywords: Cork oak; Haploid; Quercus suber; RAPD markers

Herbivore dunging and endozoochorous seed deposition in a Mediterranean dehesa - Malo, J. E.; Jimenez, B.; Suarez, F. (JOURNAL OF RANGE MANAGEMENT, 2000)
Spatial patterns of herbivore defecation within grazing systems are important as they directly affect pasture growth and composition. These effects are partially linked to seed dispersal in dung, a little studied process. This paper focuses on: (1) quantification of dung and seeds deposited by herbivores in a Mediterranean grazing system, and (ii) analysis of the spatial variability of dung and seeds deposited within and among plant communities. We carried out year-long monthly quantifications of the depositions of rabbit (Oryctolagus cuniculus), fallow deer (Dama dama), red deer (Cervus elaphus), and cow (Bos taurus) dung to 32 plots distributed in Quercus rotundifolia Lam. and Fraxinus angustifolia Vahl woodlands, mixed scrub, and Cistus ladanifer L. scrub. We also quantified the germinable seed content of dung. The results revealed differences (p < 0.05) in dung deposition, varying (i) among the 4 species, (ii) within species (except for the red deer) among plant communities, and (iii) within plant communities. An average of 735 seeds/m(2) were returned to the soil via dung, with the highest numbers in open woodlands (870-1,888 seeds/m(2)) and the lowest numbers in scrubs (83-315 seeds/m(2)). Cows dispersed the most seeds (68%), followed by red deer (20%), rabbits (7%), and fallow deer (5%). Spatial variability in deposition led to accumulations of up to several thousand seeds at points covered by the dung. The effect of seed input to the seed bank and on vegetation may be low at large and medium-sized spatial scales, but it can be very important at small scales and for colonization processes.
The following values have no corresponding Zotero field: pub-location: 445 UNION BLVD, STE 230, LAKEWOOD, CO 80228-1259 USA publisher: SOC RANGE MANAGEMENT
Keywords: dispersal; dung; endozoochory; herbivores; Mediterranean pastures; Spatial pattern

Host specificity in fungal endophytic populations of Quercus ilex and Quercus faginea from Central Spain - Collado, J.; Platas, G.; Pelaez, F. (NOVA HEDWIGIA, 2000)
A comparative study of the endophytic fungal assemblages of Quercus ilex subsp. ballota and Quercus faginea subsp. faginea was carried out on 10 trees growing in a Mediterranean forest in Central Spain. Endophytes from bark, twigs and fresh leaves were isolated from both tree species. As observed for other taxonomically related hosts, a certain overlapping between the endophytic mycoflora in both Quercus species was found. The most frequent fungus in both host species was Pyrenochaeta sp., an anamorph of Dothideales. Nevertheless, a certain degree of host specificity in fungal endophytic infection was detected, when the frequencies of the most commonly isolated endophytes were statistically analysed. The tree species affects significantly the distribution of almost all the fungi with isolation frequencies equal or higher than 2%. Moreover, some dominant fungal taxa could be isolated only from a particular host (Q. ilex or Q. faginea). A cluster analysis of the trees computed on the base of the similarity of their whole of fungal populations confirmed that there is an evident influence of the host species on the composition of the fungal assemblages of the trees. However, this effect does not appear to be always the main determinant of the composition of the fungal assemblages analysed.
The following values have no corresponding Zotero field: pub-location: JOHANNESSTR 3A, D-70176 STUTTGART, GERMANY publisher: GEBRUDER BORNTRAEGER
Keywords: fungal endophytes; Quercus faginea; Quercus ilex

IDENTIFICACIÓN Y DESCRIPCIÓN DE LAS ECTOMICORRIZAS ZONA QUEMADA Y UNA ZONA SIN ALTERAR DEL CARRASCAL DE NAZAR ( NAVARRA ) - Román, D. E.; Miguel, M. D. E. (Publicaciones de Biología, Universidad de Navarra, Serie Botánica, 2000)
Since 1998, a field study has been undertaken in a Quercus ilex L. subsp. ballota (Desf.) Samp. forest located in Nazar (Navarra, Spain). This study aims to establish a qualitative and quantitative comparison between the ectomycorrhizal morphotypes which have been collected, described and identified in a burned site and in a non- disturbed one within this forest. Thus, this study aims to contribute to the knowledge of the ectomycorrhizae associated with evergreen oak in field conditions, because most of the studies on evergreen oak ectomycorrhizae are related to truffle growing or artificial mycorrhization in the nursery.
Keywords: Ectomycorrhizae; fire; identification; morphology; Quercus ilex; Tuber melanosporum

Influence of weather on cork-ring width - Caritat, Antònia; Gutiérrez, Emilia; Molinas, Marisa (Tree Physiology, 2000)
Ring-width series of cork from Quercus suber L. trees growing at two sites in Extremadura (southwestern Spain) were analyzed in relation to monthly precipitation and temperature, and to climatic indices combining both variables. Ring width of cork showed strong positive correlations with precipitation, especially during the fall and winter. Moderately low temperatures were favorable for cork growth, except in winter and during the onset of phellogen activity. We conclude that drought or temperature, or both, can limit cork growth during the annual drought period.
10.1093/treephys/20.13.89310.1093/treephys/20.13.893
Keywords: climatic variability; cork growth; cork-ring chro- nology; dendroclimatology; phellogen activity; Quercus suber

Leaf morphology and macronutrients in broadleaved trees in central Italy - Bussotti, Filippo; Borghini, Francesca; Celesti, Carlo; Leonzio, Claudio; Bruschi, Piero (Trees, 2000)
As part of an intensive monitoring programme (MON.I.TO, Intensive Monitoring of Forests in Tuscany), a 3-year survey was carried out, which included three tree species (beech, Fagus sylvatica L.; Turkey oak, Quercus cerris L.; holm-oak, Quercus ilex L.) located at six different sites. Leaves were sampled annually and analysed for nutrient concentrations (nitrogen, sulphur, phosphorus, magnesium, calcium, potassium and sodium) and morphological parameters (leaf area, dry weight, leaf mass per area, leaf thickness and leaf density). Results indicated considerable interannual variation of all the parameters. Differences between sampling sites indicated that, of all parameters measured, leaf mass per area could explain best the differences in field performance under conditions of stress. In fact, leaf mass per area was greater in the drier sites or when sea salt deposition occurred. Nevertheless, the variation of leaf mass per area over the 3 years did not reflect the differences in rainfall. Higher leaf mass per area was accompanied by lower concentrations of phosphorus and nitrogen, which could be a dilution effect due to an increase of structural carbon compounds in sclerophyllous leaves, as revealed by the total foliar content of these elements. Leaf mass per area as a measure of sclerophylly reached very high values among mesophile vegetation. Long-range transport of sea salt from coastal areas to mountain areas was mirrored in sodium concentrations of leaves.
Keywords: Fagus sylvatica; macronutrients; Quercus cerris; Quercus ilex; sclerophylly

Light energy dissipation in Quercus ilex resprouts after fire - Fleck, I.; Aranda, X.; El Omari, B.; Permanyer, J.; Abadia, A.; Hogan, K. P. (AUSTRALIAN JOURNAL OF PLANT PHYSIOLOGY, 2000)
Holm oak (Quercus ilex) plants that have resprouted after fire have higher photosynthetic capacity than control plants in intact vegetation. In this study, branches detached from forest plants were fed with dithiothreitol (DTT) in the laboratory to inhibit zeaxanthin production and thus reduce the dissipation of light energy as heat. This allowed us to test the hypothesis that plants with greater photosynthetic capacity, and therefore greater photochemical sink strength, would suffer a lower reduction in photochemical efficiency under stressful conditions. Greater rates of photochemistry in resprouts, which exhibited increased photosynthesis (A), leaf conductance (g), quantum yield of PSII (Delta F/F-m') and photochemical quenching (q(P)), were related to lower non-radiative dissipation of excess energy as indicated by 1 - (F-v'/F-m'). However, the fraction of energy remaining of that used in photochemistry or dissipated thermally in the PSII antennae was similar in resprouts and controls and was not affected by DTT, especially under high irradiance conditions. Zeaxanthin involvement in PSII protection operated in resprouts and controls since DTT induced the same kind of response (NPQ decrease) but was lower in resprouts. These chlorophyll fluorescence results suggest the participation of some additional mechanism for energy dissipation. Light capture characteristics of the photosynthetic apparatus did not differ between resprouts and controls, and leaf age did not play a determining role in the differences observed.
APSAPSThe following values have no corresponding Zotero field: pub-location: 150 OXFORD ST, PO BOX 1139, COLLINGWOOD, VICTORIA 3066, AUSTRALIA publisher: C S I R O PUBLISHING
Keywords: DTT; photochemical sink; Quercus ilex

Litter quality and decomposition in a CO2-enriched Mediterranean forest ecosystem - Angelis, Paolo De (Plant and Soil, 2000)
Six large open top chambers were installed to test the effect of atmospheric [CO2] enrichment on clumps of natural Mediterranean vegetation starting from early spring 1992. To study the impact of [CO2] enrichment on litter decomposition, leaves of three woody species (Quercus ilex L., Phillyrea angustifolia L. and Pistacia lentiscus L.) were collected from the forest ﬂoor and subsequently incubated in situ over a two-year period. The initial slope of the exponential function, describing mass loss, indicated that there was a small negative effect of elevated [CO2] on the decomposition rate of all the species. All regressions were signiﬁcant. The decrease of decomposition rate is particularly notable during the initial stages of decomposition, when the differences of quality parameters, lignin/N and C/N were larger. This study points out that a decrease of decomposition rate may occur under elevated [CO2] conditions; if this effect is coupled to an increase of primary production, there will be a net rise of C-storage in the soils of forest ecosystems. Forest soils may, therefore, represent a potentially increasing sink for this excess carbon.
Keywords: decomposition rates; elevated [CO2]; litter quality; mediterranean forest; Quercus ilex

Modelling habitat selection of Common Cranes Grus grus wintering in Portugal using multiple logistic regression - FRANCO, ALDINA M. A.; BRITO, JOSÉ C.; ALMEIDA, JULIA (Ibis, 2000)
Predictive models of habitat suitability for the Common Crane Grus grus in a wintering area of southern Portugal were derived using logistic multiple regression and Geographic Information Systems. The study area was characterized by landscape variables and surveyed uniformly for the presence of cranes. The most important variables were distance to roosts, to open Holm Oak woods and to villages, and the occurrence of unpaved roads, shrubby vegetation, slope and orchards. Two models were built, the second having one variable fewer than the first. The selection of the best model was based on statistical and biological criteria. Crane distribution was negatively related to: distance to open Holm Oak Quercus rotundifolia woods and roosts. Additionally, unsuitable vegetation and orchard areas are avoided. In these areas movement is difficult, food availability is reduced and the risk of predation increased. We also found that villages and roads were avoided; disturbance is a significant factor for this species. Some management guidelines are proposed for the area: (1) maintenance of open Holm Oak woodlands, (2) incentives to avoid the abandonment of traditional agriculture and pastoral use of the area, which would lead to an increase of shrubby vegetation areas, (3) preservation of suitable roosting places and (4) management of new patches of forest and orchards.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Common Crane; habitat suitability models; holm oak woodlands (voyant); wintering habitats

Mycorrhization of vitroplants raised from somatic embryos of cork oak (Quercus suber L.) - Dı́ez, Jesús; Manjón, José Luis; Kovács, Gabor M.; Celestino, Cristina; Toribio, Mariano (Applied Soil Ecology, 2000)
The technique described herein allows in vitro ectomycorrhizal synthesis in Quercus suber vitroplants raised from somatic embryos with Pisolithus tinctorius and Scleroderma polyrhizum strains. Only strains of this species coming from fruit bodies collected in Quercus suber stands (strain QS241 and strain QS247) formed ectomycorrhizas, and hence these species seem to exhibit host adaptation. The in vitro mycorrhization facilitated the development of secondary roots and the ex vitro weaning of cork oak vitroplants.
Keywords: Cork oak; ectomycorrhizas; Mycorrhization; Somatic embryogenesis

Observations sur la dynamique du développement du Diplodia mutila Fr. apud Mont. sur le chêne-liège, Quercus suber L., au Maroc - El-Badri, Naïma; Abadie, Michel (Cryptogamie Mycologie, 2000)
Mamora forest in Rabat (Morocco) was a wide forest of cork oak which is rapidly disappearing. This crisis is caused by both human exploitation and overgrazing by animals. This situation is also affected by the existence of harmful insects and parasitic fungi. One of the most common species is Diplodia mutila Fr. apud Mont. (group of Coelomycetes) anamorph of Botryosphaeria stevensii Shoem., which causes withering and cankers on trunks and branches. The electron microscope observations on pycnosporogenesis and the study of the relation plant-host-pathogen show the structure and the biological cycle of Diplodia mutila, the endophytic and the systemic development of the pathogen and the irreversible damage on the plant host. This study is a contribution to the research on cork-oak forest protection.
Keywords: decline; Diplodia mutila Fr. apud Mont.; FOREST; Mamora; Morocco; pathology; Quercus suber L.; ultrastructure

Past distribution and ecology of the cork oak (Quercus suber) in the Iberian Peninsula: a pollen-analytical approach - Carrión, J. S.; Parra, I.; Navarro, C.; Munuera, M. (Diversity and Distributions, 2000)
This study presents pollen-analytical data from continental and offshore Iberian Peninsula sites that include pollen curves of Quercus suber, to provide information on the past distribution and ecology of the cork oak (Q. suber). Results centre on a new pollen record of Navarrés (Valencia, eastern Spain), which shows that the cork oak survived regionally during the Upper Pleistocene and was important during a mid-Holocene replacement of a local pine forest by Quercus-dominated communities. This phenomenon appears linked to the recurrence of ﬁre and reinforces the value of the cork oak for reforestation programmes in ﬁre-prone areas. In addition to Navarrés, other Late Quaternary pollen sequences (Sobrestany, CasablancaAlmenara, Padul, SU 8103, SU8113, 8057B) suggest last glacial survival of the cork oak in southern and coastal areas of the Peninsula and North Africa. Important developments also occur from the Late Glacial to the middle Holocene, not only in the west but also in the eastern Peninsula. It is suggested that, in the absence of human inﬂuence, Q. suber would develop in non-monospeciﬁc forests, sharing the arboreal stratum both with other sclerophyllous and deciduous Quercus and Pinus species
Keywords: Cork oak; historical biogeography; iberian peninsula; palaeoecology; pollen.

Quantitative Assessment of Polycyclic Aromatic Hydrocarbons from Corkwaste Combustion Emissions - Cabañas, Aracel; Sáez, Felicia; González, Alberto; Escalada, Ricardo (Journal of Agricultural Engineering Research, 2000)
Cork is a natural raw material obtained from the cork oak (Quercus suber). The corkwaste is a potential source of polycyclic aromatic hydrocarbons (PAHs) due to its high content of volatile compounds. A sampling method was developed for the measurement of polycyclic aromatic hydrocarbons emissions in a pilot bubbling #uidized bed combustion. This method has been designed to assess simultaneously the PAH contained in the gas phase and in the particulate matter. The samples were analysed on a gas chromatography coupled to a mass spectrometer to identify and quantify PAH compounds. The mass-selective detector was run in the selected ion monitoring mode. This study shows that lower molecular weight PAH were present predominantly in the gas phase, whereas high weight PAHs were retained in the particulate phase. As there is an existing relationship between the emission of CO and polycyclic aromatic hydrocarbons, the control and assessment of both compounds have been performed.
Keywords: Cork waste; Fluidized bed combustion (PG); GC-MS; Polycyclic aromatic hydrocarbons (PAHs)

Removal of toxic metals from solution by leaf, stem and root phytomass of Quercus ilex L. (holly oak). - Prasad, M. N.; Freitas, H. (Environmental pollution (Barking, Essex : 1987), 2000)
Increased consciousness for safeguarding the aqueous environment has prompted a search for alternative technologies for the removal of toxic metal ions from aqueous solutions. In this regard, a wide variety of biomass is being considered as adsorbents of heavy metals for treatment of industrial and domestic wastewaters as well as natural waters, including drinking water. In the present investigation, the potential of Quercus ilex phytomass from stem, leaf and root as an adsorbent of chromium (Cr), nickel (Ni), copper (Cu), cadmium (Cd) and lead (Pb) at ambient temperature was investigated. The metal uptake capacity of the root for different metals was found to be in the order: Ni>Cd>Pb>Cu>Cr; stem Ni>Pb>Cu>Cd>Cr; and leaf Ni>Cd>Cu>Pb>Cr. The highest amount adsorbed was Ni (root>leaf>stem). Data from this laboratory demonstrated that Ni is sequestered mostly in the roots, where concentrations can be as high as 428.4 ng/g dry wt., when 1-year-old seedlings were treated with Ni (2000 mg/l) in pot culture experiments, compared to 7.63 ng/g dry wt., control (garden and greenhouse soil) topsoil where Ni was present in trace amounts. This proves that the root biomass of Q. ilex has the capacity for complexing Ni. Cr exhibited the least adsorption values for all the three types of phytomass compared to other metals. The trend of adsorption of the phytomass was similar for Ni and Cd, i.e. root>leaf>stem. Desorption with 10 mM Na(4) EDTA was effective (55-90%) and, hence, there exists the possibility of recycling the phytomass. The biosorption results of recycled phytomass suggest that the selected adsorbents are re-usable. The advantages and potential of the Q. ilex phytomass as a biofilter of toxic trace metals, the scope and need for enhancing the efficiency of the Q. ilex phytomass as an adsorbent of metals are presented.
The following values have no corresponding Zotero field: accession-num: 15092842
Keywords: Biosorption; cadmium; chromium; copper; desorption; lead; Nickel; phytomass; Quercus ilex; root; stem

Seasonal variation of foraging niches in a guild of passerine birds in a cork-oak woodland - Almeida, J.; Granadeiro, J. P. (ARDEA, 2000)
Spatial foraging niches of a pariform guild in a cork-oak woodland were examined during winter and spring. Niche structure was described in terms of the niche dimensions foraging substrate, foraging height and part of tree, and seasonal changes in niche breadth and overlap were examined. Considering the difficulties of dealing with the multidimensionality of Hutchinson's niche concept, we adopted a multivariate approach and identified the most important factors for spatial segregation. Significant differences between winter and spring utilisation of the foraging dimensions were found for the guild as a whole. At the species level, however, no major seasonal differences in the utilisation of foraging dimensions were found. No consistent seasonal trend occurred in terms of niche size or niche overlap. Multivariate analysis showed that the guild structure is basically the same in winter or spring, with Little influence of species that are present in only one of the two seasons. These results suggest that there is no food shortage in winter for the pariform guild in this woodland. The niche dimensions related with tree structure and foraging substrate appeared to be the most important ones in species segregation.
The following values have no corresponding Zotero field: pub-location: C/O PAUL STARMANS, OUDE ARNHEMSEWEG 261, 3705 BD ZEIST, NETHERLANDS publisher: NEDERLANDSE ORNITHOLOGISCHE UNIE
Keywords: community ecology; cork-oak woodland; guild; niche; passerines

Soil microbial activity as a biomarker of degradation and remediation processes - Pascual, J. a; Garcia, C.; Hernandez, T.; Moreno, J. L.; Ros, M. (Soil Biology and Biochemistry, 2000)
Several organic matter fractions together with biological and biochemical parameters were measured in a range of intensively farmed soils in SE Spanish Mediterranean region, which had been abandoned (i.e. not used in agriculture) for different periods of time. These soils were compared with adjacent natural soils that had never been used for agriculture. There was a general decline of total organic carbon (TOC), extractable humic substances, water-soluble carbon (WSC) and carbohydrates, microbial biomass and respiration with the time elapsed since abandonment. There was also a decline in plant cover in the abandoned soils. When a degraded soil was amended with municipal solid waste at rates of 6.5 and 26 kg m 22 as a potential means of remediation, TOC, humic substances, WSC, microbial biomass and respiration rates signi®cantly increased but only at the higher rate of amendment. Plant cover was signi®cantly enhanced by both rates of the amendments and was still present 10 years after the amendment. These data con®rm that agricultural soil abandonment leads to soil degradation and that the addition of urban waste could be a suitable technique with which to restore their quality
Keywords: dehydrogenase; hydrolases; organic matter; soil remediation

Soil nitrogen heterogeneity in a Dehesa ecosystem - Gallardo, A.; Rodriguez-Saucedo, J. J. (Plant and Soil, 2000)
The Dehesa are savannah-like ecosystems that occupy extensive areas in the mediterranean regions of Southern Spain and Portugal. The changes in the soil nitrogen (N) potential mineralisation rate, microbial biomass-N and available mineral N in soils were studied over 1 year in a Dehesa ecosystem, in the SW of Spain. The temporal variability of soil samples was compared by using the coefficient of variation of samples taken on a monthly basis. Spatial variability of the soil samples was measured by comparing the variograms generated with geostatistical techniques. The potential N mineralisation reached a maximum in the spring and summer samples, and a minimum in the autumn. However, the soil NHC 4 , NO 3 and microbial biomass-N showed maximum levels in winter, compared with minimum levels in the spring and summer. The potential mineralisation rate showed a higher temporal variability in the samples taken under tree canopies, due to highest maximum and similar minimum levels reached during the sampling period. The potential mineralisation rate, microbial biomass-N and soil mineral N were higher under the tree canopies than in the open grassland. The spatial distribution of the soil organicmatter and available NHC 4 was strongly influenced by tree canopy size. The semivariograms were adjusted to a spherical model, indicating a maximum NHC 4 variability at a certain distance from the tree crown diameter. The same was not the case for the spatial distribution of the soil NO 3 from the tree crown. Our results indicate that the tree component of a Dehesa ecosystem is a major influence in the spatial and temporal heterogeneity of soils.
Keywords: Dehesa; geostatistics; grassland; Quercus ilex; soil heterogeneity; soil nitrogen

