Biological and biochemical indicators in derelict soils subject to erosion - Garcia, C.; Hernandez, T. (Soil Biology and Biochemistry, 1997)
n 21 derelict soils from a semi-arid Spanish Mediterranean area, with a lithological sub- strate of Ioams, submitted to a high degree of erosion, several biological and biochemical properties in- dicative of the soil degradation leve1 were determined. The organic matter content of these soils was very low (mean value = 11.8 g kg-‘), approximately one-third of the average value for organic matter content of natura1 soils in the same zone. Biological properties such as basal respiration and biomass C also had low values and were positively correlated with the organic matter content. Low values for de- hydrogenajse and catalase activity were indicative of low biological activity of the degraded soils. A positive correlation was found between the hydrolases related with the N, P, C and S cycles (urease, proteases, fl-glucosidase and arylsulphatase), as wel1 as between these hydrolases and the organic matter content. Principal component analysis showed that ah the variables studied, except catalase and qCOr, had a similar behaviour. There was a negative correlation between many of the properties studied and electrical conductivity, which agreed with the higher degree of biological and biochemical degradation found in gypsiferous soils with a higher salt content. Arylsulphatase and p-glucosidase activity were the hydrolases most affected by soil erosion processes
Keywords: biochemical parameters (PG); Biological indicators; derelict soils; Soil degradation

Chlorophyll fluorescence, stress and survival in populations of Mediterranean grassland species - Figueroa, M. E. (Journal of Vegetation Science, 1997)
Photosynthetic stress in response to a natural episode of frost and seasonal drought was assessed in a ‘dehesa’ grassland of SW Spain with a portable fluorimeter. Chlorophyll fluorescence characteristics of dark-adapted leaves of 11 abundant species of Mediterranean grassland were measured over the course of a growing season from November 1992 to July 1993. Concomitant changes in population size were estimated from censuses of permanent quadrats. There was a general decline in the photochemical efficiency (F v /Fm ) during the growing season and this was particularly evident late in the growing season (spring and early summer) when ambient temperatures were increasing rapidly and rainfall was low; it coincided with the period of most intense mortality for most species. A frost in early March (– 5 °C), when photosynthetically active radiation was relatively high, resulted in a small decrease in F v /Fm that was consistent across many species. The mechanisms of protection in species of Mediterranean grassland appear to be sufficiently effective to avoid damage to PSII for most of the year. For most species there was little evidence of photosystem II damage, as initial fluorescence (F 0 ) usually did not increase. Many of the effects observed were due to a reduction in Fm and thus were consistent with non-photochemical quenching. This could be adaptive in protecting PSII from damage in species that show little evidence of stress. The sharp increase in stress toward the end of the life cycle coincided with the fall in net population size.
Keywords: Drought; Fv/Fm; mortality; Photo-inhibition; photochemical efficiency; Photosystem II

Climatic discrimination of Mediterranean broad-leaved sclerophyllous and deciduous forests in central Spain - Gavilán, Rosario; Fernández-González, Federico (Journal of Vegetation Science, 1997)
Abstract. Climatic differences between three types of deciduous (Quercus pyrenaica) and three types of sclerophyllous (Quercus rotundifolia) Mediterranean forests in the Spanish Sistema Central were analyzed by means of Canonical Discriminant Analysis and Jancey's Discriminant Analysis, applied in successive steps to data from 252 meteorological stations. Climatic data included temperature and precipitation records as well as bioclimatic indices. Discriminant analysis was applied to broad-leaved sclerophyllous and deciduous forest communities sampled at each meteorological station using phytosociological methods. Annual and seasonal (summer, spring) water availability are the most important factor controlling the distribution of the two physiognomic forest types; southwestern associations of Quercus pyrenaica and Q. rotundifolia differ from their colder homologues by annual and monthly temperatures; western associations were separated from eastern ones in terms of annual and seasonal precipitation gradients. Discriminant analysis was a good technique to explore climatic gradients not shown by other general ordination or classification methods.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Bioclimatic indices; climate; Continentality; Discriminant analysis; Summer aridity; Water availability

Cork powder waste: an overview - Gil, Luis (Biomass and Bioenergy, 1997)
k powder, the major waste from cork processing industries, is generated throughout the industrial cork process and originates from grinding, cutting and finishing operations. Since there are various types of cork and different industrial operations, different types of cork powders are obtained. These have a high heating value, which make it suitable for energy production as well as other characteristics suitable for other uses as described here
Keywords: Cork; industry wastes; waste characterization; waste utilization

Cork-oak seedling production : Container capacity and substrate effect on seedling field performance - Costa, F.; Silva, E.; Moura, S.; Almeida, M. H.; Chambel, M. R.; Pereira, C. (Nursery production and stand establishment of broad leaves to promote sustainable forest management, 1997)
Cork oak is the second forest species in Portugal covering an area of about 721000 ha. In the context of the Common Agriculture Policy (CAP), large areas (ca. 10% of total area) were reforested between 1994-98 with low survival rates due to inappropriate nursery and establishment techniques, as well as the use of unsuitable genetic material. The main purpose of this study was to evaluate the effect of container capacity and substrate in field performance of cork oak seedling with 1 year of age during the first 3 years after plantation. Therefore 3 container capacities were tested (210, 300 and 400 cm3) in combination with 4 types of substrate: composted pine bark, composted pine bark with vermiculite 3:1(v/v), composted pine bark with peat 1:1 (v/v) and peat with vermiculite 3:1 (v/v). With the 300 cm3 container capacity 3 other substrates were also tested: F+H organic layers, F+H organic layers with composted pine bark 1:1 (v/v) and F+H organic layers with peat 1:1 (v/v). A field trial was established in the South of Portugal in April 1998. Just before plantation seedlings morphological characteristics (root and shoot biomass, leaf area, height, stem diameter, root length and root development patterns) were measured and correlated with survival and growth evaluated one, two and three years after plantation. The results showed that after three years in the field only the type of substrate had a highly significant influence in survival and early growth. Container capacity (210, 300 and 400 cm_) did not have an influence on height growth during the first 3 years, just as there was no clear influence on survival rate. Peat with vermiculite (3:1) substrate led to 30% higher survivals than other substrates. Substrate with peat favoured secondary root development (length), which seems to be an advantage in field performance.
The following values have no corresponding Zotero field: periodical: Nursery production and stand establishment of broad leaves to promote sustainable forest management pub-location: Rome
Keywords: container capacity; cork-oak seedling; Field performance; substrate

CRECIMIENTO RADIAL DEL CORCHO EN LOS ALCORNOCALES ESPAÑOLES: RELACIONES ENTRE ANATOMÍA Y BIOCLIMA. - Fos, S.; PÉREZ-RoViRA, P.; Barreno, E. (II Congreso Forestal Español, 1997)
A comparative study of the reproduction cork radial growth between the main cork productive areas in Spain is raised: Extremadura-Huelva, Cádiz, Girona and Castellón. The results show that environmental variables bring about significant differences in the annual increments and in the ratio between cork types (late/early cork). The highest average thickness had be en measured in Cádiz (Jerez de la Frontera - 5.587 mm) and the lowest in Castellón (Artana - 1.964 mm). Remaining results yield between 2.963 mm, measured in Sta. Cristina d' Aro (Girona), and 3.566 mm, in Casas de Miravete (Cáceres). These asymmetries are due to the higher early cork development. The most equilibrated corks in the contributions of each cork type are those produced in Cáceres (::::60:40) and Castellón (::::75:25), resisting with those observed in the other areas. The obtained results showed significant correlation with c1imatic (annual average temperature, precipitation) and bioc1imatic (It, Ic) parameters
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: Anatomy; bioc1imatology; Cork; Quercus suber; Radial growth

DEMANDAS SOCIALES, INTERÉS DE LOS PROPIETARIOS E INTERVENCIÓN PÚBLICA EN LOS ESPACIOS NATURALES: EL CASO DE LA DEHESA DE LA COMARCA DE MONFRAGÜE - Mariscal Lorente, Pedro Jesús; Campos Palacín, Pablo (IV Coloquio Hispano-Portugués de Estudios Rurales., 1997)
El creciente interés del público por consumir activamente (valores recreativos actual y futuro) y pasivamente (valor de existencia) los servicios ambientales de los espacios naturales adehesados junto con el continuado intento de ambientalización de la política agraria comunitaria, están produciendo una notable intervención pública hacia el fomento de la gestión conservadora de los recursos naturales y ambientales por parte de los propietarios de dehesas. En este estudio se presentan las preferencias sociales sobre los valores recreativos y de la conservación de la calidad ambiental de las dehesas de Monfragüe manifestadas por la disponibilidad al pago de los visitantes de libre acceso a través de una encuesta de valoración contingente. Se analizan las demandas de compensaciones económicas de los propietarios de dehesas en la comarca de Monfragüe para llevar a cabo mejoras en la conservación de los recursos naturales y los valores ambientales de las dehesas, dichas demandas han sido cuantificadas mediante una encuesta delphi, y se aporta una valoración contingente del auto-consumo anual de servicios ambientales controlados por los propietarios de dehesas. Los resultados de la investigación muestran que el público tiene una relevante disponibilidad al pago por el disfrute y la conservación de los atributos ambientales de la dehesa, que los propietarios aceptan en grados significativos el fomento de una ganadería más extensiva así como otras prácticas agrarias compatibles y favorecedoras de los recursos naturales, como la expansión artificial de los alcornocales y los encinares, siempre que se les recompense por el coste de oportunidad que conllevan y, finalmente, que estos propietarios actualmente auto-consumen anualmente servicios ambientales de sus dehesas por una cuantía que ellos estiman entre el 1% y el 5% del capital total invertido en su explotación adehesada.
The following values have no corresponding Zotero field: periodical: IV Coloquio Hispano-Portugués de Estudios Rurales. issue: i
Keywords: auto-consumo ambiental; demanda de compensaciones; encuesta delphi; prácticas de conservación ambientales; Reforestación de encinas y alcornoques; subvenciones públicas; valoración contingente

Distribution of an increasing roe deer population in a fragmented Mediterranean landscape - Tellería, José Luis; Virgós, Emilio (Ecography, 1997)
This paper describes roe deer Capreolus capreolus distribution in central Spain, where the species has spread from the mountains into peripheral agricultural areas In this region, it is more abundant in forest fragments near the mountains than in those further away, in pine and oak woodlands than in sclerophyllous forests, and in forests with open water than in those lacking this resource The paper also analyzes whether habitat quality and geographic location of forests with respect to roe deer source areas are the two basic causes of its distribution, as predicted by some models of the species distribution in fragmented landscapes The results corroborate this hypothesis revealing that roe deer abundance is linked negatively to sclerophyllous forest cover and distance from mountains We conclude that this type of farmland seems to be sub-optimal for roe deer in comparison with forested, moist mountains
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: abundance; Distribution patterns; forest cover; habitat quality (voyant); roe deer

Diurnal and seasonal course of monoterpene emissions from Quercus ilex(L.) under natural conditions application of light and temperature algorithms - Bertin, N.; Staudt, M.; Hansen, U.; Seufert, G.; Foster, P.; Fugit, J. L.; Torres, L. (Atmospheric Environment, 1997)
Quercus ilex is a common oak species in the Mediterranean vegetation and a strong emitter of monoterpenes. Since the short-term control of monoterpene emissions from this species involved both temperature and light, the usual exponential function of temperature may not be sufficient to model the diurnal and seasonal emission course. In the frame of the BEMA-project (Biogenic Emissions in the Mediterranean Area), we investigated the tree-to-tree, branch-to-branch, diurnal, and seasonal variability of monoterpene emissions from Q. ibex over one and a half years at Castelporziano (Rome, Italy). In addition, w,: checked the suitability of the model developed for isoprene by Guenther et al. (1991, 1993) to simulate the short- and long-term variations of monoterpene emissions from this particular species. We found that the tree-to-tree variability was rather small compared to the experimental error during air sampling and analysis by diverse laboratories. The branch-to-branch variability was noticeable between sun- and shade-adapted branches only. 80% of total emissions were represented by cc-pinene, B-pinene and sabinene, whose proportions were stable over the year and independent of light exposure. The emission factor (emission rate at 30°C and 1000 ~molphotonm-Zs-l ) estimated by the isoprene model or extrapo- lated from measurements was similar: it was about 22 pggdw -r h-r for sun-exposed branches and 2.3 pggdw.-’ h-r for shade-adapted branches. It was rather stable over the seasons except during leaf development. The diurnal and seasonal emission patterns from Q. ibex were simulated in a satisfying way by Guenther’s algorithms especially if we excluded the laboratory variability. For shade-adapted branches, an emission factor 17 times lower had to be applied, but temperature and light responses were unchanged.
Keywords: Holm oak; index; light and temperature algorithm; Mediterranean vegetation; Modelling; Monoterpene; Quercus ilex

Diurnal fluctuations of secondary photooxidants in air and of detoxification systems in the foliage of Mediterranean forest trees - Junkermann, Wolfgang; Polle, A. (Atmospheric Environment, 1997)
s-phase peroxide mixing ratios were measured in the canopy area of a Mediterranean oak/pine fo.rest. Concurrently the activities of cell wall localized peroxidases, which protect leaves from external oxidants, were investigated. The diurnal cycles of peroxidase activity showed a strong decrease when the gas-phase concentration of highly phytotoxic hydroxy hydroperoxides increased. These results suggest that ambient gas-phase mixing ratios of organic peroxides may injure the plants’ oxidative defence system
Keywords: antioxidant protection; organic peroxides; peroxidase activity

Edaphic characteristics of Quercus suber woods in Latium - Dowgiallo, G.; Testi, A.; Pesoli, P.; Pignatti, S. (Rendiconti Lincei, 1997)
{In this paper the results are reported of a soil survey done in selected sites of Latium un- der the most significant Quercus suber woods (Cytiso-Quercetum suberis Testi, Pignatti and Lucattini 1994) previously studied from a phytosociologicat point of view. After describing the dominant soil type of each area, physical-chemical characteristics have been analysed in order to point out the significance of edaphic factors in the distribution and floristic composition, of the Quereus suber co,noses. Bioclimatic, structural and edaphic features of this vegetation showed a great convergence; among all the parameters examined, AWC resulted to be the most effective one in conditioning the mesophilous character of Quercus suber coenoses growing in Latium. In this respect this type of vegetation shows rather strong affinities with mixed Quercztr cerrz} woods, both in the floristic composition and in the edaphic requirements, as already suggest- ed in the most recent phytosociological studies.
Keywords: Correlation soil-vegetation; Latium; Quercus suber oakwoods; soils

Efeitos da poda radicular na produçáo de plantas de sobreiro em viveiro (quercus suber l.) - Santos, Maria de Lourdes; PAULINO, ISABEL MARGARIDA ORFÁO (II Congreso Forestal Español, 1997)
The work was accomplished in the Seed Laboratory of National Forestry Station. The aim is to observe, in the nursery plants production, the pruning root effects made at several levels. The seeds provenance are the selected trees. The results permitted to conclude that: • The plants submitted to a radicular pruning at 1/3 and 2/3 present a better thickening and become woody plants; • The plants submitted to a radicular pruning at 1/3 present higher size of aerial parts; • The plants submitted to a radicular pruning at 2/3 present higher rate of secondary roots. K.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: Nursery; Plants; Quercus suber; radicular pruning

Effects of germination inhibition on the dynamics of Quercus ilex stands - Li, Junqing; Romane, Francois J. (Journal of Vegetation Science, 1997)
Abstract. Germination of Quercus ilex L. in coppice stands of this species in the western Mediterranean Basin was examined and a germination inhibitory process is proposed to explain some germination traits. Germination rate and seedling biomass of Q. ilex were greatly modified by watering acorns with various concentrations of aqueous soil extracts from a Q. ilex coppice stand but also when the acorns were sown in soil from Q. ilex coppice stands. In the aqueous extract experiment, Q. ilex germination and seedling weight both decreased as the aqueous extract concentration increased. In the soil type experiment, Q. ilex soil decreased the Q. ilex germination rate. Comparative studies with Q. pubescens germination (this species, replaced by Q. ilex around 5 000 B.P., is assumed to form the climax vegetation of the region) revealed that Q. pubescens was less sensitive to the aqueous extracts and soils of Q. ilex coppice stands. Inhibition of Q. ilex seed germination could be a major reason for the poor seed regeneration and suggested a possible comeback of Q. pubescens.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Allelopathy; Mediterranean vegetation; Quercus pubescens Willd

Effects of introduced exotic tree species on Collembola communities: The importance of management techniques - SOUSA, J. P.; Vingada, J. V.; Barrocas, H.; DAGAMA, M. M. (PEDOBIOLOGIA, 1997)
Studies of the impact of the substitution of autochthonous forests by plantations of exotic tree species (a quite common phenomenon in Southern European countries) on soil arthropod communities (mainly Collembola and Acarina) generally deal with the effects of the exotic species per se and disregard the management techniques used. In this study the impact of the introduced Eucalyptus globulus on the Collembola communities of Quercus ilex ballota and Quercus suber stands was analysed. Since the autochthonous tree species are similar (in terms of leaf type and the ability to produce litter) the main objective was to examine the effects of the different management techniques used in the two plantations of Eucalyptus. (i) There is a significant difference in management techniques used in the Eucalyptus plantations leading to differences in habitat configuration: the plantation associated with the Helm-Oak stand is used for cellulose paste production, with periodic removal of the shrub and herbaceous layers; the other plantation, close to the Cork-Oak stand, is not managed at all, presenting an abundant shrub layer. (ii) in both cases, the substitution of the Oak species by Eucalyptus caused a disruption of the Collembola communities, although it was more pronounced in e. ilex ballota vs E. globulus (station 1) than in e. suber vs E. globulus (station 2). The number of individuals, the number of taxa and diversity parameters are in most cases greater under Oak species but more evident in station 1. (iii) Given these results, the influence of the factor `'management technique-habitat configuration'' in analysing and interpreting effects of exotics on soil arthropod communities is discussed.
IX International Colloquium on Apterygota, DUBLIN, IRELAND, 1996IX International Colloquium on Apterygota, DUBLIN, IRELAND, 1996The following values have no corresponding Zotero field: pub-location: VILLENGANG 2, D-07745 JENA, GERMANY publisher: GUSTAV FISCHER VERLAG
Keywords: Collembola community disruption; EUCALYPTUS; Quercus illex; Quercus suber

Embriogénesis gamética para obtención de haploides en alcornoque. - Bueno, A.; GÓMEZ, A.; Boscaiu, M.; Manzanera, J. A.; Vicente, O. (II Congreso Forestal Español, 1997)
Inducción of haploid embryos and regeneration of plantlets have been obtained for the first time, in cork oak (Quercus suber L.) by combining a starvation treatment in anther culture with a mild heat shock at 33°C for 5 days, followed by culture at 25°C in a simple agar medium without growth regulator.s. The same conditions had been shown previously to be optimal for embryogenic induction in isolated microspore cultures of several model species such as tobacco and wheat. These results support the notion that stress, particularly sucrose starvation, a heat shock or a combination of both treatments could be the major and general signal responsible for the inhibition of normal gametophytic development of the microspores and for the induction of the alternative embryogenic pathway. A similar approach may be used for the production of haploid and doubled haploids for plant breeding in other species that like most forest trees, are still recalcitrant in anther culture.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: anther culture; Cork oak; Haploid plants; Stress

ENSAYO DE DIFERENTES TIPOS DE CONTENEDORES PARA Q.ILEX, P.HALEPENSIS, P.PINASTER Y P.PINEA: RESULTADOS DE VIVERO - DOMINGUEZ LERENA, S.; HERRERO SIERRA, N.; CARRASCO MANZANO, I.; OCAÑA BUENO, L.; PEÑUELAS RUBIRA, J. L. (II Congreso Forestal Español, 1997)
The influence of 16 of the most commonly utilised containers on seedling characteristics of Quercus ilex, Pinus pinea, P. halepensis and P. pinaster have been analysed. Studied plant features -height, diameter, shoot and root dry weight, and number of branches- were correlated with container dimensions. Observations on sorne practical problems in several containers and their suitability for forest plant production are given.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español
Keywords: calidad de planta; desarrollo; envases; sistemas radicales

ENSAYO DE TRATAMIENTOS HERBICIDAS EN CULTIVO DE TRES ESPECIES FORESTALES (P. halepensis, P. nigra y Q. ilex) EN VIVERO - CARRASCO MANZANO, I.; OCAÑA BUENO, L.; PEÑUELAS RUBIRA, J. L.; DOMINGUEZ LERENA, S. (II Congreso Forestal Español, 1997)
Weeds are one of the problems which more economic costs originates in forest nurseries due to their effect on crop growth. In spite of this, the effect of weeds on forest seedlings and their control in the nursery have not been much studied. In this study we have analysed the ability of five herbicides (Pendimethalin, Propizamide, Napropamide, Oxyflurofen and Simazine) in controlling weeds and their possible harmful effect on two Pinus species (Pinus halepensis, P. nigra ) and Quercus ilex in the nursery. Pendimethalin and Propizamide damaged seriously all tree species while Napropamide and Oxyflourfen did not produce any harmful effect and did not control effectively weeds. Simazine controlled weeds not affecting tree seedlings although it had to be applied periodically to mantain its effect on weeds.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: Herbicides; Nursery

ESCORRENT~ A SUPERFICIAL EN LAS VERTIENTES DE UNA CUENCA HIDROGRÁFICA EN EL ECOSISTEMA DEHESA. CUENCA DE GUADALPERAL~ N - Ceballos, Antonio; Schnabel, S. (Geographicalia, 1997)
In a sinall catchrnent under tlie deliesa landuse system overland flow production on slopes is investigated. The obtained results show tliat tl-ie determination of tl-ie tlireshold value for tl-ie generation of runoff is complex. Total precipitation and rnaxim~~m intensity in 10 minutes are the principal factors that explain tl-ie production and generatioii of slope runoff
Keywords: dehesa ecosystem; overland flow; slopes

Estudio comparativo de morfología en planta de encina cultivada en distintos envases comerciales - ÁLVAREZ LINAREJOS, L.; RAPP ARRARÁS, I. (II Congreso Forestal Español, 1997)
The aim of the present work is to analize the morfological diferences and its caracterization depending on the container used in nursery production of one year holm oak plants. Six different types of containers -those suitable to be bought in the area were the experiment has taken place- has been used for it. It has been stablished the greatest posible homogeneity in other parameters which influence could have been important such as seeds - which procedence is known-, cultivation media, watering, and microclimate -in greenhouse first and nursery later-. Results for sorne of the factors studied are shown.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español issue: 57 pub-location: Pamplona
Keywords: Containers; Holm oak; Nursery; Plant production

European and Mediterranean oaks (Quercus L.; Fagaceae): SEM characterization of the micromorphology of the abaxial leaf surface - Bussotti, Filippo; Grossoni, Paolo (Botanical Journal of the Linnean Society, 1997)
This paper examines micromorphological characteristics (trichomes, waxes, stomata) of the abaxial leaf surface of European and Mediterranean oaks. Observations were performed In-scanning electron microscopy, and the purpose of the investigation was to ascertain whether it is possible to distinguish the different species taxonomically using these features. Several species, as well as some subspecific entities and taxa considered doubtful, were taken into consideration. Subgenera appear to be well-defined: e.g. the subgenus Quercus is characterized by waxes arranged in vertical scales, the subgenera Cenis and Sclerophyllodris by smooth waxes. They differ because the former has markedly elliptical stomata, while the latter two have roundish stomata. The different species are also fairly easy to distinguish, and this fact confirms the taxonomical validity of the parameters we have taken into consideration. In some cases subspecific entities and doublful species do not diflcr at all from the related species, but in others they present such marked variations that it is difficult even to classify them with certainty. The most critical taxonomic groups (i.e. those which include a number of specific and subspecific entities often too difficult to distinguish from each other) are the series Quercus robur – Quercus petraea,– Quercus pubescens and the Quercus faginea,– Quercus Insitanica Quercus canariensis group.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: stomata; taxonomy; Trichomes; waxes

Fire and late-Holocene expansion of Quercus ilex and Pinus pinaster on Corsica - Carcaillet, Christopher; Barakat, Hala N.; Panaïotis, Christophe; Loisel, Roger (Journal of Vegetation Science, 1997)
Abstract. The natural origin of old Quercus ilex (holm oak) forests on the west coast of Corsica is a matter of dispute. This paper discusses the use of pedoanthracology, especially adapted to approach topics in palaeoecology requiring a high spatial precision. It also shows the importance of fire in vegetation change during the Holocene. Pedoanthracology relies on botanical identification and AMS 14C dating of micro-charcoal found in soil. Three test pits were dug in a forest currently protected within the ‘Man and Biosphere’ program. These pits yielded large quantities of charcoal. There is evidence that Pinus nigra ssp. laricio (laricio pine) and understorey heather species (Ericaceae) played an important role in the vegetation at the beginning of the Subatlantic (ca. 2500 BP). The importance of Pinus pinaster (maritime pine), Quercus ilex and a few mesophilic species increased between 2000 and 1000 BP. Charcoal fragments found in the soil show the role of fire in the vegetation changes recorded. The late expansion of P. pinaster results from a high fire frequency. The hypothesis proposed in the paper suggests that fires destroyed the remaining toxic humus that had accumulated during the millennia which preceded the arrival of Q. ilex to our study sites. The late development of holm oak forest is a combination of the migration of the species and the increase of fire frequency since 2500 BP, most probably resulting from slash-and-burn agriculture.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: charcoal; Evergreen mediterranean forest; Fango valley; human impact; MAB reserve; Quaternary ecology

Growth inhibition of nematophagous and entomopathogenic fungi by leaf litter and soil containing phenols - Lopez-Llorca, L. V.; Olivares-Bernabeu, C. (Mycological Research, 1997)
In a soil survey, nematophagous fungi were recovered less from agar plates sprinkled with forest soil (Quercus ilex subsp. rotundifolia) than from those incubated with agricultural (Citrus orchards) soil. Nematodes were present in all soils. The organic matter was higher in forest soils. Water extracts from forest soils with high levels of phenols, leaf litter and Q. rotundifolia fresh leaves aﬀected the development and growth of common species of nematophagous and entomopathogenic fungi. These results show that phenolics from leaf letter could play an important role in the ecology and biology of these invertebrate pathogens in soil.
Keywords: agricultural soil; entomopathogenic fungi; forest soil; fungal growth (voyant); leaf litter; nematophagous fungi; phenolic compounds; quercus ilex ssp rotundifolia

Highly specific and sensitive non-radioactive molecular identification of Phytophthora cinnamomi - Coelho, A. C.; Cravador, A.; Bollen, A. (Mycological Research, 1997)
In response to the need for a faster, more reliable method for identifying Phytophthora cinnamomi in cork oak soils in Portugal, a simple, fast, sensitive molecular identi®cation method is described. It is based on a colorimetric assay which involves an oligonucleotide capture probe covalently immobilised on microtitration wells, a multi-biotinylated oligonucleotide detection probe and the PCR-ampli®ed target DNA. The target DNA is a 349 bp DNA fragment partially covering the 3«-translated and 3«- untranslated regions of the cinnamomin gene. When the speci®city of the PCR reaction was evaluated in vitro using isolates of P. cinnamomi and eight other Phytophthora species, including the related P. cambivora, it was speci®c to P. cinnamomi. When 30 isolates of P. cinnamomi from oak roots in southern Portugal were assayed, 26 gave a strong positive response. The assay has a sensitivity of about 2±5 genome equivalents of P. cinnamomi. The reason for the negative response of four isolates remains unclear.
Keywords: Cork oak soils; Iidentification method; phytophthora cinnamomi

The impact of grazing on forage quality of the herbaceous vegetation in the Mamora cork oak forest, Morocco - Alami, M. Mejjati; Bedell, T. E.; Sharrow, S. H.; Berkat, O. (African Journal of Range & Forage Science, 1997)
This research was conducted in the Mamora cork oak forest of Morocco to describe the impacts of sheep grazing (no use, 35% use, 70% use) in March, April, May and June of 1987 and 1988 on seasonal changes in forage quality of the herbaceous vegetation. The study showed that trends in herbage quality were related mainly to plant maturity. As more species mature, forage quality declines and falls below animal nutritional requirements, especially for young animals. With declining forage quality, the manager has the option of moving stock to areas of less-mature forage, supplementing the forage or modifying the demand placed upon it.
doi: 10.1080/10220119.1997.9647913doi: 10.1080/10220119.1997.9647913The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: crude protein; IVOMD; Mediterranean-type climate; minerals; time of grazing

Influencia del tamaño de bellota y del régimen de riego en la calidad de planta de alcornoque cultivada en vivero - Pardos Mínguez, M.; Cañellas, I.; Bachiller, A. (II Congreso Forestal Español, 1997)
The effect of three acorn sizes (small, medium and large, 2.5, 5 and 8.8 g mean fresh weight, respectively) and two irrigation regimes (Rl=2R2) in the growth of cork oak containerized (Forest Pot 300) seedlings was studied. The seedlings were grown in the nursery for one year.The results showed the influence of the acorn size on caliper, root volume, shoot, root and acorn dry weights, leaf area, leaf weight ratio (L WR), leaf area ratio (LAR), midday water potential and transpiration. Irrigation was statistically significant for height and totalleaf area. Water potential reached less than -2 MPa in July. This fact reveals the adaptation of the species to drought.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español
Keywords: acorn size; irrigation; Quercus suber; seedling quality

Isoprenoid emission of oak species typical for the Mediterranean area: Source strength and controlling variables - Steinbrecher, Rainer; Hauff, Karin; Rabong, Richard; Steinbrecher, Jutta (Atmospheric Environment, 1997)
easurements of isoprenoid emission on five Mediterranean oak species in the field revealed that Quercu.s frainetto, Quercus petraea and Quercus pubescens are strong emitters of isoprene. In contrast Quercus cerris and Quercus suber emitted no significant amounts of isoprene and monoterpenes. For Q. pubenscens and Q. frainetto median emission factors of 16.68 nmoIm-2s-1 (86.06 pgg-’ dw h-‘) and 30.72 nmolrn-2s-1 (133.95 pgg-’ dw h-l) were calculated, respectively. The 25 to 75 percentiles span of the emission factor data sets ranged from - 53% to + 56% of the median values. Light and temperature are the main controlling factors for isoprene emission. The influence of other environmental and plant physiological parameters on the isoprene emission is discussed. The “Guenther” emission algorithm is able to predict the daily maximum of the isoprene emission within the plant specific uncertainty range. However, the morning increase and the afternoon drop in the isoprene emission is not well parameterized. On the basis of process oriented models for the synthesis of isoprene in plants, a further reduction in the uncertainty may be achieved resulting in a more reliable prediction of short-time variation in isoprene emission
Keywords: biogenic voc; Emission factors; isoprene; Monoterpene; Quercus

