MODELING CANOPY STRUCTURE AND HETEROGENEITY ACROSS SCALES - FROM CROWNS TO CANOPY

Canopy studies have been limited in ecological investigations due to p roblems of canopy accessibility, and the lack of efficient sampling an d modeling methods. The primary objective of this study was to develop an efficient modeling approach to describe the 3-dimensional, hierarc hical structure of individual crown shells within stands and correspon ding canopy patches. Crown shells were modeled based on crown ratio, m aximum cardinal radius, vertical position, and shape. Canopies were re presented by adding unique crowns to simulated point patterns of trees of known aggregation as measured by Pielou's index of nonrandomness. Canopy patches were delineated at multiple horizontal and vertical sca les using the ARC/INFO geographic information system (GIS). The patter ns of canopy patches are clearly variable and scale dependent. Canopy patterns become more diverse at broader horizontal scales, and change greatly from the lower to the upper canopies. The modeling approach us ed in this study has general utility in characterizing 3-dimensional c anopies of many types of forests. (C) 1997 Elsevier Science B.V.