Use of a ground-based scanning lidar for estimation of biophysical properties of western larch (Larix occidentalis)

摘要

Ground-based laser scanners represent a relatively new technology that promises to enhance the ability to remotely sense biophysical properties of vegetation. In this study, we utilized a commercially available discrete-return ground-based laser scanning system to sample properties of western larch (Larix occidentalis) in a northern Idaho forest. Three young trees < 5m in height were scanned before and after leaf abscission in the autumn of 2004. Leaf areas represented by the number of laser returns were estimated by subtracting leaf-off laser returns from leaf-on returns. Leaf areas represented by number of laser returns were significantly correlated with manual-based estimates of leaf area (r~2=0.822). Ratios of woody-to-total tree area were estimated based on number of laser returns from woody material. Ratios of woody-to-total area ranged from 0.24 to 0.58 for nine one-metre sections of tree for which estimates were made. Ratios of woody-to-total area were also estimated using intensity of laser returns and fell near the range of estimates made using the number of laser returns. Improved estimation of leaf area, woody-to-total area ratios, and other biophysical parameters using ground-based laser scanning technology may be possible with a careful consideration of instrument specifications and sampling design.