Spectral editing of 13C cp/MAS NMR spectra of complex systems: application to the structural characterisation of cork cell walls. - Lopes, M. H.; Sarychev, A.; Neto, C. P.; Gil, a M. (Solid state nuclear magnetic resonance, 2000)
A mathematical method of obtaining 13C CP/MAS subspectra of single components of a complex system is presented and applied to three- and four-component systems. The method is based on previously reported work that exploits different proton relaxation properties for different domains of an heterogeneous system. However, unlike the original method that obtained subspectra through a trial-and-error approach, the method here presented solves the problem mathematically, thus avoiding the time-consuming and non-rigorous trial-and-error step. The method is applied to mixtures of three and four polymers and to a more complex system: cork cell walls. As expected, as the number of components increases, the sharing of relaxation properties between different components is increasingly probable, either due to incidental coincidence of relaxation times or to specific interactions and intimate mixing of compounds. While this hinders the calculation of the subspectra of single chemical components, it may provide useful information about inter-component interactions. This possibility was demonstrated by the application of this method to cork cell walls. Both three-component and four-component approaches showed that three domains exist in cork cell walls: carbohydrate/lignin matrix, mobile suberin close to (probably bonded to) lignin groups (about 42% w/w) and hindered suberin close to (probably bonded to) carbohydrate-OCH2O groups (about 4% w/w).
The following values have no corresponding Zotero field: accession-num: 10868562
Keywords: 13CCPrMAS NMR; Cork; Polymer; Quercus suber L.; Relaxation; Spectral editing

Temporal and spatial variation in C, N, S and trace element contents in the leaves of Quercus ilex within the urban area of Naples. - Alfani, a; Baldantoni, D.; Maisto, G.; Bartoli, G.; Virzo De Santo, A. (Environmental pollution (Barking, Essex : 1987), 2000)
This paper presents a comparative analysis of the concentrations of C, N and S and several trace elements (Fe, Mn, Na, Zn, Cu, V, Pb, Ni, Cr, Cd) in leaves of Quercus ilex, an evergreen oak, collected in the urban area of Naples in 1989 and 1996. The samplings were carried out from 25 urban sites (roads with different traffic flows as well as urban and suburban parks) and from two remote areas as controls. Relative to 1989, the values measured in 1996 denote a strong decrement of S, Fe, Na, Pb, and Cr, with the exception of S in control sites. By contrast, C, N and Cd contents were higher in 1996 than in 1989. Cu and Ni showed a conspicuous increment in control sites as well as in urban sites facing the sea and in the parks, while in all the other urban sites these elements decreased remarkably. No significant difference was found in the leaf contents of Mn, Zn and V measured in 1989 relative to 1996. Both in 1989 and 1996 the contents of N, S, Fe, Na, Cu, Pb, V, Ni, Cr and Cd were significantly higher in leaves from urban sites than in the controls, reflecting the high degree of contamination of the urban area. Concentration factors expressed as the ratio of road/control values for most of the elements were still very high in leaves collected in 1996, though remarkably lower than in 1989.
The following values have no corresponding Zotero field: accession-num: 15092919
Keywords: air pollution biomonitoring; leaf elemental analysis; no x; so 2; Trace Elements

Agriculture and landscape in Portugal - Firmino, Ana (Landscape and Urban Planning, 1999)
Landscape is the result of a dynamic process, which changes either due to natural causes or due to human impact. Therefore, we cannot expect landscapes to stay unchangeable, although some are evolving more quickly than others. Portugal is a mosaic of landscapes, partly because of different climatic conditions and orographic and morphologic genesis but also because of the impact of human activity, especially in agriculture. This article deals with the impacts of this sector on the landscapes, the consequences of which can be found not only in the ecosystems but also in the daily life of the people, in their jobs, in the abandonment of the land and in the change of mentality, related to the inadequate national policies and the overestimation of short-term economic pro®t
Keywords: agri-environmental measures; Environment; Portugal

Altitudinal differences in UV absorbance, UV reflectance and related morphological traits of Quercus ilex and Rhododendron ferrugineum in the Mediterranean region - Filella, Iolanda; Penuelas, Josep (Plant Ecology, 1999)
We studied the variations in different physiological parameters associated with UV-B radiation defense: UV-B radiation absorbance, UV-visible spectral reﬂectance, carotenoids concentration, leaf thickness, SLW (speciﬁc leaf weigth) and trichome density in Quercus ilex growing at 200 and 1200 m and Rhododendron ferrugineum growing at 2200 m. We examined the role of these parameters as protection mechanisms in an altitudinal gradient of increasing UV radiation in northern Catalonia and in sun and shade leaves. The concentration of UV-B radiation absorbing pigments was 15% higher in sun leaves of Q. ilex at 1200 m than in those from 200 m altitude. Sun leaves of R. ferrugineum presented concentrations three times higher than those of Q. ilex. Reﬂectance ranged between 5% (in the region 300–400 nm) and 12% (in the region 280–300 nm). The variation of reﬂectance with altitude followed an inverse trend respect to absorbance in the 280–300 nm region, with higher values the lower the altitude, but in the 300–400 nm region, reﬂectance of the lower site was the lowest. In both species and altitudes sun leaves presented higher concentrations of UV-B radiation absorbing pigments and UV reﬂectance than shade leaves. Quercus ilex trees of the higher location presented higher NDPI (Normalized Difference Pigment Reﬂectance Index) values, indicating higher carotenoids/chlorophylla ratio. Actual measurements of carotenoid/chlorophyll a ratio conﬁrmed this pattern. The photochemical reﬂectance index (PRI) presented higher values the higher the location indicating lower photosynthetic radiation-use efﬁciency. Speciﬁc leaf weight (SLW) and leaf thickness were larger in Q. ilex trees of higher location than in those of lower location. In both sites, sun leaves also presented larger SLW values than shade leaves. Adaxial leaf hair density in sun leaves was signiﬁcantlly higher in the lower location. UV absorption and linked morphological traits (SLW, leaf thickness measured in Q. ilex) presented the larger differences among studied plants at different altitudes and seem to be the dominant UV protecting mechanisms.
Keywords: Altitude; carotenoids/chlorophyll a ratio; leaf hair density; Mediterranean Region; ndpi; pri; Quercus ilex; rhododendron ferrugineum; slw; Thickness; uv absorbing compounds; uv reflectance

Análisis del área foliar del alcornoque en relación con tratamientos silvo-pastorales - Caritat, A. I.; Molinas, M. I.; Vilar, I. P.; Masson, L. (Scientia gerundensis, 1999)
The fluctuations showed by ecophysiologic parameters, like leaf area and leaf area indices, in relation to silvo-pastoral treatments can be used to evaluate the effects of these treatments on o&-cork forests. Leaf area shows a close relation to production and is a good indicator of the physiological state of the plants. Leaf area, leaf area indices and specific leaf weight have been studied in four cork-oak wood stations in relation to shrub clearing and grazing treat- ments. Leaf parameters have been measured using a computer image analysis system. We found that, in general, leaf average area is increased by silvo-pastotal treatments, apparently in order to recover the wasted canopy and in answer to nutrient supply. On the other hand, leaf area index decreases after treatments because of the leaf biomass lost, but the fast apical growth showed by cork-trees in treated plots points to a quick recovery of this parameter when an appropiate tree density is reached.
Keywords: cork-oak; Grazing; leaf area; leaf index; shrub cleareing; silvo-pastoral treatments

APLICACION DEL ANALISIS DE IMAGENES AL ESTUDIO DE PARÁMETROS MORFOMETRICOS DEL CORCHO - Campos, M.; Molinas, M. (Scientia gerundensis, 1999)
In this work we propose a method to study cork quality from little samples throug the analy- sis of images. This method has aplications in all studies that need cork quality determination. The digital analysis of images is an apropiate option due to makes morphometry automati- cally and it allows a quick manipulation of the results. It is a fast and objective method because allows the comparative study between a high number of samples; so it could be pos- sible to compare populations or individual in order to study the influence of some ambiental or getnetic factors and have another aproach to three's selection. Here we describe an digital analysis program based on IMAGE 1.41 VDMi software for Macintosh developed to measu- re severa1 cork morphometric parameters.
Keywords: Cork quality; image analysis; methodology; morphometry; Quercus suber

Apoplastic Solute Concentrations of Organic Acids and Mineral Nutrients in the Leaves of Several Fagaceae - Gabriel, Reinhard; Kesselmeier, Jürgen (Plant and Cell Physiology, 1999)
Ion chromatographic methods determined organic acids and main nutrient minerals in the apoplastic solution from leaves of several Fagaceae (Quercus ilex L., Quercus cerris L., Quercus virgiliana (Ten.) Ten, and Fagus sylvatica L.). The anions of organic acids found in high amounts (250 to 650 μM) were quinate, malate, and oxalate. Lactate, pyruvate, formate and acetate were detected in relatively low amounts with concentrations between 20 and 200 μM. The total concentration of organic acids in the apoplastic sap ranged between 1.5 and 2 mM. The total concentration of inorganic cations (K+, Mg2+, NH4+, Ca2+, Na+) and anions (C1−, NO3−, SO2−4 and PO3−4) in the apoplastic sap varied between 5 and 10 mM, and 0.35 and 1.8 mM, respectively. We conclude that the concentration of organic acid ions in the leaf apoplast depends mainly on the exchange with the leaf cells and is influenced by the electrochemical gradient between the symplast and the apoplast in relation to the water potential of the leaf. The determination of formate and acetate in the apoplastic compartment of leaves lend weight to the argument that the production of these acids by trees is a important emission source to the atmosphere.
Keywords: Anions; Apoplast; cations; Fagaceae; leaf; organic acids

Belowground biodiversity in a Mediterranean landscape: relationships between saprophagous macroarthropod communities and vegetation structure - DAVID, J. F.; Devernay, S. (Biodiversity and …, 1999)
Millipedes and woodlice were sampled at 27 sites in a mosaic landscape in order to establish the extent to which the macroarthropod community changed with dierent plant for- mations. Multivariate analyses conducted on abundance data for ten species revealed four main types of macroarthropod communities. This classi®cation was highly correlated with vegetation structure and particularly the degree of openness of the sites. Communities dominated by Om- matoiulus rutilans (Julidae) occurred in open grassland; those dominated by Glomeris marginata (Glomeridae) plus Porcellio gallicus (Porcellionidae) were found at the least open sites, with a high oak cover; communities with a high proportion of the endemic glomerid Glomeris annulata oc- curred in semi-open sites with a substantial cover of shrubs. Species diversity was signi®cantly higher at the semi-open sites, this being interpreted as an edge eect. Population density and biomass were lower at wooded sites. In the context of a regional trend towards woodland ex- pansion, the results are discussed from the viewpoint of conserving the pool of millipede and woodlouse species and of maintaining the abundance of saprophagous macroarthropods in the region's ecosystems.
Keywords: diplopoda; habitat preferences; Isopoda; Mediterranean Region; vegetation changes

Biomass, nutrient content, litterfall and nutrient return to the soil in Mediterranean oak forests - Rapp, Maurice; Santa Regina, Ignacio; Rico, Mercedes; Gallego, Humberto Antonio (Forest Ecology and Management, 1999)
We estimated above-ground biomass, nutrient content, litterfall and nutrient return to the soil in deciduous and evergreen Quercus pyrenaica Will., Quercus lanuginosa Lamk and evergreen Quercus ilex L. oak forests, respectively, near Salamanca (Spain) and Montpellier (France). The calculated biomass ranged from 64 to 121 Mg ha ÿ1 . Perennial material (trunks and branches) represented 96±97% in the four Spanish Q. pyrenaica stands and 93% in the French Q. lanuginosa and Q. ilex stands. Q. pyrenaica had higher P, Mg, Fe and Mn contents than the other two species from southern France. In contrast, these latter species had higher N and Ca concentrations. All of these differences were related to soil nutrient availability, especially Ca, Mg, P, Fe and Mn. Comparison of the chemical composition of leaves on trees with that of leaf litter indicated retention and translocation of N, P and K from leaves to perennial biomass and recycling of Ca and Mg from trees to the soil
Keywords: forest biomass; forest ecosystems; litterfall; Q. ilex; Q. lanuginosa; Q. pyrenaica

Competitive strategies for water availability in two Mediterranean Quercus species - Nardini, A.; Gullo, M. A. Lo; Salleo, S. (Plant, Cell & Environment, 1999)
Competition for water availability was studied in a mixed natural stand of Quercus suber L. and Quercus cerris L. growing in Sicily by measuring diurnal changes of leaf conductance to water vapour (gL), water potential (ΨL) and relative water content (RWC) in April, July and October 1997 as well as the seasonal changes in root hydraulic conductance per unit leaf surface area (KRL). Quercus cerris behaved as a drought-tolerant species, with strong reductions of KRL, ΨL, and RWC in the summer. By contrast, Q. suber appeared to withstand summer drought by an avoidance strategy based on reducing gL, maintaining ΨL and RWC high and KRL at the same level as that measured in the spring. A ‘conductance ratio’ (CR) was calculated in terms of the ratio of gL to KRL. Seasonal changes of this ratio contrasted in the two species, thus suggesting that Q. suber and Q. cerris did not really compete for available water. In the summer, when Q. suber was extracting water from the soil to maintain high leaf hydration, Q. cerris had restricted water absorption, thus suffering drought but tolerating its effects. The possibility that cohabitation of drought-tolerant with drought-avoiding species can be generalized is also discussed.
Keywords: leaf conductance; leaf water status; Quercus cerris (Turkey Oak); Quercus suber (cork oak); root hydraulic conductance.

Cuticular waxes of the holm (Quercus ilex l. subsp. ballota (desf.) samp.) and cork (Q. suber l.) oaks - Martins, C. M. C.; Mesquita, S. M. M.; Vaz, W. L. C. (Phytochemical Analysis, 1999)
The epicuticular leaf waxes of young leaves of the Holm oak (Quercus ilex L. ssp. ballota (Desf.) Samp.) and the cork oak (Q suber L.) were extracted in chloroform and separated into their constituent wax classes by preparative thin layer and high pressure liquid chromatography. The wax coverage was about 125 μg/cm2 in Q. suber and about 71 μg/cm2 in Q. ilex. The main classes encountered (by weight) were odd chain n-alkanes (9% in Q. ilex, and 4–27% in Q. suber) and even chain amphiphilic compounds. The major classes of amphiphilic compounds were n-alkan-1-ols (20–27% in Q. ilex, and 18–50% in Q. suber), n-alkanals (<3% in Q. ilex, and up to 25% in Q. suber), n-alkanoic acids (11–12% in Q. ilex, and <5% in Q. suber) and n-alkyl esters (50–56% in Q. ilex, and 25–45% in Q. suber). The major components of each class, identified by gas chromatography coupled to mass spectrometry were C29 for the n-alkanes (54–58% in Q. ilex, and 47–57% in Q. suber), C24 for the n-alkan-1-ols (78–87% in Q. ilex, and 77–93% in Q. suber), C30 for the n-alkanals (up to 57% in Q. ilex, and up to 77% in Q. suber), C22 and C24 for the n-alkanoic acids in Q. ilex (39–62%) and C30 in Q. suber (49%). The n-alkyl esters were composed mainly from C22 and C24n-alkanoic acids (∼38%) and n-alkan-1-ols (43–54%) in Q. ilex, whereas in Q. suber these esters were composed mainly from C22 and C24n-alkanoic acids (44–52%) and C20 and C22n-alkan-1-ols (32–66%). In addition to the above compounds, trace amounts (<5%) of C28 and C30n-alkenes and the triterpenone, friedelin, were encountered in Q. suber and both plant waxes contained small amounts of the triterpenols α- and β-amyrin (5–9% of the total alkanol content). The variability observed in the chemical composition of the leaf waxes were attributable to seasonal causes and/or leaf age. Copyright © 1999 John Wiley & Sons, Ltd.
The following values have no corresponding Zotero field: publisher: John Wiley & Sons, Ltd.
Keywords: chemical composition; cuticle; cuticular waxes; Quercus ilex; Quercus suber

Datos sobre la flora y vegetación del Parque Natural de los Alcornocales (Cádiz-Málaga, España) - Pérez Latorre, A. V. (Acta botánica malacitana, 1999)
We have carried out a study about the flora, vegetation and landscape inthe Natural Park Los Alcornocales, located in the provinces of Cádiz and Málaga (SW of the Iberian Peninsula, Andalusia). The maximum altitude in the Park is 1091 m.; the dominant litology is characterised by sandstones and clays, in the NW prevail the limestones. The annual rainfalls are very abundant (between 800 and 1400 mm.) as well as the fogs regime, caused by the nearness to the Strait of Gibraltar; we have recognized two bioclimactic belts, thermo (annual mean temperature 17-18°C) and mesomediterranean (14-16°C) with accused oceanity. As a result, more than 1300 taxa of vascular plants have been catalogued, emphasizing in this work 77, because they are protected species, endemics or first records for western Andalusia; among them, 9 species are relictic ferns and have a great phytogeographic value. A total of 89 associations and communities have been inventoried. We have accomplished commentaries on sintaxa with a range superior to association. We lectotypified a subassociation and one association is neotypified. We describe as new sintaxa one order (Rhododendro pontici-Prunetalia lusitanicae), two alliances ldodendro ponticiPrunion lusitanicae and Salicion pedicellatae), 6 associations, 8 subassociations ad 1 combination. We have recognized 6 climactic series, among them one is new and characterised by forests of Quercus:broteroi on calcareous soils (Oleo sylvestris-Querceto broteroi S), other two are forests of Quercus suber on sandstones, another one is characterised by Quercus canariensis in wet slopes, one of Quercus pyrenaica in the summits and one of Quercus rotundifolia on lowland calcareous soils. As a mixed serie bound to the conditions of the vertisols occurs forests ofOlea sylvestris. As permanent vegetation on calcareous solis appears Ceratonia siliqua; on sandstones appears Junipertts oxycedrus; in summits flogged by strong winds we recognize a community with Quercus lusitanica and on rocky sandstones a relictual variant with Pinus pinaster. A mixed serie bound to the environmental humidity conditions as well as to wet soils is characterized by Rhododendron ponticum, similar to the macaronesian laurisilva. The series linked to rivers in the Park are characterised by: Alnus glutinosa (permanent stream rivers on sandstones), Salix pedicellata (partially droughted rivers), Populus alba (fluvisols), Fraxinus angustifolia (riverine sandyargilic soils), Nerium oleander (totally droughted rivers), Tarnarix africana (erratic or halophyll streams) and wet heaths with Erica ciliaris. Also exist communities mosaics bound to ecological corridors, human environments, rocks and cliffs, epiphytes, acrohalophylls and those tipycal of saline and aquatic environments. Finally, a commented syntaxonomic scheme, some inventories tables corresponding to the new or commented syntaxa and a map of the vegetation series of the Park are presented
Keywords: Andalucía; España; Flora; Los Alcornocales; Natural Park; sintaxonomy; Vegetation

Diurnal changes in antioxidant and carotenoid composition in the Mediterranean schlerophyll tree Quercus ilex(L) during winter - García-Plazaola, J. I.; Artetxe, Unai; BECERRIL, J. M.; Garcı, Ignacio (Plant Science, 1999)
Seasonal changes of pigment composition and antioxidant content were characterized in the Mediterranean evergreen holm oak (Quercus ilex L.). Higher contents of antioxidants and carotenoids, with a photoprotective role during winter, indicated that this period was highly stressful, so a study of diurnal changes in photosynthesis, pigments and carotenoids was conducted during January in sun and shade leaves. Sun and shade leaves were used to compare the effects due only to low temperature separate from those resulting from the interaction of light. During winter, a relatively high rate of CO2 ﬁxation on sun leaves represented an important sink for photosynthetic electrons contributing to the annual carbon balance of the plant. This high rate contrasted with a reduced Fv :Fm, even at predawn. This reduction was correlated with the accumulation of zeaxanthin at the expense of violaxanthin by de-epoxidation. Sun leaves were also protected by a higher concentration of antioxidants (ascorbate, glutathione and tocopherol) and carotenoids (except lutein epoxide). Ascorbate was 10–50-fold greater than the other antioxidants, indicating a central role in protection against photooxidative stress. Nevertheless those mechanisms were unable to avoid a loss of hydrophilic antioxidants (glutathione and ascorbate) and xanthophylls during the initial morning hours after dawn, indicating that the ﬁrst target of photooxidative damage was these molecules
Keywords: Holm oak; low-temperature stress; Mediterranean evergreens; photoinhibition; photoprotection; xanthophyll cycle

Efecto de los tratamientos silvopastorales en el crecimiento del alcornoque - Caritat, A.; Molinas, M.; Vilar, L.; Masson, Ph (Scientia gerundensis, 1999)
Comparative effects of shrub clearing and grazing on the apical and radial growth of the cork oak have been studied in four cork oak wood stations. Shoot growth segments and annual wood rings were measured in 10 selected trees in every plot. Average shoot elongation's oscillate between 2.5 to 4.8 cm; annual wood rings from 0.95 to 2.05 mm and annual radial growth of wood plus cork from 2.3 to 5.7 mm. Significative differences were found between silvo-pastoral treatments in relation to apical elongation. In treated plots, the apical growth of segments that reach the maximum elongation can be a 75% higher than in control plots. This increment on shoot growth can be explained by the decrease in plant competition and by the nutrient contribution of grazing. No significative effects of treatments on radial growth have been found.
Keywords: Alcornoque; crecimiento apical; Crecimiento radial; desbroce; pastoreo (voyant)

Effect of pre-lambing supplementation on milk production of Merino ewes at grazing - Gallego, F. L.; Parra, M. L.; Sanchez, F. P. (MILKING AND MILK PRODUCTION OF DAIRY SHEEP AND GOATS, 1999)
Milk production of Merino ewes has been studied under the effects of two different prelambing supplementations (4 and 7 weeks, L1 and L2, respectively). Throughout the trial, the ewes remained under extensive grazing in a ``dehesa{''} from Extremadura. Lambing took place in September and lactation continued until the 6(th) week. After weaning, the ewes were subjected to machine milking until drying in the 19(th) week. During milking, the ration for both lots was the same. Similar daily values of production potential were noted, being greater in L2, 12% during lactation (1120ml) and 14% in milking (375ml). The milk obtained by the lamb at 42 days of lactation (40 l) was 11% superior in lot 2. The difference in body condition is balanced out during the 90 days of milking during which the milk production obtained in L2 (27 l) represents a 16% improvement in production.
The following values have no corresponding Zotero field: periodical: MILKING AND MILK PRODUCTION OF DAIRY SHEEP AND GOATS issue: 95 pub-location: POSTBUS 220, 6700 AE WAGENINGEN, NETHERLANDS
Keywords: grazing and supplementation; Merino; milk production