Landscape structure and breeding bird distribution in a sub-Mediterranean agro-ecosystem - Farina, Almo (Landscape Ecology, 1997)
Richness, abundance and distribution of birds were investigated in the Aulella watershed, a mountainous area of 300 km2 , located in the extreme northwestern corner of Tuscany, Italy in spring and summer, 1995. The study area encompasses five vegetation types (from Mediterranean maqui to upland beech forest) and three main land use categories (woodlands, mixed cultivated + urban areas, montane prairies). The recent history of land abandonment in the study area has produced a rapid expansion of shrubland and woodland, reducing cultivated areas to small patches interspersed in a woodland matrix. Richness, abundance and distribution of birds recorded at 414 points, randomly selected along secondary roads, and located using a Global Positioning System (GPS), were compared with topography, vegetation type and land use in a Geographic Information Systems (GIS) with a grid cell resolution of 200 × 200 m. Bird richness (55 species in all) and abundance are correlated: (a) negatively with the increasing altitude and increasing distance from cultivated areas; (b) positively with the increasing distance from woodlands and mountain prairies. Slope orientation appears to have a negligible effect on bird assemblages. Bird richness and abundance are significantly correlated with vegetation type. Cultivated areas support the highest bird richness and abundance that increase with patch size of the cultivated areas. Local extinction and/or reduction in within-species abundance of birds are expected to continue if the process of land abandonment continues.
Keywords: aulella watershed; geographic information systems; global positioning system; sub-mediterranean agro-ecosystem; tuscany

Leaf morphology and leaf chemical composition in three Quercus (Fagaceae) species along a rainfall gradient in NE Spain - Castro-Díez, P. (Trees-Structure and …, 1997)
mLeaf features were examined in three Quercus species (Q. coccifera, Q. ilex and Q. faginea) along a steep rainfall gradient in NE Spain. The analyzed leaf traits were area, thickness, density, specific mass, leaf concentration of nitrogen, phosphorous, lignin, cellulose and hemicellulose, both on a dry weight basis (Nw, Pw, Lw, Cw, Hw) and on an area basis (Na, Pa, La, Ca, Ha). These traits were regressed against annual precipitation and correlated with each other, revealing different response patterns in the three species. Q. faginea, a deciduous tree, did not show any significant correlation with rainfall. In Q. coccifera, an evergreen shrub, Nw, Na, Lw, La and Ca increased with higher annual rainfall, while Hw decreased. In Q. ilex, an evergreen tree, leaf area, Pw and Lw increased with precipitation, whereas specific leaf mass, thickness and Ha showed the reverse response. Correlations between the leaf features revealed that specific mass variation in Q. faginea and Q. coccifera could be explained by changes in leaf density, while in Q. ilex specific leaf mass was correlated with thickness. Specific leaf mass in the three species appeared positively correlated with all the chemical components on a leaf area basis except with lignin in Q. ilex and with P in Q. ilex and Q. faginea. In these two tree species Pw showed a negative correlation with specific leaf mass. It is suggested that each species has a different mechanism to cope with water shortage which is to a great extent related to its structure as a whole, and to its habit.
Keywords: environmental gradient; Leaf fibre content; leaf morphology; Leaf nutrient content; Mediterranean climate

Liquid medium culture of Quercus suber L somatic embryos comparation between liquid and solid culture and among different growing media - Garcia, G.; Fernandez-Galiano, E.; Mauri, P. V. (HORTICULTURAL BIOTECHNOLOGY IN VITRO CULTURE AND BREEDING, 1997)
The objective of this study was to overcome two of the limiting factors of the standard culture protocol, in agar solidified medium, of cork oak somatic embryos: the low rate of mature embryos obtained, and the high labor and time consumed. First experiment. Immature somatic embryos of 2 mm. length were cultured for 30 days in four different growing media: 1/2SH{*}, SH{*}, 2xSH{*} and MS, both in solid and liquid phase. Higher fresh weights were detected, in every media, using liquid culture. In relation to developmental pattern, liquid culture in 1/2SH{*} has demonstrated to be the most effective combination for the first developmental stages producing lower percentages of secondary embryogenesis. Second experiment. Immature somatic embryos were cultured for 15 days in liquid 1/2SH{*} and transferred to the four different media. The richest media were shown to be more appropriated for the maturation stage giving higher rates of mature embryos.
The following values have no corresponding Zotero field: periodical: HORTICULTURAL BIOTECHNOLOGY IN VITRO CULTURE AND BREEDING issue: 447 pub-location: PO BOX 500, 3001 LEUVEN 1, BELGIUM
Keywords: Cork oak; liquid culture; mature embryos

Low Molecular Weight Polyphenols in Cork of Quercus suber - Conde, Elvira; Cadahía, Estrella; García-Vallejo, María Concepción; Fernández de Simón, Brígida; González Adrados, José Ramón (Journal of Agricultural and Food Chemistry, 1997)
Low molecular weight polyphenols were studied by HPLC in samples of cork from different trees of Spanish Quercus suber and at different industrial processing stages. Gallic, protocatechuic, vanillic, caffeic, ferulic, and ellagic acids; protocatechuic, vanillic, coniferylic, and sinapic aldehydes, and aesculetin and scopoletin were identified and quantified. Ellagic acid was the main component in all of the samples, followed by the rest of the phenolic acids, which had very much lower concentrations. Four components, caffeic, ferulic, and protocatechuic acids and vanillin, were selected as those that provided the greatest differences among the trees studied. In relation to the four industrial processing stages considered, marked differences were observed between the first two stages, stripping and first rest, and the stages after boiling. In this case, the discriminant variables were coniferaldehyde, sinapaldehyde, and ellagic acid. Keywords: Quercus suber; cork; polyphenols; phenolic acids and aldehydes; coumarins; high-performance liquid chromatography
doi: 10.1021/jf960486wdoi: 10.1021/jf960486wThe following values have no corresponding Zotero field: publisher: American Chemical Society
Keywords: Cork; coumarins; high- performance liquid chromatography; phenolic acids and aldehydes; polyphenols; Quercus suber

Mate guarding in the spotless starling (Sturnus unicolor): Timing and duration pattern in intermediate breeding pairs - Deceuninck, B.; Peris, S. J.; Calvo, J. M.; Pascual, J. A.; DelaCruzCardiel, P. J. (FOLIA ZOOLOGICA, 1997)
Mate guarding behaviour in the spotless starling Sturnus unicolor, acolonially breeding passerine was observed in five focal pairs of a nestbox colony in a Spanish `'dehesa'' (extensive pastured helm oak wood) in 1993. Daily observations were performed since the day of pair formation. Escorting behaviour began 4 days prior to laying and declined sharply between the 2 and 3 days of the laying period. Males followed their females more than the reverse, and spent more than 90% of time in the colony with the female during her fertile period. When escorting the females, males actively chased off other males to prevent them appproaching their mate. While males escorted females during fertile period up to 100% of times when they left colony, females came back to colony without their mate nearly 30% of times, showing that females succeeded in escaping their mate Vigilance when moving outside the colony. These results suggest that males guard in aim to keep other males away from their female, but also to keep females from approaching other males. Most of the observed copulations occurred during the guarding period. No extra-pair copulations (EPC) were witnessed between individuals of breeding pairs during the study time. One attempt of EPC occurred between a male of focal pair and a female of non-focal unstable pair. Nestbox occupation by unstable pairs and the shortness of time separating pair formation and laying in intermediate breeding pairs are discussed.
The following values have no corresponding Zotero field: pub-location: KVETNA 8, BRNO, CZECH REPUBLIC 603 65 publisher: INST VERTEBRATE ZOOLOGY
Keywords: male behaviour; Sturnus unicolor; intermediate clu

Medicinal plants used in the Barros Area, Badajoz Province, Spain. - Vázquez, F. M.; Suarez, M. a; Pérez, A. (Journal of ethnopharmacology, 1997)
A study of the wild and cultivated medicinal plants used in the Barros Area (southern Spain) is reported, 48 plants distributed among 20 different families are used in the treatment of various human diseases. The use of Bellis annua L. Centaurea ornata Wild., Leuzea conifera (L.) DC., Pulicaria paludosa Link and Asparagus aphyllus L. is reported.
From Duplicate 2 (Medicinal plants used in the Barros Area, Badajoz Province, Spain. - Vázquez, F M; Suarez, M a; Pérez, A)From Duplicate 2 (Medicinal plants used in the Barros Area, Badajoz Province, Spain. - Vázquez, F M; Suarez, M a; Pérez, A)The following values have no corresponding Zotero field: accession-num: 9032619
Keywords: Data Collection; Humans; Medicinal; Medicinal plants; Medicinal: classification; Medicine; Phytotherapy; Plants; southern Spain; Spain; Structure-Activity Relationship; Traditional; Traditional phytotherapy

Mineralogical composition of African dust delivered by red rains over northeastern Spain - Avila, A.; QueraltMitjans, I.; Alarcon, M. (JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 1997)
The African dust deposition, mineralogy, source regions, and influence on rain chemistry were analyzed for a site in the Montseny mountains (Catalonia, northeastern Spain) for the period August 1, 1983, through August 1, 1994. Dust deposition was highly variable: two events (collected on November 9-11, 1984, and March 22-25, 1991) accounted for 62% of the total dust input in the 38 red rain events recorded in the period. The average annual dust deposition was 5.3 g m(-2) (SE 2.6). Three source regions in the African continent were identified with back trajectory analysis: (1) Western Sahara, (2) Moroccan Atlas, and (3) Central Algeria. Events from the Moroccan Atlas predominated in terms of number of events, amount of rainfall, and dust deposition. The meteorological situations during red rains were identified: Western Sahara events occurred principally with a depression at high latitudes (50 degrees N) forming a trough in the North Atlantic, Moroccan Atlas events occurred with a depression in front of Portugal, and events from central Algeria were associated with a depression over Spain or North Africa. By order of abundance (median of n=13) the minerals identified in the dust by X ray diffraction were as follows: illite > quartz > smectite > palygorskite > kaolinite > calcite > dolomite > feldspars. Differences in mineralogy between source regions were significant for smectite, kaolinite, quartz, and dolomite. Smectite and kaolinite content was highest in the Algerian events, while quartz and dolomite content was lowest. Events from the Moroccan Atlas had the lowest smectite and kaolinite. The red rain soluble chemistry was clearly influenced by the dissolution of calcite (high alkalinity, calcium concentration and basic pH) and by marine components (high Na+, Cl- and Mg+2 concentrations). Because of the very alkaline character of red rains they had a strong weight on the annual mean pH of rainwater. This was reflected by the significant relationship (r=0.71, p<0.01) between the percentage of annual precipitation as red rain and annual mean precipitation pH. Red rains provided 25-45% of the annual dissolved input of the major ions in precipitation and 34% of the calcium required for helm oak (Quercus ilex L.) forest growth at the study site.
APSAPSThe following values have no corresponding Zotero field: pub-location: 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA publisher: AMER GEOPHYSICAL UNION
Keywords: Africa; dust deposition; Montseny mountains; Quercus ilex L.

Morphological adjustments of mature Quercus ilex trees to elevated CO 2 - Hättenschwiler, S.; Miglietta, Franco; Raschi, Antonio; Körner, C. (Acta Oecologica, 1997)
It is still not known whether mature forest trees respond to increasing atmospheric CO 2 concen- trations in similar ways as seedlings do. Mature Mediterranean oaks (Qaercus ilex) growing in a CO 2 enriched atmosphere around natural CO 2 vents since the seedling stage showed a moderate, age- dependent increase in stem biomass production, but had significantly lower biomass of 6-year-old branches, decreased branching, and lower leaf area per unit branch biomass, compared to control trees at a nearby unenriched site. Our data indicate that trees in natural forest stands morphologically adjust to increasing CO 2 and reduce COz-induced initial growth stimulations. Allometric adjustments such as reduction in leaf area may be regarded as a "down-regulation" of canopy photosynthesis and may be an effective mechanism for saving water.
Keywords: allometric adjustments; biomass allocation; branch morphology; branching; leaf area; Mediterranean; natural co 2 springs; Quercus ilex

Multiplicación vegetativa de alcornoque mediante embriogénesis somática. - Garcia-Martin, G.; Fernandez-Galiano, E.; Mauri, P. V.; Somática, Embriogénesis (II Congreso Forestal Español, 1997)
In order to obtain cork oak clones from selected individuals, somatic embryogenesis was induced in leaves. Somatic embryos can be continuously subcultured with high proliferation rates. This culture system has sorne limiting factors: low percentage of mature embryos obtained, low rate of shoot emergence during germination and high labour and time consumed. Exogenous addition of ABA (l0-6M) concentration during proliferation increased maturation rateo In the same way addition of. BAP (0,001 mg/l) had a positive effect on shoot production. With the aim to obtain a first approach to automation the best culture media for both culture cycles of maturation in liquid medium were determined.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: ABA; BaP; Cork oak; germination; liquid culture; maturation; somatic embryos

Nitrogen availability in composted cork - Carmona, E.; Ordovas, J.; Ortega, M. C.; Aguado, M. T. (INTERNATIONAL SYMPOSIUM ON GROWING MEDIA AND PLANT NUTRITION IN HORTICULTURE, 1997)
Previous studies showed that plants grown in fresh cork (Quercus suberL. bark) had a reduced growth compared with peat and low rates of N. In composted cork, however, plant growth was similar with those in peat, but the N content of plants was still slightly lower. The purpose of this study was to investigate N availability in fresh and composted cork during 4, 5.5 and 7 months, using peat as control medium. The substrates were also incubated at 25 degrees C during 60 days after adding 0.25, 1.0, 1.75 or 3.0 g ammonium nitrate per 1 of substrate. Samples were taken periodically to measure NO3-N, NH4-N and total N. Also the Nitrogen Drawdown Index (NDI) for the addition of 75 mg.l(-1) N and 150 mg.l(-1) N was measured after incubation at 25 degrees C. N immobilization rates were well correlated to NDI. NH and soluble N drawed down rapidly in cork substrates while total N stayed constant. High rates of ammonium nitrate should be added to maintain a constant level of available N to plants in cork.
The following values have no corresponding Zotero field: periodical: INTERNATIONAL SYMPOSIUM ON GROWING MEDIA AND PLANT NUTRITION IN HORTICULTURE issue: 450 pub-location: PO BOX 500, 3001 LEUVEN 1, BELGIUM
Keywords: bark; growing media; N immobilization

Organic carbon and nitrogen mineralization under Mediterranean climatic conditions: the effects of incubation depth - Rovira, P.; Vallejo, V. R. (Soil Biology and Biochemistry, 1997)
n a soil profile, temperature and humidity regimes change with depth. Under Mediterra- nean conditions, upper horizons are more affected by water deficits and drying-rewetting cycles than deep horizons. Our aim was to study how carbon and nitrogen mineralization are affected by depth, and special attention is paid to separating the effects of pedoclimate from the effects of other con- straints like amount and quality of organic matter. To this end, mixtures of plant + soil material were exposed by incorporation in the field, at depths of 5, 20 and 40 cm, in nylon mesh bags. Mineralization of C and N was studied for 2 y. For all types of plant material studied (Eucalyptus globulus, Quercus ibex and Pinus halepensis), mineralization of both carbon and nitrogen was lower at 5cm. No differ- ences were between 20 and 40 cm. This result, probably as a result of the higher drying of the upper- most horizons, contrasts with the usual findings on this topic. The amounts of both C and N mineralized were lower than expected, probably because plant materials were finely ground, allowing stabilization in the mineral matrix of soil. With the possible exception of Pinus, depth affected the rate of mineralization, not the relation between C and N. It is concluded that, at least under Mediterranean conditions, the pedoclimate in deep layers is more favourable to microbial activity than in upper layers, in which drought is a strong limiting factor. Reduced oxygen availability in the subsoil layers did not inhibit decomposition and mineralization to the same extent as did desiccation in the surface layer. The higher mineralization of C and N usually found in upper horizons may be attributed to the higher amount and quality of organic matter in these horizons, rather than to pedoclimatic constraints
Keywords: mineralization; organic matter (voyant); Soil depth; water content

Os principais tipos de utilização do solo no Alentejo meridional: evolução de 1885 e 1951 - Feio, M.; Cordeiro, A. M. (Finisterra: Revista portuguesa de …, 1997)
Partindo das Cartas Agrícolas de G. Pery, do fim do século XIX, e da Carta Agrícola e Florestal do SROA, de meados do século XX, apresenta-se a evolução dos principais tipos de utilização do solo no Alentejo meridional: charneca, culturas arvenses, montado, olivais e vinha. A evolução foi muito grande, principalmente na redução da charneca e no grande aumento das culturas de cereais, causadas pelo proteccionismo do trigo (Elvino de Brito), instituído no fim do séc. XIX, de que resultou considerável aumento de preço deste cereal.
Keywords: agricultura; Alentejo; evolução

Photosynthetic activity of Quercus ilex at the extremes of a transect between Mediterranean and submediterranean vegetation (Trieste NE Italy) - Tretiach, M.; Bolognini, G.; Rondi, A. (FLORA, 1997)
Microclimatic data and CO2 gas exchange rates were measured in thecoastal area near Trieste (NE Italy) in two groups of plants rowing at the extremes of a floristic-vegetational gradient between an evergreen Mediterranean maquis on the coast and a winter deciduous submediterranean woodland on the Karst plateau, where Q. ilex persists only sporadically but is still a co-dominant tree. Field data were recorded from sunrise to sunset during the periods of highest productivity and of maximum physiological stress. i.e. high temperatures and water deficit in summer, and low temperatures and strong, dry winds in winter. Photosynthesis was measured with a portable Infrared Gas Analyzer. Microclimatic data showed that summer and winter stress were more intense on the Karst plateau. Assimilation of the coastal population was higher because a positive CO2 balance was maintained during both stress periods. During summer drought stress diurnal assimilation of the inland population was just in balance with nocturnal leaf respiration. In winter, on the contrary, photosynthetic activity ceased almost completely for almost a week, due to the lower temperature regime and to strong, dry winter winds that caused severe mechanical damages and, more generally, a drastic shortening of the leaf life span. The competition ability of Q. ilex in ecotonal areas is briefly discussed on the basis of these results. Winter stress seems to be the main factor limiting the distribution of Q. ilex northwards.
The following values have no corresponding Zotero field: pub-location: VILLENGANG 2, D-07745 JENA, GERMANY publisher: GUSTAV FISCHER VERLAG
Keywords: competition; CO2; drought stress; gradient; photos

Plan de calas de corcho y establecimiento de rodales selectos de alcornoque en andalucía - Carrasco, Angel; BORRERO, GUMERSINDO; CAMPAYO, P.; RODRIGUEZ, M.; ÁLVAREZ, J. Ma; FARIÑA, J. Ma; E. TORRES; Privado, Consultor; La, C. I.; Manojo, D. E. L.; Madrid, D. E. Rosas (II Congreso Forestal Español, 1997)
Since 1995, the "Consejería de Medio Ambiente" of the "Junta de Andalucía" has been developping a "Cork samples Plan and Establishment of select "Areas" of the Quercus suber". This plan is intended to collect technical-scientifical information, used both for a better knowledge of the cork oak forests and their principal product, cork, as well as for the elaboration of a cork quality map of the Andalusian Community. They also provide cork- tree owners with information about the explotation quality, for which cork samples are taken both from cork trees and from cork-piles. Using the collected samples, once they are classified and analised in the laboratory, and according to the data collected in the field, quality reports on cork are effec~ll(lted for the owner. Subsequently, these samples are show in a permanent exposition in thejaboratorywhere buyers or any other person interested can obtain information about the quality offered in the different Andalusian forests. Since 1995, the obtained information is also being used, amplifying the data taken referent to select "areas" of the cork oak forests to be able to establish a select "areas" network of Quercus suber capable of producing high quality acorns.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español
Keywords: Andalucía; Cork; cork-oak; Quercus suber; Select "areas"

PLANTACIÓN Y SIEMBRA DE Quereus ilex L.: EFECTOS DE LA PREPARACIÓN DEL TERRENO Y DE LA UTILIZACIÓN DE PROTECTORES EN LA SUPERVIVENCIA DE PLANTAS - Ambiente, Ministerio D. E. Medio; NICOLÁS PERAGÓN, J. L.; DOMINGUEZ LERENA, S.; HERRERO SIERRA, N.; VILLAR- SALVADOR, P. (II Congreso Forestal Español, 1997)
In a first experiment the effect of two tillage treatments, a deep mechanical tillage and no tillage, on the survival of seeded Quercus ilex seedlings was analysed. In a second experiment the influence of acorn seeding versus plantation of containerized seedling, as well as the effect of two types of treeshelters (with and without lateral ventilation holes) and treeshelter removal in summer on the survival of Q. ilex seedlings was studied. Microclimate inside treeshelters containing seedlings was also measured along a typical summer day. Deep tillage increased germination and survival in comparison with untilled treatment. Temperature and leaf to air vapor pressure deficit was higher inside the treeshelters, specially in those without wholes, than outside. In spite of this fact, both treeshelter types, and particularIy those with lateral ventilation holes, exhibited a higher survival percentages than the control without treeshelter. Neither acorn seeding nor the removal of treeshelters in summer improved survival. significantly.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: Acorn seeding; Holm oak; microclimate; Reforestation; Tillage

A quantitative approach to cork oak forest management - Borges, JoséG; Oliveira, Ângelo C.; Costa, Maria a (Forest Ecology and Management, 1997)
Mathematical programming is one quantitative technique that can be used for strategic and tactical natural resources planning. It has been extensively used both at private and public forest planning levels. Nevertheless, most applications concentrate on modelling of systems involving timber harvesting. This paper focuses on cork oak (Quercus suber L.) forest management. It summarizes the methodology to follow in order to generate information needed for modelling purposes. It formulates a cork oak forest management problem using a linear programming model. A case study is used to illustrate the procedure used. The results of the research on a modelling approach to cork oak forest management for an area extending over 5272 ha in the Portuguese submediterranean ecological region are presented. Extensions to this study are identified.
Keywords: Forest regulation; Harvest scheduling; Linear programming; Mediterranean forestry; Quercus suber L.; Strategic planning

Quantitative ethnopharmacological study of the Campidano Valley and Urzulei district, Sardinia, Italy. - Bruni, a; Ballero, M.; Poli, F. (Journal of ethnopharmacology, 1997)
A new method has been developed for quantitative, phytotherapeutical analysis with a goal to create a general tool suitable for a wide range of research situations. This tool would allow one to gather data in such a format as to facilitate comparison with studies from other areas. The method was applied to data gathered from two sites in Sardinia, Italy (Campidano and Urzulei). Analysis was performed on 2635 responses (a) by plant, (b) by plant part, (c) by medicinal preparation and (d) by therapeutic use. This yielded specificity indexes which proved useful in comparing phytotherapeutic applications in the two geographic areas under study. In Urzulei the original phytotherapeutic heritage is deeply rooted in the local socio-economic history and clearly reflects the area's geographic isolation. Indeed, in this area, there is little reliance on modern health care. On the other hand, in Campidano, the body of phytotherapeutic application is more extensive. Indeed, due to migration-and to a lesser extent isolation- the latter area has been more affected by technological interference and cultural overlapping. In this area attention is widely focused on such modern ailments as glycemia, hypertension and constipation.
The following values have no corresponding Zotero field: accession-num: 9254113
Keywords: Medicinal plants; Quantitative ethnopharmacology; Sardinia; Traditional phytotherapy

Quercus ilex resprouts after fire: response to photoinhibition. - Aranda, X.; Hogan, K.; Llorens, L.; Fleck, I. (PLANT PHYSIOLOGY, 1997)
The study was located on Serra del Garraf mountains, Barcelona, NE Spain, overlooking the Mediterranian sea at 530 m. On August 1995 a wild fire consumed 100 hectares of the forest. In spring 1996 four plots were set (100 x
APSAPSThe following values have no corresponding Zotero field: pub-location: 15501 MONONA DRIVE, ROCKVILLE, MD 20855 publisher: AMER SOC PLANT PHYSIOLOGISTS
Keywords: Mediterranean; wild fire

Relación entre la densidad de la masa y la producción de corcho en montes alcornocales del sur de españa - Álvarez, E. Torres; González, G. Montero; Suárez, M. A.; Cámara, D. E. L. A.; TORRES ÁLVAREZ, E.; Montero González, G.; Suárez de la Cámara, M. A. (II Congreso Forestal Español, 1997)
In this paper the influence of cork-oak stand density on quantity and quality cork production is studied. Seventy five experimental plots were installed at Cortes de la Frontera (Málaga, Spain) cork-oak forests. Sorne stand and productive variables for different basal area were studied. The statistical analysis of the data permit to propose 20-25 m2!ha basal area as the optimum stand density
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: cork-oak; Quercus suber; silviculture; stand density

Restauración del bosque mediterráneo: aplicación de modelos de restauración a los encinares. - DE SIMÓN NAVARRETE, E.; Investigaci, Nnavarrete Centro D. E.; Apartado, Agraria D. E. Granada (II Congreso Forestal Español, 1997)
The activities in order to restore the mediterraneam forests have been constitued by the restoration of the structures and natural vegetation communities in order to preserve the water and soil in the drainage basins. A restoration of the vegetation covers in a drainage basin with hydrological and biological criteria have been projected, using sorne reforestation works in order to the best utilitation of the water resources and the conservation of the soil. The Quercus rotundifolia is one of the most extended species in the mediterranean area and it is apply for the forestation of the lands. This paper proposes a model of applied for its restoration. K.W.:
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: Evolution; hydrological process; mediterranean forest; Restoration; structure

Seasonal changes in xanthophyll composition and photosynthesis of cork oak (Quercus suber L.) leaves under mediterranean climate - García-Plazaola, J. I.; FARIA, T.; Abadía, J.; Chaves, M. M.; Pereira, J. S. (Journal of Experimental Botany, 1997)
Seasonal changes in pigment composition of sun and shade leaves of cork oak (Quercus suber) were studied under field conditions in Portugal. Expanding leaves showed a high concentration of xanthophyll cycle components, violaxanthin, antheraxanthin and zeaxanthin. The pool of violaxanthin plus antheraxanthin plus zeaxanthin (V+A+Z) varied greatly between the seasons, being higher at the end of summer and in winter when photosynthesis was limited by water stress and cold, respectively. The size of V+A+Z pool was associated to synthesis of zeaxanthin in response to an excess of light. In sun leaves, midday A+Z relative content was positively correlated with the V+A+Z pool, whereas in shade leaves A+Z decreased with leaf ageing. In both leaf types A+Z was positively correlated with the non-photochemical quenching (NPQ) of chlorophyll a fluorescence. However, in winter NPQ did not change significantly throughout the day, whereas the (A+Z)/(V+A+Z) increased following the typical daily trend observed in other seasons.
10.1093/jxb/48.9.166710.1093/jxb/48.9.1667
Keywords: chlorophyll fluorescence; pigments; Quercus suber; thermal dissipation; xanthophylls

Seed Proteins from Quercus suber - Fonseca, Paula A.; Ferreira, Ricardo B.; Teixeira, Artur R. (Journal of Agricultural and Food Chemistry, 1997)
A study on the extraction and characterization of the cotyledonary proteins from cork oak (Quercus suber L.) seeds is reported. The seed proteins, which constitute approximately 5% of the seed weight, are glutelins on the basis of solubility criteria. They are readily solubilized in sodium borate buffer, pH 10, 50 mM, containing 1% (v/v) ?-mercaptoethanol and 1% (w/v) sodium dodecyl sulfate. This fraction is made up of a large number of polypeptides with molecular masses ranging from 10 to above 100 kDa and occurs in the form of large aggregates. The level of glycosylation is low, with two main glycopolypeptides present (43 and 65 kDa). However, the major polypeptides are not glycosylated. In vitro digestibility studies indicated that trypsin and α-chymotrypsin produce a partial proteolysis of the cotyledonary proteins, particularly among the larger molecular mass polypeptides. The partial proteolysis seen in trypsin digests is not due to the presence of enzyme inhibitors in the seeds. On the other hand, pepsin almost completely digests the seed proteins. Taken together, these results may be considered as a good indication of the potential nutritional quality of the proteins from Q. suber seeds. Keywords: Cork oak; glutelin; in vitro proteolysis; protein; Quercus suber; seed
doi: 10.1021/jf9609486doi: 10.1021/jf9609486The following values have no corresponding Zotero field: publisher: American Chemical Society
Keywords: Cork oak; glutelin; in vitro proteolysis; protein; Quercus suber; seed

Selectivity and efficacy of some herbicides in forest plant nurseries. - Del Busto, A.; Bimbo, B.; Garcia-Espana, V.; De Barreda, D. G. (CONGRESS 1997 - SOCIEDAD ESPANOLA DE MALHERBOLOGIA, PROCEEDINGS, 1997)
A experiment was conducted in a 4 especies of forest plants nurseries Quercus ilex L. Pinus halepensis Mill, Pinus pinea L. and Pistacia terebinthus L. with the following residual herbicides simazine, isoxaben, and thiazopyr. The treatment was done in preemergence of the weeds and the crops. Simazine, isoxaben and the mixture of both herbicides were selective in the four forest plants but thiazopir was phytotoxic.
The following values have no corresponding Zotero field: periodical: CONGRESS 1997 - SOCIEDAD ESPANOLA DE MALHERBOLOGIA, PROCEEDINGS pub-location: DEPARTAMENTO HORTOFRUTICULTURA , BOTANICA I JARDINERIA ETSEA, UNIVERSITAT LLEIDA, 25198 LLEIDA, SPAIN
Keywords: Herbicides; Pinus halepensis Mill; Pinus pinea L.; Pistacia terebinthus L.; plant nurseries; Quercus ilex L.; weeds control

