Abstract
Airborne Light Detection and Ranging (LiDAR) is a useful tool for scaling up physiological processes from an individual tree to the landscape level, because it can measure parameters that are related to canopy structure. The objectives of this study were (1) to calculate the canopy and stand parameters that characterize the heterogeneity of beech canopies and stands from LiDAR data and (2) to examine the applicability of these parameters by comparing them with field census measurements. A total of eight census plots with various stand structures were set up in beech forests on the Appi plateau (Iwate Pref., northern Japan) and on Mt. Naeba (Niigata Pref., central Japan). LiDAR data was used to calculate several parameters for describing canopy structure: gap ratio; mean canopy height; standard deviation (SD) and coefficients of variance (CV) of canopy height models (CHMs); canopy and stand surface area derived from the CHMs and digital surface models. The gap ratios and CVs of the CHMs were closely related to basal area (BA), and it may be possible to use them to quantify this variable when factors such as low gap ratio and topographic condition are considered. The CV tended to increase with the gap ratio. In contrast, canopy surface area was not strongly related to the canopy structure parameters. Consequently, the gap ratio and the CVs of the CHMs are the preferable parameters for representing structural properties of beech stands. Further analyses are needed to understand uncertainties in the relationships (inter alia) between, gap sizes, canopy height and individual tree size.