Effects of disturbance caused by traditional Spanish rural land use on the regeneration of Cytisus multiflorus - Fernández-Santos, B.; Gómez-Gutiérrez, J. M.; Moreno-Marcos, G. (Applied Vegetation …, 1999)
. Cytisus multiflorus is a leguminous matorral shrub native to the NW Iberian Peninsula, where it is one of the most important species in the extension of matorral at the expense of set-aside agricultural land. Dehesas have traditionally been used for extensive livestock raising and matorral was periodically burnt, cut or pulled out. The two latter practices are now out of use. However, burning is more frequent than in the past. The effects of fire, cutting, and pulling out of C. multiflorus on its regeneration was studied in order to ascertain whether the presently increasing distribution of the species relates to firestimulated regeneration or to the reduction of other traditional practices. Three years after treatment two sets of parameters were determined: 1. Plant origin: seedlings and different ramet types ( ramets = resprout clumps), density, weight, and biomass as well as the percentage of resprouting. 2. Seed persistence at various soil depths. The possible mechanisms of breaking dormancy and plant emergence in different years after fire were studied in other experiments. The results suggest that the regeneration mechanism in C. multiflorus is stimulated by fire, but it is not an exclusive relationship. Stimulation occurs also after other disturbances leading to the total elimination of aerial biomass. The present expansion of the species does not appear to result from the abandonment of some traditional practices, such as cutting or pulling out, but from frequent fires (resulting in aerial-biomass elimination).
Keywords: Cutting; fire; Mediterranean shrubland; Pull-out; Ramet; seed bank; Seedling

Effects of electron beam irradiation on cork volatile compounds by gas chromatography mass spectrometry - Careri, M.; Mazzoleni, V.; Musci, M.; Molteni, R. (CHROMATOGRAPHIA, 1999)
The effects of electron beam irradiation on cork volatile compounds was studied at different doses (25, 100, 1000 kGy), Volatiles we:re isolated from cork using the dynamic headspace-sampling technique, then identified by gas chromatography-mass spectrometry (GC-MS). Similar gas chromatographic profiles were obtained for non-irradiated and irradiated corks. Quantitative differences induced by the three doses were evaluated by calculating peak areas for each compound identified. The quantitative differences between non-irradiated corks and those irradiated at 25 kGy were significant for only a few substances, when:as significant quantitative differences were found in samples irradiated at 100 and 1000 kGy. For these doses, the content of volatile compounds generally increased, especially that of aliphatic hydrocarbons and carbonyl compounds. The behaviour of radiolytic hydrocarbons indicates that the mechanisms proposed for their formation in irradiated foods could take place even in cork.
The following values have no corresponding Zotero field: pub-location: ABRAHAM-LINCOLN-STRABE 46, POSTFACH 15 47, D-65005 WIESBADEN, GERMANY publisher: VIEWEG
Keywords: cork volatiles; dynamic headspace sampling; electron beam irradiation; gas chromatography mass spectrometry; radiolysis-induced compounds

Effects of forest fragmentation on the winter body condition and population parameters of an habitat generalist, the wood mouse Apodemus sylvaticus: a test of - Díaz, M.; Santos, T.; Tellería, J. L. (Acta Oecologica, 1999)
Three main causal hypotheses have been proposed to explain the inverse relationships between habitat patch size and density of gen- eralist mouse species in fragmented habitats: 1) enhanced habitat conditions as habitat patch size decreases; 2) inhibited emigration of excess indi- viduals in small and isolated habitat patches; and 3). reduced territoriality in small patches because they are occupied temporarily by non- reproductive individuals. From the mechanism underlying each hypothesis, we derived predictions on the effects of fragment size on the body condition of individuals (measured both as absolute body size and as body mass relative to body size) and some demographic parameters of mouse populations redated to reproductive output (sex-ratio and proportions of sexually active and recently-born individuals), and we tested such predic- tions with data from wood mice Apodemus sylvaticus wintering in three Spanish forest archipelagos in which the inverse relationship between for- est patch size and mouse abundance had been previously proven. No differences in average body size or in average body mass relative to body size were detected among fragments. Mouse populations wintering in small fragments showed more male-biased sex-ratios, a larger proportion of sex- ually active adults and fewer juveniles as compared to mouse populations wintering in large fragments nearby. Results clearly rejected the third hypothesis and did not support the second one. It thus seemed that habitat conditions for mice improved as forest fragment size decreased, although the expected positive effects on individuals could have been prevented by relaxed territoriality and increased food resource depletion by denser mouse populations. Bearing in mind the negative effects of dense wood mice populations on the distribution, abundance and population dynamics of forest species, this apparent enhancement of habitat conditions for mice in small forest fragments could have far-reaching conse- quences for the long-term persistence of such fragments.
Keywords: Body condition; Body size; demography; Forest fragmentation; population density; winter; wood mouse

Effects of grazing and topography on long-term vegetation changes in a Mediterranean ecosystem in Israel - Carmel, Yohay; Kadmon, Ronen (Plant Ecology, 1999)
The dynamics of Mediterranean vegetation over 28 years was studied in the Northern Galilee Mountains, Israel, in order to identify and quantify the major factors affecting it at the landscape scale. Image analysis of historical and current aerial photographs was used to produce high resolution digital vegetation maps (pixel size = 30 cm) for an area of 4 km2 in the Galilee Mountains, northern Israel. GIS tools were used to produce corresponding maps of grazing regime, topographic indices and other relevant environmental factors. The effects of those factors were quantiﬁed using a multiple regression analyses. Major changes in the vegetation occurred during the period studied (1964–1992); tree cover increased from 2% in 1964 to 41% in 1992, while herbaceous vegetation cover decreased from 56% in 1964 to 24% in 1992. Grazing, topography and initial vegetation cover were found to signiﬁcantly affect present vegetation patterns. Both cattle grazing and goat grazing reduced the rate of increase in tree cover, yet even intensive grazing did not halt the process. Grazing affected also the woody-herbaceous vegetation dynamics, reducing the expansion of woody vegetation. Slope, aspect, and the interaction term between these two factors, signiﬁcantly affected vegetation pattern. Altogether, 56% and 72% of the variability in herbaceous and tree cover, respectively, was explained by the regression models. This study indicates that spatially explicit Mediterranean vegetation dynamics can be predicted with fair accuracy using few biologically important environmental variables.
Keywords: aerial photographs; GIS; landscape ecology; regression model; spatial structure; Vegetation dynamics

Endangered stands of thuriferous juniper in the western Mediterranean basin: ecological status, conservation and management - Gauquelin, Thierry; Bertaudiere, Valerie; Montès, Nicolas (Biodiversity and Conservation, 1999)
Thuriferous juniper is only found in isolated parts of the western Mediterranean: France (Alps, Pyrenees and Corsican highlands), Spain, Algeria and Morocco. These semi-arid mountain stands, where thuriferous juniper trees grow in low-density open woodland, are seriously endangered: (i) In the Atlas mountains, the thuriferous juniper stands are heavily degraded as a result of the intensive wood removal and livestock activity in these densely populated areas. This situation, which will soon become irreversible unless remedial measures are urgently taken, has produced impoverished soils and hillside instability while contributing to desertiﬁcation. (ii) In Spain, although livestock activity and cultivation have strongly reduced areas occupied by Juniperus thurifera, stands are still numerous and, in some regions, show a good regeneration due to conservation measures. (iii) In France, the decline in human and livestock activities over recent decades has led to a recolonization of some of the Juniper stands by pines or oak. A forest management system that enables these original stands to survive and regenerate must be undertaken without delay. The dynamics of evolution of these stands is quite different north and south of the Mediterranean. In both cases, conservation measures are urgently required to protect or rehabilitate these original stands with ﬂoristic, ecological and socio-economic interest.
Keywords: conservation; degradation; Juniperus thurifera; management; Mediterranean basin; thuriferous juniper woodland

Environmental constraints at the edge of a species distribution, the Eurasian badger (Meles meles L.): a biogeographic approach - Virgos, E.; Casanovas, J. G. (JOURNAL OF BIOGEOGRAPHY, 1999)
Aim This paper describes the distribution pattern (occurrence) of badgers (Meles meles L. 1758) in a Mediterranean mountain area of central Spain, in relation to landscape characteristics and climatic data. We test the fit of the badger occurrence pattern to the niche hypothesis predictions. Location We sampled twenty-four survey plots randomly distributed in the mountains of central Spain (Sierra de Guadarrama, Madrid): ten in the north and fourteen in the south slopes. All habitat types and climatic conditions typical of central Spain can be found. Methods The ocurrence of badgers ill the plots were recorded through an exhaustive search of setts and latrines in four different (and evenly spaced) points in each plot. The index of occurrence was made by dividing the number of positive points (badger presence) by the total number of points sampled (four in all plots). Landscape patterns (% type of habitat in each plot) were obtained from detailed maps and climate data from meteorological stations placed in the plot. We analyse the contribution of landscape variables and climate data to explain the differences in badger occurrence through Pearson correlations and fixed one-way ANCOVA with climatic data as fixed factor, vegetation cover as covariates and badger occurrence as response variable. Additionally, we use an one-way ANOVA to check the differences in occurrence between north and south plots with the location of each plot as fixed factor. Results The results indicate that the badger is more abundant in rainy areas of the mountains, and in open landscapes vegetated by ash-tree forests than in closed landscapes vegetated by helm oak forests. In addition, the species is more abundant in the northern plots than in the southern ones. Northern plots were homogeneous areas characterized by their open landscape and wet climate, while southern plots were characterized by their dry climate and closed landscapes. In addition, climate (measured as summer rain) is more determinant than habitat type (holm oak cover) to explain the pattern of badger occurrence. Main conclusions Overall, we consider that the typical Mediterranean landscapes are poor habitats for badgers due to changes in the environmental conditions associated with. concomitant changes in food resources. These data support the niche hypothesis to explain the changes in abundance or occurrence close to the edge of the distribution of species, and in particular, in Palearctic species in the Mediterranean area.
The following values have no corresponding Zotero field: pub-location: P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND publisher: BLACKWELL SCIENCE LTD
Keywords: Environmental factors; Mediterranean mountains; meles meles; niche hypothesis; species distributions

Epiphytic lichens and bryophytes of forest ecosystems in Tuscany (Central Italy) - Loppi, Stefano; Bonini, Ilaria; de Dominicis, Vincenzo (Cryptogamie Mycologie, 1999)
The distribution of epiphytic bryophytes and lichens on three species of trees (Quercus ilex, Quercus cerris and Fagus sylvatica, representing the forest ecosystems of central Italy at low, medium and high elevations, respectively) was examined with respect to host specificity and habitat differences. Although most species were host-specific, the results suggested that habitat characteristics are more important than phorophyte properties in determining the distribution of lichens and bryophytes. Factors affecting the diversity of the epiphytic flora were different for lichens and bryophytes. In the case of lichens, climatic parameters and forest monospecificity were important factors, whereas tree cover (i.e. shade) and to a certain extent the number of available trees seemed more important for bryophytes.
Keywords: distribution (voyant); epiphytic bryophytes; epiphytic lichens; forest ecosystems; Host specificity

Etiology of oak decline in Spain - Gallego, F. J.; de Algaba, A. Perez; Fernandez-Escobar, R. (European Journal of Forest Pathology, 1999)
In different areas of Extremadura, Western Spain, soil samples were taken at the bottom of holm oak (Quercus ilex) trees that were showing decline symptoms. Half of each sample was sterilized, and acorns were sown in both sterilized and nonsterilized soil samples. The resulting seedlings were used as baits for the isolation of fungi. Seedlings growing on the natural, nonsterilized substrate were characterized by having a lower vegetative growth than the ones growing on the sterilized soil samples, and most of them died. Phytophthora dnnamomi was consistently isolated from their roots. Fusarium oxysporum was also isolated as well as different species of Pythium, although to a lesser extent. Pathogenicity tests were performed on holm oak seedlings with five different isolates of P. chinnamomi, with F. oxysporum, Pythium and with a mixture of the three fungi. All the inoculated seedlings with P. chinnamomi developed root rot and grew slowly, and 35.7% of them died up to the end of the experiments. P. chinnamomi was consistently isolated from their roots, indicating that this fungus is the causal agent of holm oak decline. However, F. oxysporum caused similar symptoms on oak seedlings as P. chinnamomi, and was isolated also from the roots, although its frequency was lower than that of. P. cinnamomi.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Holm oak; Oak decline; Pathogenicity; Phytophthora cinnamomi (PG)

Factors controlling the emissions of volatile organic acids from leaves of Quercus ilex L.(Holm oak) - Gabriel, R.; Schäfer, L.; Gerlach, C. (Atmospheric Environment, 1999)
Direct emissions and emission of precursor compounds of acetic and formic acid from higher plants are a signiÞcant source of these acids in the atmosphere. To travel from the plant cell to the atmosphere, a gas molecule must Þrst leave the liquid phase and then enter the internal leaf gas phase. The apoplast (cell wall) is the last barrier before the molecule can escape through the stomata. During Þeld experiments we monitored the gas exchange (H 2 O, CO 2 , organic acids) of Quercus ilex L. leaves. The exchange rates of acetic and formic acid under Þeld conditions followed a typical diurnal pattern and ranged between!10 (uptake) and 52 (emission) nmol m~2 leaf area min~1 with the maximum around noon. Growth chamber experiments indicate that the emission is related to the stomatal conductance. We discussed the exchange rate of organic acids between the cell wall and the atmosphere in connection with HenryÕs law, and the physicochemical conditions in the cell wall. The evaluation showed that for apoplastic pH values between 4 and 5, 26Ð130% of the measured acetic acid emission based on leaf area could be predicted. ( 1999 Elsevier Science Ltd. All rights reserved.
Keywords: aba abscisic acid; Gas exchange; organic acids; Quercus ilex

Fine-resolution Upper Weichselian and Holocene palynological record from Navarrés (Valencia, Spain) and a discussion about factors of Mediterranean forest succession - Carrión, J. S.; Geel, B. Van (Review of Palaeobotany and Palynology, 1999)
A detailed study is presented of the Upper Pleistocene and Holocene pollen sequence of the Navarre´s peat deposit (Valencia, eastern Spain) including non-pollen palynomorphs, Characeae gyrogonites, seeds and charcoal abundance. The study covers the period from ca. 30,900 to 3160 yr B.P. The last glacial vegetation is characterised by Pinus–Artemisia– Ephedra assemblages. This dominance is interrupted between ca. 30,260 and 27,890 yr B.P. by the development of Quercus, Pinus pinaster, deciduous trees and Mediterranean shrubs, suggesting the proximity of glacial refugia and an expansion of their vegetation under inﬂuence of a milder climate. A Younger Dryas signal is noticed by increases of Artemisia and Ephedra around 10,380 yr B.P. There is no immediate response of Quercus to the Late Glacial and Holocene climatic ameliorations and Pinus continues to dominate the landscape until removed at ca. 5930 yr B.P., presumably by severe ﬁre events whose causes are discussed in the light of palynological, anthracological and paleoclimatical data
Keywords: Holocene; navarrés; paleoecology; pollen; quaternary; Spain; vegetation history; younger dryas

Geographical and seasonal influences on the distribution of fungal endophytes in Quercus ilex - Collado, J.; Platas, G.; GONZÁLEZ, I.; Pelaez, F. (New Phytologist, 1999)
A systematic survey of the endophytic assemblages of Quercus ilex in central Spain has been performed, with the goal of evaluating the importance of geographical and seasonal factors on these fungal communities. Four sampling sites were selected; one of them was sampled twice, in the spring and the autumn. The collected plant material consisted of bark, twigs and leaves from eight trees per site. Fungal strains were isolated with the use of a surface-sterilization method with sodium hypochlorite. A total of 2921 fungal strains grouped into 149 ‘species’ or morphological types were recovered. The 10 dominant species, with isolation frequencies >1.5%, were Pyrenochaeta sp., Periconiella anamorph of Biscogniauxia mediterranea (De Not.) Kuntze, Pseudonectria sp., Cryptosporiopsis quercina Petrak, Alternaria alternata (Fr:) Keissl., two undetermined coelomycetes, Penicillium funiculosum Thom, Diplodia mutila Fr. apud Mont. and Ascochyta sp. Medians of fungal species per tree were significantly different among the sampled sites. The isolation frequencies of the dominant species, as well as other less frequent species, were significantly dependent on the sampling site. The degree of endophytic infection and the diversity of fungal species were significantly higher in the spring. The frequencies of all dominant species at one of the sites depended significantly on the season, except for C. quercina, Acremonium sclerotigenum (F & V Moreau ex Valenta) Gams. and D. mutila. Cluster analysis of the whole endophytic mycoflora of the sampled trees suggested that the geographical factor affects the endophytic distribution patterns more significantly than the seasonal factor.
The following values have no corresponding Zotero field: publisher: Cambridge University Press
Keywords: fungal endophytes; geographical distribution; Quercus ilex; seasonal distribution; Spain

Habitat correlates of European rabbit (Oryctolagus cuniculus) distribution after the spread of RVHD in Cadiz Province, Spain - Fa, John E.; Sharples, Colin M.; Bell, Diana J. (Journal of Zoology, 1999)
European rabbit Oryctolagus cuniculus abundance was evaluated relative to habitat variables within two zones in Cadiz Province (south-east Spain), 2 years after the spread of rabbit viral haemorrhagic disease (RVHD). The study areas were low-lying regions of mixed pasture/agriculture, Mediterranean forest and matorral, west (Zone A) and east (Zone B) of the Sierra de Cadiz mountain chain. A total of 111 sites was selected to sample all existing habitat types. Relative rabbit density in each site was estimated using a pellet count method in one 5062 m transect. Mean pellet densities were 21.05 pellet m -2 in Zone B and signi®cantly lower, 5.85 pellets m -2 in Zone A. Physical variables, such as vegetation characteristics (density, height and patchiness of cover-layer vegetation, etc.), topographical characteristics and human in¯uences, cover-layer vegetation species (woody stemmed shrub species or trees forming dense stands), and ground-layer vegetation species (herbaceous species forming a low-lying layer) were determined within transects. In addition to these variables, soil types, rock type and land form, as well as the presence of aquifers, irrigation, and the proximity of rivers, were determined for each site. Signi®cantly higher pellet densities were found in mixed grassland/matorral and cork oak/matorral than in all other habitats. Pellet density was negatively correlated with density of ground-layer vegetation, while high pellet densities were associated with medium-height ground-layer vegetation (50±100 cm). The presence of Entisols was negatively associated with pellet density. The cover-layer species Pistacia lentiscus, Quercus coccifera, Quercus suber, Opuntia ®cus-indica and the ground-layer grasses all showed positive associations with pellet density, while the ground-layer species Echium gaditana and Scorpiurus vermiculatus were negatively associated with pellet density. Multivariate analyses identi®ed the mixed grassland/matorral and cork oak forest/matorral habitats as explaining most of the variation in pellet density. The height of cover-layer vegetation was negatively associated, while Opuntia and table-and/calcareous sandstone were positively associated, with mixed grassland/matorral. Distance from habitation and human impact were negatively associated and Quercus suber was positively associated with cork oak forest/matorral. Com- parison with previous studies suggest that the low pellet counts in this study represent very low rabbit densities and the population as a whole appears depleted and fragmented
Keywords: habitat; oryctolagus cuniculus; rabbit viral haemorrhagic disease; Spain

Heavy Metals in Moss and Bark From Urban Area of Florence: A New Cleaness Procedure for Removing Superficial Particulate Matter - Ducceschi, L.; Legittimo, P. Cellini; Bonzi, L. Morassi (Chemistry and Ecology, 1999)
Abstract Hypnum cupressiforme epiphytic moss and tree bark (elm and holm oak) samples have been collected in three sites of the city of Florence in the period 1995?1998. Lead, zinc, copper, and cadmium were determined by differential pulse anodic stripping voltammetry (DPASV) in about 200 samples collected at different heights above ground. A new clean-up procedure by nitrogen jet has been followed and its efficiency has been also verified by electron microscopy (SEM and ESEM techniques). Lead median contents in moss and bark samples fall within the ranges of 0.052?0.86 and 0.20?1.30 ?moles g?1 (dry weight), resulting values for moss and bark are proportional to the vehicular traffic density. the increasing use of lead-free gasoline has not been followed by a decrease of lead moss concentration.
doi: 10.1080/02757549908037642doi: 10.1080/02757549908037642The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: Bark; biomonitoring; environmental scanning electron microscopy (ESEM); Heavy metals; Moss

Improving the use of lichens as biomonitors of atmospheric metal pollution. - Branquinho, C.; Catarino, F.; Brown, D. H.; Pereira, M. J.; Soares, A. (The Science of the total environment, 1999)
The data reported on this study supported the hypothesis that the absence of the lichen Ramalina fastigiata near a copper mine site located on the south of Portugal was related to toxic levels of Cu-dust near the centre of the mine. Lichen biodiversity reflected the impact of the copper-mine dust emissions which were more widespread towards the east, correlated with wind direction and frequency. The chemical analysis of R. fastigiata collected at different distances and in different directions from the mine showed that Cu, K and Mg were derived from the centre of the mine site, confirming thus as the major source of atmospheric dust. Total inhibition of PSII photochemical reactions occurred in R. fastigiata both under field and controlled conditions, when intracellular Cu concentrations exceeded a threshold of approximately 2.0 mumol g-1. No samples of this species were found under field conditions beyond the Cu threshold. Thus, the fluorescence parameter Fv/Fm proved to be a good estimator of the survival capacity of R. fastigiata under field conditions and thus a useful parameter in determining the sensitivity of the lichens (photobiont) to Cu pollution. The intracellular location of Cu allowed an explanation of the physiological changes and the survival of the species in the surroundings of the copper-mine.
The following values have no corresponding Zotero field: accession-num: 10474262
Keywords: Atmospheric dust pollution; Cellular location of Cu; chlorophyll fluorescence; Cu-mine; Fv Fm; Intracellular Cu; K and Mg; Lichen biodiversity; lichens; Ramalina fastigiata

