INFLUENCE OF SHADING ON THE RELATIONSHIP BETWEEN LEAF-AREA AND CROWN SURFACE-AREA IN SUGAR MAPLE STANDS

A functional relationship is proposed between leaf area, fractal dimen sion of the crown surface, shade tolerance and light availability. Thi s relationship is obtained by setting an arbitrary limit between crown porosity to light and crown convolution. A crown profile is modeled f rom the total length and horizontal extension of second-order branches to estimate the crown surface area. A submodel simulates total canopy openness from geometrical characteristics of the crown of first-order neighbors to estimate light availability. To allow its insertion into growth and yield models, the model is simplified and validated with d ata gathered in six stands dominated by sugar maple (Acer saccharum Ma rsh.), in southern Quebec. (C) 1997 Elsevier Science B.V.