Forest canopy structure analyzed by using aerial photographs

Abstract

AbstractA method was developed using aerial photographs to analyze forest canopy structure. Digital elevation models of both the land and canopy surface in a mesh of 5 m intervals were made from aerial photographs taken in winter (without tree leaves) and summer (with leaves), respectively, in a 60 ha area of temperate deciduous forest. The difference between the two elevation values at each point was regarded as the canopy height, and a canopy height profile was constructed. The estimated canopy structure was compared with that obtained by ground observations in a 6 ha part of the study area. Large gaps (>100 m2) were adequately detected by the method, and the gap size distribution obtained was similar to the one observed on the ground. The method was found to be effective in analyzing the forest canopy structure of large areas, but it is not suitable for the detection of small gaps.