Influence of increased atmospheric CO2 concentration on quality of plant material and litter decomposition - Coûteaux, Marie-Madeleine; Kurz, Cathy; Bottner, Pierre; Raschi, Antonio (Tree Physiology, 1999)
Nitrogen (N) and lignin concentrations in plant tissues and litter of plants grown in greenhouses or open-top chambers in elevated atmospheric CO2 concentration were compared with those of plants grown in ambient air in short-term studies. We also compared the N concentration of plant material of Quercus ilex L. and Q. pubescens Willd. growing in the vicinity of natural CO2-springs with that of the same species growing at a control site. In the short-term studies, elevated CO2 caused significant decreases in tissue N concentration and the extent of the decrease varied with species. Nitrogen amendment of the soil lessened the CO2-enrichment effect. Lignin concentration was modified by elevated CO2 and the effect was species specific, but no general positive or negative trend was evident. A comparison of trees growing under natural conditions near a natural CO2-spring and at a control site revealed no site differences in N concentration of the plant material. A comparison of published results on decomposition rates of litter produced in elevated atmospheric CO2 and in ambient air indicated that CO2 enrichment can cause both enhancements and decreases of carbon mineralization. We conclude that (1) long-term responses to elevated CO2 could differ from the results obtained from short-term studies and that (2) biodiversity could be an important factor altering the sign of the feedback on atmospheric CO2 concentration. We also discuss the implications of our finding of a long-term, inhibitory effect of the initial N concentration of litter on the decomposition rate of litter and its consequence on ecosystem feedback.
10.1093/treephys/19.4-5.30110.1093/treephys/19.4-5.301
Keywords: Biodiversity; Carbon dioxide; Global change; lignin content; nitrogen content

Laccase activity of forest litter - Criquet, S.; Tagger, S.; Vogt, G. (Soil Biology and Biochemistry, 1999)
Laccases are blue-copper enzymatic proteins involved in the transformation of polyphenolic compounds, such as lignin, into forest litter. A method to measure their activity was developed using an evergreen oak litter as a model system. We considered factors that aect the extraction of these enzymes and the measurement of their activity. The factors studied included powdering of the leaves, adding polyvinylpolypyrrolidone or Tween 80, adsorption of enzymes on centrifugation pellets, concentration of the extracts, nature and molarity of the extraction solvent, amount of powdered leaves used for enzymatic extraction, extraction time, pH, and temperature during the measurement of the activity
Keywords: Extraction; laccase; litter

Mediterranean vegetation dynamics: modelling problems and functional types - Pausas, J. G. (Plant Ecology, 1999)
Gap models have been applied to a wide range of ecosystems, mainly temperate and boreal forests, but rarely have such models been applied to Mediterranean ecosystems. In the present review we address some problems of gap models for predicting the long-term dynamics of Mediterranean ecosystems, and we suggest plant functional types suitable for modelling based on responses to disturbance. Most gap models do not take into account different life forms, interactions with ﬁre (e.g., resprouting and stimulation of the germination), and underground structures. Long term human impact on Mediterranean ecosystems has made a signiﬁcant impact on the current landscapes. That intense land use, involving long-lived slow-growing species, has had long-term consequences. It is not possible to understand Mediterranean vegetation and to validate any model without considering these factors. The lack of data for Mediterranean species may be overcome by taking into account correlations of traits and trade-offs between different functional types. A simple disturbance-based functional group system is discussed.
Keywords: disturbance; Fire ecology; gap models; Mediterranean; resprouting

metal contents in Parmelia caperata(L.) Ach. compared to bulk deposition, throughfall and leaf-wash fluxes in two holm oak forests in Montseny (NE Spain) - Rodrigo, A.; Avila, A.; Gómez-Bolea, A. (Atmospheric Environment, 1999)
The metal concentrations of V, Cr, Co, Ni, Cu, Zn, Cd, Hg and Pb were analysed in distilled water extracts of Parmelia caperata and in bulk deposition, throughfall and an experimental in situ washing of leaves at two forests at Montseny (NE Spain) submitted to di¤erential exposure to the industrial and tra¦c activities around Barcelona. Lichen concentra- tions of Zn, Cu, V, and Cd were higher at the site of greater exposure to pollutants. Consistently, there was higher dry deposition of these metals at the more exposed site. The order of abundance of trace metals in the lichen was similar to that in the deposition variables, although Pb and Cu had intermediate concentrations in the lichen but were very low in the deposition measurements. This indicated the higher a¦nity of Pb and Cu for the exchange sites in the lichen cell wall and the fact that lichens accumulated Pb for the last 12Ð18 y when emissions were much higher than today. The ability of Parmelia caperata to indicate the deposition of heavy metals, together with its easy sampling and handling, its broad distribution and its easy identiÞcation suggest that the lichen extract procedure described here could be used to establish gradients of atmospheric deposition of heavy metals at a general geographic level
Keywords: atmospheric deposition; bulk deposition; parmelia caperata; Quercus ilex; throughfall; trace metal

Modelling leaf gas exchange in holm-oak trees in southern Spain - Infante, J. M.; Damesin, C. (Agricultural and Forest …, 1999)
This paper presents a mechanistically based C3 leaf CO2 assimilation model linked with an empirical stomatal model to simulate Quercus ilex leaf net photosynthesis and transpiration in oak-savannah ecosystems of southern Spain. The model estimates (time integration) daily and seasonal changes in carbon ®xation, transpiration, and water use ef®ciency of a single leaf in free air. Simulations were carried out on two trees for a dry year. Results shown in our study demonstrate that the modelling approach, compared to ®eld measurements, provides a realistic description of diurnal and seasonal patterns of leaf gas-exchange response to different environmental conditions, and as affected by water availability
Keywords: carbon dioxide assimilation; Drought; leaf gas exchange; oak savannah; photosynthesis model; Quercus ilex

PARÁMETROS PRODUCTIVOS Y REPRODUCTIVOS EN UN REBAÑO DE OVINO TALAVERANO DURANTE LA TRANSFORMACIÓN EN PASTOS DE UN CULTIVO - López-Carrasco, C.; Rodriguez, R.; Robledo, J. C. (Pastos, 1999)
The aim of the present paper is to evalúate the effects of phosphate fertilization on animal performance in a trial of pasture regeneration on an abandoned oat culture in a dehesa system at NW of Toledo province (Spain), during four consecutive years. Fertility, prolificacy and other productive features (meat production, flock live weight evolution , stocking rate, etc.) were compared between an abandoned culture with or without fertilisation and a semi-natural pasture. Reproductive Índices were similar between treatments across experimental period. Live weight variations and body condition were affected by years through the different pasture production; the results of fertilized pastures were better than natural pasture, especially in wet springs. Although the stocking rate was higher in fertilised pasture than in natural pasture, meat production (kg lamb/ha) was similar for both treatments. If higher stocking rates had been established meat production (kg/ha) could have been increased according to the results of pasture production, live weight and body condition. The low number of weaned lambs per ewe at tupping and the difficulties to adjust the stocking rates, limited the positive effects of fertilization. Key
Keywords: dehesa system; fertilized pasture; meat production; Pastures regeneration

Penetration of UV-A, UV-B and blue light through the leaf trichome layers of two xeromorphic plants, olive and oak, measured by optical fibre microprobes - Karabourniotis, George; Bornman, Janet F. (Physiologia Plantarum, 1999)
Quartz fibre-optic microprobes were used to monitor the light microenvironment beneath trichome layers of the xeromorphic leaves of two Mediterranean evergreen sclerophylls, Olea europaea and Quercus ilex. Young developing leaves of both plants were densely pubescent on both surfaces of the lamina, whereas the mature leaves were pubescent only on the abaxial side. Trichome layers of young as well as of mature leaves of both plants attenuated almost all incident ultraviolet (UV)-B (310 nm) and UV-A (360 nm) radiation and a considerable portion of blue light (430 nm). Abaxial trichome layers of young leaves were more effective in screening out the incident radiation compared to the adaxial ones of the same leaves and also compared to the abaxial layer of the mature leaves. The abaxial epidermis of dehaired mature leaves of O. europaea was ineffective in absorbing most of the incident UV-B and UV-A radiation. UV and visible spectra beneath trichome layers of O. europaea in mature leaves confirmed that the light microenvironment on the epidermis was deprived in the UV-B, UV-A and partly in the blue spectral regions. It is proposed that the occurrence of a dense trichome layer, especially in young leaves, may play a protective role against not only UV-B radiation damage, but also against high visible irradiance. This function is performed irrespective of the differing anatomy of individual hairs of both plants. The protection provided by the trichomes could afford advantages under stress conditions, especially during leaf development.
The following values have no corresponding Zotero field: publisher: Munksgaard International Publishers
Keywords: Abaxial; Adaxial (voyant); leaves; light; trichome layers

Plant functional types and ecosystem function in Mediterranean shrubland - Barradas, Díaz; Zunzunegui, M. (Journal of Vegetation Science, 1999)
This study attempts to identify Plant Functional Types (PFTs) within the scrub vegetation of the stabilized sand dunes of the Doñana National Park (southwestern Spain) and to explore possible links with ecosystem function. Two 10-km long transects were sampled along a gradient of water table depth from elevated and dry dunes to a border area close to the salt marsh. A matrix of cover values for 20 woody species × 58 plots and a matrix of 24 morphological and physiological traits × 20 species were analysed by means of DCA and TWINSPAN to identify the main vegetation types and PFTs. In order to know the predominant plant traits, the matrix of 20 species × 58 plots was multiplied by the 24 traits × 20 species matrix. The resulting 24 traits × 58 plots matrix was analysed by means of DCA. The main vegetation types coincide with the previous descriptions of the Park with Juniperus phoenicea woodland and xerophytic species dominating the top of the dunes and hygrophytic species with isolated Quercus suber trees in the depressions. Previous classifications of Mediterranean woody plants resulted in two main PFTs. The present analysis confirmed these two groups: maquis versus garrigue, but added four new groups. The analysis of the traits × plots matrix revealed that the main trend of variation is related to the water table gradient, while the traits related to the species of mature plant communities had little weight in the analysis because these communities are restricted to isolated patches.
Keywords: Doñana; Plant trait; Regeneration; water potential; Water table depth

Relation between climate and vegetation along a Mediterranean-Temperate boundary in central Italy - Blasi, C.; Carranza, M. L.; Filesi, L.; Tilia, A.; Acosta, A. (Global Ecology and Biogeography, 1999)
The relationship between climate and vegetation was investigated along a Mediterranean-Temperate boundary in central Italy. The study area is a transition zone between the Temperate (Eurosiberian) and Mediterranean regions and has an altitudinal range of almost 1750 m. Ordination and cluster analysis were used. The results did not show any sharp boundary but a climate-vegetation mosaic ranging from upper mountain thermotype and lower hyperhumid ombrotype with Fagus sylvatica L. woodlands at higher altitudes, to meso-Mediterranean thermotype and lower subhumid ombrotype with Mediterranean maquis and Quercus ilex L. woods on the coast. Six phytoclimatic groups are distinguished and described in terms of climatic parameters, vegetation types and morphological and chorological traits. These parameters indicate a change without sharp discontinuities between groups. The Mediterranean to Temperate transition in this Tyrrhenian sector is broad and includes most of the study area.
The following values have no corresponding Zotero field: publisher: Blackwell Science Ltd
Keywords: bioclimatology; climatic indices; Mediterranean vegetation; phytoclimatic groups; temperate woodlands; transition areas

Relations entre la qualité du liège, sa composition minérale et la composition minérale des feuilles du chêne-liège (Quercus suber L.) - Courtois, Michèle; Masson, Philippe (Ann. For. Sci., 1999)
Relationships between the quality of cork, its inorganic content and the inorganic content of the leaves of the cork-oak (Quercus suber L.). The aim of this work is to set up a relationship between the quality of cork, its inorganic content and the inorganic content of the leaves of the cork-oak. The mineral contents of both leaves and cork were identified for a range of elements (nitrogen, phosphorus, potassium, calcium, magnesium, iron, copper, zinc and manganese). The quality of the cork was evaluated by experts in the cork industry on the basis of visual assessment of cork stoppers resulting from each tree. A study of correlations between the cork inorganic contents and the quality of cork demonstrates that, among those measures, only the potassium content of cork is related to the cork quality. The cork quality seems to be independent of the leaf inorganic content, which is held to be an indicator of the cork-oak mineral nutrition. (© Inra/Elsevier, Paris.)
Keywords: Cork; inorganic content; leaf; Quality; Quercus Suber L

Role of Photoprotective Systems of Holm-Oak (Quercus ilex) in the Adaptation to Winter Conditions - García-Plazaola, Josá I.; Artetxe, Unai; Duñabeitia, Miren K.; Becerril, Josá M. (Journal of Plant Physiology, 1999)
Holm-oak (Quercus ilex L.) is a Mediterranean evergreen sclerophyllous species adapted to a wide range of environmental conditions and consequently its leaves must be able to withstand variable stresses. Changes in pigment and antioxidant composition were assessed in relation to chilling stress, light environment and leaf aging. Photosynthetic capacity during winter was rwo-fold higher than in spring. However, the photochemical efficiency of PSI! was reduced in sun leaves probably because of an increased rate of thermal energy dissipation related to the superior zeaxanthin concentration. Lutein, neoxanthin, ~-carotene and the xanthophyll cycle pool increased during winter especially in sun leaves, while lutein epoxide and a-carotene decreased markedly. The main antioxidant accumulated during winter was ascorbate, while glutathione and a-tocopherol were not seasonally affected. Catalase increased in spring as a consequence of higher photorespiration rates, while GR and MOHAR activities were higher in sun leaves during winter. The high MOHAR activity indicates an important role for this enzyme in the adaptation to environmental factors associated to winter. The present study demonstrates that holm-oak is able to acclimate to a variety of environmental stress factors by inducing dramatic changes in their photosynthetic characteristics, pigment composition and antioxidant defences.
Keywords: antioxidants; chilling; Mediterranean evergreens; Quercus ilex; sun/shade; xanthophylls

Sexual reproduction in the cork oak (Quercus suber L.). I. The progamic phase - Boavida, L. C.; VARELA, M. C.; Feijo, J. A. (Sexual Plant Reproduction, 1999)
Cork oak (Quercus suber L.) is a monoecious wind-pollinated species with a protandrous system to ensure cross-pollination. To the best of our knowledge, this report provides the first insight into the sexual reproduction cycle in this species. The cork oak flowering season extends from April until the end of May. Our results show that, at anthesis, the pistillate flower is not completely formed and ovules are just starting to develop. Pollen reaching the dry stigmatic surface adheres to the receptive cells, germinates and penetrates the epidermis in aproximately 24 h, and grows through the intercellular spaces of a solid transmitting tissue. In cross-pollination, a sequential arrest of pollen tubes was observed along the style, providing preliminary evidence for a pollen tube competition mechanism. As a consequence, few pollen tubes reach the basal portion of the style. Furthermore, pollen tube growth is a discontinuous process since tubes are arrested in the basal portion of the style about 10–12 days after pollination. While tubes are latent, the ovarian loculus starts to develop from an emerging mass of sporogeneous cells which later will differentiate into the placenta and ovules. One and a half months after pollination ovules complete their differentiation, tubes resume growth and fertilisation occurs. Ovular abortion is frequent at this stage, and only one ovule will successfully mature during autumn into a monospermic seed.
Keywords: Cork oak; Ovule abortion; Pollen tube arrest; Pollen tube competition; Quercus suber

Short-term responses of terpene emission rates to experimental changes of PFD in Pinus halepensis and Quercus ilex in summer field conditions - Penuelas, J.; Llusia, J. (Environmental and Experimental Botany, 1999)
The diurnal relationships of monoterpene emission with PFD and photosynthetic rates were studied in the Mediterranean trees Pinus halepensis, a terpene storing species, and Quercus ilex, a non-storing species, under summer ﬁeld conditions. At morning, midday and evening, leaves were submitted to different irradiance levels by differentially shading them. Both species emitted large amounts of monoterpenes (about 20 mg g DM1 h1 ). The most emitted terpene by P. halepensis was D 3 -carene followed by b-myrcene, a-pinene and b-pinene. The most emitted terpene by Q. ilex was limonene followed by a-pinene and b-pinene. No clear correlation to temperature was found for Q. ilex emission within the diurnal range of 21–33°C, whereas P. halepensis emissions increased with the temperature. There was no consistent link between terpene emissions and PFD or photosynthetic rates for P. halepensis but there were signiﬁcant relationships for Q. ilex. However, emissions by Q. ilex became inhibited at highest PFDs and during the course of the day when net photosynthesis decreased under summer drought. The study shows that the emission rates of both species are highly variable and that during a hot Mediterranean summer day (with limited water availability) the diurnal variation of emission is not only driven by the common light and temperature dependencies. Water stress, branch-to-branch variability and other inﬂuences must explain great part of the observed variability
Keywords: a-pinene; d 3 -carene; field conditions; limonene; pfd; photosynthetic rate; Pinus halepensis; Quercus ilex; Temperature; Terpene emission

Terpenoid emissions of Mediterranean oaks and their relation to taxonomy - Csiky, O.; Seufert, G. (ECOLOGICAL APPLICATIONS, 1999)
This paper presents results of a laboratory screening study of biogenic emissions from Mediterranean oak species. The experiment aimed at improving our understanding of oak contributions to overall emissions of volatile organic compounds and to the atmospheric chemistry in the Mediterranean area. We measured type and amount of terpenoid emissions (isoprene, mono- and sesquiterpenes) under standard conditions of light and temperature from 14 different Quercus species of Mediterranean and American origin. Tree saplings were exposed in a controlled environment chamber, and leaf-level trace-gas exchange was analyzed with a minicuvette system and gas chromatography, to study the relation between the emission types and emission spectra found and the taxonomy of Quercus. The holarctic group Lepidobalanus and the North American groups Erythrobalanus and Protobalanus were found to be strong isoprene emitters. The Eurasian oak group Sclerophyllodrys emits monoterpenes; Cerris include mostly non-emitters, but also an isoprene and a monoterpene emitter has been found in this group. Results are discussed with respect to their implications for presently used emission scenarios.
The following values have no corresponding Zotero field: pub-location: 1707 H ST NW, STE 400, WASHINGTON, DC 20006-3915 USA publisher: ECOLOGICAL SOC AMER
Keywords: atmospheric chemistry; BEMA (Biogenic Emissions in the Mediterranean Area; Biogenic emission; chemo-taxonomy; isoprene; Mediterranean Region; Monoterpenes; oak taxonomy; oaks; Quercus; terpenoid emissions; trace-gas exchange; volatile organic compounds (VOCs)

Treatment of oak decline using pressurized injection capsules of antifungal materials - Fernandez-Escobar, R.; Gallego, F. J.; Benlloch, M.; Membrillo, J.; Infante, J.; de Algaba, A. Perez (European Journal of Forest Pathology, 1999)
Quercus ilex and Quercus suber trees growing at several sites in Extremadura, Western Spain, that were showing symptoms of oak decline were injected with potassium phosphonate, quinosol or carbendazim using a low-pressure method of trunk injection composed of a pressurized capsule system. A team of four people injected between 120 and 189 trees per day, depending upon the density of the undergrowth vegetation. This labour cost represented, approximately, 15–20% of the total cost of the treatment. The potassium phosphonate-injected trees showed a significant improvement in vegetative growth within 2 years of the injection treatment, and they also showed some recovery from the decline symptoms during the third year. Only one injection treatment of an average of 3.5 capsules (corresponding to 24.5 g phosphonic acid) per tree of approximately 36 cm in diameter, was necessary to reduce the disease severity significantly. Indirectly, these results corroborate the implication of Phytophthora cinnamomi in oak decline within Spanish Quercus woodlands.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Oak decline; phosphonic acid; trunk injections (PG)

Urethanes and polyurethanes from suberin 2: synthesis and characterization - Cordeiro, N.; Belgacem, M. N.; Gandini, A.; Neto, C. P. (INDUSTRIAL CROPS AND PRODUCTS, 1999)
Polyurethanes based on suberin from cork of Quercus suber L. and conventional isocyanate monomers were prepared and fully characterized in terms of both structure (FTIR and H-1 NMR spectroscopy) and thermal properties (differential scanning calorimetry and thermogravimetric analysis). Two fractions were systematically isolated, namely (i) methylene-chloride soluble products, which corresponded to linear and branched macromolecules and (ii) methylene-chloride insoluble products, representing the crosslinked material. The structures of these polymers were regular and no appreciable side reactions were detected. DSC analyses provided information about the glass transition temperature of both fractions and this parameter was correlated with the stiffness of the isocyanate used. The TGA of these polyurethanes showed that they started to degrade at about 175 degrees C and that the residue at 400 degrees C was around 50%. The highest amounts of insoluble fractions, as well as the highest T-g,s, were reached when an initial \{[\}NCO]/\{[\}OH] of unity was used. (C) 1999 Elsevier Science B.V. All rights reserved.
The following values have no corresponding Zotero field: pub-location: PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS publisher: ELSEVIER SCIENCE BV
Keywords: Cork; glass transition; polyurethanes; Quercus suber L.; suberin; thermal properties

Variability of suberin composition of reproduction cork from Quercus suber throughout industrial processing - Conde, E.; GARCIA-VALLEJO, M. C.; Cadahia, E. (HOLZFORSCHUNG, 1999)
The chemical composition of suberin was studied in cork planks fromthree different trees of Spanish Quercus suber at four different stages of the industrial processing of first transformation: stripping (a), first rest (b), boiling followed by open air rest (c1) and boiling followed by store-room rest (c2). The monomeric composition was determined by gas chromatography/mass spectrometry in the product of depolymerization of the free of extractives cork with sodium methoxide-methanol. The average concentrations of the main monomers were: 1-alkanols (C-20-C-26) 4.17 %; alkanoic acids (C-20-C-26) 5.99 %; alpha, omega-alkanedioic acids (C-16-C-24) 6.20 %; omega-hydroxy-alkanoic acids (C-20-C-26) 29.41 %; erythro- and threo-9, 10-dihydroxyoctadecanedioic acids 6.76 %, erythro- and threo-9,10,18-trihydroxyoctadecanoic acids 9.50 %, 9,10-epoxy-18-hydroxyoctadecanoic acid 2.72 % and 9,10-epoxy-octadecanedioic acid 2.93 % and ferulic acid 5.05 %. Significant differences were observed between samples taken at the stripping and after boiling with store room rest, and both groups of samples differed from those picked after the other two processing stages. Ten components were selected as providing the greatest discrimination among stages: 9-octadecenedioic, 18-hydroxy-9-octadecenoic, eicosanedioic and 9,10-epoxy-18-hydroxy-octadecanoic acids, tetracosanol, and five unidentified components.
The following values have no corresponding Zotero field: pub-location: GENTHINER STRASSE 13, D-10785 BERLIN, GERMANY publisher: WALTER DE GRUYTER & CO
Keywords: Quercus suber; suberin; cork; industrial processin

