Seasonal and spatial patterns of foliar nutrients in cork oak (Quercus suber L.) growing on siliceous soils in Provence (France)

Cork oak forests in Mediterranean, southeastern France represent animportant ecosystem in terms of both ecological and economical values, but aredeclining due to conservation problems. While management protocols are now inplace for the long-term conservation of this ecotype, we require a betterunderstanding of cork oak nutrition to assist with management. Here we usefoliar nutrient analyses for two objectives: firstly, to assess to what extentvariations in nutrient content are explained by seasonal and spatialvariability, and second, to document the nutrient dynamics of cork oak trees innatural conditions during one biological cycle (16 months) in the Maures massif(western part of the siliceous Provence). Main results showed that time was theprimary factor influencing cork oak nutrition and was mainly expressed by leafageing process. Spatial variability was a 'secondary determinant' of nutrient variations, but was more important at the very early stages of leafgrowth according to leafing and nutrient flushing, and reduced with leaf age.Nutritional responses of cork oak trees fitted general trends observed in theliterature, with some regional differences. The properties of siliceous soilalso influenced the uptake of some nutrients.