Self- and cross-pollination effects on pollen tube growth and seed set in holm oak Quercus ilex L (Fagaceae) - Yacine, A.; Bouras, F. (Ann. For. Sci., 1997)
Patterns of the self-incompatibility system have been more often described for hermaphroditic, entomophilous and short-lived plant species. Quercus ilex is a long-lived, monoecious, anemophilous and highly self-incompatible species. We used pollination experiments to investigate phenotypic responses of the self-incompatibility system. Flowers from 14 individuals of the same stand were hand-pollinated with self-pollen, cross-pollen from a single donor and a mixture of the two types. We observed a slower pollen tube growth and no or nearly no seed production after self-pollination. The more self-pollen tubes reach the style, the more flowers will stop their ovule development, resulting in a high flower abortion rate. In open pollination, pollen load is not a limiting factor, but incompatible pollen may reach stigma simultaneously or before compatible cross-pollen, which will induce an early abortion of flowers. When pollination is qualitatively and quantitatively effective, the regulation of seed production related to the resources availability acts by the late abortion of fruit.
Keywords: pollen tube growth; Quercus ilex L; seed set; self-incompatibility

Stress-induced formation of haploid plants through anther culture in cork oak (Quercus suber) - Bueno, Maria Angeles; Gomez, Arancha; Boscaiu, Monica; Manzanera, Jose Antonio; Vicente, Oscar (Physiologia Plantarum, 1997)
Induetion of haploid embryos and regeneration of plantlets have been obtained, for the first time, in cork oak (Quercus suber L.) by combining a starvation treatment in anther culture with a mild heat shock at 33°C for 5 days, followed by eulture at 25°C in a simple agar medium without growth regulators. The same conditions had been shown previously to be optimal for embryogenic induction in isolated microspore cultures of' several model species such as tobacco and wheat. These results support the notion that stress, particularly sucrose starvation, a heat shock or a combination of both treatments could be the major and general signal responsible for the inhibition of normal gametophytie development of the mierospores and for the induetion of the alternative embryogenic pathway. A similar approach may be used for the production of haploid and doubled haploids for plant breeding in other species that, like most forest trees, are still recalcitrant in anther culture.
Keywords: anther culture; Cork oak; flow cytometry; Haploid plants; heat shock; Quercus suber; starvation; Stress

The terpenoid emission pattern of Quercus coccifera L coincides with the emission pattern found with Quercus ilex L - Hansen, U.; Seufert, G. (PROCEEDINGS OF EUROTRAC SYMPOSIUM `96 - TRANSPORT AND TRANSFORMATION OF POLLUTANTS IN THE TROPOSPHERE, VOL 2: EMISSIONS, DEPOSITION, LABORATORY WORK AND INSTRUMENTATION, 1997)
Monoterpene and isoprene emission rates from Kermes or Holly oak (Quercus coccifera L.), an evergreen shrub or small tree which is widely present in the Mediterranean area, were investigated in a greenhouse using a dynamic enclosure technique, Monoterpenes emitted with the highest rates from Quercus coccifera were alpha-pinene, sabinene and beta-pinene. alpha-pinene contributed 41 % to the total monoterpene emission, sabinene 28 % and beta-pinene 25 %. The isoprene emission rate was 0.7 % of the total monoterpene emission rate. Standardisation to 30 degrees C revealed a total monoterpene emission rate of 18.7 mu g gLDW(-1) h(-1). The data show that terpenoid emissions from Kermes oak (Quercus coccifera L.) are qualitatively and quantitatively similar to those of Helm oak (Quercus ilex L.). Both species have to be considered as strong monoterpene emitters, Emissions are considerably higher compared to the emission factor of 1.2 mu g C gLDW(-1) h(-1) which was assumed to represent the monoterpene emission rate from Mediterranean ecosystems at standard conditions in a study about a global model of natural VOC emissions.
The following values have no corresponding Zotero field: periodical: PROCEEDINGS OF EUROTRAC SYMPOSIUM `96 - TRANSPORT AND TRANSFORMATION OF POLLUTANTS IN THE TROPOSPHERE, VOL 2: EMISSIONS, DEPOSITION, LABORATORY WORK AND INSTRUMENTATION pub-location: ASHURST LODGE, SOUTHAMPTON, HANTS, ENGLAND S04 2AA
Keywords: alpha-pinene; beta-pinene; isoterpene; Mediterranean area; Monoterpene; Quercus coccifera L.; sabinene; terpenoid; VOC emissions

Testing somaclonal variation using RAPDs in Quercus suber L. somatic embryos. - Gallego, F. J.; Martinez, I. (International Journal of Plant Sciences, 1997)
Focuses on the use of Random Amplified Polymorphic Deoxyribose nucleic acid (RAPD) profiles to test somaclonal variation in Quercus suber L. somatic embryous during recurrent embryogenesis. Number of primers used to amplify DNA from isolated embryos; Use of somatic embryogenesis from immature zygotic embryos; How somaclonal variation was detected.
Keywords: Cork oak; SOMATIC embryogenesis (citation)

Tolerance of Quercus sp. young trees to residual herbicides. - Jimenez, M. J.; Saavedra, M. M. (CONGRESS 1997 - SOCIEDAD ESPANOLA DE MALHERBOLOGIA, PROCEEDINGS, 1997)
Residual herbicides were applied over Quercus rotundifolia Lam. (oak) and e. suber L. (cork-tree), before and active growing of trees by spraying and irrigation. Diuron and norflurazone were very phytotoxic. Orizalin and oxyfluorfen were tolerated satisfactorily. The other herbicides (simazine, thiazopyr, linuron + pendimethalin, isoxaben, tribenuron and glyphosate + diflufenican) showed variable responses. The tolerance of the trees was better before shooting than after active growing.
The following values have no corresponding Zotero field: periodical: CONGRESS 1997 - SOCIEDAD ESPANOLA DE MALHERBOLOGIA, PROCEEDINGS pub-location: DEPARTAMENTO HORTOFRUTICULTURA , BOTANICA I JARDINERIA ETSEA, UNIVERSITAT LLEIDA, 25198 LLEIDA, SPAIN
Keywords: diuron; norflurazone; Quercus ilex; Quercus suber; residual herbicides

Use of the isoprene algorithm for predicting the monoterpene emission from the Mediterranean holm oak Quercus ilex L.: Performance and limits of this approach - Ciccioli, Paolo; Fabozzi, Concetta; Brancaleoni, Enzo; Cecinato, Angelo; Frattoni, Massimiliano; Loreto, Francesco; Kesselmeier, Jürgen; Schäfer, Luise; Bode, Kirsten; Torres, Liberto; Fugit, Jean-Luc (Journal of Geophysical Research: Atmospheres, 1997)
The algorithm developed by Guenther et al. [1991] to describe the organic emission of isoprene-emitting plants has been used for predicting monoterpene emission from Quercus ilex L., an evergreen oak typical of the Mediterranean basin. The dependence of monoterpene emission on photosynthetically active radiation and temperature has been verified through laboratory experiments carried out on single leaves as well as through field measurements at branch level. While the algorithm describes well monoterpene emission under stationary state conditions, it is less accurate when rapid fluctuations of light and temperature take place. Because of this, the isoprene algorithm is capable of predicting the response of Quercus ilex L. with an accuracy better than ±25% only in 65% of the environmental situations experienced by the plant. Field and laboratory observations consistently indicate that temperature oscillations can be an important source for the discrepancies between predicted and observed values as they can generate bursts of emission with values twice as high as those predicted by the algorithm. Possible causes generating these effects are analyzed and critically discussed. In spite of the observed limitations, the isoprene algorithm can successfully describe the biogenic emission from Quercus ilex L., and its use is advantageous as it greatly simplifies regional and global emission models, especially if the light dependence of monoterpene emission is proven to be a widespread phenomenon.
Keywords: Biogenic emission; isoprene algorithm; monoterpene (voyant); Quercus ilex; Temperature

Variaçáo da porosidade da cortiça determinismo fenotípico - Fonseca, Fortunato M. A.; Louzada, José Luis P. C.; Gomes, César A. M. (II Congreso Forestal Español, 1997)
Analyses were made of the variation in the porosity of cork collected from 100 trees at the BHD level and in 30 trees, with reproduction cork collected at three levels of height with a fourth level of virgin cork. Despite verifying the recognizable and elevated variability (1 to 10) among trees, it (44%) is greatly exceeded by the internal variability (56%) of the porosity of cork in the individuals, without a presumable systematization with the growth or funcionality. The phenotype determinism, within the reproduction corks for the number of pores is relatively elevated (R2 =40% to 60%) but already reduced (R2 =20% to 30%) for the porosity. On the other hand, there doesn't exist any such type of phenotypical determinism between the poro sities of reproduction cork anf of virgin cork, something which also supports the hypothesis of elevated abnormalities or reaction in the formation of reproduction cork.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español issue: 1982 pub-location: Pamplona
Keywords: Cork; phenotypical determinismo; Porosity; variation

Variation for male success in Holm oak, a monoecious and a highly self-incompatible species - Yacine, A.; Valero, M.; Bouras, F. (SEVENTH INTERNATIONAL SYMPOSIUM ON POLLINATION - POLLINATION: FROM THEORY TO PRACTISE, 1997)
In natural populations, male success is determined by pre-and post-pollination events. The latter could be separated to pre-and post-fertilization stages at which different mechanisms control pollen donor success. It is currently assumed that there is a direct relationship between pollen tube growth rapidity and fertilization ability. In this study, pollination experiments were conducted on a Helm oak (Quercus ilex) population to test male success. Pollen was used in two ways (1) as a single source and (2) mixed with the self pollen of the recipient. We analyzed differences between pollen donors at the prezygotic level by evaluating the relative proportions of the pollen tube presence in the style in comparison to those on the stigma and likewise between the style and the ovary, on five different dates after pollination. At the post-zygotic level, male success was measured as the proportion of fertilized ovules relative to pollinated flowers and as seed sired relative to fertilized ovules. At the pre-and post-zygotic level there were statistically significant differences between recipients that are however not significant between donors. In Quercus species pollination occurs before the ovules develop; our results indicate that different arrangements between pollen tube growth and ovule development may occur. Self-incompatibility may be one factor in differential recipient success through the interactions between out and self-incompatible pollen.
The following values have no corresponding Zotero field: periodical: SEVENTH INTERNATIONAL SYMPOSIUM ON POLLINATION - POLLINATION: FROM THEORY TO PRACTISE issue: 437 pub-location: PO BOX 500, 3001 LEUVEN 1, BELGIUM
Keywords: fertilization; male success; pollen tube; pollination; Quercus ilex

Vegetative compatibility and pathogenicity of Diplodia mutila isolates on oak - Ragazzi, A. (European journal of forest pathology, 1997)
Forty isolates of Diplodia mutila, a dieback agent on oaks were characterized by their capacity to produce heterokaryons, by their vegetative compatibility, and by their pathogenicity tests on Quercus cerris. The forty isolates were collected from Quercus cerris, Quercus frainetto, Quercus ilex, Quercus pubescens, Quercus robur and Quercus suber in different regions in Italy. Three nit mutants (nit,, nit, and nit,) were identified with different nitrogen sources: sodium nitrite, sodium nitrate, uric acid, ammonium tartrate and hypoxanthine. O n the two nutrient media employed, a potato dextrose agar (PDA) medium with chlorate (PDC), and a minimal agar medium with chlorate (MMC), isolates obtained from Q. cerris Felded the greatest number of mutants: 254 on PDC (out of a total of 583) and 190 on MMC (out o a total of 440). Nine vegetative compatibility grou s (VCGs) were identified. There was a strong association between these VCGs and host species. Alfisolates tested except one from Q. cerris were pathogenic.
Keywords: diplodia mutila; disease (voyant); nit mutants; Pathogenicity; Quercus; vegetative compatibility

Vertebrate predation on Holm Oak, Quercus ilex, acorns in a fragmented habitat: effects on seedling recruitment - Santos, T.; Tellería, J. L. (Forest Ecology and Management, 1997)
Rodent and avian consumption of Holm Oak, Quercus ilex, acorns were examined in central Spain during two high-production seasons, 1990-1991 and 1993-1994, in 1 and 3 large stands and in 6 and 10 small stands (0.2-12 ha) respectively, to study the effects of vertebrate predation on seedling recruitment. Previous data indicate that wood mouse abundance is much higher in small stands. Tree size, frequency of acorn-bearing oaks and acorn abundance were similar in the two sizes of forest stands. Overall acorn consumption was 33.7 times higher in the small stands compared to that in the large stands in 1991, and 3.1 times larger in 1994. Consumption of acorns by mice in the small stands was 49 and 95 times greater than that by birds in the first and second year, respectively. Seedling recruitment was significantly higher in the large stands in both study seasons. Regeneration by ramets was roughly similar in small and large stands in both seasons. Thus, predation by mice was apparently responsible for the failure of sexual reproduction in the small stands. The results suggest that vegetative regeneration might be the prevalent reproductive method of Holm Oaks in small forest tracts.
Keywords: acorns; Forest fragmentation; oak; Seedling; Vertebrate predation

The voluntary intake and rumen digestion by grazing goats and sheep of a low-quality pasture from a semi-arid land - Alcaide, E. M.; Garcıa, M. A.; Aguilera, J. F. (Livestock Production Science, 1997)
An experiment was carried out in late autumn with goats and wethers fitted with permanent ruminal cannulae, grazing in a semi-arid area of South Spain. Shrubs were the most available plant species, although natural vegetation also included trees and grasses. In general, the dominant species of the available vegetation accounted for the highest proportion in the selected diet. Similar proportion and species of grasses were found in the pasture selected by goats and wethers, whereas interspecies differences were observed regarding the selection of shrubs and tree species. Crude protein content was similar in selected diets by goats and sheep, but a higher unavailable N proportion was found for sheep (27.1 and 30.0% of total N for goats and sheep, respectively). Digestibility of forage selected was higher for goats than for wethers. Voluntary intake was significantly (P < 0.05) higher in goats than in sheep; the metabolizable energy intake for goats was higher than their maintenance requirements but failed to meet maintenance needs for wethers. Fermentative rumen activity was moderate and similar for goats and sheep. No interspecies differences were found in rumen fermentation parameters except for molar proportions of acetic and propionic acid and for acetic/propionic ratio, which were significantly higher in wethers. The degradation rate tended to be faster in goats, whereas potential and effective degradability tended to be similar in goats and sheep.
Keywords: Goats; intake; rumen fermentation; semi-arid land; Sheep

Annual cork-ring width variability of Quercus suber L. in relation to temperature and precipitation (Extremadura, southwestern Spain) - Caritat, A.; Molinas, M.; GUTIÉRREZ, E. (Forest Ecology and Management, 1996)
A 14 year sequence of cork-ring width chronology is correlated with rainfall and temperature data. Cork specimens were obtained from three cork peel samplings carried out in 1989, 1991 and 1993 from a cork ‘dehesa’ in Ckeres, Spain. Average width of cork-rings varied between 2.05 and 4.37 mm. The cork-ring width chronologies of the three peel-off samplings show definite agreement patterns. Differences in ring width in years of greater and lesser growth are clearly marked. Correlation between ring width and rainfall indicates that the rain periods with the greatest influence on cork growth are those occurring from November to June, followed by those from November to September. Temperature, on the other hand, shows a negative correlation with cork growth, except during the coldest months and the months of April and September when temperature possibly has a crucial influence on phellogen activation.
Keywords: climatic fluctuations; cork growth; cork-oak; cork-ring chronology; Quercus suber L.

Biomasse végétale et production fourragère sur terres de parcours sous climat méditerranéen ou tropical sec - Etienne, M. (Ann. Zootech., 1996)
After an overview on the regions concerned and a review of the concepts of rangeland, fodder production and pastoral value, the vegetation, productivity and potential improvement of mediterranean and dry tropical rangelands are assessed. The main range vegetation types are described and characterised by their physiognomy, plant morphology and main ecological constraints. Rangeland fodder production is assessed by analysing the main limiting production factors and by comparing the intra and interannual variations of fodder productivity and quality. Vegetation dynamics of some common range types is discussed according to range management techniques (fire, cutting, cultivation) or livestock management criteria (stocking rate, type of animal, fodder system). Some examples of range improvements applied to contrasted ecological and socio-economical conditions are discussed by analysing their impact on soil, fodder species, vegetation dynamics and range management. To conclude, the need of splitting from fodder production models to range management models is evoked.
Keywords: dynamique de la végétation (voyant); gestion des ressources; Parcours; production fourragère; qualité nutritionnelle

Carbon isotope discrimination in Quercus ilex resprouts after fire and tree-fell - Fleck, Isabel; Grau, Daniel; Sanjose, M.; Vidal, D. (Oecologia, 1996)
Ecophysiological differences related to photo- synthesis were compared in holm oak Quercus ilex leaves from undisturbed holm-oak vegetation, resprouts after fire and resprouts after tree-fell. No significant dif- ferences in any parameter measured were observed be- tween the two kinds of resprout throughout the first growing season following disturbance. Resprouting leaves showed lower carbon isotope discrimination (A) and intercellular CO 2 concentration (Pi), and higher pho- tosynthesis, leaf conductance and transpiration rates than leaves from undisturbed stands. Nitrogen, soluble protein content and ribulose bisphosphate carboxylase (RuBP- Case) activity were 88%, 96% and 45% higher respec- tively, in both kinds of resprout. The results indicate that photosynthetic capacity, rather than stomatal conduc- tance, is the limiting factor in photosynthesis in re- sprouts. Chlorophyll content and chlorophyll a/b ratio did not differ between resprouts and undisturbed leaves, indicating that the observed differences were not a result of differences in light environment during leaf develop- ment. Leaf mass per area (LMA), was 80% higher in the resprouts, and was negatively related (r= -0,86) to A and positively related (r=0.87) to N content. Enhanced car- bon assimilation after disturbances resulted in higher wa- ter use efficiency, as indicated by lower A values in the resprouts. We conclude that the cause of defoliation was not relevant in the physiology of the resprouts, suggest- ing the importance of underground organs.
Keywords: carbon isotope discrimination; Fire and tree-fell resprouts; Gas exchange; RuBPCase activity

Characteristics of internal porosity of cork container media - Ordovas, J.; Carmona, E.; Moreno, M. T.; Ortega, M. C. (HORTSCIENCE, 1996)
The structure of cork (Quercus suber L.) bark presents a series of characteristics, suggesting that internal porosity is partly occluded. This study determined the porosity in the waste cork industry (C) and when such waste product had been composted during 4 (CC-4), 7 (CC-7), and 10.5 months (CC-10.5). The particle density of the intact and finely ground material differed significantly in all particle size ranges larger than 0.5 mm. The porosity of the cork substrates ranged from 80% to 94% of the total volume, according to granulometry and the degree of decomposition. However, large particles and less decomposed material with a high porosity had up to 10% of the total volume as occluded pores. The material's effective porosity varied slightly between the various particle sizes and degrees of decomposition, which ranged between 80% and 89%, having an average value of 85%. The ash content was highly correlated with the particle density of the finely ground material. Nevertheless, and due to occluded porosity, we cannot estimate the `'effective porosity'' from the ashes; therefore, we must resort to techniques that involve the displacement of a fluid, such as liquids or gas pycnometry or submersion.
The following values have no corresponding Zotero field: pub-location: 701 NORTH SAINT ASAPH STREET, ALEXANDRIA, VA 22314-1998 publisher: AMER SOC HORTICULTURAL SCIENCE
Keywords: ash content; effective porosity; particle density; total porosity

The dense indumentum with its polyphenol content may replace the protective role of the epidermis in some young xeromorphic leaves - Karabourniotis, George; Fasseas, Costas (Canadian Journal of Botany, 1996)
The bright, yellow-green, ammonia-induced fluorescence of polyphenol compounds contained in the nonglandular hairs and within the epidermis of Olea europaea and Quercus ilex leaves was age dependent. Epifluorescence microscopic examination of transverse sections of leaves from both species showed that abaxial and adaxial epidermal layers emitted the characteristic green-yellow bright fluorescence only in late developmental stages, when a considerable decrease of the trichome density had already occurred. At earlier developmental stages, only the dense and thick trichome layer emitted the bright green-yellow fluorescence. In addition, the trichomes of young leaves of Olea and Quercus resembled the glandular ones of other species morphologically and possibly functionally. These findings suggest that the protective role of the trichome against ultraviolet-B radiation damage and (or) other environmental factors is particularly significant during the early stages of leaf development and may be less important at later stages, when the protective role is taken over by the epidermis. Keywords: leaf hairs, phenolics, UV-B radiation damage, leaf development, Olea europaea L., Quercus ilex L.
doi: 10.1139/b96-043doi: 10.1139/b96-043The following values have no corresponding Zotero field: publisher: NRC Research Press
Keywords: leaf development; leaf hairs; Olea europaea L.; phenolics; Quercus ilex L.; UV-B radiation damage

Diversity and structure of ant communities associated with oak, pine, eucalyptus and arable habitats in Portugal - Cammell, M. E.; Way, M. J.; Paiva, M. R. (Insectes Sociaux, 1996)
In central Portugal, 28 species of ants were found in oak, 25 in pine, 35 in eucalyptus and 12 in arable habitats, a total of 43 species. They include five numerically dominant species, the exotic Argentine ant. Linepithema (Iridomyrmex) humile and four native species, Crematogaster scutel- laris, Pheidole pallidula, Tapinoma nigerrimum and Tetramorium hispanicum. L. humile occurred in 34 % of sampled sites. When present, it was abundant in all three arboreal habitats, where it was associated with strikingly decreased ant species richness and equitability. Such diversity was greater in L. humile - colonised arable habitats, where the ant was much less abundant than in the arboreal habitats. Where L. humile was absent, C. scutellaris and P pallidula were usually co-dominants in oak and pine, and T. nigerrimum and T. hispanicum in the arable habitat, but all were absent or rare in eucalyptus. Ants were numerically least abundant in eucalyptus but, in the absence of L. humile, species richness was greater and the community more equitable than in the other habitats. L. humile - absent arable habitats supported the poorest and least equitable ant community.
Keywords: Ants; community ecology; diversity; Dominance; Linepithema humile; Portugal.

The ecology of an endemic and rare species with a fragmented distribution: Cyclamen balearlcum Willk in France - Debussche, M.; Grandjanny, M.; Debussche, G.; Affre, L. (ACTA BOTANICA GALLICA, 1996)
The ecology of rare species is largely unknown. Though informations on the ecology of these species, as well as on their biological traits and genetics, are necessary to achieve their conservation. Ecology of Cyclamen balearicum Willk. in France was studied by analysing a set of 40 phyto-ecological releves. This late successional species grows in France under a mediterranean climate, in shaded situations, in sites characterized by moderate to copious precipitations (650 to 1800 mm per year) and frosts occurring each year commonly (mean of the minima of the coldest month from - 0,7 degrees C to + 0,7 degrees C), steep relief and north aspect, stony calcareous soils with blocks, important cover of evergreen woody plants, small number of therophytes, very Low human impact. Quercus ilex L. and Buxus sempervirens L. are very often the dominant tree and shrub species In these sites. Two kinds of habitat were distinguished. They mainly differ on geomorphological features, vegetation height and floristic composition. Ecological patterns were discussed in relation with decisive factors such as shade, frost and drainage, and human impacts. The farm or rarity showed by the species in France was discussed according to the criteria proposed by Rabinowitz. As numerous endemic species with narrow distribution, Cyclamen balearicum Willk. has in France a restricted habitat, but where it grows it is sometimes abundant.
The following values have no corresponding Zotero field: pub-location: RUE J B CLEMENT, 92296 CHATENAY-MALABRY CEDEX, FRANCE publisher: SOC BOTANIQUE FRANCE
Keywords: cyclamen balearicum Willk; ecology; endemic species France; habitat specificity; Mediterranean Region; rare species

Effect of scale on surface runoff processes - Barbancho, A. C.; Schnabel, S.; Bolinches, C. (CADERNOS DO LABORATORIO XEOLOXICO DE LAXE 21, 1996)
In a small catchment under the so-called dehesa landuse system, the production of surface runoff is investigated at different scales. This includes experiments with simulated rainfall at micro-plots, event-based measurements of overland flow at 17 open plots and 1 closed plot, and discharge production of the catchment and subcatchment. The runoff coefficients of the considered scales form two groups, with low values for the catchment and sub-catchment and high values for the microplots and hillslope plots. The results show that large part of runoff produced at the slopes is infiltrated afterwards at colluvial sites and the valley floors. Furthermore, they indicate the importance of studying at various scales in order to understand the hydrological processes operating in catchments.
The following values have no corresponding Zotero field: periodical: CADERNOS DO LABORATORIO XEOLOXICO DE LAXE 21 pub-location: O CASTRO DE SAMOEDO, 15168 SADA, LA CORUNA, SPAIN
Keywords: ecosystem dehesa; scale; soil erosion; surface runoff

Fungal endophytes in leaves, twigs and bark of Quercus ilex from Central Spain - Collado, J.; Platas, G.; Pelaez, F. (NOVA HEDWIGIA, 1996)
Fungal endophytes were isolated from leaves, twigs and bark discs of the main stem of 16 individuals of Quercus ilex at two sites in the forests of El Pardo, Madrid, central Spain. From 512 segments of each sample type, 1084 fungal isolates were obtained, distributed among 98 species of filamentous fungi, yielding about 21 species/tree. Four isolation media were tested, which showed different behaviour depending on the type of sample. The use of fungitoxic compounds, such as benomyl or cycloheximide, resulted in a decrease in the number of isolates and species recovered, especially from leaves. Most of the dominant fungal species were not isolated from the four media indistinctly, but were preferentially recovered from one of the media. Twigs exhibited a higher degree of fungal infection than bark discs and leaves. The mycota isolated from bark and twigs were more similar to each other than to the fungal populations recovered from leaves. The frequency of isolation of most of the dominant fungal species depended significantly upon the sample type. A Phoma sp. was the only taxon similarly distributed among the three sample types. The height from which the bark discs were removed also influenced the population recovered. Both sampling sites were similar with respect to the number of species recovered from twigs and bark discs, but differed in the number of species from leaves. As in other plant and non-plant fungal communities, the population recovered from Q. ilex was characterized by a few species which accounted for most of the isolates, and a much larger number of species present with low frequencies. Five species (Nodulisporium sp., Acremonium strictum and three Phoma-like coelomycetes) represented more than 50% of the whole isolates. Coelomycetous anamorphs of ascomycetes bearing small, hyaline ameroconidia, were the most abundant group of fungi, whereas teleomorphs were rarely seen.
The following values have no corresponding Zotero field: pub-location: JOHANNESSTR 3A, D-70176 STUTTGART, GERMANY publisher: GEBRUDER BORNTRAEGER
Keywords: endophytes; isolation; microbial diversity; Quercus ilex

GC−MS Study of Volatiles of Normal and Microbiologically Attacked Cork from Quercus suber L. - Rocha, Sílvia; Delgadillo, Ivonne; Ferrer Correia, A. J. (Journal of Agricultural and Food Chemistry, 1996)
The volatile compounds of cork were studied by gas chromatography and combined gas chromatography?high-resolution mass spectrometry using simultaneous distillation?extraction to prepare the samples. To assess the origin of the volatiles, three different types of samples were analyzed:? ?normal?, attacked by Armillaria mellea, and infested by molds. The study of the volatiles of these different types of corks allowed the identification of the chemical modifications which may occur in cork polymers. The cork attacked by A. mellea showed higher amounts of phenols, vanillin, benzaldehyde, benzyl alcohol, and chlorinated compounds than normal cork; this may indicate lignin degradation. The cork infested by molds contained higher levels of 3-methyl-1-butanol, 1-octen-3-ol, 1-octanol, 2-methylisoborneol, chlorinated compounds, and methyl ketones. These components resulting from microbial metabolism were also present in cork attacked by A. mellea. The use of cork attacked by A. mellea is not recommended in the manufacture of cork stoppers, since these types of cork have volatile compounds likely to cause off-flavors in wine. For the same reason it is important to reduce the likelihood of mold development during the standing period. Keywords: ?Normal? cork; Armillaria mellea; molds; volatile components; musty and moldy odors
doi: 10.1021/jf9500400doi: 10.1021/jf9500400The following values have no corresponding Zotero field: publisher: American Chemical Society
Keywords: Armillaria mellea; molds; musty and moldy odors; volatile components; “Normal” cork

Growth at elevated CO2 leads to down-regulation of photosynthesis and altered response to high temperature in Quercus suber L. seedlings - FARIA, T.; Wilkins, D.; Besford, R. T.; Vaz, M.; Pereira, J. S.; Chaves, M. M. (Journal of Experimental Botany, 1996)
The effects of growth at elevated CO2 on the response to high temperatures in terms of carbon assimilation (net photosynthesis, stomatal conductance, amount and activity of Rubisco, and concentrations of total soluble sugars and starch) and of photochemistry (for example, the efficiency of excitation energy captured by open photosystem II reaction centres) were studied in cork oak (Quercus suber L.). Plants grown in elevated CO2 (700 ppm) showed a down-regulation of photosynthesis and had lower amounts and activity of Rubisco than plants grown at ambient CO2 (350 ppm), after 14 months in the greenhouse. At that time plants were subjected to a heat-shock treatment (4 h at 45°C in a chamber with 80% relative humidity and 800–1000 µmol m−2 s−1 photon flux density). Growth in a CO2-enriched atmosphere seems to protect cork oak leaves from the short-term effects of high temperature. Elevated CO2 plants had positive net carbon uptake rates during the heat shock treatment whereas plants grown at ambient CO2 showed negative rates. Moreover, recovery was faster in high CO2-grown plants which, after 30 min at 25°C, exhibited higher net carbon uptake rates and lower decreases in photosynthetic capacity (Amax as well as in the efficiency of excitation energy captured by open photosystem II reaction centres (FvJFm than plants grown at ambient CO2. The stomata of elevated CO2 plants were also less responsive when exposed to high temperature.
10.1093/jxb/47.11.175510.1093/jxb/47.11.1755
Keywords: acclimation; Elevated CO2; photo- synthesis; Quercus suber L.; Temperature

Habitat selection patterns of common cranes Grus grus wintering in holm oak Quercus ilex dehesas of central Spain: Effects of human management - Díaz, M.; González, E. (Biological Conservation, 1996)
Most of the western European population of common cranes Grus grus spends the winter in Iberian wooded dehesas, a kind of wood-pasture composed of grasslands, cereal croplands and Mediterranean scrub, densely inter- spersed with holm oak trees Quercus ilex in a savanna- like landscape. Three main types of wooded dehesas can be distinguished according to management." grazed dehesas, shrubby dehesas with occasional grazing, and cultivated dehesas without livestock. Cranes depend largely on acorns during winter and mainly select dehesas cultivated with cereals where acorn abundance is not reduced by livestock. Apparent positive effects of livestock on earth- worm abundance, the main alternative food source for cranes, does not compensate for acorn depletion. Thus, any increase in livestock grazing pressure would have a strong impact on European crane populations during their wintering in Spain.
Keywords: common agricultural policy; Cranes; livestock management; winter feeding