Waxes composition of Quercus suber reproduction cork from different Spanish provenances - Conde, E.; GARCIA-VALLEJO, M. C.; Cadahia, E. (Wood Science and Technology, 1999)
The chemical composition of waxes was studied in Quercus suber cork planks collected in seven localities of the three main production areas of Spain. Waxes were extracted with chloroform (CHCl3 ) and the extract was submitted to saponi®cation in order to obtain the neutral and acid fractions. The trimethylsilyl derivatives of both fractions were analysed by GC-MS. The seven populations cannot be distinguished by their total contents of waxes (Chloroform extract) and of the neutral and acid fraction. This lack of differences could be due to the important variability among samples of each population. The neutral fraction was mainly composed of fatty alcohols (all the even members from C18 to C26 , with traces of the intermediate odd members and some unsaturated groups) and triterpenes (11 components, among them friedelin, betulin and cerin were identi®ed) and a very small amount of monocarboxylic fatty acids (C16 and C24 members) was also present. The main group of compo- nents of the acid fraction was that of fatty acids (saturated even C14±C24 and odd C15 , C17 , C21 members, accompanied by a great amount of unsaturated terms and some x-hydroxyacids, 18-hydroxy-9,12-octadecadienoic and 18-hydroxy-9-oct- adecenoic acids). Four triterpenes and the C20 and C24 alcohols were also detected in the acid fraction. Signi®cant differences were found among the corks of the various provenances in the global contents of alcohols and triterpenes and in these individual components contents of the neutral fraction. Concerning the differences among the various provenances in the contents of the groups of fatty acids, alcohols, and triterpenes in the acid fraction, a higher number of differ- ences were obtained in the comparisons of the contents of acids and triterpenes, whereas the differences were practically null in the case of the alcohols. When the differences were studied considering the individual compounds, the relation with the behaviour of the contents of the groups of components was not as clear as it happens in the neutral fraction. In this case, the differences were scarcer and they did not show a unique pattern, neither in the components, nor the populations. There is no correspondence in the differences among the provenances regarding the components of the neutral fraction or those of the acid fraction. No clear relationship was found between the geographical proximity of the provenances and chemical similarity of the waxes composition.
Keywords: Acid fraction; component (voyant); Cork; neutral fraction; provenance; waxes

Waxes composition of reproduction cork from Quercus suber and its variability throughout the industrial processing - Conde, E.; GARCIA-VALLEJO, M. C.; Cadahia, E. (Wood Science and Technology, 1999)
The chemical composition of waxes was studied in cork planks from three different trees of Spanish Quercus suber at four different stages of the in- dustrial processing of the ®rst transformation: stripping, ®rst rest, boiling fol- lowed by open air rest and boiling followed by store-room rest. Waxes were extracted with chloroform (CHCl3 ) and the extract was submitted to saponi®cation in order to obtain the neutral and acid fractions. The trimethylsilyl derivatives of both fractions were analysed by GC-MS. An important decrease of the total content of waxes -CHCl3 extract-(average values: 10.13 to 4.91%) and of the acid fraction (average values: 2.51 to 0.96%) was observed throughout the industrial processing. Some differences were also found among trees, two of them being richer in total waxes (average, 8.14 and 7.71%) than the other one (average, 4.67%). Concerning the three groups of identi®ed components (fatty acids, fatty alcohols and triterpenes), the contents of the fatty alcohols and acids suffer an important reduction during the ®rst rest (average values: 30.39 to 17.53% and 58.73 to 31.48%, respectively), while after boiling, there is a decrease of the triterpenes concentrations (79.16 to 58.00% -neutral fraction- and 40.23 to 23.20% -acid fraction-), being greater when the second rest is carried out in a store room. Signi®cant differences among trees were only found in the fatty alcohols contents. The neutral fraction was mainly composed by fatty alcohols (all the even members from C18 to C26 , with traces of intermediate odd members and some unsaturated groups, C20 and C21 ) and triterpenes (14 components, among them friedelin, betulin and cerin were identi®ed), and a very small amount of monocarboxylic fatty acids (C16 , C18 , C22 and C24 members) was also present. The main group of components of the acid fraction was that of fatty acids (saturated even C12±C24 and odd C15 , C17 , C21 members, accompanied by a great amount of unsaturated terms and some x-hydroxyacids, 18-hydroxy-9,12-octadecadienoic and 18-hydroxy-9-octadecenoic acids). Four triterpenes, the C20 , C24 and C28 alcohols and ferulic acid were also detected in the acid fraction. Some of these individual components of each fraction were also affected by the industrial processing and presented signi®cant differences among the studied trees.
Keywords: Acid fraction; component (voyant); Cork; indutrial processing stage; neutral fraction; waxes

Analysis of dehesas with multiple use. Physical and economic indexes of sustainable management - Garcia, F. P.; Sanchez, M. E.; Diaz, F. J. M.; Vega, A. R. D. (BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS, 1998)
The wide surface that dehesas hold in Spain, together with their economic, social and environmental importance, give enough justification to the researchs that widen the scientific knowlege about the economics of dehesa systems. However, the dehesa agroforestry farms do not appear in the different statistical documentary sources of the Agricultural Accounting Net. The lack of technical-economic data about these systems impede neither to observe the effects of the Common Agricultural Policy on the natural environment, nor to know as a whole the dynamics and structure of their flows and the stock of resources and income. This paper deals with the technical and economic management of dehesas in the field of the environmental economics. Its main aim has been to carry out an analytical case study. In order to develop it, four dehesa farms in the Southwest of the Badajoz Province were selected. These farms have collaborated on the development of the Research Project UE CAMAR CT 90-28 ``Technical and economic analysis of dehesa and montado systems{''}. Its importance lies in the basis of the case analysis, with a description of the systems and an identification of the structure and dynamics of their resources, either at physical and economic level.
The following values have no corresponding Zotero field: periodical: BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS issue: 90 pub-location: POSTBUS 220, 6700 AE WAGENINGEN, NETHERLANDS
Keywords: Dehesa; environmental econ; sustainable management

Analysis of vegetation response to naturally occurring gaps in old-growth forests of Quercus ilex L. in Corsica - Panaiotis, C.; Loisel, R.; Roux, M. (CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE, 1998)
Green oak (Quercus ilex L.) is the most common forest species growing under Mediterranean climate. Because of important past anthropic perturbations, green oak old-growth forests are very unfrequent and constitute, for that reason, a most interesting domain where to analyze the natural evolution of green oak stands. Such forests exist in Corsica and this study deals with vegetation successions as they occur in naturally occuring gaps. Because of the taxonomic poorness (32 species), two statistical tools (canonical correspondence analysis and random permutations) were used to take into account vegetation spatial structure according to types (herbaceous, shrubby, or arborescent). These statistical analyses show that plant succession does not really exist in gaps of green oak old-growth forests but rather a structural organization of common species found in the maquis. Results support the hypothesis about the internal dynamics of these forests going through a maquis phase.
The following values have no corresponding Zotero field: pub-location: RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA publisher: NATL RESEARCH COUNCIL CANADA
Keywords: natural gaps; quercus ilex forest; spatial structure; vegetation succession

Anaphylactic reaction to ingestion of Quercus ilex acorn nut - Vega; DomÍnguez; Cosmes; MartÍnez; BartolomÉ, B.; Palacios; Vega, a; Domínguez, C.; Cosmes, P.; Martínez, a; BartolomÉ, B.; Martínez, J.; et al. (Clinical & Experimental Allergy, 1998)
Background A patient experienced an anaphylactic reaction after eating acorn nuts, fruit of the holm oak (Quercus ilex), one of the most abundant trees in Spain. Several urticaria episodes upon ingestion of peanuts were also referred. Objective To assess the hypersensitivity reaction to acorn and to characterize the allergenic proteins involved. Methods Cutaneous tests were performed using the skin-prick technique, using a large variety of grass, tree and weed pollens as well as fresh nuts and nut extracts. Specific IgE determination was assessed by RAST. IgE binding bands were determined by SDS-PAGE immunoblotting. Results Skin-prick tests were strongly positive with acorn and peanut. Olea europaea, Quercus alba, Quercus ilex and grass pollens also elicited a weal higher than negative control. Patient serum had measurable levels of IgE antibodies especially to acorn, peanut and grass pollens. Only one protein band, of 17.9 kDa molecular mass, showed IgE-binding properties in the acorn extract. The possible homology of this strong allergenic protein with the group 1 tree pollen allergens was evidenced by the partial inhibition of the western blot with Bet v 1. Conclusions We present a case of anaphylaxis to acorn ingestion as demonstrated by in vivo and in vitro results. A 17.9 kDa IgE-binding band, showing some homology to group 1 pollen tree allergens, was recognized by patient serum.
The following values have no corresponding Zotero field: publisher: Blackwell Science Ltd, UK accession-num: 9677139
Keywords: acorn allergens; Anaphylaxis; Anaphylaxis: drug therapy; Anaphylaxis: etiology; Bet v 1; Cross Reactions; Electrophoresis; Food Hypersensitivity; Food Hypersensitivity: drug therapy; Food Hypersensitivity: etiology; Humans; Immunoblotting; Immunoglobulin E; Immunoglobulin E: blood; Male; Middle Aged; nut allergy; Nuts; Nuts: adverse effects; Nuts: immunology; Polyacrylamide Gel; Quercus ilex allergy; Radioallergosorbent Test; Skin Tests

Biogenic emissions by oak trees common to Mediterranean ecosystems - Simon, V.; Dutaur, L. (Environmental Monitoring and Assessment, 1998)
An inventory describing the fluxes of volatile organic compounds (VOCs), isoprene and monoterpenes, and other VOCs (OVOCs) from the biosphere to the atmosphere, has been constructed within the framework of the ESCOMPTE project (fiEld experimentS to COnstrain Models of atmospheric Pollution and Transport of Emissions). The area concerned, located around Berre-Marseilles, is a Mediterranean region frequently subject to high ozone concentrations. The inventory has been developed using a fine scale land use database for the year 1999, forest composition statistics, emission potentials from individual plant species, biomass distribution, temperature and light intensity. The seasonal variations in emission potentials and biomass were also taken into account. Hourly meteorological data for 1999 were calculated from ALADIN data and these were used to predict the hourly isoprene, monoterpene and OVOC fluxes for the area on a 1 km × 1 km spatial grid. Estimates of annual biogenic isoprene, monoterpene and OVOC fluxes for the reference year 1999 were 20.6, 38.9 and 13.3 kt, respectively, Quercus pubescens, Quercus ilex, Pinus halepensis and garrigue vegetation are the dominant emitting species of the area. VOC emissions from vegetation in this region contribute approximately 94% to the NMVOC (non-methane volatile organic compounds) of natural origin and are of the same order of magnitude as NMVOC emissions from anthropogenic sources. These results complete the global ESCOMPTE database needed to make an efficient strategy for tropospheric ozone reduction policy.
Keywords: biogenic VOCS; Emission inventory; isoprene; Mediterranean ecosystems; Monoterpenes (citation)

Changes in Tannic Composition of Reproduction Cork Quercus suber throughout Industrial Processing - Cadahía, Estrella; Conde, Elvira; Fernández de Simón, Brígida; García-Vallejo, María Concepción (Journal of Agricultural and Food Chemistry, 1998)
Tannic composition was studied in reproduction cork samples from three different trees of Spanish Quercus suber and at different industrial processing stages. The ellagitannins, roburins A and E, grandinin, vescalagin, and castalagin, were identified and quantified by HPLC. Global evaluations of tannins were also carried out, using classical chemical methods. The group of hydrolyzable tannins was the most abundant in the tannic extract in all samples; among them, castalagin was the main component, followed by vescalagin, grandinin, roburin E, and, to a much lesser extent, roburin A. The changes in tannic composition throughout the industrial processing are mainly related to the boiling process and are more pronounced in total phenol and proanthocyanidin contents than in individual ellagitannins content. Vescalagin and roburins A and E were selected as those variables that provided the greatest discrimination among stages. Important differences in the ellagitannin contents were observed among the trees studied, all of the ellagitannins being discriminant variables in this case. Keywords: Quercus suber; cork; tannins; ellagitannins; proanthocyanidins; polyphenols; high-performance liquid chromatography
doi: 10.1021/jf9709360doi: 10.1021/jf9709360The following values have no corresponding Zotero field: publisher: American Chemical Society
Keywords: Cork; ellagitannins; high performance liquid chromatography; polyphenols; proanthocyanidins; Quercus suber; Tannins

Chemical Characterization of Reproduction Cork from Spanish Quercus Suber - Conde, Elvira; Cadahía, Estrella; Garcia-Vallejo, Maria Conceptión; Gonźalez-Adrados, José Ramón (Journal of Wood Chemistry and Technology, 1998)
Abstract The chemical composition of Quercus suber reproduction cork was studied in planks from three different trees at different stages of their industrial processing and in samples collected in seven locations in the three main Spanish production areas. Extracts in chloroform, methanol and water, ne[ugrave]tral and acid fractions of waxes, suberin, lignin, holocellulose and pentosans, and polyphenols (low molecular weight polyphenols and tannins), were quantified. Suberin was the main component in all the samples, followed by lignin and holocellulose in lower concentrations. The most affected variables throughout the industrial processing were: lignin, chloroform and water extracts and the acid fraction of waxes. These variables did not allow one to distinguish the studied trees, which are differentiated by the percentages of methanol extracts, the tannic fraction of polyphenols, the free of suberin residue and the holocellulose content. Four variables were selected as those which provided the greatest discrimination among provenances: methanol extract, low molecular weight polyphenols, desuberinized residue and acid fraction of waxes. However, the studied populations can not be clearly distinguished by their chemical composition and no relationship was found between geographical proximity of their provenances and chemical resemblance.
doi: 10.1080/02773819809349592doi: 10.1080/02773819809349592The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: chemical composition; Cork; suberin; waxes (voyant)

Chlorophyll degradation effected by lichen substances - Bouaid, K.; Vicente, C. (ANNALES BOTANICI FENNICI, 1998)
Epiphytic lichens can exert some negative actions on trees, since they penetrate to different degrees into several tissues of the phytophore. Evernia prunastri (L.) Ach. hyphae progress into xylem vessels of Fagus sylvatica, Quercus pyrenaica and Betula alba. This is on the basis of a mechanism through which Lichens inject metabolic inhibitors in the xylem vessels, and, after their translocation in the xylem sap, they reach different organs of the phytophore and produce defoliation. In this report, we have noted that usnic acid is more impermeant than atranorin through the chloroplast membrane of Quercus rotundifolia leaves. On the other hand, we have also noted the degradation of chlorophyll in response to Lichen substances.
The following values have no corresponding Zotero field: pub-location: UNIV HELSINKI P O BOX 17 (P. RAUTATIEKATU 13), FIN-00014 HELSINKI, FINLAND publisher: FINNISH ZOOLOGICAL BOTANICAL PUBLISHING BOARD
Keywords: chlorophyll degradation; Evernia prunastri; lichen phenols; Quercus rotundifolia

Collembola populations under sclerophyllous coppices in Provence (France): comparison between two types of vegetation, Quercus ilex L. and Quercus coccifera L. - Cortet, Jérôme; Poinsot-Balaguer, Nicole (Acta Oecologica, 1998)
A comparative analysis of soil Collembola using two types of sclerophyllous vegetation (Quercus ilex and Quercus cocc@ru) was performed at a calcareous site in Provence (France). Collembola populations were examined over a one-year period (1 I successive months) in three different soil layers. Although no statistically significant differences could be observed for Collembola abundance and diversity, multivariate analyses (FCA) differentiated the two coppices. Phenologies of some species showed specific responses to the microclimate induced by edaphic conditions. Even though the two coppices were sclerophyllous, the structure of each vegetation, the quantity and quality of litter, which were dif- ferent, could influence environmental conditions and thus the dynamics of collembolan populations.
Keywords: Collembola; litter decomposition; Phenology; Quercus coccifera; Quercus ilex

Comparative field study of spring and summer leaf gas exchange and photobiology of the mediterranean trees Quercus ilex and Phillyrea latifolia - Penuelas, J.; Filella, I.; Llusia, J.; Siscart, D.; Piñol, J. (Journal of Experimental Botany, 1998)
Summer-induced changes in gas exchange, fluorescence and reflectance were measured on leaves of two co-occurring Mediterranean small trees, Quercus ilex and Phillyrea latifolia, in May, June and July 1996 in Central Catalonia (NE Spain). The humid 1996 summer only produced mild water stress conditions. However, photosynthesis (A) and stomatal conductance (gs) decreased in June and July in both species. In June P. latifolia had higher net photosynthetic rates and lower stomatal conductances than Q. ilex, thus exhibiting higher instantaneous plant water use efficiencies. In agreement with these results, the photo-chemical reflectance index (PRI, calculated as (R570-R531)/(R531+R570)) of P. latifolia was lower, suggesting a possible lower xanthophyll de-epoxidation state. However, P. latifolia had lower ΔF/F′ and therefore a lower electron transport rate (ETR). The behaviour of PRI confirmed previous studies indicating a strong relationship between PRI, ΔF/F′ , and photosynthetic radiation-use efficiency (PRUE). PRI offers a simple, portable means of assessing PRUE with the potential for remote sensing applications. Finally, the possible ecological consequences of these results on the behaviour of the two species studied under the predicted warmer and drier conditions of global change are discussed.
10.1093/jxb/49.319.22910.1093/jxb/49.319.229
Keywords: fluorescence; intrinsic water use efficiency; net photosynthetic rates; phillyrea latifolia; photochemical efficiency; photochemical reflectance index; photosynthetic radiation-use-efficiency; Quercus ilex; reflectance; Stomatal conductance; summer; water index

Comparative study of Spanish and Italian terrestrial small mammal coenoses from different biotopes in Mediterranean peninsular tip regions - Cagnin, M.; Moreno, S.; Aloise, G.; Garofalo, G.; Villafuerte, R.; Gaona, P.; Cristaldi, M. (Journal of Biogeography, 1998)
A comparison of terrestrial small mammal coenoses belonging to nine different biotopes in the tips of the Iberian and Italian peninsulas was carried out using the pitfall trapping method. The influence of both habitat type and peninsular effect on composition of small mammal coenoses was analysed. In Southern Italy, 203 specimens belonging to seven species were trapped: Suncus etruscus (Savi, 1822), Crocidura suaveolens (Pallas, 1811), C. leucodon (Hermann, 1780), Microtus savii (de Sélys-Longchamps, 1838), Apodemus sylvaticus (L., 1758), A. flavicollis (Melchior, 1834) and Mus musculus domesticus Schwarz & Schwarz, 1943. In Southern Spain 428 specimens belonging to five species were trapped: Suncus etruscus, Crocidura russula (Hermann, 1780), Microtus duodecimcostatus (de Sélys-Longchamps, 1839), Apodemus sylvaticus and Mus spretus Lataste, 1883. The relative density of small mammals occurring in the nine Spanish sampling stations was twice that recorded in the Italian stations; however the number of species recorded in the different biotopes show similar mean values, ranging from three to five in Andalusia and from three to six in Calabria. Apodemus sylvaticus was the dominant species in the Calabrian stations, whereas Crocidura russula prevailed in Andalusia. The biotic diversity values are very similar in the Calabrian and Andalusian biotopes. By contrast, the Insectivora/Rodentia ratio was always higher in Andalusia. The more xerophytic biotopes showed greater similarities between the communities in Southern Spain and Southern Italy, while the cooler biotopes differed between these two peninsulas.
The following values have no corresponding Zotero field: publisher: Blackwell Science Ltd
Keywords: habitat type; Italy; peninsular effect; sclerophyll biome; Small mammal communities; Spain

Co-occurrence of trees with different leaf habit: A functional approach on Mediterranean oaks - Damesin, Claire; Rambal, Serge; Joffre, Richard (Acta Oecologica, 1998)
Tree species can be split into two groups in terms of their leaf life-spans: evergreens and deciduous. Their distinct geographical dis- tribution suggests that these two groups have functional characteristics adapted to specific environments. However, deciduous and evergreen trees co-exist in some regions, such as those with a Mediterranean climate. They provide good models for comparing the properties of both trees and obtaining an understanding of how diversity is maintained. This is the case in southern France, where the evergreen holm oak (Quercus ilex) and the deciduous downy oak (Quercus pubescens) co-exist. A research programme has been conducted which compares the functioning of these two species at various scales, with the aim of anticipating their distribution in the event of climatic change. The ‘cost-benefit‘ model of Mooney and Dunn has been tested at leaf scale. Q. pubescens has a lower area-based construction cost than Q. ibex, but does not have a higher photosynthetic capacity. Despite differences in biochemical composition, size and mass per unit area, the leaves of the two species respond similarly to limited water conditions. Furthermore, the carbon isotope composition suggests that they have similar intrinsic water-use efficiencies. At the ecosystem scale, preliminary data are available on water, carbon and nitrogen use: i) measurements of leaf water potentials show that drought constraint starts at the same time and with the same rate and intensity in both species: ii) leaf area index was higher in Q. ilex woodlands; and iii) the release rate of nitrogen from the litter was faster in Q. ilex ecosystems. Together, these results indicate that the key factors distinguishing functions of deciduous and evergreen Quercus are more apparent at the ecosystem level than at the leaf level
Keywords: carbon isotope composition; construction cost; deciduous tree; evergreen tree; leaf area index; leaf gas exchange; Leaf habit; Mediterranean-type climate; nitrogen content; Quercus ilex; Quercus pubescens

