<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Orgeas, J</style></author><author><style face="normal" font="default" size="100%">Bonin, G</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Variabilité des nutriments foliaires de Quercus suber L dans différentes situations écologiques dans le massif des Maures (Var, France), et relations avec la production de liège</style></title><secondary-title><style face="normal" font="default" size="100%">Ann. For. Sci.</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cork Production</style></keyword><keyword><style  face="normal" font="default" size="100%">disturbance</style></keyword><keyword><style  face="normal" font="default" size="100%">ecological conditions</style></keyword><keyword><style  face="normal" font="default" size="100%">foliar nutrients</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus Suber L</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1996</style></year></dates><volume><style face="normal" font="default" size="100%">53</style></volume><pages><style face="normal" font="default" size="100%">615-624</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Variability of foliar nutrient contents of Quercus suber L in several ecological conditions in the Maures Mountains (Var, France), and relations with cork production. A monitoring of foliar nutrients has been undertaken on cork-oaks (Quercus suber L), in the Maures Mountains (Var, France). Simultaneously, the thickness of cork age rings has been studied to define the relationship of the cork production to nutrient contents under different ecological conditions. Foliar concentrations of ions evolved according to the season, the degradation state and the xericity of plots. Nitrogen appeared proportional to the physiological activity of the leaf, while calcium and potassium were stocked gradually. The calcium-magnesium antagonism was confirmed. Furthermore, changes of the nutrient concentrations in the undergrowth-clearing sites are reduced from the spring resumption of the metabolism. The growth of primary cork is linear with time, irrespective of year, climatic conditions and perturbations. The secondary (or reproductive) cork production is not linear with time and the age of trees, but it remains much higher than the primary cork production. The higher secondary cork productions are linked to the high contents of potassium and nitrogen, and to the moist and weakly disturbed plots. Magnesium is linked to small width thicknesses of cork age rings. Sodium and calcium do not appear to influence this cork production.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Barbero, M</style></author><author><style face="normal" font="default" size="100%">Bonin, G</style></author><author><style face="normal" font="default" size="100%">Loisel, R</style></author><author><style face="normal" font="default" size="100%">Quezel, P</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Changes and disturbances of forest ecosystems caused by human activities in the western part of the Mediterranean basin</style></title><secondary-title><style face="normal" font="default" size="100%">Plant Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">changes</style></keyword><keyword><style  face="normal" font="default" size="100%">disturbances</style></keyword><keyword><style  face="normal" font="default" size="100%">dynamic models</style></keyword><keyword><style  face="normal" font="default" size="100%">human activities</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean forests</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1990</style></year></dates><volume><style face="normal" font="default" size="100%">87</style></volume><pages><style face="normal" font="default" size="100%">151-173</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The development of socio-economic activity over the past ten years in the Mediterranean region has induced severe changes in the main natural forest ecosystems. In the northern Mediterranean, rural depopulation has accelerated since the end of the second World War, particularly since the establishment of Common Market agricultural policies, and led to an under-utilization of species causing a strong biological resurgence of the forest, even at high altitudes. This means that, at the present time, the extension of expansion model coniferous forests is favored by their capacities for spatial, biological and ecological selection. Along with this, the under-utilization of sclero- phyllous (resistance model) and deciduous (stabilization model) oak coppices has led to the establishment of new forest structures and architectures which are notably different from the main climatic groups defined up to now by phytosociological and synchronic methods. Two new forms of disturbances have appeared: - increasingly important wild fires have replaced disturbances caused by burn beating and are at the origin of the very strong spatial and temporal heterogeneity of current forest species. - In addition, the geographical continuity of the main groups of same-aged sclerophyllous and deciduous species, due to their non-use over the