Incidence des caractéristiques structurales du sous-sol sur l'entrée en production de Tuber melanosporum et d'autres champignons mycorhiziens - Callot, G.; Jaillard, B.; Braye, J. P.; Jalade, M. (Agronomie, 1996)
Effect of structural characteristics of subsoil on the fruiting of Tuber melanosporum and other mycorrhizal fungi. The collection sites for ascocarps of Tuber melanosporum Vitt were noted over four consecutive years in a truffle bed of live oaks (Quercus ilex) mycorrhized by T melanosporum. The mycorrhizas of Tuber and other fungi were checked 11 years after planting. At the same time, a detailed soil survey made it possible to distinguish different soil units within the truffle bed. Cartographic analysis of the data set showed that the mycorrhizal status and the location of the fungus collection sites were related to the structural characteristics of the subsoil. The presence of a slightly permeable clay subsoil discourages fruiting in both epigeal and hypogeal fungi. Soils presenting a shallow calcareous crust discourage the growth of hypogeal Tuber-type fungi, but encourage that of epigeal fungi. T melanosporum grows best in soils with a very porous horizon developed in contact with the calcareous bedrock. This horizon (termed Bbio by the authors) is characterized by an intensive biological activity.
Keywords: autoecology; fungi; limestone; Mycorrhizas; subsoil; Tuber

Influence of fire and tree-fell on physiological parameters in Quercus ilex resprouts - Fleck, I.; Grau, D.; Sanjose, M.; Vidal, D. (Ann. For. Sci., 1996)
Variations in the physiology of two kinds of resprout (originated after fire and after tree-fell) of Quercus ilex were analyzed under field conditions and compared with respect to the original, undisturbed vegetation, located within a Mediterranean watershed (northeast Spain). Resprouting vegetation of Quercus ilex after fire or after tree-fell showed, during the next growing seasons, enhanced photosynthesis, leaf conductance and Rubisco activity with respect to the original vegetation, especially under high temperature, irradiance and vapor pressure deficit (VPD). The lack of differences in nutrient (N,C,P,K and Ca) and soluble carbohydrate concentrations in leaves of resprouts originated after fire or after tree-fell indicates the independence of nutrients released by the action of fire and the contribution of underground organs. Differences in leaf mass per area (LMA) were due to increased thickness in resprouts whereas density was the same. N investment in chlorophylls or Rubisco was not different in control or either kind of resprout. The increased amount of carotenoids in resprouts contributed to providing protection from photoinhibitory processes
Keywords: fire; Gas exchange; Nutrients; photosynthetic pigments; Quercus ilex; tree-fell

Influence of the wetting properties of polymeric adhesives on the mechanical behaviour of cork agglomerates - Teixeira, M. J.; Fernandes, A. C.; Saramago, B.; ROSA, M. E.; BORDADO, J. C. (JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY, 1996)
A series of adhesives, polyurethane prepolymers with alkane chains of different functionalities, were used in the production of cork agglomerates. The polymeric structure varied from long, linear chains in adhesive M1 (14% isocyanate groups) to short, branched chains in adhesive M4 (30% isocyanate groups). The wetting properties of the adhesives were studied through surface tension and contact angle measurements of the polymeric liquids deposited on cork substrates. The mechanical behaviour of the cork agglomerates was studied through compression and three-point bending tests, and the agglomerate structure was analysed by scanning electron microscopy (SEM). The relationship between the structural and wetting characteristics of the adhesives and the mechanical properties of the agglomerates was investigated. The experimental results indicate that it is the work of adhesion for the adhesive/cork system, and not only the contact angle, which determines the mechanical resistance of the cork agglomerate.
The following values have no corresponding Zotero field: pub-location: PLANTIJNSTRAAT 2, P O BOX 9000, 2300 PA LEIDEN, NETHERLANDS publisher: BRILL ACADEMIC PUBLISHERS
Keywords: adhesives; cork agglometares; mechanical properties; WETTING

Influência do genótipo, idade da planta mãe e posição do explante inicial, na capacidade de multiplicação in vitro do sobreiro (Quercus suber L.) - Peixe, A.; Cavaleiro, C.; Mendes, A.; Gonçalves, J. C. (Simpósio de Propagação Vegetativa de Espécies Lenhosas, Castelo Branco, 18 a 20 de Abril de 1996, 1996)
O material utilizado foi recolhido em árvores adultas e em plantas provenientes da enxertia de árvores adultas sobre jovens plantas de origem seminal. Como explantes iniciais foram utilizados ramos do ano, tendo-se separado por grupos os explantes provenientes do gomo terminal e do primeiro, segundo e terceiro gomos axilares bem diferenciados. O meio de cultura utilizado foi o Woody Plant Medium (WPM) suplementado com 0,1 mgl-1 de BAP, 7gl-1 de Difco Bacto Agar e 20gl-1 de sacarose. Foram encontradas diferenças significativas entre os genótipos, tanto ao nível da idade da planta mãe como da posição do gomo utilizado. Os resultados obtidos com as plantas enxertadas, foram sempre significativamente superiores aos obtidos com as árvores adultas. Quanto à posição relativa do gomo, verifica-se que tanto ao nível do abrolhamento, como ao nível das taxas de multiplicação, no primeiro subcultivo, os melhores resultados foram obtidos quando se utilizaram os gomos terminais. Note-se no entanto que estas diferenças inicialmente significativas, se encontram já bastante atenuadas ao nível do segundo subcultivo. Outro aspecto com interesse e que mostra a dificuldade para multiplicar in vitro o sobreiro através de rebentação axilar utilizando genótipos adultos, é dado pela percentagem de explantes não evoluídos, que chega a atingir os 75%. As plantas enxertadas apresentaram um comportamento bastante melhor a todos os níveis, o que nos leva a pensar na provável ocorrência de um rejuvenescimento dos tecidos devido ao facto de a enxertia ter sido realizada sobre jovens plantas de semente.
The following values have no corresponding Zotero field: periodical: Simpósio de Propagação Vegetativa de Espécies Lenhosas, Castelo Branco, 18 a 20 de Abril de 1996 pub-location: Castelo Branco
Keywords: cultura in vitro; propagação; sobreiro

Isozyme variation in natural populations of cork-oak (Quercus suber L) - Population structure, diversity, differentiation and gene flow - ElenaRossello, J. A.; Cabrera, E. (SILVAE GENETICA, 1996)
Genetic variation of cork-oak (Quercus suber L.) was investigated in 7 Mediterranean populations in Spain using 13 loci from 7 enzyme systems. Quercus suber was found to possess higher values of heterozygosity (H = 0.288 +/- 0.069), percent of polymorphic loci at the 99% criterion (P = 76.9%) and average number of alleles per locus (A = 2.46), than any other oak species. Interpopulation diversity was about 16.9% of the total diversity. The average estimated of Nm based on 10 loci is 2.57, and shows current or recent gene now among populations. Genetic identities among populations were moderate, ranging from I = 0.829 to I = 0.999, and a cluster analysis revealed no patterns related to geography. Our results revealed that the Q. suber populations studied share a common gene pool. The number of alleles and genotypes and the levels of genetic variability in the study populations, indicate that the Spanish populations are genetically rich. These high levels of genetic variability, coupled with the ecological and economic importance of the species make Q. suber a strong candidate for a gene conservation program.
The following values have no corresponding Zotero field: pub-location: FINKENHOFSTRASSE 21, W-6000 FRANKFURT, GERMANY publisher: SAUERLANDERS VERLAG
Keywords: gene diversity; gene flow; genetic differentiation; genetic identities; isozymes; population structure; Quercus suber

La gestion des taillis de chênes vert et pubescent dans les garrigues du Gard - Curt, Thomas (Ingénieries EAT, 1996)
Medium term management of ageing Holm Oak (Quercus ilex L.) and Downy Oak (Quercus pubescens Willd.) coppices in the Gard requires a thorough understanding of the natural environments and yields of the plantations. This paper puts forward a method for analysing the environment and plantation in order to assess the yield of the oak coppices. 118 small stands were studied in different types of coppices. In general, two environmental parameters determined the dominant height of the stand: geopedological conditions (rock, parent material and soil) and topoclimate which depends on the position of the plantation (orientation and topography). The growth height is affected by the structure and composi- tion of the plantation, together with the forestry and plant growth characteristics. Multivariate ana- lyses enabled 9 types and sub-types of sites to be distinguished with particular environmental con- ditions (soil and topoclimate). The type of site is closely correlated to the variation in the dominant height of the plantations. Growth classes are proposed for the Holm Oak (3 classes) and the Downy Oak (4 classes). These results should assist plantation management selection: the best coppices should possibly be allowed to develop as standards, plantations of average fertility should be treated as simple coppices, coppices with low growth rate should be allowed to grow on. 83
Keywords: Chêne pubescent; chêne vert; conditions geopedologiques (voyant); croissance en hauteur; Gard; Garrigue; peuplements; taillis

Le chêne blanc et le chêne vert, essences truffières par excellence - CHEVALIER, G. (Forêt Mediterranéenne, 1996)
Truffies grow in association with a num ber of deciduous and coniferous tree spe cies. However, not ail of these species offer the same interest for the cultivation of top quality truffles. The oaks (Quercus ssp) feature among the best symbiotic hosts for the truffle, as muchfor the longevity ofproduction asfor the quality of the truffles obtained. Downy oak (Q. pubescens) and holm oak (Q. ilex) are the truffle trees of the Périgord par excellence (T. de Tricastin, T. de Noria and Spoletto, T. melanospo rum ) , because they are the best adapted to the particular conditions of soil and clima te in which the mushroom develops. Furthermore, the morphology of their root system and their slow rate of growth facili tate optimal development of the mushroom in the soil. The downy oak - thermophilic, heliophi Lous, xerophilous to mesoxerophilous, hardy, lime- resistant - is adapted above alt to the production of the truffle of Périgord but is also suitable of obtaining other varieties of fine truffles, including the celebrated piedmont white truffle (T. magnatum). The holm oak, heliophilous, thermoxero philo us, hardy, with a wide range of habi tat is adapted above all to the production of the truffle of Périgord and the summer truffle (T. aesti vum ). Since 1973, sorne 850,000 downy and holm oaks and 250,000 hazels, innoculated with truffle mycorrhiza under the supervi sion of the INRA (French national agricul tural research body), have been planted in numerous areas in the south of France and even in the north. Studies have shown the superiority of the oak over the hazel, parti cularly with regard to the frequency and regularity of production. In respect to rapidity of coming into production, sorne holm oaks were as early as hazels (three and a halfyears after planting). Mycorrhiza-innoculated plants presently available appear, wh en planted, as very heterogenious (aspect, habit, yield) due to the fact that they are multiplied by sowing. Selecting of vegetatively reproduced plants is currently under way. One study is inves tigating whether in a "good producer" there exists a relationship between yield and certain ofils genetic characteristics.
Keywords: Chênes; Périgord (voyant); plants mycorhizés; Truffes

Leaf Contamination by Atmospheric Pollutants as Assessed by Elemental Analysis of Leaf Tissue, Leaf Surface Deposit and Soil - Alfani, Anna; Maisto, Giulia; Iovieno, Paola; Rutigliano, Flora a; Bartoli, Giovanni (Journal of Plant Physiology, 1996)
In order to evaluate the influence of air pollutants influx on leaf elemental composition, the concentration ofN, S, Cu, Fe and Pb were analyzed in the surface deposit and tissue of Quercus ilex L. leaves from 8 sites of the urban area of Naples. The soil from the trunk base area of Q. ilex trees in the same sites was also analyzed for total contents of Nand S and for available contents ofCu, Fe and Pb. In the leafsurface deposit S content was high though significantly (P<O.OOl) lower than in the leaf tissue, whilst N was not detectable. Cu, Pb and Fe contents in leafsurface deposit were conspicuous. The Pb content was higher in the leafsurface deposit than in the leaf tissue. No correlation between leaftissue and surface deposit contents was found for S or for Fe. By contrast, positive and significant correlations (P < 0.01) were found between leaf deposit and leaf tissue for both Cu and Pb. Nand S contents in the leaves were not correlated to the respective contents in the soil and the same was also found for Cu and Fe. In contrast with the presence of limiting concentrations in the soil, N, S and Fe leaf contents were significantly higher than in the leaves from remote sites. The data suggest that direct uptake of airborne pollutants, in addition to root absorption, may influence leaf elemental composition of Q. ilex L. leaves.
The following values have no corresponding Zotero field: publisher: Gustav Fischer Verlag, Stuttgart
Keywords: air pollution; leaf contamination; nitrogen; Quercus ilex L; sulphur; Trace metals

Limitation of photosynthetic activity by CO2 availability in the chloroplasts of oak leaves from different species and during drought - Roupsard, O.; Gross, P.; Dreyer, E. (Ann. For. Sci., 1996)
It has recently been suggested that the low photosynthesis rates in tree species as compared to highly productive crops is at least partly due to resistances opposing the CO 2 fluxes in the mesophyll of tree leaves. To validate this assertion, values of CO2 mole fractions in the chloroplasts of leaves from Quercus petraea, Q robur, Q ilex and Populus sp were estimated on the basis of the analysis of the partitioning of light driven electron flow between fractions used for the carboxylation or the oxygenation of RuBP by Rubisco. The procedure used included: i) a measure of total light driven electron flows derived from the chlorophyll a fluorescence ratio ΔF/Fm', which is proportional to the photochemical efficiency of PS II, multiplied by incident irradiance and a calibration coefficient; ii) an estimation of the electron flux devoted to carboxylation obtained from net CO2 assimilation and respiration rate measurement, and using the known electron requirements (four electrons for CO2 or O2 fixation); iii) the derivation of the CO2 mole fraction in the chloroplasts from the specificity factor of Rubisco, and the ratio of carboxylation/oxygenation of RuBP. Results showed that in the absence of drought stress, the mole fraction of CO2 in the chloroplasts (35-45% of the atmospheric one) was much lower than the calculated substomatal one (60-70% of the atmospheric) in all species. Moreover, lowest values were recorded in the species with lowest assimilation rates, suggesting that the differences in the net CO 2 assimilation rate between species are linked to the CO2 availability in the chloroplasts. Finally, the CO2 availability decreased with increasing drought in the soil, stressing the importance of reduced influx of CO2 as an important factor for drought-induced declines of photosynthesis. These results are discussed with respect to the occurrence of significant resistances in the leaf mesophyll, in addition to the stomatal resistances.
Keywords: chlorophyll fluorescence; chloroplasts; CO2 diffusion; Drought; mesophyll conductance; oaks; Stomatal conductance

Litterfall and mineral return in two cork-oak forests in northeast spain - Caritat, A.; Bertoni, G.; Molinas, M.; Oliva, M.; Domínguez-Planella, A. (Ann. For. Sci., 1996)
Seasonal trends in littertall and potential mineral return were studied in two cork-oak forest sites in the northeastern Iberian peninsula. The estimated average litter production was 3.9 Mg.ha-1.year -1 for one site and 4.6 Mg.ha-1.year-1 for the other; these figures are similar to those reported for holm-oak (Quercus ilex) forests in the same area. Seasonal litterfall patterns were typical of Mediterranean forest ecosystems. Leaves accounted for 46 to 78% of the total dry matter. Their annual weighted-average mineral composition was low in macronutrients (N 8-9; K 4-5; Mg 0.8-1.3; Ca 9-10 and P 0.4-1 mg.g-1) and relatively high in micronutrients such as Mn (2-2.2 mg.g-1) or Fe (0.3-0.4 mg.g-1). Minimum N and P concentrations were found during the growth period. Estimates of potential mineral return for an annual cycle were N 38-52, P 2.1-5.2, K 20-28, Ca 44-53 and Mg 5.4-5.0 kg.ha -1, depending on the site biomass and fertility.
Keywords: cork-oak; litterfall; Mediterranean forest ecosystems; nutrient cycling; Quercus suber

Lixiviation as a tool for radionuclide fractionation in holm oak leaves - Tent, J.; Rauret, G. (JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-ARTICLES, 1996)
A sequential extraction scheme, using distilled water and chloroform : hexane(1:2) was applied in a study of radionuclide retention by helm oak leaves. To perform this study, holm oak leaves were contaminated by dry deposition using a thermogenerated radioactive aerosol containing Cs-134, Sr-85 and Ag-110m. The experimental parameters tested were: type and lime of shaking, number of successive extractions in each step, and the volume of extractans. From the results obtained, two schemes which give complementary information about radionuclide retention are proposed. The first scheme, using a single water extraction with mechanical shaking, allows us to define two fractions: the fraction removed by water, which is related to total radionuclide retention on leaf surfaces, and the residual fraction, which is associated with radionuclides incorporated into the leaves. The second scheme is based on a two-step extraction with manual shaking using water and chloroform :hexane, and permits us to distinguish among three fractions:the fraction removed by water(which is related to the radionuclide fraction easily leached by rain), the fraction removed by organic solvent (which is associated with the radionuclide fraction strongly retained on leaf surface), and the residual fraction, which may represent the absorbed radionuclide content. Since our objective was to study the retention of Cs-134, Sr-85 and Ag-110m, simultaneously, the experimental conditions chosen were a compromise of individual suitable conditions for each radionuclide.
APSAPSThe following values have no corresponding Zotero field: pub-location: PO BOX 245, H-1519 BUDAPEST, HUNGARY publisher: AKADEMIAI KIADO
Keywords: Holm oak; radionuclide

Mammals and fire in mediterranean ecosystems Ecological responses from the shrew Crocidura russula (Insectivora Soricidae) and the rodent Eliomys quercinus (Gliridae) in burned cork oak forest - Fons, R.; Grabulosa, I.; Marchand, B.; Miquel, J.; Feliu, C.; Mas-Coma, S. (VIE ET MILIEU-LIFE AND ENVIRONMENT, 1996)
Mammals and fire in mediterranean ecosystems. Ecological responses from the shrew Crocidura russula (Insectivora - Soricidae) and the rodent Eliomys quercinus (Gliridae) in burned crock oak forest. In the present work we report the ecological responses of two small mammals to fire. During a six-year post-fire period, both species were studied by the capture-mark-recapture on a 9 ha quadrate established in a recently burned cork oak forest. The white-toothed-shrew, Crocidura russula, was the least resistant species to fire, disappearing completely during the first two years. Reappearing on the third year, the population maintained a low effective with the same fluctuation similar to that observed within the control. Although faster than on other studied mediterranean ecosystems, its allochthonous ristablishment on the burned cork oak forest, seems to be dependent on the litter reconstitution. Due to its rupicolous habits, its biotope specialization, highly favored by the presence of rocks on the capture quadrate, and some physiological apects (hibernation), the dormouse Eliomys quercinus, showed a better pre-adaptive response to the post-fire stress. The survival of a nucleus of autochtonous individuals insured, from the first year, a slow, but progressive recovery of the population.
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: Cork Oak Forest; Crocidura russula; ELIOMYS QUERCINUS; fire; mammals

Nutrient content and seasonal fluctuations in the leaf component of coark-oak (Quercus suber L.) litterfall - Robert, B.; Caritat, A.; Bertoni, G.; Vilar, L.; Molinas, M. (Plant Ecology, 1996)
Nutrient content and seasonality of the leaf component in cork-oak litterfal were studied over a two year period in two cork-oak forest sites differing in biomass and edaphic condition in the north-eastern Iberian peninsula. Fallen senescent leaves compared to young leaves showed higher non-mobile nutrient concentrations and lower mobile nutrient concentrations, specially P, N, K, and Mg. At both sites, seasonal fluctuations affected both leaf production and leaf mineral content. The maximum leaf fall period correspond to the start of the vegetative growth and to the lowest N and P concentration in the falling leaves. The opposite was true for the winter, when litterfal was minimal and N and P content in falling leaves was at a maximum. The comparison between falling leaves and canopy leaves suggests that the analysis of fallen leaves can be a useful measure of N and P nutrition in cork-oak. We found site dependent differences in nutrient content and nutrient remobilization. In comparison with Q. ilex, although litter production was in the same range, nutrient retranslocation was greater for Q. suber.
Keywords: litterfall; nutrient return; nutrients in leaves; Quercus Suber L; retranslocation; seasonal trends

Optimization of carbon gain in canopies of Mediterranean evergreen oaks - Rambal, S.; Damesin, C.; JOFFRE, R.; Méthy, M.; Lo Seen, D. (Ann. For. Sci., 1996)
The main goal of this study was to analyze the depth-distribution of leaf mass per area (LMA) measured in ten canopies of Mediterranean evergreen oaks, five canopies of Quercus coccifera and five canopies of Q ilex, across soil water availability gradients in southern France, Spain and Portugal. There was a significant site effect on LMA with values being lower in mesic sites compared to those on xeric sites. In all canopies, LMA decreased by up to 50% from the top to the bottom. The relationships between cumulative leaf area index and LMA could be represented by an exponential function. For two canopies of Q ilex growing in contrasting environments, we analyzed the interrelationships among LMA, mass-based nitrogen, mass-based metabolic versus structural (total fiber) content, photosynthetic electron transport and carbon isotope composition. There was no difference in mass-based nitrogen or fiber content among upper and lower canopy positions in both locations. The maximum quantum yield of linear electron flow can be considered to be constant within the canopy. The area-based maximal electron transport rate and the carbon isotope composition were significantly linearly related to the LMA. Finally, we tested whether the observed depth-distribution follows the pattern suggested by some optimization theories.
Keywords: Leaf mass per area; Mediterranean evergreen canopy; photosynthesis-related leaf property; Quercus coccifera; Quercus ilex

Photoinhibition in cork-oak leaves under stress: influence of the bark-stripping on the chlorophyll fluorescence emission inQuercus suber L. - Werner, Christiane; Correia, O. (Trees-Structure and Function, 1996)
Quercus suber is the primary source for industrial cork and becomes bark-stripped every 9 – 10 years. Recurring cork extraction is a major stress factor and the large water loss from the stripped trunk surface may affect the water balance and tree productivity. To evaluate the effect of bark-stripping, fluorescence emission and stomatal conductance of leaves were determined in groups of barkstripped and control trees. Fv/Fm ratio was found to be significantly lower in bark-stripped trees indicating a reduced photosynthetic efficiency of PSII. Photosynthesis was not found to be stomata limited. The reduction in Fv/Fm resulted from a decline in maximum and variable fluorescence while the initial fluorescence of the darkadapted state (Fo) remained constant. A general decline in photosynthetic efficiency of PSII was found in all trees during the summer, probably reflecting the prolonged environmental stresses during a hot and dry season. Additional stress caused by the bark-stripping seems to enhance the susceptibility to photoinhibition of the trees.
Keywords: bark-stripping; fluorescence emission; Quercus Suber L; water relations

Pollen production in anemophilous trees - Molina, Rafael Tormo; Rodríguez, Adolfo Muñoz; Palaciso, Inmaculada Silva; López, Francisco Gallardo (Grana, 1996)
Abstract A study was made of the total pollen production per individual tree in ten anemophilous arboreal species (including wild, cultivated and ornamental species) of considerable aerobiological importance: Pinus pinaster, Ulmus minor, Juglans regia, Platanus hispanica, Quercus rotundifolia, Salix atrocinerea, Populus nigra, Acer negundo, Olea europaea and Fraxinus angustifolia. For each species three isolated well-shaped specimens of medium height were chosen, and the number of flowers per individual tree and the number of pollen grains per anther was estimated. The values of total pollen production varied between a little over 1000 million grains in Juglans regia and more than 500,000 million in one single tree in Quercus rotundifolia. For the production of pollen grains per anther, the values oscillated between 3000 grains in Juglans regia and 100,000 in Olea europaea. There is an exponential correlation between the size of the anthers and the number of pollen grains they contain. A linear correlation is also evident between the volume of the tree crown and the total production of inflorescences, flowers, anthers and pollen grains per individual tree. Based on this, a mean coefficient of the number of grains/meter of diameter of the tree crown is obtained which varies between 3.4 ? 108 for Juglans regia and 550.9 ? 108 for Quercus rotundifolia. The ratio between the number of anthers per inflorescence and the number of pollen grains per anther carries out a hyperbolic function; thus, the inflorescences with the most anthers have the anthers with the least pollen and viceversa. This ratio is also manifest between the number of grains per flower and the number of flowers per tree, as well as the number of grains per inflorescence and the number of inflorescences per tree.
doi: 10.1080/00173139609430499doi: 10.1080/00173139609430499The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: anthers; flowers; inflorescences; pollen production; tree crown (voyant)

Root respiration, growth and nitrogen uptake of Quercus suber seedlings - Mata, C.; Scheurwater, I.; MartinsLoucao, M. A.; Lambers, H. (PLANT PHYSIOLOGY AND BIOCHEMISTRY, 1996)
We tested the influence of two N-sources, NO3- and NH4+, on root growthand respiration of Quercus suber L. Seedlings were grown on hydroponics with 0.5 mM N as NO3- or NH4+ in a growth chamber. Root relative growth rate (RGR) of NO3--fed seedlings ranged from 9 to 34 mg g(-1) day(-1). These values are lower than those described for slow-growing herbaceous and for most woody species. Root respiration and the activity and capacity of the alternative pathway (AP) showed no differences between the two N-sources. Both activity and capacity of the AP were very low and the cytochrome pathway was fully engaged. Specific respiratory costs were calculated for maintenance, 6.3 nmol O-2 g(-1) s(-1), for nitrate uptake, 0.99 mol O-2 mol N-1, and for growth 5.4 mmol O-2 g(-1). These values are similar to those found for slow-growing herbaceous species. The major part of total root respiration, over 64%, was used for maintenance processes, and a much smaller fraction for growth and nitrate uptake.
The following values have no corresponding Zotero field: pub-location: S P E S-JOURNAL DEPT, 120 BD ST GERMAIN, F-75006 PARIS, FRANCE publisher: GAUTHIER-VILLARS
Keywords: NO3-; NH4+; relative growth rate; root respiration

Signatures of lipid assemblages in soils under continental Mediterranean forests - ALMENDROS, G.; Sanz, J.; VELASCO, F. (European Journal of Soil Science, 1996)
The analysis of free lipids in 12 soils from three representative types of Mediterranean forest has been carried out in an attempt to describe diagnostic molecules reflecting differences between the ecosystems and the intensity of the soil organic matter turnover. The study centred on the analysis by gas chromatography–mass spectrometry of the soil compounds extracted with petroleum ether from soils in central Spain, developed under monospecific formations of stone pine (Pinus pined), evergreen oak (Quercus rotundifolia) and Spanish juniper (Juniperus thurifera), the lipid extracts from their leaves also being analysed as reference material. The comparison between the distribution patterns of alkanes and fatty acids in plant lipids and the corresponding soil lipids was used to assess the extent to which the former accumulate in soil or are substituted by other biogenic or diagenetic homologues. In general, the alkane patterns showed the greatest variation in soils under oak, and the differences between lipid patterns in plant and soil were greatest in the juniper forests. As indicators of the vegetation type, the soil fatty acids had little value. Up to 60 major cyclic compounds were identified, including mainly di- and sesquiterpenes, in addition to some monoterpenes and nonterpenic naphthalenes and decalins. Of these major constituents, 33 compounds were found in soil but were not present in plant extracts, and 18 compounds were identified in plants but were not in the soils. The results suggest an arrangement of the soil samples based on the composition of the signature lipid assemblages.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: GC-MS; Lipids; Lipids assemblage (voyant); mediterranean forest soils

The SLOSS dilemma: A butterfly case study - Baz, A.; GarciaBoyero, A. (BIODIVERSITY AND CONSERVATION, 1996)
Butterfly species richness is examined on simulated archipelagoes of 2, 3, 4 and 5 holm oak forest fragments in the Guadalajara Province (central Spain). It is shown that there are more species on several small `islands' than on a single island. Also, species number increases with the number of fragments that form the archipelago, and with the average distance between islands within the archipelago. Thus, we conclude, at least for butterflies in a system of fragmented helm oak forests in central Iberia, that the best strategy in order to maximize the conservation of species richness is the creation of a net of some small and scattered reserves.
The following values have no corresponding Zotero field: pub-location: 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN publisher: CHAPMAN HALL LTD
Keywords: average distance; butterflies; Central Spain; simulated archipelagoes; SLOSS

Trace metal biomonitoring in the soil and the leaves of Quercus ilex in the urban area of Naples. - Alfani, a; Bartoli, G.; Rutigliano, F. a; Maisto, G.; De Santo, a V. (Biological trace element research, 1996)
The concentrations of Pb, Cu, Fe, and Mn were analyzed in surface deposit and tissue of Quercus ilex leaves from several sites of the urban area of Naples, exposed to different degrees of air pollution. These included some major roads with heavy traffic loads, squares, and three urban parks. The soil from the trunk base area of Q. ilex trees in the same sites was also analyzed for total and available metal contents. Pb, Cu, and Fe contents in the surface deposit and leaf tissue were significantly higher (p < 0.01) in leaves from roadside sites than in leaves from parks; significant correlations were found between deposit- and tissue-contents of Pb, Cu, and Fe. Mn content in leaves from roadside sites and in leaves from parks were similar and Mn content in the leaf deposit was irrelevant. Significant differences (p < 0.001) in both total and available Pb and Cu soil content were found between sampling sites. Also for available Fe and Mn soil content differences among sites were relevant, although the highest values were measured in soil from urban parks. A positive correlation between leaf and soil metal content was found only for Pb, thus suggesting that trace metal contents of leaves directly depend on atmospheric depositions. Seasonal variations of Pb, Cu, and Fe were pronounced at a polluted site, whereas no relevant seasonal variation was observed at a control site; moreover, metal accumulation was high at the polluted site. Mn content and seasonal dynamics were comparable at control and polluted sites.
The following values have no corresponding Zotero field: accession-num: 8834387
Keywords: Air Pollutants; Air Pollutants: analysis; biomonitoring; copper; Copper: analysis; Environmental Monitoring; Holly Oak; Iron; Iron: analysis; lead; Lead: analysis; leaves; Manganese; Manganese: analysis; Plants; Plants: chemistry; seasonal dynamics; Soil; Soil: analysis; Trace Elements; Trace Elements: analysis; urban area pollution