Cork suberin as a new source of chemicals. 1. Isolation and chemical characterization of its composition. - Cordeiro, N.; Belgacem, M. N.; Silvestre, a J.; Pascoal Neto, C.; Gandini, A. (International journal of biological macromolecules, 1998)
Extractive-free cork from Quercus suber L. was submitted to a solvolysis treatment with methanolic NaOH which yielded 37% (o.d. cork) of suberin. This mixture of compounds was thoroughly characterized by FTIR, 1H- and 13C-NMR, gas chromatography coupled with mass spectrometric (GC-MS) analysis, vapour pressure osmometry (VPO), mass spectrography (MS) and gel permeation chromatography (GPC). After derivatization, the main components of the volatile fraction, representing less than half of the total, were found to be omega-hydroxymonocarboxylates, alpha, omega-dicarboxylates, simple alkanoates and 1-alkanols, all with chain lengths ranging from C16 to C24. A second fraction, with an average molecular weight about three times higher, was detected by VPO, MS and GPC. The presence of this important fraction in cork suberin had not been recognized in earlier studies. Both fractions constitute interesting precursors for the elaboration of new materials.
The following values have no corresponding Zotero field: accession-num: 9585884
Keywords: Alkaline methanolysis; Chemical characterization; Cork; Molecular weight distribution; Quercus suber L.; suberin

Cork suberin as a new source of chemicals: 2. Crystallinity, thermal and rheological properties - Cordeiro, N.; Belgacem, N. M.; Gandini, A.; Neto, C. P. (Bioresource technology, 1998)
Suberin samples, obtained by alkaline methanolysis from cork (Quercus suber L.), were submitted to various physical characterizations; DSC, TGA, optical microscopy, density and rheological properties. A sub- stantial proportion of these oligomers possessed a microcrystalline character with a melting range between 0 and 50°C. The amorphous part was liquid at room temperature and did not display a detectable glass transition upon cooling because of its wide molecular weight distribution. The viscous behaviour of suberin at room temperature was both plastic and thixotropic because of the structuring role of the micro- crystals
Keywords: Alkaline methanolysis; cork of Quercus suber L.; crystallinity; Density; rheological properties; suberin; thermal characterization

Decomposition of the organic matter in two forest ecosystems (Natural Park of Montseny, Spain) - I. Abundance, biomass and distribution of the soil microarthropods - Andres, P.; Athias-Binche, F. (VIE ET MILIEU-LIFE AND ENVIRONMENT, 1998)
This paper represents the first part of a larger work concerning the importance of the oribatid mites in the edaphic trophic chains of two forests (holm-oak and beech woods) under Mediterranean conditions. We offer here the data relating to annual changes of abundance, biomass and vertical distribution of the mesofauna sorted according taxonomic and trophic criteria. The soil was divided into three layers : fresh fallen leaves (L), fermentation layer (F) and organic horizon (S). Rate of leaf imput, dynamics of decomposition, environmental trophic supply, physical structure of the soil and seasonal drought constitute the factors determining the richness and the spatial arrangement of the fauna.
The following values have no corresponding Zotero field: pub-location: LABORATOIRE ARAGO, BP 44, 66651 BANYULS-SUR-MER CEDEX, FRANCE publisher: OBSERVATOIRE OCEANOLOGIQUE BANYULS
Keywords: decomposition; green oak woodlands; microarthropods; Soil

Deriving indicators of soil degradation from soil aggregation studies in southeastern Spain and southern France - Cammeraat, L. H.; Imeson, A. C. (Geomorphology, 1998)
Soil degradation is perceived as a major threat in the Mediterranean region due to changes in land-use and possible future climate change. Soil aggregation parameters are used here to demonstrate their potential as a key-indicator for land degradation studies. The monitoring of these indicators offers a means of establishing the vulnerability and resilience of geo-ecosystems. Soil aggregation stability and distribution were studied on soils with an open shrubby vegetation cover, from several places in southeastern Spain and southern France, by applying drop tests and determining aggregate size distributions. Aspect and vegetation cover were incorporated in the soil sampling. Several indices were derived from these analyses to indicate the degree of soil aggregation. This was done by referencing to a base level of aggregation bare soil aggregation . It was found that soil aggregates were more stable and were often coarser under vegetation, when compared to . their immediate surrounding bare areas. A similar, slightly less clear effect was noted on N-facing exposed slopes when compared to S-facing exposed slopes. Long-term changes were found by studying cultivated land, abandoned fields and land covered by semi-natural vegetation, on comparable substrate and comparable land units. It is clear that soil aggregation and aggregate stability increases with time years . It is argued that soil aggregation indices can be used as a key-indicator for . degradation processes at a fine scale with implications for runoff and sediment generating processes at the hillslope scale
Keywords: degradation; Soil; Vegetation

Detection of Cork Taint in Wine Using Automated Solid-Phase MicroExtraction in Combination with GC/MS-SIM - Butzke, Christian; Evans, Thomas; Ebeler, Susan (Chemistry of Wine Flavor, 1998)
Cork taint is a musty/moldy off-odor in wine. It is related to the cork stopper, a wine bottle closure made from the bark of the cork oak (Quercus suber). In a correlation between sensory evaluation and chemical analysis, 2,4,6-trichloroanisole (TCA) has been identified as a major impact component. In sensitivity tests of a group of trained wine judges, a geometric mean of the minimum detectable concentrations of TCA has been determined at 4.6 ng/L. Solid Phase MicroExtraction (SPME) is a solvent-free sample preparation method based on the adsorption of analytes directiy from an aqueous sample onto a coated fused-silica fiber. Headspace SPME was used in combination with gas chromatography-mass spectrometry/ selective ion monitoring (GC/MS-SIM) to analyze for TCA in wine. Wines were spiked with TCA, and its deuterated stable isotope, 2H5-TCA, was used as an internal standard. The extraction fiber of the SPME, coated with polymethylsiloxane, was exposed for 25 minutes in the headspace of the sample vial, and then injected into the injection port of the GC-MS by a Varian 8200 CX autosampler. Limit of quantification of this method was 5 ng/L. The method was linear from 5 to 250 ng/L with an overall coefficient of variation for replicate analyses of less than 13%.
doi:10.1021/bk-1998-0714.ch015doi:10.1021/bk-1998-0714.ch015The following values have no corresponding Zotero field: periodical: Chemistry of Wine Flavor electronic-resource-num: doi:10.1021/bk-1998-0714.ch015
Keywords: Cork stoppers; Cork taint; SPME/GC-MS (voyant); TCA

Diet selection by sheep and goats on Mediterranean heath-woodland range - Bartolomé, J.; Franch, J.; Plaixats, J.; Seligman, N. G. (JOURNAL OF RANGE MANAGEMENT, 1998)
The study determined the species components of the diets of small ruminants grazing mountain ranges of the Montseny Biosphere Reserve (Catalunya, NE Spain). Three mixed flocks of sheep and goats, led by shepherds, were monitored for a year. Animals grazed a mountain rangeland composed of Qeurcus ilex woodland and Calluna-Erica heathland during the day and were returned to their corrals every night. Diet selection was estimated using fecal analysis. Of the 111 species that were identified, 71 were common to both sheep and goat. Of these, 23 were represented in proportions of more than 1% of the annual diet. Even though goats and sheep grazed together, their diets were significantly different (p < 0.0001), the animal factor accounting for 18% to 60% of the total variation among the main diet components. Variation between seasons was also a major (5% to 56%) highly significant factor, while differences between flocks accounted for a significant, but relatively small part (3% to 10%) of the total variation in diet. The outstanding difference was the avoidance of the tree, Quercus ilex, by the sheep while the goats selected it throughout the year. Sheep selected graminoids throughout the year while goats tended to avoid them. For the rest there.was substantial overlap in species composition between the diet of sheep and goats, especially when analysed over an entire cycle.
The following values have no corresponding Zotero field: pub-location: 445 UNION BLVD, STE 230, LAKEWOOD, CO 80228-1259 USA publisher: SOC RANGE MANAGEMENT
Keywords: calluna vulgaris; Erica arborea; fecal analysis; microhistological analysis; Quercus ilex

The dispersal of a dry-fruited shrub by red deer in a Mediterranean ecosystem - Malo, Juan E.; Suárez, Francisco (Ecography, 1998)
Seed dispersal of dry-fruited shrubs has received little attention in Mediterranean areas despite their frequency in the vegetation and the consideration given to the dispersal of fleshy-fruited shrubs in the area. Red deer faeces has recently been found to contain large numbers of seeds from one of the most common shrubs of this group, gum cistus Cistus ladanifer, although its importance in the reproduction of the species is unknown. This study examines the role of the red deer as an effective disperser of C. ladanifer. For this purpose, we quantify i) the C. ladanifer seed content in red deer dung over a year, ii) the seed shadow generated by the red deer wish their faeces during the same period, and iii) the ability of the dung-borne seeds to germinate and establish as seedlings under field conditions within five years following excretion. The results reveal an extremely high seed Content of the species in red deer dung (up to 80.5 ± 41.9 germinable seeds g-1), which is virtually confined to the summer (July–August), when we estimate that a red deer defecates up to 24 000 seeds of the species per day. Furthermore, red deer mainly deposit gum cistus seeds amongst plant formations lacking the species: over the year, red deer excrete <2600 seeds m-2 in C. ladanifer-dominated scrub and 7400–8800 seeds m-2 in other plant formations. Under natural conditions, the dung-borne seeds have a more sniggered among-years germination pattern than free seeds in the soil. Though no seedling survived its first summer drought, the survival of seedlings sprouted from dung was significantly longer than that of control seedlings in the first and third years after deposition, and indistinguishable from it the second, fourth and fifth years. This is the first quantification of the importance of red deer to C. ladanifer dispersal and establishment, and suggests that endozoochory by mammalian herbivores can be very valuable for dry-fruited shrubs in the Mediterranean region.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: endozoochory; red deer; seed dispersal; seedling establishment (PG)

Ecological food production from animal origin in the dehesa agrosystem of Andalucia and Extremadura - Mata, C.; Caballero, I.; Labrador, J.; Casco, J. M. G. (BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS, 1998)
Andalucia and Extremadura gather certain advantages and conditions for the development of ecological stockbreeding which place them among the European territories of greatest potential in this sense. There are wide areas of high environmental balance, some of them declared as Natural Protected Areas-, with soils of only forestal and silvopastoral use, and with a lot of farms used for the traditional extensive stockbreeding. In this area the management is close to the ecological stockbreeding, and the location coincides with the one of dehesa farms. Most of these farms suffer problems derived from the pressure to which they are subjected because of a management towards greater intensification. Their functions are not valued properly. Many times their products are not competitive with the usual market prices. Being, however of greater organoleptic, sanitary, environmental quality and being even greater, their possibility of profitability. The conversion of extensive stockbreeding farms into a type of ecological production may provide solutions to these problems, favouring a consolidated development; and at the same time, it may encourage an action integrated with other agrarian farms, producing sites of pluriactivity and much more profitability. This work shows a description of the most relevant aspects of extensive stockbreeding productions in relation to its conversion into the ecological production.
The following values have no corresponding Zotero field: periodical: BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS issue: 90 pub-location: POSTBUS 220, 6700 AE WAGENINGEN, NETHERLANDS
Keywords: animal ecological production; Dehesa

Environmental impact of neolithic and bronze age farming in the eastern Pyrenees forelands, based on multidisciplinary investigations at La Caune de Blesta (Blesta Cave), near Perpignan, France - Brochier, Jacques E.; Claustre, Franoise; Heinz, Christine (Vegetation History and Archaeobotany, 1998)
Results of multidisciplinary studies, involving anthracology, archaeology and geoarchaeology, that have been carried out on Neolithic to Brenze Age depos- its from B61esta Cave, eastern Pyrenees, are reported. These show that the type of human activity, i.e. pastoral- ism alone or a more diversified farming economy, and continuity/discontinuity of occupation are the main fac- tors that determine the structure and evolution of the Holocene vegetation in the region. Neolithic pastoral ac- tivities were not continuous and so did not have an en- during influence on the natural environment. The more continuous and diversified exploitation associated with Bronze Age cultures was responsible for the develop- ment and maintenance of the low garrigues.
Keywords: Agro-pastoral system; Bronze Age; Eastern Pyrenees; Neolithic; Vegetation dynamic

The EU Habitats Directive in Spain: can it contribute effectively to the conservation of extensive agroâ€ecosystems? - Beaufoy, G. (Journal of Applied Ecology, 1998)
1. By adopting the Habitats Directive (Directive 92/43 of 21 May 1992 on the con- servation of natural habitats and of wild fauna and flora) in 1992, the governments of the European Community committed themselves to the creation of the Natura 2000 ecological network, with the aim of conserving an extensive range of European habitat types and wildlife species. In doing so, they set in motion the most significant initiative for nature conservation in the history of Europe. 2. In Spain, Natura 2000 will have a considerable impact on the conservation of habitats and species, potentially increasing the percentage of national territory within protected areas from 6% to as much as 20%. 3. This paper aims to illustrate the importance of extensive farming systems to the maintenance of habitats within Natura 2000, and vice versa.
Keywords: Biodiversity; European policy; Extensive farming; policy instruments.

Experimental research in ageing holm oak (Quercus ilex L.) coppices: preliminary results - la Marca, Orazio; Marziliano A., Pasquale; Moretti, Nicola (Ann. For. Sci., 1998)
The initial data of a long-term research programme aimed at determining the silvicultural choices for management of ageing holm oak coppices are reported. The various treatments being tested are the following: treatments A and B, respectively, with 50 and 250 reserve trees per hectare, all of the same age; treatment C with 140 reserve trees per hectare, with three different ages; treatment D, conversion into high forest; and treatment E, natural evolution (the control). A total of 15 permanent plots were established (five treatments x three replicates) and the experimental design used is that of randomized blocks. The results presented regard the structural development of the coppice during the first 2 years after coppicing. Regeneration from seed showed a significant correlation with treatment. Data relative to the characteristics of the stands existing before the various interventions also are given. Such preliminary results need further periodical observations
Keywords: coppice; cutting method; Quercus ilex L.; Regeneration; snow breakage

Field decomposition of leaf litters: earthworm–microorganism interactions—the ploughing-in effect - Cortez, J.; Bouché, M. B. (Soil Biology and Biochemistry, 1998)
We describe a new decomposition model including the consequences of earthworm mechan- ical activity, especially the ploughing-in eect. In an experiment we tested this ploughing-in eect on the disappearance of leaf litter from four tree species (sessile oak, Quercus petraea L., holm oak, Quer- cus ilex L., sweet chestnut, Castanea sativa Mill and beech, Fagus sylvatica L.) during two 2 y exposure at the site of Anduze which contained the highest earthworm biomass. Our experiment, carried out with leaf litter placed in litterbags allowing (0.5 cm mesh size) or preventing (0.1 cm mesh size) the access of earthworms, con®rms (1) the rates of litter decomposition observed in the ®rst experiment and (2) the important eect of earthworms on litter decomposition (from 20.5% to 30.2% depending on the litter). The breakdown of the dierent litters by soil fauna varied from 24.2% to 40.6% depending on the litters after 2 y exposure in the ®eld at Anduze and the litter decomposition rate was increased by a mean factor of about 5.2. We describe a technique for detecting litter contamination attributed to earthworm casts. This technique is based on the change of the litter total weight loss (TWL)-to-litter total C loss (TCL) ratios which varied from 0.652 to 0.915 in the presence of earthworms and were close to 1 (from 0.952 to 0.995) in the absence of earthworms. We assumed that this large change in these ratios indicated a mineral contamination of litters due to earthworm casting. This hypothesis was con®rmed by the litter ash contents varying from 2.6% to 9.6% with earthworms and from 1.3% to 2.1% without earthworms only. These results point out the ecological importance of contamination of the litter by casts during decomposition.
Keywords: decomposition; earthworm; litter; microbial decomposition; ploughing-in (voyant); weight loss

Food resource matching by foraging tits Parus spp. during spring-summer in a Mediterranean mixed forest; evidence for an ideal free distribution - Díaz, Mario; ILLERA, JUAN CARLOS; ATIENZA, JUAN CARLOS (Ibis, 1998)
We analysed whether patterns of microhabitat use by Blue Tits Parus caeruleus, Great Tits Parus major and Crested Tits Parus cristatus inhabiting a mixed forest consistently matched the patterns of food availability experienced by foraging birds during spring-summer. The use of five microhabitats by each bird species (the foliage of three tree species, shrubs and ground) and the availability of food in trees during the prebreeding, breeding and post-breeding periods of the birds' annual cycle were measured. All three tit species foraged mainly in the outer part of tree canopies (small branches and leaves or needles). Tit distributions between tree species matched food resource distributions irrespective of overall food resource levels, which varied four-fold between the study periods, and tit species. Tits also exploited secondary microhabitats (shrubs and ground) in periods of low food availability; Blue Tits tended to use shrubs, whereas Great and Crested Tits foraged on the ground. Between-trees distributions fitted that expected from an ideal free distribution, suggesting that food availability and intraspecific exploitative competition were the main factors governing tree use by tits. In contrast, patterns of use of secondary microhabitats (shrubs and ground) seemed to indicate a role for the species-specific morphological configurations of each tit species since Blue Tits are better adapted to hang and tended to forage in shubs, whereas Great and Crested Tits are better adapted to feed on horizontal surfaces and tended to forage on the ground. No evidence of interspecific interactions was observed. Overall, the results pointed to an independent exploitation of Mediterranean mixed forest by each bird species, food availability and food accessibility being the main factors affecting microhabitat use by foraging tits.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: food availability; Foraging (voyant); microhabitat use; tits; Tree species

Growth and survival in Quercus ilex L. seedlings after irrigation and artificial shading on Mediterranean set-aside agricultural land - Rey Benayas, José M. (Ann. For. Sci., 1998)
Considerable quantities of agricultural land are being transformed into forested lands in E.U. countries. To assess afforestation practice, we analyzed the growth and survival of 800 Quercus ilex sp. ballota seedlings in set-aside agricultural land under semi-arid Mediterranean climate conditions in central Spain. The survival and growth of the seedlings were monitored for 3 years after planting with an experimental design that included all four combinations of: i) irrigation or no irrigation during the dry season; and ii) artificial shading or no shading. Significant differences in survival and growth (height, stem diameter and crown projected area) were found among treatments. Survival was lowest (53 %) in the control plots, and very similar (around 93 %) for the irrigation, shade and combined treatments. Most of the mortality occurred after the first dry season. The high survival rate in irrigated but not shaded plots coincided with a thick layer of the weed Amaranthus retroflexus L. (in the first dry season). Seedling growth was greatest on average under irrigation and shade conditions. Shade was found to have a significant effect for all growth measurements, while irrigation alone only affected stem diameter growth and crown projected area in interaction with shade. Growth measurements were correlated to microclimatic conditions in the plots as measured by the amounts of water and actual evapotranspiration. We conclude that the attenuation of summer stress must be considered in the early stages of successful plantation practice of set-aside agricultural land in a dry environment.
Keywords: Agricultural land; Growth; irrigation; shade; Survival

A hierarchical view of the interactions of runoff and infiltration with vegetation and microtopography in semiarid shrublands - Bergkamp, Ger (Catena, 1998)
Measurements of runoff and infiltration were made at five spatial scales, terracette . -1 m , 2 . 2 hummock 10–20 m , part-slope 1000–2000 m , slope 1 ha and catchment 50 ha , on a . . . shrubland and an open forest site. The study was aimed at understanding the relationships between runoff production, vegetation patterns and microtopography at different spatial scales within a sparsely vegetated, semiarid area. The results of runoff monitoring and rainfall simulation experiments showed that runoff did not occur at the slope scale. It was buffered at the terracette level by nonuniform infiltration at the rims of terracettes and at the hummock scale by rapid infiltration under oak shrubs and trees. Slope and catchment runoff were not connected to runoff at these fine scales. The field evidence is discussed within the context of hierarchy theory, and the implications for management of these shrublands are related to maintaining both the vegetation mosaic and runoff on these slopes
Keywords: infiltration; mediterranean hillslopes; runoff; semiarid; vegetation patterns

Holocene climatic change in Morocco: a quantitative reconstruction from pollen data - Cheddadi, R.; Lamb, H. F.; Guiot, J.; van der Kaars, S. (Climate Dynamics, 1998)
Annual precipitation, July and January tem- peratures were reconstructed from a continuous Holo- cene pollen sequence from the Middle Atlas, Morocco, using the best modern analogues method. The recon- structions show a clear difference between the early and late Holocene: from &10 ka to &6.5 ka the climate was drier and warmer than during the period since 6.5 ka. The average value of annual precipitation was &870mm until 6.5 ka, then rose to &940 mm. Be- tween 10 ka and 6.5 ka January and July temperatures were about 4 °C higher than the present. Both temper- atures show a marked decrease between 7 ka and 6 ka. After 6.5 ka July and January temperatures fluctuated between 21 and 23 °C, and 2.5 and 5 °C respectively. January temperatures show a period of intermediate values (&3.5 °C) between 4 ka and 5.5 ka. The recon- structed climate values generally match palaeolim- nological data from the same core, which show five intervals of low lake level during the Holocene. They are also consistent with regional-scale COHMAP simulated palaeoclimate that shows contrasting pat- terns of rainfall variation between the northwester- nmost part of Africa and the intertropical band
APSAPS
Keywords: climate; Holocene; Morocco; paleoclimate; pollen

Hydrogen Peroxide Production is a General Property of the Lignifying Xylem from Vascular Plants - BARCELÓ, A. R. O. S. (Annals of Botany, 1998)
Production of hydrogen peroxide (H2O2) by the lignifying xylem of several vascular plants has been studied using a new histochemical method based on the H2O2-dependent oxidation of 3,5,3′5′-tetramethylbenzidine (TMB) catalysed by cell wall peroxidases. This method allows H2O2to be determined in the range of 5–100 μm, where other methods, such as the KI/starch reagent, fail. With this method, it has been possible to determine H2O2production in the lignifying xylem of a wide range of vascular plants (gymnosperms and angiosperms). The capability of xylem tissues of sustaining H2O2production lends support to the hypothesis that cinnamyl alcohol polymerization in xylem vessels is caused by an H2O2-dependent oxidative coupling process.Copyright 1998 Annals of Botany Company
10.1006/anbo.1998.065510.1006/anbo.1998.0655
Keywords: H2O2 generation; lignification; peroxidase; tetramethylbenzidine; Xylem

