ON THE ESTIMATION OF LEAF SIZE AND CROWN GEOMETRY FOR TREE CANOPIES FROM HOTSPOT OBSERVATIONS

A computer-graphics based model for radiation interception in vegetati on canopies is used to investigate the feasibility of estimating leaf size and crown size, for deciduous and coniferous trees, from canopy r eflectance in the hotspot region. For deciduous trees, as represented by aspen trees, it appears that under certain conditions one can estim ate leaf size we specify optimal Sun-view geometry, wavelength, and in dex, which can minimize the impacts of other structural parameters (e. g., leaf area index, leaf angle distribution, and interplant spacing) for the most accurate estimation of leaf size. However, for coniferous trees an accurate estimation of crown size seems unlikely, except pos sibly for sparsely spaced canopies.