Abstract

Leaf N and P resorption efficiency and proficiency were explored in three permanent (non–tiled) and unfertilised plots: a Castanea sativa mill. paraclimax coppice (CC), a chestnut orchard (CO), and Quercus pyrenaica Wild. climax forest (Oak), adjacent to the CO plot, all located in central western Spain. To estimate the seasonal variation of the nutrients contained in the leaves, 9, 3 and 3 trees with different diameters were selected at the three plots respectively. Over three years (2001 to 2003), three annual samplings of leaf nutrients were made (June, September and October) at different heights of the trees (low, middle and high). The evolution of foliar N concentration along the growing period of both species was found to be similar and independent of year and the height of the tree at which the leaves developed. No significant differences were observed between evolution of foliar N concentration along the growing period in either chestnut or Oak. As in the case of the N resorption efficiency measurement in which no significant differences among plots were found for N resorption efficiency and proficiency. The levels of P in leaves were inversely proportional to the concentrations of this element in the soil, which decreased in the order Oak plot, Chestnut coppice and Chestnut orchard, although differences were only significant between the former and the latter.

Key words: Castanea sativa, efficiency, forest management, N and P resorption, proficiency, Quercus pyrenaica.