Lidar remote sensing of forest canopy structure and related biophysical parameters at H.J. Andrews Experimental Forest, Oregon, USA

Scanning lidar remote sensing systems have become generally available for use in ecological applications. Unlike microwave and conventional optical sensors, lidar sensors directly measure the distribution of vegetation material along a vertical axis and can be used to provide three-dimensional characterizations of vegetation structure. Ecological applications of scanning lidar have previously used uni-dimensional indices of canopy height. A new, three-dimensional, approach to interpreting lidar waveforms was developed to characterize the total volume of both vegetation and empty space within the forest canopy, and their spatial organization. These aspects of the physical structure of canopies have been infrequently measured, either from field or remote methods. Applying this approach to 21 plots with coincident lidar measurements and field surveys, we were able to predict both biomass and leaf area index from the volumes of four classes of canopy structure. These predictions were non-asymptotic over a wide range, up to 1200 Mg ha/sup -1/ of biomass and an LAI of 12, with 90% and 88% of variance explained, respectively.