Urban Green and Atmospheric Pollution: A Biomonitoring Study on Leaves of Quercus Ilex L. - Anselmi, S.; Giannini, M. A.; Allegrini, I.; Manes, F. (Giornale botanico italiano, 1996)
doi: 10.1080/11263509609439723doi: 10.1080/11263509609439723The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: air quality; atmospheric pollution; leaf functional conditions; Quercus ilex (PG)

13C solid-state nuclear magnetic resonance and Fourier transform infrared studies of the thermal decomposition of cork. - Pascoal Neto, C.; Rocha, J.; Gil, A.; Cordeiro, N.; Esculcas, a P.; Rocha, S.; Delgadillo, I.; de Jesus, J. D.; Correia, a J. (Solid state nuclear magnetic resonance, 1995)
The thermal decomposition of cork has been studied by Fourier transform infrared (FTIR) spectroscopy and 13C solid-state nuclear magnetic resonance (NMR) spectroscopy with cross-polarization and magic-angle spinning (CP-MAS), high-power 1H decoupling (HPDEC) and cross-polarization depolarization-polarization (CPDP). Waxes and other soluble components of cork begin to decompose at ca. 150 degrees C. This is accompanied by partial decomposition of suberin, probably initiated at the points of attachment to the cell wall. The carbohydrates begin to decompose at ca. 200 degrees C. The decomposition of lignin begins at 250-300 degrees C, while suberin undergoes further degradation. Significant amounts of coke are formed in the process. At 400 degrees C cork has been transformed into coke with traces of partially decomposed suberin. The thermal decomposition of cork is dependent on the calcination time, particularly in the 200-350 degrees C range.
The following values have no corresponding Zotero field: accession-num: 7773647
Keywords: Fourier Transform Infrared (citation); Hot Temperature; Lignin; Lignin: chemistry; Lipids; Magnetic Resonance Spectroscopy; Membrane Lipids; Membrane Lipids: chemistry; Polysaccharides; Polysaccharides: chemistry; Spectroscopy

Absorbed water in the cork structure. A study by thermally stimulated currents, dielectric relaxation spectroscopy, isothermal depolarization experiments and differential scanning calorimetry - Dionísio, M. S. C.; Correia, N. T. (Journal of materials …, 1995)
This paper reports on a modification of the dielectric properties of cork which occurs as a consequence of heating above 60 ~ C or evacuation for several days. This phenomenon was observed using different experimental techniques (thermally stimulated currents, dielectric relaxation spectroscopy, isothermal depolarization experiments and differential scanning calorimetry), and the corresponding kinetics were analysed. It was observed that the original properties of cork were recovered if the sample was exposed to room air for several weeks. It is suggested that the reported modification of the dielectric properties arises from desorption, induced by heating or evacuation, of water molecules absorbed in the cork structure.
Keywords: Cellular structure (voyant); Cork; dielectric loss; dielectric relaxation; TSDC; water desorption

Biodiversity components and conservation of mediterranean healthlands in Southern Spain - Ojeda, F.; Arroyo, J.; MARAÑON, T. (Biological Conservation, 1995)
Biodiversity is a complex issue which has frequently been extremely simplified both by equating it with species richness, and by addressing it at the level of regional floras or faunas. In this paper we carry out a detailed assessment of biodiversity for conservation of Mediterranean heathlands and related woodland understoreys on acidic ‘islands’ in the Gibraltar Strait region which are remarkable for their high species richness, high endemism and low ratio of species per genus. The relationship between the cover of woody plant species and environmental variables was studied by multivariate (DCCA) analysis of 30 samples. Species richness shows a unimodal relationship along the main environmental gradient primarily determined by physiological tolerance to low pH and ecological competition. Quercus suber woodland understoreys under intermediate environmental conditions are highest in species richness. Woody plant species are assigned to one of seven types of geographic ranges, and distributional spectra of community samples are represented. Open heathlands on nutrient-poor soils on mountain ridges are highest in endemism. Species distinctness was estimated as the inverse of the average number of species per genus (‘taxonomic singularity’) within the Mediterranean Basin, Ibero-North African and Southwestern Spain ranges. Quercus canariensis woodland understoreys on more fertile soils on valley bottoms present the highest taxonomic singularity. The analysis at the community level of the three proposed biodiversity components (species richness, endemism richness and taxonomic singularity) is interpreted with the aim of formulating sound conservation strategies of the communities examined. Although we use communities in the Gibraltar Strait area as a particular case study, we suggest that this methodology would help conservation efforts in other areas.
Keywords: acid soils; endemism; Gibraltar Strait; historical biogeography; Species richness

Carbon dioxide efflux and pCO 2 in soils of threeQuercus ilex montane forests - Piñol, J.; Alcañiz, J. M.; Roda, F. (Biogeochemistry, 1995)
Soil CO2 efflux and pCO2 in the soil atmosphere were measured during one year at three montane sites of Mediterranean sclerophyllous forests in NE Spain. Two sites were located in the upper and lower slopes of a small catchment in the Prades mountains (mean precipitation 550 mm year-'), and a third site was located on a lower slope in the Montseny mountains (mean precipitation 900 mm year-'). The three sites were similar in bedrock and vegetation, but differed in soil characteristics and water availability. Seasonal variation of CO2 efflux and soil pCO2 were affected by soil temperature and, to a lesser extent, by soil moisture. Annual mean soil CO2 efflux (considered as soil respiration) was similar at Montseny and at the comparably located site at Prades (83 ± 18 S.E. vs. 75 4 9 mg CO2 m - 2 hour- , respectively), and was highest at the Prades upper slope site (122 ± 22 mg CO2 m -2 hour-l). Despite those relatively similar CO 2 effluxes, mean soil pCO2 was much higher at both Prades sites than at Montseny. Soil pCO2 always increased with depth at Prades while maxima pCO2 at Montseny were often at 20-30 cm depth. A model based on gas diffusion theory was able to explain why soil pCO2 was much higher at Prades than at Montseny, and to reproduce the shape of the vertical profile of pCO2 at the Prades soils. Nevertheless, the model failed to simulate the soil pCO2 maximum found at 20-30 cm depth at the Montseny site. Model simulations using a time-variable CO2 production rate suggested that pCO2 maxima at intermediate depth could be the result of a transient situation instead of an equilibrium one.
Keywords: carbon cycle; Carbon dioxide; Mediterranean ecosystems; soil atmosphere; Soil respiration

Characterization of the cork surface by inverse gas chromatography - Cordeiro, N.; Neto, C. P.; Gandini, A.; Naceur Belgacem, M. (Journal of colloid and interface science, 1995)
Inverse gas chromatography (IGC) at infinite dilution has been used to study the surface properties of cork from Quercus suber. The dispersive component of its surface energy was determined at different temperatures using n-alkanes as probes, and a GDS value of 38+-1mJ.m-2 at 40ºC was obtained. The surface acid (A)/base(B) properties were also evaluated by using polar probes and the results indicate that cork has an amphoteric character, with a KA/KB=1.1. The advantages of IGC, compared with the technique of contact angle measurements in the characterization of the cork surface, are discussed
Keywords: Cork; Inverse Gas Chromatography (IGC); surface properties (PG)

Crown status of holm oak (Quercus ilex L.) trees as related to phenology and environmental stress - Bussotti, F.; Ferretti, M.; COZZI, A. (Water, Air, & Soil …, 1995)
In order to study the possible interactions between air pollution and climate coaditions in Mediterranean evergream broadleaf species, since 1987 we have been monitoring the annual and infra-annual variations in crown density of Quercus ilex L. (holm oak) in a permanent sample plot. The behaviour of crown density has been compared with litterfall pattern and aging processes in leaves. The results of this study confirm the important impact of climate on crown condition in Meditea-raneeaa broadleaves, so that even the role of non- acute pollution can be disguised. Xeromorph adaptations in holm oak leaves are also a mechanism providing a greater protection against poltutants.
Keywords: abscission; crown condition; holm oak (voyant); leaves

Dung Beetles (Coleoptera: Scarabaeidae, Geotrupidae) Attracted to Fresh Cattle Dung in Wooded and Open Pasture - Galante, Eduardo; MENA, JAVIER; LUMBRERAS, CARLOS (Environmental Entomology, 1995)
The biomass of dung beetles attracted to fresh cattle dung was studied in a Mediterranean holm oak pasture ecosystem with a continental Mediterranean climate (supramediterranean level). Results indicated a nonuniform biomass distribution of dung beetles throughout the year. Major peaks of species activity and biomass concentration of dung beetles occurred in open areas of the pasture in the spring followed by minor peaks in the fall. Beetle biomass in the open pasture was greater than that in the wooded pasture. The species of dung beetles comprising the greatest amount of biomass and the most important species available to destroy cattle dung pats in Mediterranean ecosystemswith a continental climate were Bubas bubalus Olivier, Onthophagus opacicollis d'Orbigny, Copris hispanus (L.), Copris lunaris (L.), and Onthophagus vacca (L.).
Keywords: biomass; dung beetles; Holm oak; Mediterranean ecosystem; pastureland

Effect of geographical discontinuity on genetic variation in Quercus ilex L.(holm oak). Evidence from enzyme polymorphism - Michaud, H.; Toumi, L.; Lumaret, R.; Li, T. X. (Heredity, 1995)
Allozymes at a maximum of eight loci were used to analyse the spatial patterns of genetic variation in 1942 hoim oak trees (Quercus ilex L.) from 57 provenances distributed in the six main disjunct areas of the species distribution area. Polymorphism and genetic diversity were high except in the six marginal populations growing in various locations under unfavourable climatic conditions. Ten per cent of the total genetic diversity (H =0.262) was accounted for by among-population variation. In this long-lived species, the effect of geographical discontinuities on gene flow restriction was shown by the occurrence of: (i) numerous rare alleles limited to a single disjunct region; and (ii) allele frequency variation among the disjunct regions for four alleles. This result was obtained by comparing spatial autocorrelograms from the 57 populations of the entire distribution area and from the 31 populations of the Mediterranean continental region which constitutes the largest continuous area in that distribution. Life history traits (e.g. long life span and high outcrossing rate) and past changes in climate and geographical continuity are assumed to be the main factors responsible for the present genetic variation patterns observed in the species.
Keywords: allozyme differentiation; long-term isolation; Quercus ilex

Effects of urban heavy metal pollution on organic matter decomposition in Quercus ilex L. Woods - Cotrufo, M. F.; Santo, A. V. De; Alfani, Anna (Environmental Pollution, 1995)
Decomposition of oak (Quercus ilex) leaves containing different concentrations of Fe, Zn, Cu, Cr, Ni and Pb was measured in laboratory microcosms. The leaves were collected from a polluted site inside the city of Naples and from a control site away from the city. Soil was sampled from the upper A horizon (0-5 cm) at both sites and analyzed for respiration, microbial biomass and abundance of fungal mycelia. The soils from the two sites differed significantly in heavy metals concentrations. The accumulated mass loss reached an asymptotic value after four months both for the control and polluted litters. However, control and polluted litters significantly differed in accumulated mass loss, that was respectively 40 % and 29 % of the initial weight, after 10 months. Moreover decomposition rates appeared to be strongly influenced by metal contamination in the early stages, while in later stages, they did not differ significantly. Litter respiration appeared to be inhibited by metal contamination and showed pattern and rates consistent with those found for litter decomposition. Fungal mycelia were significantly less abundant both in litter and soil from the polluted site than from the con- trol site. Metabolic activity (both as soil respiration and degree of mineralization) was lower in the polluted soil. Soil respiration and amount of soil mycelia correlated negatively with soil Pb, Zn and Cr concentration.
Keywords: Fungal biomass (voyant9; Heavy metals; litter decomposition; pollution; Soil microbial biomass; Soil respiration

Influence of external factors on secondary embryogenesis and germination in somatic embryos from leaves of Quercus suber - Fernández-Guijarro, Bárbara; Celestino, Cristina; Toribio, Mariano (Plant Cell, Tissue and Organ Culture, 1995)
Somatic embryogenesis was obtained in cultures of leaves from young seedlings of Quercus suber L. A two- stage process, in which benzyladenine and naphthaleneacetic acid were added first at high and then at low concentrations, was required to initiate the process. Somatic embryos arose when the explants were subsequently placed on medium lacking plant growth regulators. The embryogenic lines remained productive, by means of secondary embryogenesis, on medium without growth regulators. However, this repetitive induction was influenced by the macronutrient composition of the culture medium. Both low total nitrogen content and high reduced nitrogen concentration decreased the percentage of somatic embryos that showed secondary embryogenesis. Our results suggest that alternate culture on medium that increases embryo proliferation and a low salt medium prohibiting embryo formation will partially synchronize embryo development. Chilling slightly reduced secondary embryogenesis but gave a modest increase in germination. Maturation under light followed by storage at 4 °C for at least 30 days gave the best results in switching embryos from an embryogenic pathway to a germinative one. Under these conditions 15% of embryos showed coordinated root and shoot growth and 35% formed either shoots or mostly roots. These percentages were higher than those of embryos matured in darkness. This result indicates that a specific treatment is required after maturation and before chilling to activate the switch from secondary embryo formation to germination.
Keywords: Cork oak; culture media; plant regeneration; recurrent embryogenesis; repetitive embryogenesis; Somatic embryogenesis

Leaf metabolism during summer drought in Quercus ilex trees with lifetime exposure to elevated CO2 - Chaves, M. M.; Pereira, J. S.; Cerasoli, S.; CliftonBrown, J.; Miglietta, F.; Raschi, A.; Chaves J. S. ;Cerasoli, S. ;Clifton Brown (JOURNAL OF BIOGEOGRAPHY, 1995)
A marginal improvement in the response of Quercus ilex adult trees to drought appears to occur under a long-term natural CO2 enrichment. This is expressed, for example, by the absence of midday stomatal closure in trees growing under elevated CO2. Some protection against high irradiance and high temperature seems also to occur at the photochemical level, presumably as a result of more carbon available to the consumption of excess light energy. This would allow a better performance of the plants grown under elevated CO2 during the warmer hours of the day and therefore playing an important adaptation role under drought conditions. A marginal increase in the concentration of soluble sugars and starch was observed in the leaves of trees growing at elevated CO2 as compared with plants at ambient CO2, mainly during the midday hours. We may speculate that this will be advantageous both in terms of carbohydrate reserves for growth (e.g. more roots) and osmotic adjustment.
From Duplicate 2 (Leaf metabolism during summer drought in Quercus ilex trees with lifetime exposure to elevated CO2 - Chaves, M M; Pereira, J S; Cerasoli, S; CliftonBrown, J; Miglietta, F; Raschi, A)From Duplicate 2 (Leaf metabolism during summer drought in Quercus ilex trees with lifetime exposure to elevated CO2 - Chaves, M M; Pereira, J S; Cerasoli, S; CliftonBrown, J; Miglietta, F; Raschi, A)The following values have no corresponding Zotero field: pub-location: OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL publisher: BLACKWELL SCIENCE LTD label: Fisiologia - CO2 elevado
Keywords: Elevated CO2; Fisiologia - CO2 elevado; fluorescence; long-term acclimation; stomata; sugars; water deficits

MULTIPURPOSE GENE CONSERVATION IN QUERCUS-SUBER - A PORTUGUESE EXAMPLE - VARELA, M. C.; ERIKSSON, G. (SILVAE GENETICA, 1995)
Quereus suber, the native forest tree of highest economic value to Portugal is continuously declining. Creating good conditions for future evolution is the most important gene conservation objective for Quercus suber A simple breeding programme to improve the production of good cork is also included in the gene conservation objective. Gene conservation of species accompanying Quercus suber, or even dependent on Quercus suber, is a third objective. The suggested sampling of gene resource populations is mainly based on climatic, soil and management conditions of Quercus suber populations. Active selection of trees with good cork in small multiple populations growing over a broad array of site conditions is suggested to match the joint evolutionary and breeding objective in gene conservation. Management of large natural populations to create maximum habitat diversity is suggested to take care of the gene conservation of accompanying species. Knowledge of the genetic structure of Quercus suber and of gene now is urgently needed and ought to be given priority in genetic research.
AuthorAuthorThe following values have no corresponding Zotero field: pub-location: FINKENHOFSTRASSE 21, D-60322 FRANKFURT, GERMANY publisher: J D SAUERLANDERS VERLAG
Keywords: Cork oak; GENE CONSERVATION OBJECTIVES AND METHODS; Quercus suber; RESEARCH NEEDS

Presente y futuro de la producción de vacuno de aptitud cárnica en extensivo - Bellido, M. Martín (Archivos de zootecnia, 1995)
Se presenta la producción de carne a nivel mundial, europeo y nacional, haciendo énfasis en los datos de The meat production of the world, Europe and Spain is presented, with enphasis on the Extremadura data. In this region, the number of cattle in 1994 was 462553, of which 319508 were beef cows, managed under extensive conditions. The beef meat produced in extensive system, reached 55199.8 t with a value of 19201.7 millions of pesetas, representing a 20.26 per cent of the total meat produced in the region and the 26.24 per cent of the total value. The steers are feedlot mainly outside the region, due to different causes. The importance of the subsidies coming from the beef cows Commom Market Organization, in the farmers income maintenance, is pointed out. Also, the necessity to improve the breeders association, to comercialize this quality beef, produced under extensive systems compatible with the environment conservation, with the goat to get quality tags for this meat, their promotion and to organice their offer in the market.
Keywords: Dehesa; meat marketing; Quality meat

Red deer (Cervus elaphus hispanicus) management in the dehesa system in central Extremadura, Spain - Vargas, J. D.; Calvo, J. C.; Aparicio, M. A. (Agroforestry systems, 1995)
In this paper we report the results of a study on the suitability of the dehesa (Mediterranean woodlands) as habitat of red deer (Cervus elaphus hispanicus) in a closed country estate of about 4300 ha total surface situated in the San Pedro Mountain, in Central Extremadura, Spain. We have described the d e e r management with respect to habitat, exploitation mode, deer feeding, population control and production of goods and services. It is concluded that the dehesa system is a rich natural resource that preserves and improves the degraded environment.
Keywords: antlers; Dehesa; red deer (Cervus elaphus); Spain; wildlife habitat

The role of marine salt and surfactants in the decline of tyrrhenian coastal vegetation in Italy - Bussotti, F.; Grossoni, P.; Pantani, F. (Annales des Sciences Forestières, 1995)
The decline of coastal vegetation is a phenomenon affecting some areas of the Mediterranean region and Australia; it is due to the presence of surfactants in marine aerosols, a consequence of sea pollution by detergents. This paper gives some observations made at various sites along the Tyrrhenian coast in Italy. The authors show that the presence of surfactants in the environment correlates with the presence of sea salt, and that the impact of surfactants on vegetation is local and occurs in association with strong sea winds. The study of the synergistic effect of surfactants and sea salt on the crowns of trees exposed to aerosols suggests that the surfactant can cause direct damage, while the absorption of sea salt is enhanced by the presence of the surfactant only when exposure to aerosol is prolonged, or if it is administered in very high concentrations.
Keywords: crown damage; leaf absorption; marine aerosol; NaCl; Pinus pinea L; surfactant

SEASONAL ABUNDANCE OF MILLIPEDES IN A MEDITERRANEAN OAK FOREST (SOUTHERN FRANCE) - DAVID, J. F. (ISRAEL JOURNAL OF ZOOLOGY, 1995)
The millipede community of a helm oak forest (Quercus ilex) in southern France was sampled seasonally for 2 yr, at two depths in the forest floor. Despite the strong seasonality of climatic conditions, both recruitment periods and vertical displacements in the soil change markedly according to species; contrasting examples are provided by Glomeris marginata, which breeds in summer and burrows in winter, and by Opisthocheiron elegans, which behaves the opposite way. At the community level, biomass changes significantly between a spring minimum and an autumn maximum. Such a pattern results from the high abundance of G. marginata, a drought-resisting species which grows and reproduces during summer but experiences substantial winter mortality. The seasonal pattern is different in number of individuals due to the minute litter-dweller Polyxenus lagurus, which has a low population density in early autumn. The biomass of macrosaprophagous millipedes on the site (annual mean of 10.5 g live weight m(-2); autumn peak of 14.6 g live weight m(-2)) is much higher than that recorded further north in Europe, and its significance for litter consumption in Mediterranean forest is discussed.
The following values have no corresponding Zotero field: pub-location: PO BOX 50257, JERUSALEM 91502, ISRAEL publisher: LASER PAGES PUBL LTD
Keywords: Bioclimatic limit; Elevation gradient; Oak trees; Regeneration; Shrub encroachment; Species distribution

THE STRUCTURE AND DYNAMICS OF AN ABIES PINSAPO FOREST IN SOUTHERN SPAIN - ARISTA, M. (FOREST ECOLOGY AND MANAGEMENT, 1995)
The forest composition and age-diameter relationships of Abies pinsapo were studied in a natural forest in the Nature Reserve of the Sierra de Grazalema (southern Spain). The composition and structure of the forest was very different with respect to gaps and closed forest. Altitudinal differences in forest composition were also found. Abies pinsapo was the dominant species, Quercus rotundifolia and Quercus faginea were the other important overstorey species. The diameter distributions of A. pinsapo were skewed toward the larger size classes, with a large seedling proportion of about 70%. Abies pinsapo establishment rates were higher in the gaps. Seedlings of Abies pinsapo established under the closed canopy forest had suppressed growth, as indicated by their relatively advanced ages. Seedlings and saplings with suppressed growth can survive for a mean of 40 years, constituting a pool from which canopy trees may be recruited. Results show that the pinsapo forest of the Sierra de Grazalema is in equilibrium and that its dynamics are conditioned by a small-sapling bank and canopy gap formation.
The following values have no corresponding Zotero field: pub-location: PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS publisher: ELSEVIER SCIENCE BV
Keywords: ABIES PINSAPO; forest dynamics; MEDITERRANEAN FIR; Regeneration; SIZE STRUCTURE

BASIS AND ORGANIZATION OF THE EUROPEAN FOREST TREE GENE CONSERVATION NETWORKS - ARBEZ, M. (GENETICS SELECTION EVOLUTION, 1994)
The first ministerial conference on the protection of forests in Europe, held in Strasbourg in 1990, engaged 32 signatory countries to initiate or to follow a concerted policy for forest tree gene conservation and to establish a provisional monitoring structure. This resolution has resulted in an international survey on the present status of forest tree genetic resources in Europe and relevant technical and regulatory measures. In parallel the first 4 pilot gene conservation networks concerning Norway spruce (Picea abies), Cork oak (Quercus suber), black poplar (Populus nigra) and the noble hardwoods (Rosaceaes essentially) were established. Each species or group of species represents a distinct model of spatial distribution and mating system. The second ministerial conference on the protection of forests, held in Helsinki in June 1993, has confirmed these orientations and has proposed the creation of a permanent European cooperative programme under the aegis of the International Board for Plant Genetic Resources and the forest department of the Food and Agriculture Organization. Further research is necessary on the structure of the genetic variability, the mechanisms to maintain this variability in natural forests, and management and sylvicultural methods able to generate maximum adaptability.
The following values have no corresponding Zotero field: pub-location: 141 RUE JAVEL, 75747 PARIS CEDEX 15, FRANCE publisher: EDITIONS SCIENTIFIQUES ELSEVIER
Keywords: EUROPE; FOREST; GENETIC RESOURCE; INTERNATIONAL COOPERATION; NETWORK

BIRD-DISPERSED SEED RAIN AND SEEDLING ESTABLISHMENT IN PATCHY MEDITERRANEAN VEGETATION - Debussche, M.; Isenmann, P. (OIKOS, 1994)
The composition and spatial patterns of the seed rain produced by bird dispersers and of the seedlings of fleshy-fruited plants have been studied in patchy Mediterranean vegetation in southern France. The seeds of fleshy-fruited plants were collected in seed traps during a 17-month period (1981-1983) and the fecal samples of bird dispersers mist-netted on the same 2.5-ha site over a 25-month period (1981-1984) were analysed. The locations of the 5 sets of seed traps and the 6 mist-nets were chosen in order to take into account the various plant communities and the successional gradient from old fields to Quercus ilex coppice. Seedling establishment of fleshy-fruited plants was censused in 1983 adjacent to the seed traps. In 1992 seedlings were again censused in the open coppice and in the old fields. The seeds of 38 fleshy-fruited plants were collected, including 13 alien and cultivated species. Among them, 25 species were dispersed by Sylvia atricapilla, which dispersed the most diverse and mixed seed rain of the various bird dispersers. Species richness of the seed rain increased log-linearly with seed density, ranging from 3 to 21 species per 0.25 m2. Seed density was very heterogeneous in space. The maximum density of seeds was observed under the canopy of isolated trees and saplings in the old fields (up to 829 per 0.25 m2) which are the favoured perching places for the dispersers. Minimum density was observed in the same old fields outside the canopy of these same trees and saplings (down to 12 per 0.25 m2). In the Quercus ilex coppice, the higher the canopy, the higher the seed density. Dispersal was a short distance process. A large majority of the seeds of Pyracantha coccinea and Sambucus nigra were dispersed by birds less than 100 m from the maternal plant. However, a dispersal distance of > 300 m was observed for a seed of Ligustrum vulgare, In 1983 the < 1 yr-old seedlings of 17 fleshy-fruited plants, including only one alien species, and the 1-2 yr-old seedlings of 7 native species were censused. Though important components of the seed rain, no 1-2 yr-old seedlings of several alien (e.g. Pyracantha coccinea) or native (e.g. Rhus coriaria) species were observed in the studied vegetation. Seedlings were more numerous under tree cover than in the coppice clearings. In the old fields, < 1 yr-old seedlings were more numerous under the canopy than in open areas. No such difference was observed under saplings in 1983 and very few seedlings were observed in the old fields. The 1992 census suggested that the positive role of the cover of pioneer plants on seedling establishment progressively increased with successional development. This is probably due to an increase in the nurse effect and a decrease in the herbaceous cover under the canopy. It is suggested that. in old fields. the establishment of fleshy-fruited plants is favoured when seeds are deposited under pioneer woody plants rather than in open areas. The bird dispersers thus trigger dynamic processes initiated by the pioneer woody plants in Mediterranean old field succession. More generally, dispersal of fleshy-fruited plants by birds is more significant in the central stages of succession gradient than it is in open herbaceous communities and in dense forest when both have an homogeneous structure.
APSAPSThe following values have no corresponding Zotero field: pub-location: 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK publisher: MUNKSGAARD INT PUBL LTD
Keywords: bird dispersers; fleshy-fruited; France; Mediterranean; Quercus ilex; seedlings

Crecimiento radial del corcho de reproducción de los alcornocales catalanes y valencianos - Fos, S.; Barreno, E. (Scientia gerundensis, 1994)
Eastern cork-oak forests are present in territories with different environmental characteristics, allowing to raise comparative studies between them. This work is an attempt to evaluate the radial growt differences of the reproduction cork, using tschniques of optical microscopy, having developed a new methodology. Thus, severa1 sites from catalonian and valencian cork-oak forests have been selected. In the quantification of this growth, the contribution of each cork type (early cork and late cork) in the annual growing rings have been differentia- ted. The annual increments measwed in catalonian corks have an average of 2.958 mm, being a bit lower in Castell6n with 1.622 mm. These differences in the annual growing rings are due to the early development higher in catalonian cork (2.623 mm) than in valencian ones (1.235 mm), late cork thickness is similar in the two areas. These differences seem to be related with the escarce summer dry period in catalonian cork-oak forests. Important anato- mical differences related with the mentioned ombroclimatic asimetries have been observed too.
Keywords: Anatomy; bioclimatology; cork-oak; Quercus suber L.; Radial growth

Datos sobre la vegetación de andalucía. III. Series de vegetación caracterizadas por "Quercus suber" L. - Pérez Latorre, Andrés V.; Nieto, José M.; Cabezudo, Baltasar (Acta botánica malacitana, 1994)
Data about andalusian vegetation. III. Vegetation series with Quercus suber L. presence. Quercus suber woods are one of the natural forests with more diversity and more expanse in Andalusia (Spain). Quercus suber is a dominant or common species in eight vegetation series or subseries: Myrto communis-Querceto suberis S, Teucrio baetici-Querceto suberis S, Smilaci mauritanicae-Querceto rotundifoliae quercetoso suberis subsigmetum, Tamo communis-Oleeto sylvestris quercetoso suberis subsigmetum, San guisorbo hybridae-Querceto suberis S, Pyro bourgaeanae-Querceto rotundifoliae quercetoso suberis subsigmetum, Paeonio coriaceae-Querceto rotundifoliae quercetoso fagineae subsigmetum, var. of Quercus suber, Adenocarpo decorticantis-Querceto rotundifoliae quercetoso suberis subsigmetum. These vegetation series show peculiar sucesional dynamism of their communities depending on their traditional use, environmental factors and biogeographical location. Two new subasociations, Ulici eriocladi-Cistetum ladamferi cistetosum albidi and Phyllireo angustifoliae-Quercetum lusitanicae cytisetosurn tribracteojati, are described in this paper.
Keywords: Andalusia; Quercus suber woods; Spain; vegetation series

Deposition on holm oak leaf surfaces of accidentally released radionuclides - Rauret, G.; Llauradó, M.; Tent, J.; Rigol, A.; Alegre, L. H.; Utrillas, M. J. (Science of The Total Environment, 1994)
The retention of aerosols by canopies of holm oak trees in a typical Mediterranean forest is studied. Firstly, dry deposition is measured both under and outside the canopy during several months. No clear differences are observed either in the amount or in the chemical composition of the particles collected under and outside the canopy. Secondly, the leaf morphology and anatomy as well as the aerosol deposited onto the leaf surfaces are studied by scanning electron microscopy. Cuticle thickness is measured and differences are observed between young and old leaves. The distribution of aerosol particles over leaf surface is also established. Finally, the possible incorporation into leaves of a radioactive aerosol released in an accidental situation is studied, by means of a sequential extraction procedure using water and an organic solvent. From the results it can be deduced that neither the abiotic layer nor the cuticle play any important role in the retention of caesium. The studied radionuclides are mainly found in particulate form, soluble in water, or incorporated into leaves.
Keywords: Cuticle thickness; Holm oak; Leaf surface; Radionuclide deposition; Radionuclide incorporation; Sequential extraction