Hydrological behaviour of a small catchment in the dehesa landuse system (Extremadura, SW Spain) - Ceballos, Antonio; Schnabel, Susanne (Journal of Hydrology, 1998)
Investigations of the hydrological processes operating in a small experimental catchment representative of the dehesa ecosystem were carried out. The dehesa constitutes a system of agro-silvo-pastoral landuse, which is characterized by a Mediterranean, semi-arid climate. The study includes an analysis of the relationships between rainfall, soil water content and discharge, as well as the establishment of the annual water budget. The results demonstrate a complex hydrological response. The relationships between the factors involved and the operating processes are difﬁcult to explain because of the decisive role played by the valley bottoms. These areas typically possess a sediment ﬁll, and contrast with the shallow soils developed on the hillslopes. Genesis and quantity of runoff (Hortonian or saturation) measured at the outlet depend on the antecedent moisture conditions of the valley bottoms because of their water-retention capacity. Annual runoff coefﬁcients are similar to those reported from other semi-arid areas. The analysis of the annual water budget shows that rainfall is positively related with both actual evapotranspiration and discharge
The following values have no corresponding Zotero field: publisher: Elsevier
Keywords: Dehesa; Runoff–rainfall relationship; Semi-arid areas; Small catchment; Water budget

Hydrological influences on the resilience of Quercus spp. dominated geoecosystems in central Spain - Bergkamp, Ger (Geomorphology, 1998)
Differences in vegetation cover within a landscape having a similar land use history, can be used to identify differences in recovery following disturbance according to landscape position. The objective of this study was to determine the resilience of oak-dominated communities at different landscape positions in a research area in central Spain as indicated by the relative recovery of Quercus ilex and Q. coccifera, and to relate this to the most important hydrological processes and properties at the slope sections scale. The results indicate that the geoecosystems on slope sections on north-facing slopes are more resilient than those on south-facing slopes. On the more degraded shrubland sites, the higher values of vegetation cover on the lower slope sections indicate the systems on these slope sections to be more resilient than those on the slope sections located higher up the slope. The hydrological factors that could possibly explain differences in vegetation type and cover were found to be distance to water resources at greater depths and incoming radiation controlling evapotranspiration. A conceptual model is presented that links the resilience of these systems to the hydrological conditions. On the basis of the presented model, it is postulated that recovery of the system is determined partly by access to deep water resources. It is suggested that differences in or degree of access to such water resources may cause these comparably looking systems to react differently to degradation and recovery
Keywords: Mediterranean; Quercus; resilience; Shrubland; water balance

Identification of the main fatty acids component of the cork suberine by GC/MS - Bleton, J.; Mejanelle, P.; Goursaud, S.; Tchapla, A. (ANALUSIS, 1998)
The aim of this work was to verify the presence of cork (Quercus Suber) in two samples of linoleum the beginning of the twentieth century Using GC/MS after acidic methanolysis and silylation, it was possible to identify most of the components of a modern sample of cork. The dominant is a lipid polymer: the suberin. Its monomeric composition is examined in details.
APSAPSThe following values have no corresponding Zotero field: pub-location: 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE publisher: E D P SCIENCES
Keywords: Cork; GC/MS; Quercus suber L.; suberin

Influence of 50 Hz electromagnetic fields on recurrent embryogenesis and germination of cork oak somatic embryos - Celestino, Cristina; Picazo, M. L. (Plant cell, tissue and …, 1998)
Plant tissue culture techniques are carried out under environmentally controlled conditions in phytotrons. However, electric components of phytotrons generate electromagnetic ﬁelds that may act as a environmental factor inﬂuencing plant growth and morphogenesis. Isolated somatic embryos of Quercus suber, picked from embryogenic lines, were chronically exposed to a 50 Hz and 15 µT electromagnetic ﬁeld generated in a Helmholtz-coil system for 8 weeks, in order to examine if the extremely low frequency (ELF) magnetic ﬁeld (MF) affected the morphogenic behaviour of embryogenic cultures during recurrent embryogenesis. Germination of somatic embryos from genotype G7.1 was carried out under the same electromagnetic ﬁeld, and also under conditions in which the local geomagnetic ﬁeld was suppressed. The ELF MF did not inﬂuence the growth of embryogenic clumps of the assayed genotypes, but reduced the number of detachable embryos produced by genotype G3.27. The ELF MF did not modify the percentages of germination or plant formation of somatic embryos. However, somatic embryos had better germination when cultured under the suppressed geomagnetic ﬁeld condition.
Keywords: bioelectromagnetism; elf magnetic fields; germination; Quercus Suber L; Somatic embryogenesis; tissue culture

Isotope discrimination and photosynthesis of vegetation growing in the Bossoleto CO 2 spring - Miglietta, F.; Raschi, A.; Körner, C.; Vaccari, F. P. (Chemosphere, 1998)
The Bossoleto CO2 spring emits CO2 which has a stable carbon isotopic ratio (~5~3C = - 8%o). We determined ~3C on leaves of several individual species growing in Bossoleto and in a nearby control site at ambient CO,.. ~5t3C was 6% more negative in leaves of species collected from the grassland community of Bossoleto, indicating increased discrimination (A) against the heavy carbon isotope. No such changes were found in ruderal species growing in the same spring, suggesting that photosynthetic capacity was much less affected. A was substantially increased under elevated CO2 in leaves of Quercus pubescens but not in Quercus ilex, which also did not show any increase in non-structural carbohydrates. Gas-exchange measurements made on Plantago lanceolata, supported the view that photosynthetic capacity is decreased in plants grown under elevated CO: and on poor soils
Keywords: Elevated CO2; Grassland vegetation (voyant); isotopic discrimination; photosynthetic capacity

Leaf gas exchange and ﬂuorescence of Phillyrea latifolia, Pistacia lentiscus and Quercus ilex saplings in severe drought and high temperature conditions - Filella, I.; Llusia, J.; Piñol, J.; Penuelas, J. (Environmental and Experimental Botany, 1998)
Saplings of Phillyrea latifolia, Pistacia lentiscus and Quercus ilex were witheld watering for 7 days, followed by reirrigation. Incident photosynthetic photon ﬂux density (PPFD), leaf temperature, net photosynthetic rates, stomatal conductance, and photochemical efﬁciency of the photosystem II (DF:F’m) were measured three times during the day. The watered plants had higher photosynthetic rates, stomatal conductances, DF:F’m and ETR than non-watered plants. However, watered plants were mildly water stressed as shown by low ratio of variable to maximal ﬂuorescence (Fv:Fm) and high non-photochemical ﬂuorescence quenching (qN). Their DF:F%m was low in the morning and increased in the evening, following the variations in PPFD. Watered plants of Q. ilex had lower photosynthetic activity, stomatal conductance and photosynthetic radiation use efﬁciency than Ph. latifolia and P. lentiscus, and, conversely, reached the highest DF:F%m and ETR. This seems to indicate a different relationship between photosynthetic activity and electron transport rate in Q. ilex compared to the other two species. Ph. latifolia and P. lentiscus appeared to be better adapted to severe drought than Q. ilex.
Keywords: Drought; hF/F’m; phillyrea latifolia; photosynthetic rate; Pistacia lentiscus; Quercus ilex; Stomatal conductance

Long-term CO 2-enrichment in a Mediterranean natural forest: An application of large Open Top Chambers - Angelis, P. De; Scarascia-Mugnozza, G. E. (Chemosphere, 1998)
It is crucial to be able to anticipate the possible effects of environmental changes on the Mediterranean woodland communities given their essential role on protecting lands that are under a strong pressure by man and climate. Predictions of the effects of increasing C0~ concentration on plants have been inferred by short- and long-term studies, conducted at different scales and by different technologies. Open Top Chambers (OTCs) are experimental facilities that have been widely used to expose field grown plants to different pollutant gases, and more recently to elevated [CO2] . In this paper, we present the natural site and the experimental system (six large OTCs enclosing clumps of natural vegetation) that we have been utilizing for 3 years, to assess the impact of elevated [CO2] on a Mediterranean natural forest community. The results show that large OTCs can be usefully used to simulate C02 doubling even under the harsh environmental conditions of the mediteffanean region
Keywords: decomposition; Elevated CO3; leaf litter; Mediterranean forest (voyant)

Modelling the responses to climate change of a Mediterranean forest managed at different thinning intensities: Effects on growth and water fluxes - Gracia, C. A.; Sabate, S.; Tello, E. (IMPACTS OF GLOBAL CHANGE ON TREE PHYSIOLOGY AND FOREST ECOSYSTEMS, 1998)
This study explores the effect of various climatic change scenarios over a 50 year period on plots managed at a range of thinning intensities. In order to determine how management practises can modify the effect of climatic change on Mediterranean Forests we integrated field experiments and the results of the GOTILWA model so as to take into account both water fluxes and forest structure interactions. The results show that the positive effects of atmospheric CO2 fertilisation, causing an increase in WUE, counteract with the negative effects of both temperature increase and rainfall decrease. Thinning might attenuate the effects of adverse conditions by reducing both leaf respiratory costs and the foliage turnover rate.
The following values have no corresponding Zotero field: periodical: IMPACTS OF GLOBAL CHANGE ON TREE PHYSIOLOGY AND FOREST ECOSYSTEMS pub-location: PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS
Keywords: climate change; mediterranean forest; Modelling

Modifications of the leaf surface structures of Quercus ilex L. in open, naturally CO2-enriched environments - Paoletti, E.; Nourrisson, G.; Garrec, J. P.; Raschi, A. (Plant, Cell & Environment, 1998)
Two Italian CO2 springs allowed us to study the long-term effect of a 350–2600 μmol mol–1 increase in CO2 concentrations on the surface structures of leaves of Quercus ilex L. Carbon dioxide increased the quantity of cuticular waxes, above an apparent threshold of 750 μmol mol–1 CO2. Leaf wettability was not modified by CO2 concentrations. Reduction in stomatal frequency was observable up to 750 μmol mol–1 CO2, the slope being almost the same as that estimated for the increase in CO2 concentration from pre-industrial times to the present. At higher concentrations, CO2 seemed to exert no more impact on stomatal frequency.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Elevated CO2; leaf wettability; natural CO2 spring; Quercus ilex; stomatal frequency; wax amount

On the monoterpene emission under heat stress and on the increased thermotolerance of leaves of Quercus ilex L. fumigated with selected monoterpenes - Loreto, F.; Förster, A.; Dürr, M.; Csiky, O.; Seufert, G. (Plant, Cell & Environment, 1998)
Leaves of the monoterpene emitter Quercus ilex were exposed to a temperature ramp with 5 °C steps from 30 to 55 °C while maintained under conditions in which endogenous emission of monoterpenes was allowed or suppressed, or under fumigation with selected exogenous monoterpenes. Fumigation with monoterpenes reduced the decline of photosynthesis, photorespiration and monoterpene emission found in non-fumigated leaves exposed to high temperatures. It also substantially increased respiration when photosynthesis and photorespiration were inhibited by low O2 and CO2-free air. These results indicate that, as previously reported for isoprene, monoterpenes may help plants cope with heat stress. Monoterpenes may enhance membrane stability, thus providing a rather non-specific protection of photosynthetic and respiratory processes. Monoterpene emission was maximal at a temperature of 35 °C and was inhibited at higher temperatures. This is likely to be the result of the temperature dependency of the enzymes involved in monoterpene synthesis. In contrast to other monoterpenes, cis- and trans-β-ocimene did not respond to exposure to high temperatures. Cis-β-ocimene also did not respond to low O2 or to fumigation. These results indicate that cis and trans-β-ocimene may have a different pathway of formation that probably does not involve enzymatic synthesis.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: monoterpene emission; monoterpene fumigation; photosynthesis; Quercus ilex; respiration; thermotolerance

Morpho-anatomical aterations in leaves of Fagus sylvatica L. and Quercus ilex L. in different environmental stress condition - Grossoni, P.; Bussotti, F.; Tani, C.; Gravano, E. (Chemosphere, 1998)
By means of anatomical and foliar structure observations, this paper examines the ecological behaviour of two different species of broadleaf (a mesophile one, beech, and a xerophile one, holm-oak), under different conditions of water supply. The purpose of this study was to evaluate their response in relation to possible climate changes. The results highlight certain similarities of behaviour (reduction of leaf surface, increased leaf thickness, increase of mechanical structures in xeric stands). The main difference between the two species lies in the tannins content, which increase in the epidermal cells (vacuoles and walls) only in beech trees in xeric conditions
Keywords: Fagus sylvatica; foliar structure; Quercus ilex; xeric conditions (voyant)

Myxomycetes from the bark of the evergreen oak Quercus ilex - de Basanta, Diana Wrigley (Anales del Jardín Botánico de Madrid; Vol 56, No 1 (1998), 1998)
The results of 81 moist chamber cultures of bark from living Quercus ilex trees are reponed. A total of 37 taxa are cited, extending the number of species found on this substrate to 55. The presence of Licea deplanata on the Iberian Península is confirmed. Seven new records are included for the province of Madrid. Some data are contributed on species frequency and incubation times.
Keywords: Corticolous myxomycetes; Madrid; moist chamber culture; Quercus ilex

Ozonolysis at vegetation surfaces:: a source of acetone, 4-oxopentanal, 6-methyl-5-hepten-2-one, and geranyl acetone in the troposphere - Fruekilde, P.; Hjorth, J.; Jensen, N. R. (Atmospheric Environment, 1998)
ÐThe present study gives a possible explanation for the ubiquitous occurrence of 6-methyl-5- hepten-2-one and acetone in ambient air and reports for the Þrst time on a widespread occurrence of geranyl acetone and 4-oxopentanal. We have conducted a series of laboratory experiments in which it is demonstrated that signiÞcant amounts of geranyl acetone, 6-methyl-5-hepten-2-one (6-MHO), 4-oxopen- tanal (4-OPA), and acetone are formed by the reaction of ozone with foliage of common vegetation in the Mediterranean area (Quercus ilex'Citrus sinensis'Quercus suber'Quercus freinetto'Pinus pinea). In order to rule out biological formation, epicuticular waxes were extracted from the leaves, dispersed on glass wool and allowed to react with a ßow of artiÞcial air. SigniÞcant amounts of 6-MHO and 4-OPA were formed at ozone concentrations of 50Ð100 ppbv, but not at zero ozone. A number of terpenoids common in vegetation contain the structural element necessary for ozonolytic formation of 6-MHO. Two sesquiter- penes (nerolidol; farnesol), and a triterpene (squalene) selected as representative test compounds were demonstrated to be strong precursors for acetone, 4-OPA, and 6-MHO. Squalene was also a strong precursor for geranyl acetone. The atmospheric lifetime of geranyl acetone and 6-MHO is less than 1 h under typical conditions. For the present study, we have synthesized 4-OPA and investigated the kinetics of its gas-phase reaction with OH, NO 3 , and O 3 . A tropospheric lifetime longer than 17 h under typical conditions was calculated from the measured reaction rate constants, which explains the tropospheric occurrence of 4-OPA. It is concluded that future atmospheric chemistry investigations should included geranyl acetone, 6-MHO, and 4-OPA. In a separate experiment it was demonstrated that human skin lipid which contains squalene as a major component is a strong precursor for the four above-mentioned compounds plus nonanal and decanal. The accidental touching of material which later comes into contact with ozone can lead to strong artifact formation of these carbonyl compounds. Previously published results on these compounds must be seen in this new light
Keywords: epicuticular wax; heterogenous reactions; NO3; O3; OH; products; rate; sesquiterpenes; Squalene

Photochemical response to summer drought in Quercus ilex trees growing in a naturally CO2 enriched site - FARIA, T.; Cerasoli, S.; García-Plazaola, J. I.; Guimaraes, M. P.; Abadia, A.; Raschi, A.; Miglietta, F.; Pereira, J. S.; Chaves, M. M. (IMPACTS OF GLOBAL CHANGE ON TREE PHYSIOLOGY AND FOREST ECOSYSTEMS, 1998)
The effect of the interaction between water stress and growth at elevated CO2 on the leaf photochemistry were studied in Quercus ilex trees, growing in a naturally CO2 enriched site (the Bossoleto, Italy). Those plants were compared with plants growing nearby in similar soils but at ambient CO2 concentration. Our data indicate that down-regulation of photosynthesis is lower in non-watered trees from the enriched site than in non-watered trees from the ambient-CO2 site This may be associated to the higher carbon availability for the consumption of the excess absorbed light energy or to an increased protection of the photochemical apparatus against oxidative stress in plants grown under elevated CO2.
The following values have no corresponding Zotero field: periodical: IMPACTS OF GLOBAL CHANGE ON TREE PHYSIOLOGY AND FOREST ECOSYSTEMS pub-location: PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS
Keywords: Elevated CO2; fluorescence; water stress; xanthophylls

The pollen spectrum of trees and shrubs in SW Spain (1987–1996) - Gonzalez Minero, Francisco Jose; Candau, Pilar; Morales, Julia; Tomas, Carmen (Grana, 1998)
A Cour trap was used to sample the air of Seville of continuously from 1987 to 1996. The most important climatological feature recorded during that period was the drought that began in 1990 and which was at its most severe in the first half of 1995. The behaviour of a total of 20 pollen types was studied: those exceeding 0.01% of the total pollen collected during the ten?year period. These were Quercus, Olea Cupressaceae, Platanus Myrtaceae, Pinaceae, Palmae, Moraceae, Fraxinus Ericaceae, Citrus, Pistacia, Acer, Casuarina Salicaceae, Ulmus, Alnus, Castanea Cistaceae, and Viburnum. The following aspects are described and analysed: the spectrum of tree and shrub types identified in the air, and their possible significance for allergies; the relationship between the woody vegetation of the region and the composition of the pollen spectrum in quantitative terms; and the possible effect of the drought on annual variations total pollen concentrations. A detailed study of olive pollen, aimed at finding applications in allergy and agriculture is also given. In particular, the possibility of forecasting both the date of olive pollination from observations of preceding mean temperatures, and the size of the crop from palynological and agronomical data.
doi: 10.1080/00173139809362653doi: 10.1080/00173139809362653The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: airborne pollen; Olive pollination; pollen concentrations (voyant); Pollen spectrum

Polyphenolic Composition of Quercus suber Cork from Different Spanish Provenances - Conde, Elvira; Cadahía, Estrella; García-Vallejo, María Concepción; Fernández de Simón, Brígida (Journal of Agricultural and Food Chemistry, 1998)
Polyphenolic composition was studied by HPLC and classical chemical methods in reproduction cork of Quercus suber from different Spanish provenances. The low molecular weight polyphenols (gallic, protocatechuic, vanillic, caffeic, ferulic, and ellagic acids; protocatechuic, vanillic, coniferyl, and sinapic aldehydes; and aesculetin and scopoletin) and the ellagitannins (roburins A and E, grandinin, vescalagin, and castalagin) were identified and quantified. Ellagic acid was the main component in the ether soluble fraction, and the group of hydrolyzable tannins, and among them castalagin, was the most abundant in the tannic extract in all the samples. Although there was an important variability among provenances, no significant differences were found in the total tannin content and in the individual content of each ellagitannin. However, gallic and caffeic acids and protocatechuic aldehyde provided the greatest discrimination among provenances. Keywords: Quercus suber; cork; polyphenols; tannins; phenolic acids and aldehydes; coumarins; ellagitannins; high-performance liquid chromatography
doi: 10.1021/jf970863kdoi: 10.1021/jf970863kThe following values have no corresponding Zotero field: publisher: American Chemical Society
Keywords: Cork; coumarins; ellagitannins; high-performance liquid chromatography; phenolic acids and aldehydes; polyphenols; Quercus suber; Tannins

Production of free range chickens in the Spanish South-west - Duran, A. M.; Pascual, M. R. P. (BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS, 1998)
The object of this study is to elaborate a description of the products obtained from the breeding of free range chickens in the Spanish South-west, considering the possible sex influence. 24 Redstar Shaver chickens were used, 12 males and 12 females chickens. The animals were controlled weekly to determine productive yields when alive. After their slaughter, notes on carcasses and meats were taken. The males weighted more at the slaughter time and presented a better yield of the eviscerated carcass. The females showed a greater abdominal fat content and the regional composition was virtually the same in both sexes, however a greater percentage of legs was found in the males. The dissection of the inferior extremities showed a greater edible meat content in the females chickens. The organoLeptic tests (pH and water holding capacity CRA) presented relevant differences between sexes (greater pH and CRA. in the males). The comparison of the meat nutritive Value (protein and ashes) did not show relevant differences between males and females. This study shows that male and female chickens are products with similar nutritive value but distinguishable by other parameters.
The following values have no corresponding Zotero field: periodical: BASIS OF THE QUALITY OF TYPICAL MEDITERRANEAN ANIMAL PRODUCTS issue: 90 pub-location: POSTBUS 220, 6700 AE WAGENINGEN, NETHERLANDS
Keywords: Dehesa; extensive chickens; production; Quality meat; sex poultry carcass

PRODUCTIVIDAD Y PERSISTENCIA DE ECOTIPOS AUTÓCTONOS DE TRÉBOL SUBTERRÁNEO DE LA DEHESA SALMANTINA EN CONDICIONES DE - Crespo Martínez, M. C.; Cordero Castaño, S. A. (Pastos, 1998)
Se ha estudiado el comportamiento de 10 ecotipos autóctonos de trébol subterráneo (Trifolium subterraneum L.), de la provincia de Salamanca, aprovechados bajo pastoreo continuo y cargas ganaderas de 4, 6 y 8 ovejas por hectárea, con el objeto de evaluar su persistencia y productividad. Se ha utilizado como testigo principal la variedad de trébol subterráneo 'Valmoreno' seleccionada en Extremadura. Los ecotipos autóctonos han mostrado su buena adaptación, logrando en algunos casos prácticamente duplicar en número de plantas por metro cuadrado en el segundo año del ensayo a la variedad testigo, que además fue superada en producción de materia seca por el ecotipo autóctono menos productivo en 1100 kg/ha, lo que supone un incremento del 85 %. Se considera el interés de utilizar material autóctono en la mejora de la productividad de los pastizales de esta zona ganadera. Palabras
Keywords: mejora de pastos; recursos fítogenéticos; Trifolium subterraneum L.

