Comparison of Forest Canopy Height Derived Using Lidar Data and Aerial Photos

Abstract

Forest composition and vertical structure provide essential information for understanding ecological states and processes in forest ecosystems. Recent development of lidar (light detection and ranging) technologies has led to applications of lidar in forest canopy structure investigations. The objective of this study was to develop a method to derive forest canopy height using a laser scanning instrument. Lidar data, acquired using a Leica ALS40 airborne laser scanner, of a deciduous forest were used in this study. In order to assess the capability of lidar for estimating canopy height of forest stands, a digital surface model derived from the local maximum of lidar data was compared to a digital surface model generated using a photogrammetric technique. In addition, forest canopy heights, represented by differences in the digital surface models and a 4-m digital elevation model, were calculated and compared for these 2 types of data. The results indicated that the canopy height generated from the lidar data was higher than that of the aerial photos, and the mean difference was about 0.22 m with a standard deviation of 2.59 m.