Differences between oligotrophic communities resulting from old-field succession in relation to bedrock - Puerto, A.; Rico, M. (Plant Ecology, 1994)
Dehesa ecosystems on granite and on slate clearly differ in soil characteristics. Our aim was to find out whether floristic composition differed too. We selected an equal number of plots, on both granite and slate, in different successional stages of development and at various ages after field abandonment (the youngest 15-20 years). Plots with rock-outcrops, which had never been cultivated, were also included in the study. The results showed that floristic differences between granite and slate communities were not detectable in the younger successional stages. However, they showed up with time and on stabilized grasslands became significant. But on plots with rock-outcrops the differences were not observable. This was undoubtedly influenced by the peculiar features of these plots, characterised by poor arid soils and surface parent material. In fact they did not show significant differences in the analysed soil parameters either. Species diversity and biomass showed a similar pattern of differences to floristic composition. The highest species diversity was found on plots with lower biomass (the youngest ones). The lowest biomass in conjunction with quite low species diversity was found on plots with rock-outcrops, which again is consistent with their peculiar features.
Keywords: biomass; diversity; granite; mediterranean grasslands; slate

European oak declines and global warming: a theoretical assessment with special reference to the activity of Phytophthora cinnamomi - Brasier, C. M.; SCOTT, J. K. (EPPO Bulletin, 1994)
Causes of current severe declines of the deciduous oaks Quercus robur and Q. petraea in northern and central Europe and of the evergreen Q. ilex, Q. suber and other Quercus spp. in the Mediterranean area are reviewed. Factors implicated include drought, pollution, winter cold, flooding, and stress-related attacks by insects and fungi. Additional factors in Mediterranean oak declines include changing land-use patterns and root disease caused by the aggressive, exotic oomycete root pathogen Phytophthora cinnamomi. Under conditions of global warming the survival and degree of root disease caused by this fungus seems likely to be enhanced, while the host range of the organism might also be increased. Application of the CLIMEX climate-matching program suggests that with a mean increase in temperatures of 1.5–3°C the fungus might considerably increase its disease activity in its existing locations, and to some extent spread northwards and eastwards. However, it seems unlikely to become significantly active in areas of Europe with colder winters such as parts of Scandinavia, Russia and the central Danube. The predictive value of research on major environmental problems such as oak declines could be enhanced by more highly coordinated European forestry research programmes.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Global warming; Oak decline; phytophthora cinnamomi; range expansion (PG); root disease

Fungal endophytes from the leaves and twigs of Quercus ilex L. from England, Majorca and Switzerland - FISHER, P. J.; PETRINI, O.; PETRINI, L. E.; SUTTON, B. C. (New Phytologist, 1994)
Leaves of Quercus ilex taken from sites in England, Majorca and Switzerland have been studied to detect the influence of the geographic position of the host within and outside its native range on the composition of its endophytic fungal assemblages. Samples of stem tissue of Q. ilex collected from the Swiss trees were also studied to confirm tissue-specific differences. Sixty different fungal taxa were isolated, but only 28 were frequent. Of the total number of isolates from the leaves from the Swiss, British and Spanish sites 87%, 31% and 63%, respectively, were coelomycetes. Four species of Phomopsis, which includes Phyllosticta ilicina (=Phomopsis ilicina v. d. Aa, ined.), were the most frequent endophytes of leaves and were either absent or rare in the twig units. Two distinct kinds of sterile mycelia were common in twigs. Swiss and Spanish trees possessed fungal assemblages distinct from those present in Britain. Naturalized stands were distinguished from native stands by the presence of rather cosmopolitan and non-specific fungal taxa, rare or absent in the samples collected in the native stands. Samples derived from the native stands were colonized by more host-specific fungi. The relative frequency of two sterile mycelia in the Swiss and Spanish sites determined their separation. Phyllosticta (Phomopsis) ilicina, the most numerous leaf colonizer, was virtually absent from the bark and the xylem. The frequent occurrence of coelomycetes as endophytes of woody trees is briefly discussed.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: coelomycetes; fungal distribution; fungal ecology; Quercus ilex (oak)

Phenological and growth patterns of the Mediterranean oak Quercus suber L. - Oliveira, Graca; Correia, Otflia (Trees-Structure and …, 1994)
The phenology of Quercus suber L., a dominant species of the montados in the Iberian Peninsula, was studied for 2 years in southwest Portugal. The seasonal progression of phenological events was analyzed in seven trees. Selected branches were examined monthly for shoot elongation, leaf number, branching, flowering, and fruiting. Radial stem growth and specific leaf weight were also studied. Active growth was observed from early spring to early summer. Reserves accumulated during winter and high photosynthetic activity in early spring apparently supported this strong development. The growth flush started with stem radial increment, which seemed to be impaired by spring rainfall. Male inflorescence production was the next phenological event. Old leaves were shed during new twig and leaf emergence. Shoot elongation and the number of new leaves produced were well correlated with the previous-year shoot's length, and were not clearly related to climatic factors. Radial growth resumed in au- tumn at a lower rate than in the previous spring, a possible consequence of a reserve depletion due to lower photo- synthetic production in summer and investment on fruit maturation, which was complete by late autumn. Premature and excessive new leaf production were apparently sub- jected to self-pruning strategies related to the development of each tree's crown. Younger cork-oaks produced shorter and fewer shoots per module, and more sclerophyllous leaves than the older ones. A high intra-specific variability was observed in all the results.
Keywords: Growth; Phenology; Quercus suber; specific leaf weight; Trees

Photosynthetic acclimation in trees to rising atmospheric CO2: a broader perspective - Gunderson, C. A.; Wullschleger, S. D. (Photosynthesis Research, 1994)
Analysis of leaf-level photosynthetic responses of 39 tree species grown in elevated concentrations of atmospheric CO 2 indicated an average photosynthetic enhancement of 44% when measured at the growth [CO2]. When photosynthesis was measured at a common ambient [CO2], photosynthesis of plants grown at elevated [CO2] was reduced, on average, 21% relative to ambient-grown trees, but variability was high. The evidence linking photosynthetic acclimation in trees with changes at the biochemical level is examined, along with anatomical and morphological changes in trees that impact leaf- and canopy-level photosynthetic response to CO 2 enrichment. Nutrient limitations and variations in sink strength appear to influence photosynthetic acclimation, but the evidence in trees for one predominant factor controlling acclimation is lacking. Regardless of the mechanisms that underlie photosynthetic acclimation, it is doubtful that this response will be complete. A new focus on adjustments to rising [COz] at canopy, stand, and forest scales is needed to predict ecosystem response to a changing environment.
The following values have no corresponding Zotero field: accession-num: 24311130
Keywords: elevated atmospheric CO 2; global carbon cycle; photosynthetic acclimation; Trees

RUPTURE IN A COLLEMBOLA COMMUNITY STRUCTURE FROM A QUERCUS-ROTUNDIFOLIA LAM FOREST DUE TO THE REAFFORESTATION WITH EUCALYPTUS-GLOBULUS LABILL - SOUSA, J. P.; DAGAMA, M. M. (EUROPEAN JOURNAL OF SOIL BIOLOGY, 1994)
Here we compare Collembola populations from a Quercus rotundifolia forest and an Eucalyptus globulus plantation. The overall analysis of data (using both diversity and similarity measures) have shown clear signs of rupture on the structure of collembola populations, with the fauna associated with the Quercus stand being richer (in exclusive and preferential species) and more abundant than the one connected with the Eucalyptus. Data also reflects the faunal stratification between organic and mineral horizons, with the majority of species being associated with upper soil layers in detriment of mineral horizon. These disruptions may be related to profound alterations of habitat characteristics, particularly the frequent removal of shrub vegetation and leaf layer, result of the forestry practices connected with the preparations and management of the eucalyptus plantation.
The following values have no corresponding Zotero field: pub-location: DEPT UNIV PROFESSIONNEL REVUES SCIENTIFIQUES TECHNIQUE 11 RUE GOSSIN, F-92543 MONTROUGE, FRANCE publisher: GAUTHIER-VILLARS
Keywords: Collembola; EUCALYPTUS; holm-oak; REAFFORESTATION

Vegetation changes and human action from the Neolithic to the Bronze Age (7000–4000 BP) in Alicante, Spain, based on charcoal analysis - Badal, Ernestina; Bernabeu, Joan; VERNET, J. L. (Vegetation History and Archaeobotany, 1994)
Charcoal analysis reveals various palaeo-eco- logical phases from the Neolithic to the Bronze Age. Ag- riculture starts about 7000 B.P. in favourable ecological conditions. Most of the charcoal spectra from sites iin the coast represent thermomediterranean holm-oak forest; those from the inland mountains represent mesome- diterranean holm-oak forest. The Neolithic I Impressed Ware people were the first to clear the forest to plant their crops. This clearance of primary woodland resulted in the development of secondary vegetation of pine woods or scrub. The scrub reached its maximum during the Bell Beaker phase and Bronze Age in the Cova de les Cendres. In the Neolithic II open air sites, the percent- ages of Quercus ilex/coccifera remain high. This may be the result of a different exploitation of the land, or suit- able conditions for the growth and survival of the vegeta- tion.
Keywords: bronze; CHARCOAL ANALYSIS; human impact; Neolithic; Spain

Antioxidant activity of mediterranean plant leaves: Occurrence and antioxidative importance of A-tocopherol - Chevolleau, S.; Mallet, J. F.; Debal, A.; Ucciani, E. (Journal of the American Oil …, 1993)
a-Tocopherol was identified as the main antioxidant in hexane extracts of leaves of sixteen Mediterranean plant species. The a-tocopherol content was determined by a two-step procedure involving column and gas chromatog- raphy with a-tocopherol acetate as internal standard. The tocopherol content of the extracts was in the range of 0.0-4.7%, and that of the dry leaves was 0-846 ppm. The highest a-tocopherol content was found in the leaves of a Mediterranean oak, Quercus ilex. The antioxidative ac- tivity, which was previously investigated, was correlated with the a-tocopherol content. Correlation coefficients were 0.947 and 0.904 for extracts and leaves, respectively.
Keywords: antioxidant activity; hexane extracts; Mediterranean plant leaves; o-tocopherol

CHARCOAL ANALYSIS and the VEGETATIONAL EVOLUTION of NORTH-WEST PORTUGAL - FIGUEIRAL, I. (Oxford Journal of Archaeology, 1993)
Summary: The palaeoenvironment of north-west Portugal is investigated from the late Bronze Age to Roman times. This research is based on the analysis of charcoal from seven archaeological sites. the results contain important information for a better understanding of the vegetational environment of man during this period. Man-environment relations are also examined.
APSAPSThe following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: charcoal; paleoecology; Portugal; vegetational environment

CRECIMIENTO DE LAS POBLACIONES DE INSECTOS DEL GRUPO <;ERAMBYX CERDO EN LA DEHESA ARBOLADA EXTREMEÑA - del Moral de la Vega, J.; Casado Ponce, D.; Gallego Girón, M. (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
This comunication gives the results of a study cat.:fied out on the damages caused by the Cerambyx cerdo beetles on the cork oaks Quercus suber, Quercus rotundifolia, in the oak forest of Estremadura (Southwest Spain), mainly in the Badajoz province. These species were taxonomicaly identified and their population examined in relation to different variable agrosystems. K.W.:
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: Cerambyx cerdo; Estremadura; Quercus; Spain

CROWN STRUCTURE MODIFICATIONS IN RELATION TO AIR-POLLUTION - Bussotti, F.; BROGI, L.; Grossoni, P.; COZZI, A.; GELLINI, R. (LANDSCAPE AND URBAN PLANNING, 1993)
Analysis of crown structure and crown modifications plays a role of primary importance in surveys of `new types of forest damage', since it is a decisive parameter in assessing the health status of a tree. Several forms of ramification alterations have been described in central and northern European species (Norway spruce, beech, Durmast oak, English oak, birch). This study examines the situation in Tuscany and offers a description of the alterations found in the main species typical of the Mediterranean region (Turkey oak, pubescent oak, holm oak, stone pine). The article discusses the potential impact of these alterations on the most typical forest formations, the ones which characterize the Tuscan landscape, and it describes the modifications already under way.
The following values have no corresponding Zotero field: pub-location: PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS publisher: ELSEVIER SCIENCE BV
Keywords: crown structure; forest formations; Mediterranean

Ecological aspects of the floral phenology of the cork-oak (Q suber L): why do annual and biennial biotypes appear? - Elena-Rossello, J. A.; de Rio, J. M.; Valdecantos Garcia, J. L.; Santamaria, I. G. (Ann. For. Sci., 1993)
Phenological observations (periods of flowering and pollination, floral structures, etc) were made over a 3-year period in natural populations of Q suber. We demonstrated the existence of 2 different types of seed cycles in the cork-oak. The 'annual biotype', requires only 1 season to complete its reproductive cycle (ie, similar to that of the Lepidobalanus group), whereas the 'biennial biotype' requires 2 full years (similar to Erythrobalanus). The variability observed in the cork-oak, during the reproductive cycle, and the meaning of the existence of 2 different reproductive strategies in the same species, are discussed
Keywords: annual and biennial biotypes; cork-oak; ecological variability; floral phenology; Quercus; reproductive strategies

EFFECTS OF FOOD ABUNDANCE AND HABITAT STRUCTURE ON SEED-EATING RODENTS IN SPAIN WINTERING IN MAN-MADE HABITATS - Díaz, M.; González, E.; MUNOZPULIDO, R.; NAVESO, M. A. (ZEITSCHRIFT FUR SAUGETIERKUNDE-INTERNATIONAL JOURNAL OF MAMMALIAN BIOLOGY, 1993)
The patterns of abundance and seed (acorn) predation races were analyzed in granivorous rodents (mainly the wood mouse Apodemus sylvaticus L.) wintering in two man-made habitats: cereal croplands, and a kind of wood-pasture exclusive to the western Mediterranean basin, the dehesas. Both seed (acorn) abundance ana vegetation structure were also measured. Within dehesas, neither rodent abundance nor acorn predation rates were related to acorn abundance, whereas there Tvas a significant. association between rodent abundance and shrub cover at the end of winter. These results were coincident with previous findings in croplands. Both rodent abundances and seed predation rates were lower in dehesas than in croplands, despite the better structural and trophic conditions of the first habitat for rodents (larger shrub cover and food abundance). However, the body condition of animals was better in dehesas, to the extent that we found strong evidence for mincer reproduction. Rodent predator communities appear to be more diverse and denser in dehesas than in croplands. This suggests a heavier predation pressure in dehesas which would have culled rodent populations in such a way chat food Tvas plentiful for survivors, rhus explaining their scarcity, good body condition, and low dependence on food resources.
APSAPSThe following values have no corresponding Zotero field: pub-location: VILLENGANG 2, D-07745 JENA, GERMANY publisher: GUSTAV FISCHER VERLAG
Keywords: abundance patterns; acorn predation; Mediterranean; montado; rodents

EFFECTS OF TANNIN COMPOUNDS ON 2 SPECIES OF COLLEMBOLA - POINSOTBALAGUER, N.; RACON, L.; SADAKA, N.; LEPETIT, J. (EUROPEAN JOURNAL OF SOIL BIOLOGY, 1993)
The effects of condensed and hydrolysable tannin extracted fromevergreen oak leaves (Quercus ilex L.) were tested on two species of Collembola. Concentrations lower than those present in the litter leaves were toxic to these insects. Detoxification by washing with rainwater and biodegradation of tannic compounds are necessary for litter decomposition, in which microarthropods participated, to occur.
CitationCitationThe following values have no corresponding Zotero field: pub-location: S P E S-JOURNAL DEPT, 120 BD ST GERMAIN, F-75006 PARIS, FRANCE publisher: GAUTHIER-VILLARS
Keywords: TANNINS; EVERGREEN OAK; COLLEMBOLA

Estimating tree density in oak savanna-like lsquo;dehesa’ of southern Spain from SPOT data - JOFFRE, R.; LACAZE, B. (International Journal of Remote Sensing, 1993)
Abstract The main objective of this study was to establish a method of estimating tree density in savanna-like vegetation systems using the highest spatial resolution available from satellite data (SPOT-1 panchromatic = 10 m resolution) based on the assumption that for sparse trees on a contrasting herbaceous background, spatial filters may provide a direct mapping of tree cover. The study was performed in the ?dehesas? oak-woodland of southern Spain. This particular landscape is characterized by the presence of scattered evergreen oak trees (Quercus ilex and Q. suber) whose density ranges from 0 to 80 even-aged mature trees per hectare which gives the appearance of a savanna-like vegetation. Tree density can be accurately estimated by SPOT-1 panchromatic data after numerical filtering. This method allows the mapping of tree density of the dehesas, a key parameter reflecting the functional vegetation-soil-climate equilibrium which exists for both woody and herbaceous strata.
doi: 10.1080/01431169308904368doi: 10.1080/01431169308904368The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: Dehesa; oak; savanna-like; SOPT data; southern Spain; tree density

THE EUROPEAN PINE MARTEN MARTES-MARTES IN THE BALEARIC-ISLANDS, SPAIN - CLEVENGER, A. P. (MAMMAL REVIEW, 1993)
Between March and December 1990, a survey of Pine Marten Martes martes L. on the Balearic Islands of Minorca and Majorca was carried out. Pine Marten were found distributed over 55% of Minorca and occupied Aleppo Pine and Holm Oak forests, mediterranean shrublands and riparian/cliff habitats. In Majorca, Pine Marten were found on 48% of the island and three broad physiographic areas, the Sierra de Tramuntana, Sierra de Levant and the Massif de Randa. Droppings were collected along four designated routes during five bimonthly intervals in Minorca to describe the Pine Marten's differential use of habitat types. The upland/open pine forest had the highest use index while the Holm Oak forest had the lowest. The number of Pine Marten faeces collected was greatest during the months of July-August. The Balearic Island Pine Marten populations were once on the verge of extinction; however, protection during the last 20 years has enabled the species to recover throughout most of the forested habitats on both islands. Resource managers must carefully monitor the Pine Marten populations to provide the species and its habitat with adequate protection and management in the future.
APSAPSThe following values have no corresponding Zotero field: pub-location: OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL publisher: BLACKWELL SCIENCE LTD
Keywords: Aleppo pine; Balearic Islands; Holm oak; Martes martes L.

Evidence for Phytophthora cinnamomi involvement in Iberian oak decline - Brasier, C. M.; ROBREDO, F.; FERRAZ, J. F. P. (Plant Pathology, 1993)
Rapid and sometimes extensive mortality and decline of oak, principally Quercus suber and Q. ilex, has occurred in parts of southern Spain and Portugal in recent decades. We report here isolation of the aggressive root pathogen Phytophthora cinnamomi from roots of diseased oaks or from soil at eleven out of thirteen decline foci examined. It is proposed that the introduction and spread of P. cinnamomi may be a major factor in the Iberian oak decline, interacting with drought and other site factors, and leading to stress-related attacks by insects and other fungi. By analogy, it may also be involved in the similar oak declines occurring elsewhere on the Mediterranean.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Drought; Oak decline; phytophthora cinnamomi; site factors (PG)

FACTORES QUE DETERMINAN LA CALIDAD DEL CORCHO - González Adrados, José Ramón (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
Cork quality, strongly related with economical profit 9f Quercus suber stands, is today determined by the visual characteristics of corkwood planks, mainly porosity and thickness. Variance in those'parameters is imputed to ecologic?l, selvicultural and genetic factors. Relationship between environmental factors and cork qua lit y is studied in this work. Data from two samples obteined in Extremadura and Catalonia show that this dependence is significati ve.
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: Cork; Cork quality; Quercus suber stands

Geographical variation in the density of the white stork Ciconia ciconia in Spain: Influence of habitat structure and climate - Carrascal, L. M.; Bautista, L. M.; Lázaro, E. (Biological Conservation, 1993)
The spatial variation in the density of white storks Ciconia ciconia in Spain is analysed with respect to landscape and meteorological variables. The density of breeding pairs in 1985 was negatively correlated with surface cover of woodlands and shrublands, and posi- tively correlated with the area of dry or wet grasslands, reflecting .food availability and foraging preferences of the storks. Average minimum temperature in April-May (the first .few days after hatching) was also negatively correlated with stork density, and the reproductive success in a colony at El Tietar (Avila) was inversely correlated with the number of days with precipitation in May. The negative influence of minimum temperature and precipitation on breeding density appears to be linked with the mortality of recently born nestlings. Practical recommendations are made for the conserva- tion of the Spanish population of white storks through incentive use of pastures, meadows and 'dehesas' for cattle grazing. Reintroduction efforts must be direct towards zones having large areas of these habitats, and mild weather
Keywords: climate; distribution; habitat; Spain; white stork

Germination and regeneration mechanisms in Mediterranean degenerate forests - Bacilieri, R.; Bouchet, M. A.; Bran, D.; Grandjanny, M.; Maistre, M.; Perret, P.; Romane, F. (Journal of Vegetation Science, 1993)
Abstract. Germination and developmental behaviour during juvenile stages are of importance in relation to succession mechanisms acting on plant communities. This is particularly so in the Mediterranean region, where the climatic summer drought causes stress. We investigated and compared germination and development of four tree species in two parts of the French Mediterranean region where the original dominant tree species (Quercus pubescens) has been largely replaced by Quercus ilex in the southern part, and Castanea sativa in the northern part. Observed differences in germination rates and developmental behaviour, especially shootroot ratio and the role of water supply, suggest that other species may eventually replace the current dominant species.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Castanea sativa; Pinus pinaster; Quercus ilex; Quercus pubescens

Influence of raw-material quality and process parameters in the production of insulation cork agglomerates - Pereira, H.; Baptista, C. (European Journal of Wood and Wood Products, 1993)
{Insulation cork agglomerates are produced with different low-cost raw-materials unsuitable for other products: virgin corks (from prunmgs, thinnings anti dead trees), reproduction corks (refuse and underaged) and industrial byproducts (corkback strips). These materials were analysed in relation to chemical composition, struc- ture and trituration behaviour. The industrial byproducts diffcr significantly from the other materials due to the presence of an important amount of the unsubcriscd lignocellulosic phlocm (the back of the corkboards) in a way that is detrimental to the agglomeration process. The influence of raw-material, granulometry and process parameters (time, temperature and pressure} were studied using an experimental autoclave. Temperature is the deter- mining factor for agglomeration. Insufficient adhesion is obtained under 230 ~C and adequate agglomeration is attained only with temperatures in the range 230 300 "C. corresponding to inass losses of 10 25%.
Keywords: chemical composition; CORK AGGLOMERATES; Raw materials; structure; trituration behaviour (Voyant)

INFLUENCIA DE LA POSICION DE LA COPA SOBRE LA FENOLOGIA y LAS RELACIONES HIDRICAS DEL ALCORNOQUE (QUERCUS SUBER L.) - Oliveira, G.; Werner, C.; Mertens, C.; Correia, O. (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
A tree crown may be seen as a large and heterogeneous population of branches and leaves, unequally subjected to the environmental factors. It is thus questionable if studies on a few leaves or a branch will be a good approach to the whole canopy. This is particularly important in the field, where the applieation of ecophysiological measurements to mature (and generally large) trees presents obvious human and financial problems. The purpose of this study was to determine the effeet of different levels and directions within the' crown on the phenology and water relations of a typieal cork-oak in south Portugal. Our preliminary results show that the parts of the erown exposed to higher radiation value~ present a stronger growth and biomass production (direetion effect). Crown level was not clearly related to the results, suggesting that the "height effect" is not very important in trees with wide and diffuse crowns like the ones occurring in the montado systems.
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: Crown position; Phenology; Quercus suber; Stomatal eonductance 1)

INFLUENCIA DE LAS COBERTURAS DE ENCINAS , Quercus ilex subsp. ballota , EN LA ROTURA DE LOS PERFILES TERMICOS VERTICALES - Escudero Garcia, J. C.; Cabezas Fernández, J.; Lavado Contador, F. (CONGRESO FORESTAL ESPAÑOL - Lourizán 1.993, 1993)
Vegetation cover acts intensely on vertical temperature profiles, breaking up their structure. For the particular case of holm oak parkland (dehesas) forests systems, these will affect the vertical temperature gradient by modifying it more or less sharply as a function funtamenta1ly of the height and characteristics of the canopy, the density of trees ánd of foliage load. The study was carried in Cheles (Badajoz), and consisted in periodic measurements of the temperature variations in the profile. The results show quantitatively the influence of arboreal systems on the vertical structure of air and soil temperatures. A characterlzation is thereJore given of the thermal impact that intense pruning and destruction of holm oaks have on the vertical profIle, especially that of he soil.
The following values have no corresponding Zotero field: periodical: CONGRESO FORESTAL ESPAÑOL - Lourizán 1.993
Keywords: gradients; impact; Quercus ilex; Temperature

Los alcornocales andaluces: regeneracion y REPOBLACION ARTIFICIAL - Sánchez García, J. M. (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
After a brief description of the types of cork tree groves that exist in Andalusia, a succint review of the way and necessary conditions in wich the restocking is done at present. Also data referring to the reforestation with Quercus suber in the last decade are collected. Finally a view of the place that the cork oak takes in the framework of the Andalusian Forestry Plan.
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: Andalusian Forestry Plan; Cork Oak Forest; Reforestation; Restocking

Mediterranean pasture dynamics: the role of germination - Espigares, T.; Peco, B. (Journal of Vegetation Science, 1993)
pastures were arranged along a gradient of sensitivity to temperature on the arrival of the first persistent rain. This sensitivity was manifested in both the total germination success of the species and the germination time profile. The different germination patterns of the species can provide competitive advantages depending on the autumn weather conditions.
Keywords: Autumn rain; Gradient; Phytotron; seed bank; Temperature; Weather fluctuation

OBTENCION DE PLANTAS A PARTIR DE EMBRIONES SOMATICOS DE QUERCUS SUBER L - Fernández Guijarro, B.; Celestino, C.; Toribio, M. (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
This paper gives a procedure to regenerate plants of cork oak through somatic embryogenesis. The somatic embryos were obtained in leaves from young seedlings and cotyledonary fragments from mature acorns of cork oak. The explants were cultured in three stage process in wich BA and NAA concentration were decreasing. Different methods were used to germinate the embryos. Dessication and culture in low salt concentration medium were chosen to give the best results
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: adventive embryogenesis; Cork oak; culture media; plant regeneration; secondary embryogenesis

Possible criteria for selection of Quercus suber plus trees - García-Valdecantos, J. L.; Catalán, G. (Ann. For. Sci., 1993)
The field work for selecting superior trees of cork oak is described. Requirements for selection are different from those employed for timber tree breeding, because the product to be improved is not wood, but bark. The field work is being developed in a natural forest of 16 000 ha, 8 000 of which are pure cork oak. As the trees are debarked once every 9 years, each year an area of 800-900 ha is selected. The characters assessed were tree size and form, resistance to pests and diseases, bulk production of cork, and cork quality. At the time of debarking, every 9 years, 64 superior trees are selected for progeny testing.
Keywords: breeding; Quercus suber; selection

PRODUCCION DE BELLOTA EN QUERCUS ROTUNDIFQLIA LAM.: VARIABILIDAD ANUAL E IMPORTANCIA ECONOMICA - Esparrago, F.; Vázquez, F. M.; Burzaco, A.; Perez, M. C. (Congreso Forestal Español, Lourizán - Pontevedra. 1993, 1993)
The acorn production on Q. rotundifolia Lam. has been analyzed from 1989 through 1992 in Extremadura. The efects of different areas, each tree, and the interaction between areas/years are significatives. Genetic, pruning, environment and phytosanitary factors are the possible causes of these differences. Finally, the econornic efects of acorn production on iberian pig feeding (Montanera) has been studied. This is the rnain factor for high quality products.
The following values have no corresponding Zotero field: periodical: Congreso Forestal Español, Lourizán - Pontevedra. 1993
Keywords: acorn; Econorny; evergreen oak; feeding; iberian pig; production; Quercus

RESPONSE TO MICROCLIMATE OF MORPHOLOGICAL LEAF ATTRIBUTES, PHOTOSYNTHETIC AND WATER RELATIONS OF EVERGREEN SCLEROPHYLLOUS SHRUB SPECIES - GRATANI, L. (PHOTOSYNTHETICA, 1993)
Leaf adaptations of Quercus ilex L., Phillyrea latifolia L. and Pistacia lentiscus L. to various environmental conditions namely from the viewpoint of the differences of leaf area, dry mass, chlorophyll (Chl) content, sclerophylly index, succulence index and net photosynthetic rate (P(N)), are shown. Irradiance was the most important factor to influence P(N), leaf temperature, stomatal conductance (g(s) and transpiration rate (E). Under canopy layer low red-far red ratio reduced P(N). Shade leaves were enriched by Chl b. Chl content and sclerophylly index were good leaf characteristics to express adaptability of plants to microclimate.
The following values have no corresponding Zotero field: pub-location: NA KARLOVCE 1A, PRAGUE 6, CZECH REPUBLIC CS-160 00 publisher: INST EXPERIMENTAL BOTANY, ACAD SCI CZECH REPUBLIC
Keywords: irradiance; leaf area; microclimate; Phillyrea latifolia L.; Pistacia lentiscus L.; Quercus ilex L.