Response of foliar metabolism in mature trees of Quercus pubescens and Quercus ilex to long-term elevated CO 2 - Tognetti, Roberto; Johnson, J. D. (Environmental and Experimental Botany, 1998)
Long-term effects on and adaptations of the carbon physiology of long-lived trees exposed to increasing atmospheric levels of CO2 are unknown. We compared two indigenous Quercus species, Q. ilex and Q. pubescens, growing in a natural CO2 spring located in central Italy and at a nearby control site. In May, 1995 photosynthetic rate at least doubled when measured with supplemental CO2 in both species and sites. Dark respiration was much higher at the CO2 spring site in both species. Foliar sugar and starch concentrations in Q. ilex exhibited signiﬁcant site and diurnal differences (May and September). In July, 1995 there was little difference in the water potential values of the measured trees at the different sites over the diurnal period. Photosynthetic rate was higher for both species in the CO2 spring, particularly in the early morning and late afternoon. Mid-day stomatal closure reduced photosynthesis to similar levels. In the morning leaf conductance and transpiration were generally lower in the CO2 spring trees, contributing to higher instantaneous water use efﬁciency for both species. Isoprene emission rates were higher in Q. pubescens trees growing in the CO2 spring. The maximum difference between control and CO2 spring trees occurred in late afternoon. In contrast, Q. ilex exhibited isoprene emission near background level. Foliage and branch carbon and nitrogen status showed increased concentrations of starch and tannins in Q. ilex and of soluble sugars in Q. pubescens in the elevated CO2 environment, while nitrogen concentration decreased in both species. Wood gravity increased 6 and 3% in Q. ilex and Q. pubescens, respectively, growing in the CO2 spring. Q. ilex exhibited afternoon recovery of water potential compared to Q. pubescens which had better night-time recovery. Q. ilex and Q. pubescens exposed to elevated CO2 for prolonged periods exhibit different mechanisms for dealing with additional reduced carbon and do maintain an altered carbon physiology, even in midst of the region’s characteristic summer drought
Keywords: Elevated CO2; Gas exchange; natural CO2 springs; Quercus; Secondary compounds

Response of two populations of holm oak (Quercus rotundifolia Lam.) to sulfur dioxide. - García, D.; Rodríguez, J.; Sanz, J. M.; Merino, J. (Ecotoxicology and environmental safety, 1998)
Experiments were carried out with seedlings of Quercus rotundifolia Lam., an evergreen schlerophyllous tree typical of the Spanish Mediterranean climate environments. Fruits were collected in two distant (800 km) populations located in the center (southern Spain) and northern border (northern Spain) of the area of distribution of the species. One-month-old potted plants were grown for 130 days in an enriched atmosphere of SO2 (0.23 ppm, 14 h/day) in controlled (growth chamber) conditions. Both northern and southern plants underwent a significant decrease in growth rate as a consequence of the treatment. Even so, plants appear to be quite resistant to SO2 compared with either more temperate or more productive species. The southern population was more sensitive to the treatment, as reflected by the bigger decrease in both growth and photosynthetic rates. Differences in resistance appear to be related to the biogeographic origin of the populations studied, which underlines the importance of biogeographic aspects in studies of resistance to air pollutants.
The following values have no corresponding Zotero field: accession-num: 9626534
Keywords: Adaptation; Air Pollutants; Air Pollutants: adverse effects; air pollution; biomass; Environment; GROWTH RATE; photosynthesis; Photosynthesis: physiology; Physiological; Plant physiology; Pollutants; Quercus rotundifolia; Sulfur Dioxide; Sulfur Dioxide: adverse effects; Sulphur dioxide; Trees; Trees: drug effects; Trees: genetics; Trees: physiology

Retrieving leaf conductances from sap flows in a mixed Mediterranean woodland: a scaling exercise - Filho Teixeira, José; Damesin, Claire; Rambal, Serge; Joffre, Richard (Ann. For. Sci., 1998)
Xylem sap-flux densities were monitored continuously using Granier-type sensors on five Quercus ilex, four Arbutus unedo and one Quercus pubescens from June 1993 to October 1994. Half-hourly measurements of incoming solar radiation, air temperature and humidity, horizontal wind speed and precipitation were carried out at the top of a tower at a height of 12 m, about 2 m above the canopy. Leaf physiological measurements (stomatal conductance, water potential) on individual sunlit leaves from each of the three tree species were obtained on seven complete or partial diurnal time courses. For these three species, to estimate leaf stomatal conductance, we used the big-leaf approach of Penman-Monteith. We have divided the leaves into sunlit and shaded. The model sums the individual-leaf model for only the sunlit fraction to produce the whole-canopy predictions. Transpiration was deduced from sap flux through a transfer function taking into account stem water storage. Stomatal conductance for a given species was evaluated half-hourly from transpiration and microclimate data inverting the Penman-Monteith equation. An empirical model was identified that related stomatal aperture to simultaneous variations of microclimate and plant water potential for the 1993 period. The predicted leaf conductances were validated against porometer data and those of the 1994 period. The diurnal patterns of predicted and measured transpiration indicated that stomatal conductance was accurately predicted. The leaf conductance models were also compared with already published literature values from the same tree species. In spite of the simplifications inherent to the big-leaf representation of the canopy, the model is useful for predicting interactions between Mediterranean mixed woodland and environment and for interpreting H2 O exchange measurements
Keywords: Arbutus unedo; mixed Mediterranean woodland; Penman-Monteith equation; Quercus ilex; Quercus pubescens; sap flow; stomatal and canopy conductances

Rhythmic growth rings of wood and their relationship with the foliage in oak seedlings grown in a favourable environment - MANSOUR, A.; de FAŸ, E. (Annals of botany, 1998)
{{The anatomy of wood was studied in Quercus robur L. and Quercus suber L. seedlings exhibiting 3±8 units of extension, each with a tier of photosynthesizing leaves in their upper parts, generated as the result of rhythmic shoot growth under favourable conditions. At all the axis levels examined (i.e. the base of each of the diﬀerent units of extension, four other equidistant levels within the ®rst unit of extension and the upper part of the taproot), the wood displayed rings when treated with Wiesner reagents. This indicated cinnamaldehyde groups present in lignins. No rings appeared when the Mau$le reaction was used for speci®c detection of syringyl subunits in lignins. A trend towards a periodical arrangement of xylem parenchyma bands was also found when sections were treated with I # }KI. The number of rings coincided with the number of leaf tiers above the level of measurement, and did not vary inside the ®rst unit of extension. Thus, the rings are called rhythmic growth rings. In sections of the ®rst and the second units of extension, and in the taproot, the area and width of a given rhythmic growth ring were highly correlated with the total area of leaves present above the level of measurement at the presumed time of growth ring formation. Moreover, stem diameter at the base of the units of extension was highly correlated with the leaf area above. These results indicate that diﬀerentiation of xylem, particularly its ligni®cation, varies rhythmically in oak seedlings. They imply that wood production is linked to the photosynthesizing and}or transpiring area of the plant. Thus, during a growth cycle of Q. robur and Q. suber seedlings, there appears to be integration of the primary metabolic activities with the laying down of rhythmic growth rings
Keywords: allometric relationship; juvenile wood; leaf area; lignification; oak seedling; periodic structure; quercus robur l; Quercus Suber L; rhythmic growth ring; unit of extension

Roe deer habitat selection in Spain: constraints on the distribution of a species - Virgos, E.; Tellería, J. L. (Canadian Journal of Zoology, 1998)
This study analyzes the role of summer habitat selection in determining the distribution of a population of roe deer (Capreolus capreolus L.) in central Spain, where surplus individuals have emigrated from mountains to the surrounding plateaus during the last decade. The species was more abundant in the mesic mountain forests (Scots pine (Pinus sylvestris), Pyrenean oak (Quercus pyrenaica)) than in the xeric, sclerophyllous holm oak (Quercus ilex) forests of surrounding plateaus. Roe deer prefer patches occupied by brambles (Rubus spp.) and rose bushes (Rosa spp.) and patches with higher cover on pastures and moors (Erica spp. and Calluna spp.). These vegetation types are linked to moist soils in the Mediterranean zone, indicating that roe deer prefer the moister, more productive patches. Roe deer actively selected productive patches covered by leguminous shrubs (Sarothamnus, Retama) and rejected poor patches covered by Cistus ladanifer and Cistus laurifolius (two shrubs that produce chemicals toxic to other plants). Low summer primary productivity of xeric, sclerophyllous forests can explain the low abundance of roe deer in these forests. This supports the view that habitat constraints limit numbers and distribution of this Palaearctic species at the southern edge of its range.
doi: 10.1139/z98-065doi: 10.1139/z98-065The following values have no corresponding Zotero field: publisher: NRC Research Press
Keywords: habitat selection; leguminous shrubs (PG); roe deer

Soil aggregate stability under different Mediterranean vegetation types - Cerdà, A. (Catena, 1998)
The influence of vegetation type on soil erodibility was studied by means of aggregate stability measurements using the Modified Emerson Water Dispersion Test MEWDT , water-drop impacts . . . CND and TDI and Ultrasonic Disruption UD methods on soils from north-facing slopes of the mountain range of La Serra Grossa in the eastern Iberian Peninsula. Soils with similar characteristics but covered by the main plant species at the study area were selected. Quercus ilex woodland showed the most resistant soil aggregates followed by Q. coccifera and Pistacea lentiscus scrubland, Brachypodium retusum grassland and Pinus halepensis woodland. Aggregates developed beneath dwarf shrubs like Rosmarinus officinalis, Thymus Íulgaris, Ulex parÍiflorus and Anthyllis cystisoides were least resistant. The different methods and tests applied are useful to study the soil aggregate stability. The MEWDT and TDI tests showed only minor differences between samples due to the high aggregate resistance and the low energy applied by these tests. CND and UD tests are considered to be more suitable for resistant Mediterranean soil developed on limestone due to the greater energy applied. Aggregates tested from an initially moist pF1 condition were always more stable than air dried aggregates. Rangeland management . after disturbances by fire, agriculture or grazing, etc. should try to establish natural woodland Q. ilex. in order to get the most stable soil. Alternative vegetation cover to the climax vegetation that give high aggregate stability are Q. coccifera and P. lentiscus scrublands. Immediately after disturbance, B. retusum grassland seems to be the best option for soil protection.
Keywords: Aggregate stability; Laboratory test; Mediterranean; Vegetation

Soil hydrological response under simulated rainfall in the Dehesa land system (Extremadura, SW Spain) under drought conditions - Cerdà, A.; Schnabel, S. (Earth Surface Processes and Landforms, 1998)
Soil hydrology was investigated in the Guadelperalón experimental watershed in order to determine the inﬂuence of land use and vegetation cover on runoff and inﬁltration within the Dehesa land system. Five soil–vegetation units were selected: (1) tree cover, (2) sheep trials, (3) shrub cover, (4) hillslope grass and (5) bottom grass. The results of the simulated rainfall experiments performed at an intensity of 53·6mm h −1 during one hour on plots of 0·25m 2 , and the water drop penetration time test indicate the importance of water repellency in the Dehesa land system under drought conditions. Low inﬁltration rates (c. 9–44mm h −1 ) were found everywhere except at shrub sites and in areas with low grazing pressure. Soil water repellency greatly reduced inﬁltration, especially beneath Quercus ilex canopies, where fast ponding and greater runoff rates were observed. The low vegetation cover as a consequence of a prolonged drought and grazing pressure, in conjunction with the soil water repellency, induces high runoff rates (15–70 per cent). In spite of this, macropore ﬂuxes were found in different locations, beneath trees, on shrub-covered surfaces, as well as at sites with a dominance of herbaceous cover. Discontinuity of the runoff ﬂuxes due to variations in hydrophobicity causes preferential ﬂows and as a consequence deeper inﬁltration, especially where macropores are developed
Keywords: Dehesa; Drought; hydrophobicity; rainfall simulation; soil hydrology

Stemflow and throughfall determination in a resprouted Mediterranean holm-oak forest - Bellot, Juan; Escarre, Antonio (Ann. For. Sci., 1998)
Stemflow, throughfall and precipitation data were collected for 30 consecutive months in a holm-oak forest dominated by Quercus ilex, Arbutus unedo and Phyllirea media. These flux data were obtained from 50 randomly distributed no-roving throughfall collectors and 20 stemflow measuring devices (ten on Q. ilex and five on each of the other species). The stemllow was highly influenced by tree size and amount of rainfall, showing a significant correlation for each tree. Throughfall results showed a high spatial variability for each storm, with a significant independence of collectors. At forest scale, stemflow and throughfall represented 12.1 and 75 % of precipitation, respectively, and interception was estimated as 12.9 % of precipitation. Partitioning of rainfall between stemflow and throughfall created a high spatial heterogeneity of water distribution under the canopy. Stemflow increased more than 30 times the mean amount of water received per unit soil area around tree trunks. Finally, the effect of a change in the amount of precipitation according to a regional scenario was analyzed. It was shown that the increase in high rainfall events rather than small events increased the stemflow percentage.
Keywords: Holm oak; interception; spatial heterogeneity; stemflow; throughfall

Thermally assisted transmethylation gas chromatography–mass spectrometry of suberin components in cork from Quercus suber L. - Bento, M. F.; Pereira, H. (Phytochemical Analysis, 1998)
Thermally assisted transmethylation gas chromatography - mass spectrometry with tetramethylammonium hydroxide has been applied for the qualitative and quantitative analysis of the suberin fraction of wax-free cork. With this method, hydrolysis of esters together with methylation of carboxylic and hydroxylic groups was observed. Mostly long chain aliphatic components, such as alkanols, alkanoic acids, v-hydroxyacids, v,v-alkanoic diacids, and several 9,10-epoxy and 9,10-dihydroxy forms have been found in keeping with results of other workers in the ﬁeld. Two other components that may give a more complete view of the architecture of suberin were also found, namely the phenolic compound ferulic acid, and glycerol which is probably esteriﬁed to carboxylic groups of the aliphatic building units of suberin
Keywords: Cork; pyrolysis mass spectrometry; Quercus suber; suberin; thermally assisted methylation

URBAN GROWTH DYNAMICS ( 1956-1998 ) IN MEDITERRANEAN COASTAL REGIONS : THE CASE OF ALICANTE , SPAIN - Aguilar, Juan A. Pascual; Añó, Carlos; Valera, Antonio; Sánchez, Juan (Desertification in the Mediterranean Region a Security Issue, 1998)
Among factors causing soil degradation one of the most important, although less studied in Mediterranean environments, is the irreversible loss of soil due to urbanisation processes, inserted into the more general concept of soil sealing. In coastal Mediterranean regions, such as the Valencia Region, Spain, land cover transformations are mainly produced by contemporary socio-economic changes that have produced a drift from traditional agriculture to industrial and tourism economies, reinforced by population’s trends to concentrate in cities or larger urban regions. Evaluation of soil sealing is then a key element to understand soil degradation and the disappearance, in most cases, of highly productive soils. This work, inserted within a major study on land use-cover change and soil degradation of metropolitan areas in the Valencia Region, presents the preliminary results on the urban-non urban (open agrarian and natural spaces) dynamics in the municipality of Alicante, the second largest city in the region. Three sets of panchromatic air photos for the years 1956, 1985 and 1998 have been used. After air photo scanning, on screen digitising using a base digital topographic map at scale 1:10,000, was applied to extract two major types of soil cover: agrarian and urban. A Geographical Information System vector structure has been implemented for cartographic comparison. Finally, to identify spatial and temporal changes maps and overlays together with synthetic tables were produced in order to assess soil degradation. Results show that there has been a substantial loss of soil devoted mainly to agriculture. Urban growth can be differentiated into three distinct spatial patterns: 1) edge compact enlargement of the city boundaries, including growth following the main road network; 2) compact new urbanisation alongside the coast and 3) the colonisation by groups of individual residences mainly over continental open spaces. One of the main impacts of such new urban pattern has been the loss of the most fertile soils distributed over the alluvial plains around the city, which has been mainly occupied by the tourist and residential buildings
The following values have no corresponding Zotero field: periodical: Desertification in the Mediterranean Region a Security Issue
Keywords: Aerial photograph; desertification; Geographical information Systems.; Land degradation; Mediterranean environments; Soil sealing; Urban dynamics

The use of cork oak in the ecological and landscape restoration of the Latium Hills - Bellarosa, R.; Schirone, B.; Busatto, M. (SYMPOSIUM ON PLANT BIOTECHNOLOGY AS A TOOL FOR THE EXPLOITATION OF MOUNTAIN LANDS, 1998)
The cork oak (Quercus suber L.) is a western Mediterranean speciesfrequently found in Italy along the Tyrrhenian coast and on the islands. Its economic importance is well known, but the species is also ecologically precious. Notably, in fact, it is extremely resistant to forest fires. Because of its properties a project is on its way to restore the marginal lands of northern Latium through the reforestation with selected specimens of cork oak. The main aims of the project are: the genetic comparison between cork oak of different Italian provenances the establishment of an experimental arboretum which will collect cork oak deriving from the 34 main European areas the running of experimental trials on innovative reforestation techniques, such as the Miyawaki method. The methodology and initial results of the project are reported.
The following values have no corresponding Zotero field: periodical: SYMPOSIUM ON PLANT BIOTECHNOLOGY AS A TOOL FOR THE EXPLOITATION OF MOUNTAIN LANDS issue: 457 pub-location: PO BOX 500, 3001 LEUVEN 1, BELGIUM
Keywords: cork oak; genetic variability; arboretum; reforest

Vegetation of tuscan ultramafic soils in relation to edaphic and physical factors - Chiarucci, Alessandro; Robinson, Brett H.; Bonini, Ilaria; Petit, Daniel; Brooks, Robert R.; Dominicis, Vincenzo (Folia Geobotanica, 1998)
Vegetation and soil sampling were carried out in 80 plots located in five different ultramafic (serpentine) sites of Tuscany, central Italy. The physical and chemical features of each plot. were determined and the species composition and cover recorded. The exchangeable fraction of soil metals was analysed because it gives a measure of their concentrations available to plants. The plots were classified by cluster analysis and ANOVA was used to compare the environmental variables of the groups of plots. Canonical correspondence analysis was used to detect the principal factors for gradients of species composition within the plant communities. A higher content of exchangeable metals was found under the more evolved and structured plant communities, suggesting that serpentine vegetation of Tuscany is not strongly limited by soil metals, such as chromium, cobalt, nickel and magnesium, typically associated with ultramafic soils. The low nutrient content of the soils and drought stress mainly due to topographical features, appear to have a more significant role in determining the typical scattered vegetation of the Tuscan ultramafics.
Keywords: canonical correspondence analysis; Drought; serpentine; soil features; species diversity; vegetation ecology

VOC Emissions from Cork Products for Indoor Use - Horn, W.; Ullrich, D.; Seifert, B. (Indoor Air, 1998)
Abstract Complaints about unpleasant odour from wall, ceiling and floor coverings made of composite cork, induced chamber tests to study the emissions of volatile organic compounds (VOC) from composite cork products for indoor use. Emissions of phenol and furfural were found to be high, particularly those from cork parquet. Emission factors after 1 week ranged from 150 to 650 μg m−2 h−1 and from 15 to 350 μg m−2 h−1 for phenol and furfural, respectively, and decreased only slowly over time, by a factor of approx. 10 for a 6-month period. The ranges of emission factors were found to be similar for some solvents such as cyclohexanone or toluene which are constituents of varnishes used to protect cork surfaces. The emission of furfural may result from chemical reactions in the cork during the production process or may be caused by additives such as binders.
The following values have no corresponding Zotero field: publisher: Munksgaard International Publishers
Keywords: Chamber measurements; Composite cork; Emission factors; Furfural; Phenol

Volatile compounds produced by microorganisms isolated from cork - Caldentey, Paloma; Fumi, Maria Daria; Mazzoleni, Valeria; Careri, Maria (Flavour and Fragrance Journal, 1998)
Microorganisms present on cork (i.e. the reproduction bark of Quercus suber L.) can produce odorous compounds aecting the quality of cork stoppers. This work aims to contribute to the study of the correlation between microbial growth and formation of volatile compounds in the cork. Dierent strains of microorganisms were cultivated on both malt extract and cork, and the odour of the culture was described by a panel. The volatile compounds were isolated directly from the culture media by a dynamic headspace technique followed by adsorption on to Tenax traps. The volatiles were identi®ed by GC±MS: 63 substances were identi®ed in malt extract cultures, mainly consisting of carbonyl compounds (16), alcohols (16), and sesquiterpenes (13). Cultures on cork produced only 12 volatile compounds, more than half being sesquiterpenes. Sensory evaluation con®rmed that cork is an unfavourable culture medium if compared with malt extract.
Keywords: Cork; microbial growth; Quercus Suber L; volatile components

Analysis of Cork Taint in Wine and Cork Material at Olfactory Subthreshold Levels by Solid Phase Microextraction - Fischer, Claus; Fischer, Ulrich (Journal of Agricultural and Food Chemistry, 1997)
doi: 10.1021/jf970121rdoi: 10.1021/jf970121rThe following values have no corresponding Zotero field: publisher: American Chemical Society
Keywords: 2-4-6-trichloroanisole; Cork taint; SPME; wine

Anatomical changes and evolutionary trends in the foliar epidermis of extant and fossil Euro-Mediterranean oaks (Fagaceae) - Uzunova, K.; Palamarev, E.; Ehrendorfer, F. (Plant systematics and Evolution, 1997)
The differentiation of foliar epidermis structures, cuticles, stomata, and indumen- turn of most of the extant Euro-Mediterranean taxa of Quercus have been studied by light and scanning electron microscopy, and compared with other genera and fossil material. Results allow the recognition of the subgg. Sclerophyllodrys, Cerris and Quercus, and of various sections and even individual species. The cyclocytic stomata type, regarded as plesiomorphic, is found in the geologically oldest representatives of the familiy (DryophylIum, resp. Eotrigonobalanus) and in the relatively old, evergreen to semi-evergreen species of Quercus subgg. Sclerophyllodrys and Cerris. These taxa also have relatively thick and smooth cuticles. Anomocytic stomata, thinner cuticles and the presence of crystalline wax flakes are regarded as apomorphic features and characterize the deciduous taxa ofsubg. Quercus. These changes are interpreted as ecological adaptations to the changing climates from the Tertiary to the present. An analysis of the various character combinations found in macrofossils and the often poor species separation i n Quercus suggest that hybridization has played a major role in the evolution of the Euro-Mediterranean oaks.
Keywords: epidermis characters; evolutionary trends; Fagaceae; fossil and extant taxa; Quercus