Gradients of anatomy and morphology of leaves in the crowns of cork oak

Stomatal frequency, anatomical characteristics and specific leaf area (ratio dry weight. area-l) of ashadeleavesn and asunleavesw of Quercussuber L., were studiedineight adult trees inthe field with two types of soil utilization, plot E with subterraneum clover pasture and plot G with tradicional agriculture in Besteiros near Vendas Novas, in Portugal. in boths plots the stomatal frequency is higher in leaves of upper stratum than in the lower part of the crown. The length of guard cells is higher in the proximal position of middle and superior stratra than in the inferior stratum. The dry weight.area-I does not vary significantly between two types of leaves. The trees belong to an open stand where shading among trees is minimal. However, the dry weight.area- ratio of leaves of plot with traditional agriculture is significantly higher than that of leaves of the plot with pasture probably as a consequence of the depletion of soil nitrogen caused by agriculture.