Threatened landscape in Alentejo, Portugal: the 'montado'and other 'agro-silvo-pastoral'systems - Correia, T. P. (Landscape and Urban Planning, 1993)
In Portugal agro-silvo-pastoral systems correspond to the mixed land use types characteristic of the region of Alentejo, in the southern part of the country. There is a triple and complementary use of the land, adapted to the low potentialities of the soil and to the Mediterranean climate: open evergreen forest (oaks, olive and chestnut trees), grazing and cultivation. Due to their mixed characteristics and to the extensive form of exploitation, these systems constitute varied landscapes of high biological diversity. They have been managed through decades as an almost self-maintained system, with a minimum of human work input, but furnishing nevertheless the necessary outputs for the dispersed rural population of the area. Actually, due to the decrease in the economic value of some of the products concerned and to the changing context for Portuguese agriculture, these agro-silvo-pastoral systems have registered perturbations by intensification or extensification; in both cases there is a degradation or disappearance of the corresponding landscapes.
Keywords: land use (voyant); landscape; montado

WATER-ABSORPTION BY CORK - ROSA, M. E.; FORTES, M. A. (WOOD AND FIBER SCIENCE, 1993)
A study of liquid water absorption by cork was carried out in which the anisotropy of cork was taken into account. The changes with time of the mass, volume, and linear dimensions were measured for different orientations of the sections in cork exposed to liquid water at room temperature (20 C) and at 90-100 C. Two regimes of water absorption were identified, namely, a period involving dimensional change and a period with only mass change. Diffusion coefficients at both temperatures were estimated using a special technique. There is a small anisotropy with a faster diffusion in the radial direction. Diffusion coefficients at 90 C are two orders of magnitude larger than at room temperature. Water absorption in the cell walls causes the expansion of cork, which (for the boiled specimens tested) is slightly smaller in the radial direction. The volume increase is proportional to the mass increase and ceases after relatively short immersion times. At this stage, the cell walls are apparently saturated with water. Further immersion results in penetration of water into the cells. The kinetics of absorption is rather slow at long times, but eventually the cells become full of water, the density increases above that of water, and the cork sinks.
The following values have no corresponding Zotero field: pub-location: ONE GIFFORD PINCHOT DR, MADISON, WI 53705 USA publisher: SOC WOOD SCI TECHNOL
Keywords: Cork; DIFFUSION COEFFICEIENTS; DIMENSIONAL CHANGE; WATER ABSORPTION

Antioxidant activity in leaves of some Mediterranean plants - Chevolleau, S.; Mallet, J. F.; Ucciani, E. (Journal of the American Oil Chemists' Society, 1992)
{{Hexane and methanol leaf extracts of sixteen Mediter- ranean plant species were obtained by percolation. Higher yields were observed for m e t h a n o l (16.4-47.8%} than for hexane extracts (1.3-13%}. Antioxidant activity of these extracts w a s determined by a rapid spectrophotometric method involving the combined oxidation of beta-carotene and linoleic acid. Leaf extracts were thus characterized by an Antioxidant Activity Coefficient (AAC) ranging from 0 to 1000. Hexane extracts gave m u c h higher A A C values than the corresponding methanol extracts. In both cases, myrtle (Myrtus communis) showed the best antiox- idant effectiveness.
Keywords: antioxidant activity; hexane extracts; Mediterranean plant leaves; methanol extracts

Comparative water relations of four Mediterranean oak species - Acherar, M.; Rambal, S. (Plant Ecology, 1992)
The water relations and responses of two evergreen (Quercus ilex L. and Q. suber L.) and two decidu- ous (S. afares Pomel. and Q. faginea Will.) Quercus species were studied under experimental conditions. Two-year old seedlings grown in 30 1. pots were subjected to a drying period during which stomatal conductance, pre-dawn potential and minimum foliar potential were measured. The results shows that, for all species, the daily course of stomatal conductance agrees with the patterns proposed by Hinckley et al. (1978 & 1983). Concurrent with the species responses to short-term variation in water availability, it was found that pre-dawn leaf water potential controlled the maximum daily leaf conductance. There was a strong correlation between pre-dawn leaf potential and maximum daily conductance as described by the reciprocal function g ........ = ( -0.47 + 2.61.~bp) 1 for the evergreen oaks and g ......... (-1.94+7.39.~bp) 1 for the deciduous species. These differences between the two groups may partialy explain their geograhic distributions, and suggest general questions concerning the mechanisms which optimize water-use efficiency in Mediterranean oak species.
Keywords: mediterranean species; Quercus; Stomatal conductance; water-potential; water-stress

Coroebus undatus (Coleoptera: Buprestidae) sur chêne liège dans le Sud-Est de la France : estimation des dégâts, relations entre ceux-ci et certains facteurs du milieu - Du Merle, P.; Attié, M. (Ann. For. Sci., 1992)
Coroebus undatus (Coleoptera: Buprestidae) on cork oak in southeastern France: an estimate of damage and its relationship to environmental factors. In 52 plots distributed throughout the cork oak stands (Quercus suber L) of the Maures-Esterel region in southeastern France (fig 1) 5-15 oaks were selected from those whose cork had been removed less than 1 year before. On such trees, galleries made by the late-instar larvae of the last generation of Coroebus undatus (Fabr) are clearly visible at the surface of the stripped part of the stem. On each tree, the 4 vertical lines running through the middle of the north, east, south and west sides of the stripped part of stem were divided into 50-cm long sections from soil surface, and intersections between galleries and each of these segments of lines were counted. For each tree and each plot a damage index was calculated as follows: the damage index of a tree (IA) was the mean total number of intersections per stem side counted on the first basal 1.50 m of the stem, that of a plot (IP) was the mean value of IA. IA may be considered to be roughtly proportional to the percentage of damaged stem surface (A%), ie, the ratio, expressed as a percentage, between the total surface of the galleries and the surface of the stem; both variables are approximately linked by the relationship: A % = 0.4 IA. C undatus occurred everywhere in the investigated area, but IA and IP ranged from 0 to 27.6 and 1.2 to 14.8 respectively, according to the trees and the plots (figs 2, 3). The first basal 0.50 m of stems was on average ≈ twice less damaged than the rest of their surface, while their south and west sides were slightly more damaged than the 2 others. Within plots, trees were equally damaged (same mean IA value) whatever the diameter and probably also the shade degree of their stems. Between-plot variation in IP was not explained by the mean diameter nor probably by the mean shade degree of stems. IP value tended to vary inversely with elevation, and was higher on average on southern slopes
Keywords: Coroebus undatus; damage assessment; environmental factor; inner-bark boring insect; Quercus suber; tree factor

Daily and seasonal variation in water relations of macchia shrubs and trees in France (Montpellier) and Turkey (Antalya) - Duhme, F.; Hinckley, T. M. (Vegetatio, 1992)
Based upon two different research studies in the mediterranean regions of France and Turkey, drought resistance strategies were investigated in a broad group of species. The diurnal and seasonal patterns of the water relations of different lifeforms from the thermo-mediterranean to submediterranean lifezones were compared. Three sites near Montpellier, in Southern France, and five sites near Antalya, Turkey were used for this comparison. Xylem pressure potential and relative stomatal aperture were the key water relations parameters collected in France while these parameters as well as osmotic potential and leaf conductance were studied in Turkey. From the 26 different study species investigated in France, 7 distinct types of stomatal control were observed, with the deciduous lifeforms showing the least control, the sclerophyllous and coniferous evergreens the greatest control and the malacophyllous shrublets intermediate levels of control. Predawn water potential values provided a means of classifying species according to their temporal and spatial utilization of site water reserves. The comparison of turgor potentials (difference between water and osmotic potentials) gave an insight into leaf adaptations to site moisture. Species with high predawn water potentials generally maintain positive turgor even at midday during the summer, whereas species with low predawn values were frequently at zero turgor even at predawn. Phlomis grandiJtora was the most extreme species with mid-summer predawns and midday water potentials of -6 MPa and osmotic potentials never more negative than -2.4 MPa.
Keywords: Drought resistance; Malacophyllous shrubs; Osmotic potential; Stomata control types; Turgor loss point; Xylem water potential

The dynamics of a therophytic community in relation to self-regulation, herbivores and environmental variation - Acosta, F. J.; López, F.; Serrano, J. M. (Vegetatio, 1992)
The dynamics of a therophytic plant community in Central Spain has been studied, taking into account endogenous and exogenous factors. Using a simplified descriptive resolution a multi-species grass community and four canopy density types have been described in permanent quadrats. Transition matrices expressing the changes of vegetation state have been constructed. The importance of self- regulation was shown by the dependence of successive transitions on each other (highly significative log-linear models). The functioning cannot however be explained through a strict Markovian model because the transition probabilities are not stationary. The external local factors tested (microtopography, compactness and granivory) do not have a consistent effect on the vegetation dynamics, being variable over years, implying the importance of other more general factors on vegetation dynamics. Making transition probabilities dependent on external environmental factors rep
Keywords: Ants; Environmental influence; Granivory; Grasses; Markovian models; Vegetation dynamics

Dynamics of holm oak (Quercus ilex L.) coppices after clearcutting in southern France - Floret, C.; Galan, M. J.; Floc'h, E.; Romane, F. (Plant Ecology, 1992)
Holm oak (Quercus ilex L.) forest is one of the most widespread biocoenoses in the southern part of France. Until recently, clearcutting of wood for domestic use was carried out every 20 years or so in these coppice stands. In order to study coppice stand dynamics after cutting this paper presents results of observations of some items describing the vegetation structure, the floral composition, and the life cycles in a holm oak coppice stand during a six year period after clearcutting. One of the questions addressed in this study was whether these coppice stands reach a 'steady' state based on auto-succession, or if they continue to change. The results of the floristic changes after cutting suggest that the model of auto-succession best fits with the vegetation dynamics, even if changes in the density and life cycles of herbaceous species still exist six years after clearcutting.
Keywords: Life cycles; Mediterranean climate; vegetation succession

Effect of cleaning and thinning on height growth and girth increment in holm oak coppices (Quercus ilex L.) - Ducrey, M.; Toth, J. (Plant Ecology, 1992)
This article studies the influence of cleaning or thinning intensity and of coppice age at the time of silvicultural treatment, on the growth of shoots remaining on the stool, in Quercus ilex coppices. Two experimental designs were used to answer these questions. The first studied the effect of two cleaning intensities on 4, 8, 15, 20, and 25 year old coppices. The second studied the effect of 4 thin- O O/ ning intensities (26 o, 42.0, 58%, or 78 °,/o removal of the initial basal area) on 43 and 57 year old coppices. In both cases, control plots undergoing no silvicultural treatment were maintained for each age class. The results, 4 and 5 years after silvicultural treatment, concerned girth increment and height growth of coppice shoots. Cleaning or thinning consistently had a positive influence on girth increment. In young coppices, less than 25 years old, mean annual girth increment was approximately 6 mm in the controls and double that under heavy cleaning. In older coppices, girth increment was lower in controls (3 mm per year) but the effect of thinning was very positive and, under very heavy thinning, growth was more than 11 mm per year. Cleaning and thinning often modify height growth. This effect was found to be either positive or negative and no general trend could be defined which was valid for all the age classes. Silvicultural treatments also had a positive effect on the appearance and growth of epicormic shoots on the holm oak trunks. The results were also analysed at the stool level. The number or percentage of shoots removed had a positive effect on the individual growth of selected shoots
Keywords: cleaning; coppice; Growth; Quercus ilex; thinning

The effect of individual tree shelters in growth and morphology of cork oak seedlings - Dias, A. S.; Tomé, J.; Tavares, P.; Nunes, J.; Pereira, J. S. (SCIENTIA gerundensis, 1992)
To study the effects of the tree shelters in growth and morphology of cork oak ( Quercus suber L.) seedlings two types of plastic shelters were used in this work: A, transparent PVC shelters (brown) reinforced withawhitepolyesternet, 75 cmofheight; B, translucentbrownpolypropilene, double w$led, square cross section and 120 cm of height. The plants were grown in 120 cm long tubes in Evora, Portugal and growth of sheltered and control plants was evaluated based upon measurements of height, branch lenght, number and area of leaves and biomass. Additionally the anatomy and morphology and heat tolerance of leaves of sheltered andcontrolplants was studied. The results sbow that prowth in beight was stimulated by shelters. The amount of branches was greater in seedlings with shelters seedlings in shelters B were not significant. The shootíroot ratio was higher in sheltered plants than in controls because of the above-ground biomass increased in the former whereas root biomass remained unchanged. Foliage developed inside the shelters showed characteristics of acclimation to shade and were less tolerant to heat being killed at lower temperatures than those of unsheltered controls. A than in controls but the differences between the latter and
Keywords: Acclimation to shade; heat tolerance; Quercus suber; tree shelters

Effects of bark-stripping on the water relations of Quercus suber L - Correia, O. A.; Oliveira, G.; Martins-Loução, M. A.; Catarino, F. M. (Scientia gerundensis, 1992)
Quercus suber is the primary source of industrial cork and can produce cork every 9-10 years. The main objective of this work was to investigate the influence of bark stripping on the stomatal activity and water relations of cork-oak. For this purpose, diurnal changes on transpiration, stomatal conductance and water potencial were measured before and after bark stripping during July and August 1989 and 1990. The stripping on the trees had been done at various intensities. The water loss by the stripped surface was also measured. These results show that severe bark-stripping may lead to a decrease in stomatal conductance and considerable water losses. The stripping stress is not clearly dependent on the stripping coefficients, but rather on the water lost by the trunk which varies from tree to tree probably according to the phloemic tissues composition.
Keywords: bark-stripping; Quercus suber; Transpiration; water relations

Effects of leaf longevity and retranslocation efficiency on the retention time of nutrients in the leaf biomass of different woody species - Escudero, a; Arco, J. M.; Sanz, I. C.; Ayala, J. (Oecologia, 1992)
A study was made of the retention times of N and P in the leaf biomass and their relationship with the retranslocation percentages and the leaf longevities in some woody species in Central Spain. The retention times of both nutrients were strongly related to the nu- trient status of each species. These results suggest that a prolonged retention time is a way of increasing nutrient use efficiency in conditions of low nutrient availability. Plants can increase the retention time of nutrients in their leaf biomass by means of an increase in leaf longevity and/or by means of an increase in retranslocation effi- ciency. However, the effect of the retranslocation effi- ciency on retention times was almost negligible compared with the effect of leaf longevity. This suggests that an increase in leaf longevity is probably the best adaptation for increasing efficiency in the use of nutrients.
Keywords: leaf longevity; nitrogen; Nutrient use efficiency; phosphorus; retranslocation

El crecimiento radial del alcornoque en cinco parcelas de alcornocal de Girona - Caritat, A.; Molinas, M.; Oliva, M. (Scientia gerundensis, 1992)
Tree rings of Quercus suber L. are porous and difficult to read because of the irregular growth rhythm. Radial growth has been measured in five experimental plots situated in the region of Girona (Catalonia, NE Spain). Cores of ten standard trees of each plot were extracted using a Pressler borer. In three plots woody disks from standard trees were also obtained. Tree rings were examinated under binocularlens. The CATRAS computer program (Anio1,1983 ) was used to find statistical parameters. Tree rings have an average width changing from 1,21 to 3,74 mm, while average standard deviation varies from 0,24 to 1,88 mm. and autocorrelation from 0,008 to 0.894 . These values are similar to those found in other Mediterranean Quercus, like Q. ilex L. The studied cork-oak plots ,with diametrical classes between 5 and 57 cm, show regular growth characteristic of young forest. The St. Hilari plot has the maturest trees, (diametrical classes from 24 to 57 cm) and this fact was reflectedin thegrowthcurve. Suddengrowthincreases are attributed to forestry management measures like clearing or selective cutting down. The effects of periodic cork extractions could no be clearly appreciated in this study.
Keywords: cork-oak; Mediterranean sclerophylls; Quercus suber L.; Radial growth; wood rings

Estudos de hidrologia em povoamentos de Quercus suber e caracterizaçao mesológica do ecossistema - Almeida, A. P. (Scientia gerundensis, 1992)
The main objective of the project is to assess the effect of different types of soil management under cork-oak tree stands on water use and cork productivity. The study utilized a 5.5 ha watershed near the town of Mora, center of Portugal. The watershed contained scattered cork- oak with natural pasture, which is probably the most representative formof landuse in the region. de 1990, que va mostrar la The project used the basic water balance equation, being evaluated incident rainfall, runoff, evapotranspiration and changes in soil water storage. Measurements of the tree stands and canopies were included for the characterization of throughfall and stemflow. Interception was estimated to evaluate its effects onrainfallredistribution and onthe dynarnics of evapotranspiration. Collection of data for the intensive hydrologic study begun in October 1, 1988. During 1989, surface runoff was 10.8 percent of annual rainfall. For the same period, canopy interception by the Quercus suber stand was 15.4 percent and throughfall accounted for 84.6 percent of annual rainfall, as stemfiow was considered negligible. Statistical analysis of data related to the period January, 1990 to May, 1990 is now being undertaken. Itis apparent, however, from the study, that the data sets should be extended through further research to confirm the tentative hydrological trends of the first period.
Keywords: cork-oak; land use; pasture; productivity; water balance

Evidence for hybridization between sympatric holm-oak and cork-oak in Spain based on diagnostic enzyme markers - Elena-Rossello, J. A.; Lumaret, R.; Cabrera, E.; Michaud, H. (Plant Ecology, 1992)
Hybridization has been detected in mixed populations of juvenile cork-oak and holm-oak individuals using three diagnostic enzyme loci coding for esterases, leucine amino peptidases and acid phosphatases respectively. Among the 35 studied individuals, 29, 5 and 1 were identified as holm-oak, cork-oak and hybrid respectively. Such diagnostic markers are likely to be useful to detect and remove hybrids at the juvenile stage in areas where the holm-oak is grown for acorn production and the cork-oak is cultivated for cork. This is necessary since hybrid adults produce neither cork nor acorns of high quality.
Keywords: cork-oak; enzyme markers; holm-oak; Hybridization; Quercus

Factors affecting radial growth of Quercus ilex L. in a coppice stand in southern France - Cartan-Son, M.; Floret, C.; Galan, M. J. (Plant Ecology, 1992)
Quercus ilex woodlands in the south of France are characterized by low productivity. Several hypo- theses have been put forward to provide an explanation for this phenomenon: (i) senescence of coppice stumps; (ii)limited availability of water and nutrient resources; (iii)intershoot and inter-plant compe- tition. To test some of these hypotheses, growth response to rainfall distribution and nutrient supply (NPK), and the influence of edge effects after clear-cutting were studied in a 40-yr old stand. Curves of radial increment were compared with precipitation and umbrothermic patterns for the 6 years studied. Water availability apparently accounted for some inter-annual differences in growth. However, it was not mean annual rainfall, but rather rainfall occurring in late spring-summer (June, July) which played a large role in determining radial growth. Radial growth was also increased by nutrient supply. Its positive effect was strengthened by favourable rainfall in 1987. Edge-effects following a clear-cut were also found, both in the first year and in four succeeding years following the cut. This comprised in greater radial growth rate for all shoots, with reduced repression of smaller shoots by the larger ones. The effect decreased over a distance of 10 m with increasing distance from the cut field. This could be explained by increased availabiDLy of water, nutrient resources, and light.
Keywords: clear-cutting; edge effect; Mediterranean climate; nutrient supply; productivity

HABITAT PREFERENCE OF SPANISH IBEX AND OTHER UNGULATES IN SIERRAS DE CAZORLA Y SEGURA (SPAIN) - ESCOS, J.; Alados, C. L. (MAMMALIA, 1992)
Studied the habitat preference in Autumn and Spring periods of Spanish ibex (Capra pyrenaica), fallow deer (Dama dama) and red deer (Cervus elaphus) in the Sierras de Cazorla y Segura Park (Spain). Spanish ibex occupied most altitude range studied, especially highest parts and avoiding areas below 800 m, red deer selected lowest elevations between 700 to 1100 m and fallow deer (between 1200-1600 m) occupied an intermediate annual altitudinal range. All the ungulates studied showed, except the red deer populations, a descent of altitudinal levels in the Spring period. Ibex used more covered areas specially females and young in Spring period, fallow deer occupied open habitats and red deer preferred holm-oak woods. In general terms the rut occurred in more open areas while in the birth season, females and young especially occupied covered areas. According to the overlap index (Pianka 1973) ibex with fallow deer could get a high risk of competition, while Spanish ibex and red deer, the only endemic species show the lowest level of overlapping on the resources studied. Segregation of the sexes studied in different habitats was observed. In Autumn, Spanish ibex and fallow deer showed a tendency to occupy sunny areas at dawn and dusk and this tendency occurred in red deer only at dawn but not at dusk. However in Spring, Spanish ibex, fallow and red deer occupied sunny slopes at dusk but only fallow deer do so at dawn.
The following values have no corresponding Zotero field: pub-location: 55 RUE DE BUFFON, 75005 PARIS, FRANCE publisher: MUSEUM NAT HIST NATURELLE
Keywords: APS; Capra pyrenaica; cervus elaphus; Dama dama; habitat prefference; Holm oak; Spain; ungulates

HYDROCHEMICAL BUDGETS, NUTRIENT CYCLES AND HYDROLOGICAL RESPONSES IN THE QUERCUS-ILEX-FOREST OF PRADES CATCHMENTS - Bellot, J.; Lledó, M. J.; Piñol, J.; Escarré, A. (RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES, 1992)
In this paper we present a perspective of the objetives in the Prades project, as well as some results of 7 years of study on Hydrochemical budgets, and water and nutrient fluxes in the holm-oak forest (bulk deposition, throughfall, stemflow, primary production, litterfall, runoff, etc)
The following values have no corresponding Zotero field: periodical: RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES pub-location: BARKING ESSEX
Keywords: Hydrochemical budgets; nutrient fluxes; water fluxes

Impacte das principais micoses no montado de sobro - Fonseca Neves, N. (SCIENTIA gerundensis, 1992)
Several factors have been found to contribute for the weakness o€ cork-oak stands, and among thosefactors, diseases have animportantrole. In this paper, the main diseases, their causal agents, symptoms and damages are described. Bioecological aspects of the causal agents and protection measures are referred.
Keywords: cork oak stands; diseases

Impacte do Platypus cylindrus F.(Coleoptera, Platypodidae) en Quercus suber L - Ferreira, M. C.; Ferreira, G. W. S. (Scientia gerundensis, 1992)
The main symptoms of attacked trees by Platypus cylindrus F. are given. Data on bioecology, dispersion and impact of this species on Quercus suber L. are presented. Protection mesures.
Keywords: Cork oak; Platypus cylindrus F.; Quercus Suber L

Las técnicas de selección y propagación en la mejora genética del alcornoque - García Valdecantos, J. L. (Scientia gerundensis, 1992)
The role and importance of the techniques of propagation and selection in the cork oak breeding programs are discussed. In the field of propagation, the characteristics of sexuai reproduction are discussed. The author recommends the use of medium or small acorns and empbasizes the need of improving acorn storage procedures. Considering vegetative propagation as the best method to obtain maximal genetic gains, the author emphasizes the difficulties found in the use of cuttings, the fairly good results obtained with grafts, and the promising experiences of tissue culture. The importance of rejuvenating techniques using stump sprouts and suckers for vegetative propagation is strongly emphasized. The selection superior trees for breeding programs in the cork oak is difficult because of the lack of previous experience in genetics of bark production. An experimental method, developed in the province of Cidiz with the help of ICONA, is described. This method is based in an accurate measurement of a number of tree pararneters which are evaluated at the end of a complete harvest cycle (9 years).
Keywords: Cork oak; provenances; seed orchards; tree breeding; vegetative propagation

Litter dynamics in post-fire successional forests of Quercus ilex - FERRAN, A.; Vallejo, V. R. (Plant Ecology, 1992)
Forest floor regeneration after fire in a holm oak forest was studied in a chronosequence in Catalonia (NE Spain). The sampled area represented situations of high fire disturbance because of the frequency of wildfires and the high impact of erosive processes. Forest floor bulk samples from the L, F and H layers were taken in 5 burned plots, aging from 0 to 35 years. They were analyzed for dry standing weight, and organic carbon and N content. Plant cover reached almost 100°o two years after the fire. During the first 20 years, shrubs and herbs had the highest surface covering, and thereafter, holm oaks became dominant. Holm oak litterfall stabilized by the fourth year after burning. The major shrub species which were present in the chronosequence had two different patterns with respect to nitrogen: 1) a low litter C/N ratio (i.e. nitrogen fixing species); 2) a high litter C/N ratio. The litter decay coefficients were relatively high, allowing for a rapid structuration and formation of the L and F layers after the fire. Indeed, 95 ° o of the maximum steady standing weight accumulates in 8-9 years. The pattern of cover in the different strata influenced the lateral distribution and variable accumulation of the forest floor layers and determined different turnover rates.
Keywords: C/N ratio; Decay coefficient; Holm oak; mediterranean forest; plant regeneration

Litterfall as a measure of primary production in Mediterranean holm-oak forest - Bellot, J.; Sánchez, J. R.; Lledó, M. J.; Martínez, P.; Escarré, A. (Plant Ecology, 1992)
In this paper we discuss the use of litterfall as a method to measure primary production and its between year relation to climatic fluctuation. Seven years of study in a mediterranean holm-oak forest showed a moderate inter-annual variability of litterfall (C.V. 11°;), while the annual variability of the actual or evapotranspiration was three times higher (C.V. 30/o). Furthermore, the inter- and intra-annual vari- ability of nutrient content in the various fractions are presented in relation to water availability. Monthly and seasonal variability was higher than the annual variability for all analyzed elements.
Keywords: holm-oak; litterfall; litterfall nutrient contents; mediterranean forest; primary production; Quercus ilex; temporal variability

A mass spectrometry study of thermal dissociation of cork - Filomena Bento, M.; Aurea Cunha, M.; Moutinho, A. M. C.; Pereira, H.; FORTES, M. A. (International Journal of Mass Spectrometry and Ion Processes, 1992)
Mass spectrometry has proved a convenient technique for the analysis of plant cell-wall material. In this work a comparative study is made of chemically treated cork and untreated cork, applying a method in which samples were continuously heated in vacuum. The outgassing products, upon electron-induced fragmentation, are analysed by a quadrupole mass spectrometer. Sequence of spectra at increasing temperatures were obtained for each sample, which allowed identification of the main groups of fragmentation. From such sequences of spectra one may derive intensity—temperature curves for each peak. Analysis of these curves for samples subjected to different treatments proved useful to identify the peaks, to assign the component which originates the species and even to derive activation energies.
Keywords: Cork; electron-induced fragmentation; thermal dissociation

A MEDITERRANEAN BIRD DISPERSER ASSEMBLAGE - COMPOSITION AND PHENOLOGY IN RELATION TO FRUIT AVAILABILITY - Debussche, M.; Isenmann, P. (REVUE D ECOLOGIE-LA TERRE ET LA VIE, 1992)
This study deals with a fleshy-fruited plant-bird dispersal system at a site in Mediterranean France, characterized by Quercus ilex coppices, shrublands and old fields. Among the 19 bird dispersers recorded, 14 were of small size (< 25 g), with Sylvia atricapilla, Erithacus rubecula and S. melanocephala accounting for 86.6 % of those caught in mist nets. The importance of small-sized dispersers seems to characterize the Mediterranean shrublands and evergreen woodlands in the whole of the temperate systems. The highest numbers of dispersers occurred from October to January. The seeds of 38 fleshy-fuited plants (native, cultivated and alien) were collected in seed traps. Seed rain occurred throughout the year except in May, with a maximum fruiting period extending from September to early December and the greatest number of native species being dispersed in October. When we compare our data to those collected in Spain, England and Sweden a shift of the peak of fruit availability in relation to latitude (the higher the latitude the earlier the peak) is very likely in Europe. Such a shift is obvious in the United States. We suggest that 1) this shift is the result of climatic constraints on plants rather than that of the selective pressures of dispersers, and 2) that the coincidence between high fruit availability and dispersers' abundance can simply result from the opportunist behaviour of frugivorous birds.
Keys: APSKeys: APSThe following values have no corresponding Zotero field: pub-location: 57 RUE CUVIER, 75005 PARIS 5, FRANCE publisher: SOC NATL PROTECTION NATURE ACCLIMATATION FRANCE
Keywords: birds; dispersal system; evergreen woodlands; Mediterranean; Quercus ilex

Mediterranean evergreen oak diversity: morphological and chemical variation of acorns - Afzal-Rafii, Zara; Dodd, Richard S.; Pelleau, Yvonne (Canadian Journal of Botany, 1992)
Acorns of mediterranean evergreen oak were collected from eight ecogeographically contrasting localities in Italy and Spain. Biometrical analysis of acorns and their cupules showed much greater variation among Spanish populations, encompassing the variation in Italy. The Spanish population at El Pardo, considered the type locality for Quercus rotundifolia, separated from all others. Multivariate analyses of the chemical data indicated, on the one hand, separation of Spain from Italy, and on the other hand, a separation of interior Spanish populations from coastal populations. The importance of lipid composition in the former separation may reflect genetic differentiation between these two origins. Coastal populations were closer to Italian and we suggest were a zone of introgression and hybridization between Quercus ilex and Q. rotundifolia and probably also Quercus coccifera at Bonete Albacete
doi: 10.1139/b92-184doi: 10.1139/b92-184The following values have no corresponding Zotero field: publisher: NRC Research Press
Keywords: biometry; chemistry; diversity; ecogeography; Quercus ilex; Quercus rotundifolia

Notes on Quercus ilex L. in Liguria (NW Italy) - Barberis, G.; Peccenini, S.; Paola, G. (Plant Ecology, 1992)
The climatic characteristics of the Liguria region have been outlined by means of raw data and derived indices (water balance related to potential evapotraspiration, Rivas-Martinez's index of mediterraneity and thermicity, De Martonne's index of dryness, and Emberger's pluviothermic quotient and index of summer dryness). Their interpretation suggests that Liguria is a boundary region between two different climatic areas: the Mediterranean and that of Central Europe. The distribution of Quercus ilex communities in Liguria have suffered the heavy consequences of human activity on the coastal belt of the region. There is, however, sufficient evidence to show that their presence is closely linked to climatic conditions. Quercus ilex communities are absent from the western coastal belt where the annual water balance is below -50 mm and high mean temperatures occur. They are also absent from marly limestone dominated areas where annual water balance is below 300 ram. Quercus ilex woods show a preference for water balance values between 0 and 600, with the better de- veloped forests being found in central and eastern coastal Liguria. The Ligurian Quercus ilex woods are ascribed to Quercetum ilicis Br.-BI. 1915. Given that the pres- ence within their floristic composition of a group of species of Querco-Fagetea (more species in eastern stands, few in western ones) is an almost constant characteristic, the subass, fraxino-ostryetosum Mariotti 1984 can be retained for many of them. Quercus ilex is not present in the initial succession stages of Mediterranean Liguria vegetation. It can be found in later stages when the vegetation is more fully de- veloped towards a maquis type structure. In this case it tends to become dominant and the community develops (if no fire or other human interference occurs) into a Quercus ilex forest. Frequently, this succession takes place under an old tree layer cover (generally Pinus sp.), a remnant of man's past management of the vegetation in the area.
Keywords: Mediterranean climate; quercus ilex communities; quercus ilex ecology

