Ground monitoring the light-shadow windows of a tree canopy to yield canopy light interception and morphological traits

Monitoring the light-shadow windows of a tree via a grid system on the grou nd,vas performed on sunny summer days at high spatial resolution using a cu stom-built, inexpensive scanner, The measurements were taken with two goals : (1) to quickly and remotely quantify the overall, short-wave solar radiat ion (300-1100 mn) intercepted by the tree canopy, and (2) to yield such cro wn geometric: traits as shape, size anti the number of theoretical canopy l eaf layers (leaf layer index, LLI) in relation to the section orthogonal to sunbeam direction (sun window). The ground readings at cad measurement ove r the day were used to project a digitized shadow image. Image processing w as applied and the intercepted radiation was calculated as the difference f rom the corresponding incoming radiation above the canopy. Tree-crown size and shape were profiled via computer imaging by analysing the different sha dow images acquired at the various solar positions during the day. It is no table that these combined images yielded the crown features without having to parameterize such canopy characteristics as foliage Extension and spatia l distribution.