past ten years, has accelerated a phytosanitary imbalance by an increase in the action of pests. In the southern Mediterranean, particularly in North Africa, demographic pressure and grazing have widely disturbed the main forest ecosystems which show a continual regression of their surface. Many forest tree species with a low spatial and biological selection, such as Mediterranean firs and black pines (Pinus nigra subsp, mauritanica), are threatened with extinction, as are the deciduous oak forests which, considering the climatic stress and edaphic constraints, are permanently in a state of imbalance. Human disturbances induce a complete modification of structures and architectures tending towards the instal- lation of simplified forest models (trees-grasses) where tree regeneration is nearly impossible. The sclero- phyllous coppices well-adapted to stress are also threatened by shorter and shorter cutting cycles and by the high usage of tree canopies for grazing. - The forest understory structures have witnessed a decrease in their characteristic sylvatic species and the matorralization of most of the forests can be seen by the replacement of typical forest groups by preforest groups (Tetraclinis forests, Aleppo pine forests). - New geopedological constraints linked to the removal of the surface soil layer combined with regular climatic stress (duration of drought periods) strongly decrease the resilience of these ecosystems which are under continual pressure (unbalanced models). - In diverse regions, particulary in semi-arid bioclimates, hyperdegradation affects the shrub cover which disappears for a time in favor of perennial grasses (forest steppization): Andropogon div. sp., Ampelodesmos, Stipa div. sp. In all bioclimatic groups, the increase in grazing pressure throughout the southern Mediterranean ecosystems can even lead to the total disappearance of perennial species from the ecosystem with the exception of the dominant tree. Regardless of the altitude or ecosystem, invasive therophytes are then the only plants to occupy the understory and indicate hyperdegradation (forest therophytization).</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Bonin, G</style></author><author><style face="normal" font="default" size="100%">Aubert, G</style></author><author><style face="normal" font="default" size="100%">Barbero, M</style></author><author><style face="normal" font="default" size="100%">Gamisans, J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Mise en évidence de la dynamique de quelques écosystèmes forestiers et préforestiers provençaux aux étages méditerranéens SL à l'aide des taxons indicateurs</style></title><secondary-title><style face="normal" font="default" size="100%">Plant Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Analyse des correspondances</style></keyword><keyword><style  face="normal" font="default" size="100%">Ecosyst~mes forestiers</style></keyword><keyword><style  face="normal" font="default" size="100%">France</style></keyword><keyword><style  face="normal" font="default" size="100%">Provence</style></keyword><keyword><style  face="normal" font="default" size="100%">Successions dynamiques</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1983</style></year></dates><volume><style face="normal" font="default" size="100%">54</style></volume><pages><style face="normal" font="default" size="100%">79-96</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Evidence is presented for dynamic successions in the Provence on the basis of a multivariate analysis, of a very large sample. Different phases in the Quercus suber series on silicious substrate are shown. Also the evolution of the vegetation groupings on Ventoux and Sainte-Baume mountains on calcareous substrate and at different levels in the zonation is specified. The succession of the grasslands is as follows: Isoetes and Nasturtium groupings, Serapias, Lotus and Trifolium, then Vulpia and Aira groupings, and finally Helianthemum guttatum grasslands, preceding the shrub groupings: Cistus ladaniferus, then Cistus albidus and Cistus monspeliensis. Then follow either Erica and Calluna maquis or Quercus suber formations. On Mont Ventoux, the stages of degradation of the Quercus pubescens forests are Aphyllantes and Thymus vulgaris grasslands, and Buxus sempervirens and Genista scorpius scrubs. On the oromediterranean level, the transition from Avena setacea and Galium villarsii grasslands, then Ononis caenisia grasslands to Pinus uncinata forests is demonstrated. The development of reforestation is predicted on the basis of the floristic composition of the previous stages. On Sainte-Baume Mountain, the Quercuspubescens supramediterranean series is formed by the following stages: low scrubs of the Lavandulo-Astragaletum, and Prunus mahaleb and Phillyrea media, Acer monspes- sulanum groves, and forests with prevailing Quercuspubescens. The succession on rocky traverses and crests is slightly different. The first stages are Sesleria grasslands and the later ones are woodland groupings of Tilia platyphyllos, Acer opalus and llex aquifolium.</style></abstract></record></records></xml>