Old holm oak coppices... new sylvopastoral practices - Bellon, S.; Guerin, G. (Plant Ecology, 1992)
In the south of France, holm oak (Quercus ilex L.) woodlands, particularly coppices, are currently used by livestock farmers. For this vegetation, a grazing allowance is available, based on the relationship between various layers. As far as livestock is concerned, such woodlands can be utilized for many purposes, e.g. stock feeding during critical periods and to provide flexibility to the pasture grazing se- quence. Furthermore, the related grazing intake patterns determine the level of holm oak utilization. Practices integrating both wood and livestock production provide a new perspective to the management of these woodlands in that the presence of livestock promotes specific operations which can lead to more diversified forestry. The renewal of both wood and pastoral resources depends on: (i) the initial level of integration of these two activities and (ii) subsequent technical operations. In the present paper a mid- term management scenario is developed which describes the likely development of woodlands with multiple use and periodic thinning.
Keywords: grazing allowance; resource management; sylvopastoral; thinning; Vegetation dynamics

PALYNOLOGY OF A RESIN FROM AN EGYPTIAN COFFIN OF THE 2ND-CENTURY BC - MARIOTTI LIPPI, M.; MERCURI, A. M. (REVIEW OF PALAEOBOTANY AND PALYNOLOGY, 1992)
A palynological analysis was carried out on a small amount of resin from the inside of an anthropoid Egyptian stone coffin from the second century B.C. Pinus halepensis Miller is the best represented resiniferous plant (5.3%) in the pollen spectrum and the botanical origin of the resin can be ascribed to it. The only group of pollen which is relatively abundant in the spectrum is Poaceae (29.6%). This high percentage suggests that grasses were in bloom during the period the resin was collected (late spring or summer). Pollen of Quercus ilex. Olea europaea, Ostrya carpinifolia, Castanea sativa were also found. Pollen grains of Hordeum and Avena/Triticum types together with those of Plantago, Urtica, Chenopodiaceae, Rumex and Artemisia represent anthropogenic indicators. A phytogeographical interpretation of the found pollen assemblage suggests the eastern part of the Mediterranean as the most probable area where the resin was collected. The presence of Cedrus libani pollen suggests an origin from south-eastern Turkey, north-western Syria or northern Lebanon. The flora of this area is in accordance with the pollen assemblage found in the studied resin.
APSAPSThe following values have no corresponding Zotero field: pub-location: PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS publisher: ELSEVIER SCIENCE BV
Keywords: Castanea sativa; Ostrya carpinifolia; palynological analysis; Pinus halepensis; Quercus ilex. Olea europaea; resin

Plant regeneration through somatic embryogenesis in Quercus suber - Bueno, M. A.; Astorga, R.; Manzanera, J. A. (Physiologia Plantarum, 1992)
Cork oak (Quercus suber L.) zygotic embryos, endosperm and ovules were treated with different concentrations of 2,4-D for induction of somatic embryos. Plant material was collected during the embryo development season, from June to September. Immature embryos proved to be the most reactive initial explant. Callus and somatic embryos developed a few weeks after the beginning of the 2,4-D treatment. For embryo development experiments, different growth regulators and cold and desiccation treatments were tested. Cold storage of somatic embryos matured in vitro at 5°C was the best treatment for breaking dormancy.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: Cork oak; plant regeneration; Quercus suber; Somatic embryogenesis; tissue culture

POTENCIALIDAD DEL TERRITORI0 PARA EL ALCORNOQUE EN EXTREMADURA - González Adrados, J. R.; Elena Rosselló, R.; Tella Ferreiro, G. (Scientia gerundensis, 1992)
Most important aspects of a work titled 4ork oak Atlas of Extremaduran are presented here. A set of maps about: cork oak stands distribution; cork quality in the several zones; and ecological factors wich may limit the appearence of cork oak stands, are elaborated from the availahle thematic cartography. The Geographical Information SystemPC-ARC-IhFO ha beenused to get it. The final result is the Land Suitability for Cork Oak and Cork Quality Map of Extremadura. This map defines for the whole studied area the relative cork quaiity to be obteined and the presence of ecological factors wich may be adverse or exclusive for cork oak.
Keywords: Cork oak; Cork quality; land classification; Quercus suber; thematic cartography

PRELIMINARY ASSESSMENT OF METAL BIOAVAILABILITY TO PLANTS IN THE NEVES CORVO AREA OF PORTUGAL - FARAGO, M. E.; COLE, M.; XIAO, X. Y.; VAZ, M. C. (CHEMICAL SPECIATION AND BIOAVAILABILITY, 1992)
Cistus species and Quercus rotundifolia were collected from near the Neves Corvo copper mine and from an area 12 km from the mine. These species are widely distributed in southern Portugal. Aerial parts of the plants have been analysed and the concentrations of elements in the plants have been compared with those of the soils. There is more copper available in the soils near the mine, and this is reflected in an accumulation of copper in both Cistus and Quercus tops. Both plants can be considered to be of the following general types: accumulators of Cu in the mine area; excluders of Mo and Ni; concentration indicators of Pb and possibly Zn. We conclude that both copper and lead have migrated from the concealed orebody through geological faults. These elements in the soil resulting from the ore deposit contribute large portions ot the available metals near the mine area. It is further concluded that there is aerial contamination near to the mining activities, but copper from this source is less available to the plants.
The following values have no corresponding Zotero field: pub-location: PO BOX 314, ST ALBANS AL1 4ZG, HERTS, ENGLAND publisher: SCIENCE REVIEWS 2000 LTD
Keywords: CISTUS SPECIES; MINES; OREBODY; QUERCUS-ROTUNDIFOLIO

Primeros ensayos de inducción de embriones somáticos de Quercus suber L. - Bueno, A. J.; Manzanera, M. A. (Scientia gerundensis, 1992)
Susceptibility of cork oak (Quercus suber L.) embryos, endosperm and ovules to somatic embryogenesis induction has been studied. 2,4-D at different concentrations was tested. Samples were collected every two weeks, dong the fruit development period, from June till September. The embryos formed callus, from which globular and heart and torpedo-shaped structures and somatic embryos at different developing degrees were obtained.
Keywords: Cork oak; Quercus suber; Somatic embryogenesis; tissue culture; vegetative propagation

Quercus ilex browse utilization by Caprini in Sierra de Cazorla and Segura (Spain) - Cuartas, P.; García-Gónzalez, R. (Plant Ecology, 1992)
The impact of domestic and wild Caprini browsing on Quercus ilex has been examined in an area of the Sierra de Cazorla. Vegetation as a herbivore food supply, herbivore feeding regime and density in the study area during six sampling periods throughout two years, has been quantified. Wild Caprini show diets similar to the available vegetation, whereas domestic Caprini tend more towards the trophic spe- cialities (browsing or grazing) of their genus. Nevertheless, this tendency was more pronounced in do- mestic goats than in sheep. A hypothetical estimate of Q. ilex intake by each species under the study conditions was carried out. It was found that domestic Caprini have a greater impact on the holm oak than wild Caprini, density and feeding-niche deviations being the main factors responsible for this sit- uation.
Keywords: Browsing; herbivore impact; quercus ilex ecosystems

Recent changes in landscape structure and function in a Mediterranean region of SW Spain (1950–1984) - Ales, R. F.; Martin, Angel; Ortega, Fernando; Ales, E. E. (Landscape Ecology, 1992)
Recent economic development has altered landscape structure and function of a mediterranean region in Southwestern Spain. Intensive agricultural systems have concentrated in the more fertile areas, while margi- nal ones have been abandoned. As a result, landscape structure has changed. Consequences of this structural change on landscape processes are discussed.
Keywords: agroecology; biological conservation; dofiana national park; guadalquivir valley; sierra morena; Spain

Recrû naturel dans des taillis de chêne vert (Quercus ilex L) à la suite d'exploitations partielles - Ducrey, M.; Boisserie, M. (Ann. For. Sci., 1992)
Natural regrowth of holm oak coppice (Quercus ilex L) following partial cuts. The aim of this article was to study the influence of coppice age (4 to 57 years old) and of intensities of cleaning (light and heavy) or thinning (26-78% of removed basal area) on the appearance and growth of new stump sprouts in Quercus ilex coppice. The sprout layer at soil level can be quantified by degree of closure, biomass and Quercus ilex sprout height. This layer grew regularly for the 5 years following harvest and increased in direct proportion to increase in thinning intensities; it was found to be greater for young coppice (25 years old and less) than for old coppice. Coppice functioning was then studied at the stool level. Number and growth of new sprouts inside each stool were then related to the initial characteristics of the initial stool as well as to the degree of thinning in the stool. Sprout number was proportional to number of cut shoots, while sprout growth tended to be related to percentage of shoot or basal area removed by thinning. Finally an attempt has been made to explain the functioning of the stools by separating the effects of the mean thinning intensity of each plot and of the degree of cutting for each stool. In conclusion, hypotheses have been proposed on physiological origin of the observed phenomena.
Keywords: coppice; Quercus ilex = holm oak; stool; stump sprout; thinning

The role of Diplopoda litter grazing activity on recycling processes in a Mediterranean climate - Bertrand, M.; Lumaret, J. P. (Plant Ecology, 1992)
Variation in Diplopoda density and biomass were studied in mediterranean holm oak formations in order to estimate the impact of the feeding activity of these Arthropod s. Field and controlled experiments have shown the importance of the litter age and of the nature of leaves on the consumption rate. The con- sequences of faecal pellet restitution on microbial activity are discussed.
Keywords: diplopoda; edaphic macrofauna; faecal restitution; litter breakdown; sclerophyll formation

SOIL EVOLUTION AFTER FIRE IN QUERCUS-ILEX AND PINUS-HALEPENSIS FORESTS - FERRAN, A.; SERRASOLSAS, I.; Vallejo, V. R. (RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES, 1992)
Four contrasted burned sites in Catalonia (NE Spain) have been compared to-illustrate the diversified response to fire depending on the interaction of substrate-vegetation characteristics. Data from plant cover evolution, forest floor layers and soil chemical properties demonstrated that the garrigue on limestone is the most resilient ecosystem as a result of the resprouting capacity of Ouercus coccifera and the high soil stability. The shrubland on marls was however, the least resilient, with the poorest plant regeneration and greatest erosion rates. The plant communities on conglomerates and the holm oak forest on schists, represented intermediate situations, where the variable degree of erosion and nutrient losses were compensated by a rapid plant colonization just after the fire.
The following values have no corresponding Zotero field: periodical: RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES pub-location: BARKING ESSEX
Keywords: burned sites; ecosystem resilience; fire; Quercus coccifera; Quercus ilex; Shrubland; Spain

Stomatal patchiness in Mediterranean evergreen sclerophylls Phenomenology and consequences for the interpretation of the midday depression in photosynthesis and transpiration - Beyschlag, Wolfram; Pfanz, Hardy; Ryel, Ronald J.; Botanik, Lehrstuhl; Universitfit, I. I.; Dallenbergweg, Mittlerer; Republic, Federal; Science, Range (Planta, 1992)
Midday depression of net photosynthesis and transpiration in the Mediterranean sclerophylls Arbutus unedo L. and Quercus suber L. occurs with a depression of mesophyll photosynthetic activity as indicated by cal- culated carboxylation efficiency (CE) and constant diur- nal calculated leaf intercellular partial pressure of CO 2 (Ci). This work examines the hypothesis that this midday depression can be explained by the distribution of patches of either wide-open or closed stomata on the leaf surface, independent of a coupling mechanism between stomata and mesophyll that results in a midday depres- sion of photosynthetic activity of the mesophyll. Pressure infiltration of four liquids differing in their surface ten- sion was used as a method to show the occurrence of stomatal patchiness and to determine the status of sto- matal aperture within the patches. Liquids were selected such that the threshold leaf conductance necessary for infiltration through the stomatal pores covered the ex- pected diurnal range of calculated leaf conductance (g) for these species. Infiltration experiments were carried out with leaves of potted plants under simulated Mediterranean summer conditions in a growth chamber. For all four liquids, leaves of both species were found to be fully infiltratable in the morning and in the late after- noon while during the periods leading up to and away from midday the leaves showed a pronounced patchy distribution of infiltratable and non-infiltratable areas. Similar linear relationships between the amount of liquid infiltrated and g (measured by porometry prior to de- tachment and infiltration) for all liquids clearly revealed the existence of pneumatically isolated patches containing only wide-open or closed stomata. The good correspon- dence between the midday depression of CE, calculated * Dedicated to Professor Otto L. Lange on the occasion of his 65th birthday ** To whom correspondence should be addressed Abbreviations: A = net photosynthesis rate; Ci = actual leaf internal CO2 partial pressure; Ci *=apparent leaf internal CO2 partial pressure; CE = actual carboxylation efficiency; CE* = apparent car- boxylation efficiency; E = transpiration rate; g = leaf conductance under the assumption of no stomatal patchiness, and the diurnal changes in non-infiltratable leaf area strongly indicates that the apparent reduction in mesophyll activ- ity results from assuming no stomatal patchiness. It is suggested that simultaneous responses of stomata and mesophyll activity reported for other species may also be attributed to the occurrence of stomatal patchiness. In Quercus coccifera L., where the lack of constant diurnal calculated C i and major depression of measured CE at noontime indicates different stomatal behavior, non- linear and dissimilar relationships between g and the infiltratable quantities of the four liquids were found. This indicates a wide distribution of stomatal aperture on the leaf surface rather than only wide-open or closed stomata.
Keywords: arbutus; Mediterranean; Quercus; Sclerophyll; stomate (control-patchiness)

STRUCTURE OF MIXED HOLM-OAK (QUERCUS-ILEX) ALEPPO PINE (PINUS-HALEPENSIS) FORESTS IN NORTHEASTERN SPAIN - Espelta, J. M.; GENE, C.; Retana, J.; TERRADAS, J. (RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES, 1992)
Mixed forests of Aleppo pine (Pinus halepensis) and holm-oak (Quercus ilex) cover a great part of Northeastern Spain. Nevertheless, little is known about their structure, dynamics and regeneration. For some years, a research group in CREAF has collected data about those aspects, in order to use them to develop models that could be used as a tool for forest management. Previous results obteined about the structure of these stands are presented in the present paper.
The following values have no corresponding Zotero field: periodical: RESPONSES OF FOREST ECOSYSTEMS TO ENVIRONMENTAL CHANGES pub-location: BARKING ESSEX
Keywords: mixed forests; Pinus halepensis; Quercus ilex; Spain

Variation in tissue element concentrations in Quercus ilex L. over a range of different soils - CANADELL, J.; Vilà, M. (Plant Ecology, 1992)
In order to study the variability in nutrient concentrations in four tissues of Q. ilex in relation to soil properties, we selected fifteen stands in both Q uercus ilex forests and Q. ilex-Pinus halepensis mixed forests. These stands had developed on soils derived from eight different parent materials. Three soil groups were differentiated according to their chemical properties: calcareous soils, siliceous soils, and volcanic soils. Across sites, nutrient concentrations were generally less variable in current-year tissues than in older tissues. Nitrogen and potassium showed the lowest variability among sites, their concen- trations in current-year leaves ranging from 1.17°o to 1.39°i, for N and from 0.530{, to 0.68°o for K. There were few statistically significant correlations between tissue element concentrations, the most frequent being the antagonistic relationship between calcium and magnesium. Nitrogen concentration in current-year leaves was negatively correlated with soil chemical fertility (nitrogen, phosphorus and potassium). This may reflect a nutritional imbalance between nitrogen and other nutrients, some of which may be more limiting than nitrogen to Q. ilex growth in Catalonia forests. Negative correlations were also found between plant magnesium and soil calcium, and positive correlations between plant calcium and soil calcium.}
Keywords: N/P ratio; Nutrient antagonism; Plant nutrient concentrations; Plant-soil relationships; Soil fertility

What are the consequences of being a downy oak (quercus pubescens) or a holm oak (Q. ilex) for breeding blue tits (Parus caeruleus)? - Blondel, J.; Isenmann, P.; Maistre, M.; Perret, P. (Plant Ecology, 1992)
By comparison with deciduous oaks, the lower yearly production of new leaves in sclerophyllous oaks is hypothesized to have several consequences on animal communities. In particular, the production of arthropod communities that feed upon the leaves should be lower in sclerophyllous than in deciduous oaks, this causing changes in breeding patterns and the demographic balance in insectivorous birds. Studies in both deciduous and sclerophyllous habitats in southern France have shown that: 1) the spring development of new leaves occurs later and more slowly in sclerophyllous than in deciduous oaks, 2) the biomass of caterpillars is much lower in sclerophyllous oak forests, and 3)there is a large variation in life history traits of the Blue Tit depending in which type of habitat they breed. Laying date occurs later and clutch size is lower in sclerophyllous habitats than in deciduous habitats. The evolution of life history traits is discussed according to whether poor sclerophyllous habitats are isolated (e.g. on Corsica) or are parts of landscapes including both habitat types.
Keywords: breeding traits; caterpillars; leafing phenology; Parus caeruleus; Quercus ilex; Quercus pubescens

Chemical characteristics and temporal variations of nutrients in throughfall and stemflow of three species in Mediterranean holm oak forest - Bellot, J.; Escarré, A. (Forest Ecology and Management, 1991)
In this study on chemistry of throughfall and stemflow of three dominant species in a Spanish holm oak forest few significant differences were detected in the ion concentrations between Quercus ilex, Arbutus unedo and Phillyrea media. Comparison of annual average concentration of throughfall, stemflow and bulk deposition indicated nitrate and hydrogen uptake by the plants. At the same time, the data show the importance of precipitation as a source of nutrients.
Keywords: bulk deposition; Holm oak forest; nutrients (PG); stemflow; throughfall

RESPONSE OF MEDITERRANEAN GRASSLAND SPECIES TO CHANGING RAINFALL. - Figueroa, M. E.; Davy, A. J. (Journal of Ecology, 1991)
Investigates the long-term changes in the composition of a species-rich Mediterranean grassland in south-western Spain. Determination of the frequency of every species of herbaceous vascular plants annually; Domination of winter annual vegetation; Correlations between the logit of the total annual frequency of each species and rainfall totals; Link between species abundance and rainfall.
Keywords: BOTANY; Grasslands; MEDITERRANEAN Coast (Spain); RAINFALL frequencies; SPAIN (citation)

Contributo alla conoscenza dei boschi a Quercus ilex della Sicilia - Bartolo, Giuseppina; Brullo, Salvatore; Minissale, Pietro; Spampinato, Giovanni (Acta Botanica Malacitana, 1990)
In this paper the Quercus ilex woods occurring in Sicily were examined. Apart from the associations previosly observed in this territory, the presence of Ostryo-Quercetum ilicis is reported for the first time; besides some new subassociations of the Querco-Teucrietum siculi and of the Aceri obtusati-Ostryetum curpinifoliae are described. Syntaxonomic, ecological and syndynamic considerations are given for every associations.
Keywords: phytosociology; Quercus ilex woods; Sicily

A kinetic study on chemical activation of holm oak wood - Blasco, J. M.; Cordero, T. (Journal of Analytical and …, 1990)
Activation energy distribution functions for thermal decomposition of untreated and chemically treated holm oak wood have been obtained from temperature-programmed TG experiments. H,SO,, H,PO, and ZnCl, have been used as pretreating agents. When using HaSO, the results obtained become quite comparable with those corresponding to the original untreated wood whereas in the cases of H,PO, and ZnCl, significant differences are evident in the distribution functions. Using the activation energy distribution functions, a very good reproduction of the experimental weight-loss curves has been achieved.
Keywords: Activation energy distribution functions; chemically treated wood; pyrolysis.

Ribosomal RNA genes inQuercus spp.(Fagaceae) - Bellarosa, R.; Delre, V.; Schirone, B.; Maggini, F. (Plant Systematics and …, 1990)
The taxonomy of the genus Quercus is still unclear. In order to elucidate the taxonomy of Mediterranean oaks we have analyzed ribosomal RNA genes of Quercus cerris, Q. coccifera, Q. trojana, Q. ilex, Q. suber, and Q. macrolepis by means of Southern blot hybridization. Oak nuclear DNA was extracted from root tips of 300 acorns and from catkins of single plants. EcoRI and BamHI restriction endonucleases were used. DNA electrophoresis and rRNA/DNA hybridization were performed using Vicia faba rRNA 18 S and 25 S as probes. The rRNA genes of all the species studied have an identical restriction mapping in the 18 S and 25 S regions, while differences in length are present in the intergenic regions. Q. cerris possesses at least four types of genes of 12.1, 11.5, 8.5, and 8.3 kb; Q. coccifera at least three types of 12.4, 10.4, and 10.1 kb; Q. trojana possesses the same rRNA genes as Q. cerris plus another gene type 12.0 kb long, with EcoRI and BamHI restriction sites in the intergenic spacer; Q. ilex at least three types of 12.4, 10.85, and 9.5 kb; Q. suber at least five types of 11.5, 11.0, 8.6, 8.5, and 8.3 kb; Q. macrolepis, finally, at least seven types of 11.5, 11.0, 10.2, 8.6, 8.5, 8.3, and 8.15kb. Q. coccifera and Q. ilex rDNA appears quite different respect to other species examined, while high similarity seems to exist between Q. cerris, Q. trojana, Q. suber, and Q. macrolepis. These results are in agreement with the taxonomic model proposed by SCnWARZ for the genus Quercus.
Keywords: Angiosperms; Fagaceae; Gene mapping; Quercus; ribosomal RNA genes; rRNA/DNA hybridization; taxonomy

Use of pressure volume curves in water relation analysis on woody shoots: influence of rehydration and comparison of four European oak species - Dreyer, E.; Bousquet, F.; Ducrey, M. (Ann. For. Sci., 1990)
Pressure volume analyses were undertaken on leafy shoots of 4 European oak species (Quercus robur, Q petraea, Q pubescens and Q ilex) in order to determine the relationship between leaf water potential, average osmotic potential and volume averaged turgor. Some technical limitations of pressure volume analysis, as shown by the influence of the resaturation method on computed turgor, were overcome by accounting for losses of intercellular water during the first stages of dehydration. Variations in leaf to stem ratio, which are very important between large leaved oaks and small leaved evergreens, surprisingly did not influence the relative symplasmic volume of our samples. Differences in mean osmotic potential at full turgor (&Pi0) were related to species, with higher values in drought adapted species, and to leaf age and growing conditions. Values of volumetric modulus of elasticity (ε o) did not significantly influence the relations between leaf water potential (Ψw) and turgor (P) in different species. This relationship was mostly related to &Pi0. Finally, tolerance to drought appeared to be related more to the ability to osmotically adjust in response to changes in environment rather than to the absolute values of &Pi0.
Keywords: pressure-volume curve; Quercus sp; turgor; water potential; water relations

Conditions d'apparition d'une embryogénèse somatique sur des cals issus de la culture de tissus foliaires du chêne vert (Quercus ilex) - Féraud-Keller, C.; ESPAGNAC, H. (Canadian Journal of Botany, 1989)
The proliferation of parenchymatous foliar tissue of Quercus ilex was obtained from current year leaves taken from old trees and cultivated in vitro on modified Murashige and Skoog's medium supplemented with benzylaminopurine (4 mg ∙ L−1) and naphthyl acetic acid (0.5 mg ∙ L−1). Only the fragments cultured in October reacted. The neoformations only appeared on calluses that had not been subcultured for 7 months. Primary nodules arising on these calluses were removed and subcultured on the same medium either in the dark or in the light. In the dark only, they produced secondary nodules, which were the source of somatic embryos both in light and dark. Presently, they seem to regulate their structure in the dark but they do not develop in a way that leads to germination.
doi: 10.1139/b89-139doi: 10.1139/b89-139The following values have no corresponding Zotero field: publisher: NRC Research Press
Keywords: Callus; Quercus ilex; tissue culture

Estudio silvopastoral de la dehesa boyal de Alia (Caceres) - Bravo Oviedo, F. (Ecologia, 1989)
Se analizan los diferentes factores que intervienem en el agroecosistema dehesa. Se hace una crítica concreta del índice de productividad animal empleado en la Ley de la Dehesa en Extremadura
Keywords: arbolado; Dehesa; ganado (voyant); pasto

Metal contamination in leaves and fruits of holm-oak (Quercus rotundifolia Lam.) trees growing in a pyrites mining area at Aljustrel, Portugal - Fernandes, J. C.; Henriques, F. S. (Water, Air, & Soil Pollution, 1989)
Pyrites extraction at Aljustrel mines, south Portugal, is causing severe metal pollution of soil, water and air, leading to a growing concern with environmental degradation in the mining area and its surroundings. In this work we measured levels of Fe, Mn, Zn, Cu, and Pb in leaves and fruits of holm-oak (Quercus rotundifolia Lain.) trees growing at the outskirts of the mining area. The trees showed pronounced stunting, reduced leaf size and extensive necrotic and chlorotic spotting. The leaves from trees growing in the area under study had much higher concentrations of metals than the controls - ca. 50 times higher for Cu, 20 times for Pb and Zn, 10 times for Fe, and 2 times for Mn - but is is possible that part of the metals associated with the leaves are actually retained in the dense hair cover present on their lower surface. The acorns from the contaminated areas were also metal polluted, particularly with Fe, Zn, and Cu, and this finding raises the threat of animal and human health hazards, since these fruits are commonly used for feeding livestock and are occasionally consumed directly by man. 1.
Keywords: acorns; holm oak (voyant); leaves; Metal pollution

Metals in Leaves as Indicators of Atmospheric Pollution in Urban Areas - Valerio, F.; Brescianini, C.; Lastraioli, S.; Coccia, S. (International Journal of Environmental Analytical Chemistry, 1989)
Abstract The use of biological indicators to monitor atmospheric pollution is widely distributed. The analysis of heavy metals in leaves is suggested as a method for a rapid identification of polluted areas. Reproducibility and representativity of this method must be assessed. We have verified if the concentration of lead, chromium, copper, nickel and manganese in ?Quercus Ilex? leaves may be used to classify urban areas according to the level of their atmospheric pollution. Particular emphasis was placed on reproducibility of sampling and the analytical method. Preliminary results show a linear correlation between concentration of metals in atmosphere (particularly lead) and in leaves collected in the same sampling areas.
doi: 10.1080/03067318908026901doi: 10.1080/03067318908026901The following values have no corresponding Zotero field: publisher: Taylor & Francis
Keywords: atmospheric pollution; Heavy metals (PG); Quercus ilex leaves

New types of damage to forest trees typical of the Mediterranean region - Clauser, F.; GELLINI, R.; Bussotti, F.; Cenni, E.; Bottacci, A. (European Journal of Forest Pathology, 1989)
Since 1984 a new type of damage to the typical tree species growing in the mediterranean area has been observed. The pathological picture includes the typical features of “Waldsterben”. The new symptoms occurring in Pinus pinea, P. pinaster, P. halepensis and Quercus ilex are described.
The following values have no corresponding Zotero field: publisher: Blackwell Publishing Ltd
Keywords: crown damage; damage; decline (voyant); foliage reduction

Planta of resurrection plants to desiccation and rehydration - Schwab, K. B.; Schreiber, U.; Heber, U. (1989)
Using non-invasive techniques (CO2 gas exchange, light scattering, light absorption, chloro- phyll fluorescence, chlorophyll luminescence), we have analysed the response of respiration and pho- tosynthesis to dehydration and rehydration of leaves of the resurrection plants Craterostigma plantagineum Hochst., Ramonda mykoni Reichb. and Ceterach officinarum Lam. et DC. and of the drought-sensitive mesophyte spinach (Spinacia oleracea L.). The following observations were made: (i) The rate of water loss during wilting of detached leaves of drought-tolerant resurrection plants was similar to that for leaves of the sensitive mesophyte, spinach. Leaves of Mediterranean xerophytes lost water much more slowly. (ii) Below a residual water content of about 20%, leaves of spinach did not recover turgor on rewatering, whereas leaves of the resurrection plants did. (iii) Respiration was less sensitive to the loss of water during wilting in the resurrection plants than in spinach. (iv) The sensitivity of photosynthesis to dehydration was similar in spinach and the resur- rection plants. Up to a water loss of 50% from the leaves, photosynthesis was limited by stomatal closure, not by inhibition of reactions of the photo- synthetic apparatus. Photosynthesis was inhibited and stomates reopened when loss of water became excessive. (v) After the leaves had lost 80% of their water or more, the light-dependent reactions of photosynthetic membranes were further inhibited by rewatering in spinach; they recovered in the resurrection plants. (vi) In desiccated leaves of the resurrection plants, slow rehydration reactivated mitochondrial gas exchange faster than photosyn- thetic membrane reactions. Photosynthetic carbon assimilation recovered only slowly.
Keywords: Carbon dioxide (gas exchange); Chlorophyll (fluorescence - luminescence); Drought tolerance; Light scattering (thylakoids); Resurrection plants; water stress

Pyrolysis of holm-oak wood: influence of temperature and particle size - Figueiredo, J. L.; Valenzuela, C.; Bernalte, A.; Encinar, J. M. (Fuel, 1989)
The pyrolysis of holm-oak wood sawdust was studied to determine the characteristics of the charcoal and the nature and amounts of gases produced. The temperature was varied from 300 to 900 °C and the wood particle size from 0.40 to 2 mm diameter. The fixed carbon content of the charcoal increased with temperature up to 700 °C, and then remained essentially constant. The gases produced were mainly CO, CO2, H2 and CH4. The rate constants and activation energies for the production of each gas were calculated assuming first order kinetics. The composition of the pyrolysis gas produced at each temperature was determined, and its heating value was calculated. Taking into consideration the quality of the charcoal and the heating value of the gases produced, it can be concluded that the optimal pyrolysis temperature is ≈ 600 °C.
Keywords: charcoal; Particle Size; pyrolysis

The convergent trajectories of bird communities along ecological successions in european forests - Blondel, Jacques; Farré, H. (Oecologia, 1988)
There is much more variation in the composition of bird communities in the earlier open and semi-open seral stages of ecological successions in forested landscapes of Europe than later on in preforested and forested climactic stages. The demonstration of this trend is achieved from the study of four habitat gradients, two in the mediterra- nean region (Provence and Corsica) and two in central Eu- rope (Burgundy, France and Poland). A multivariate analy- sis has been used to illustrate the dynamics of communities along these successions. Displays of the results in bivariate space as well as an illustration of the distributional profiles of some of the most characteristic species show that: i) there is a discrimination between the two mediterranean gradients and the two medioeuropean ones and ii) each succession starts with a very distinct set of species and then the four gradients regularly converge in the last climactic stage where there is almost no discrimination between com- munities. These results are discussed in the light of the histo- ry of European biotas during the Pleistocene. The reason why there is more variation in species composition in the earlier seral stages than in the later forested stages are dis- cussed according to current theories on the role of habitat selection on speciation processes.
Keywords: Community dynamics; Ecological succession; historical biogeography; Mediterranean; speciation