Delineation of individual tree crowns for LiDAR tree and stand parameter estimation in Scottish woodlands

There is an increasing need for accurate forest inventories to assist forest managers and decision-makers in the planning of their forest resource. Airborne LiDAR methods enable the construction of Tree Canopy Models (TCM) at a fine resolution, thereby facilitating the delineation of individual tree crowns. This information can be useful in predicting forest parameters such as top height, basal area, standing volume and biomass. In this paper, we present a comparative analysis of the algorithms developed independently by Gougeon (1995), Popescu (2003) and Weinacker (2002) for delineating individual tree crowns, and as a means to extract forest parameters. The comparison was achieved as follow. Firstly, the algorithms were tested in their efficiency for delineating tree crowns. Secondly, single tree parameters were estimated using the crown delineation and finally, stand parameters were estimated by averaging single tree parameters. Results of the three algorithms were compared to each other and to field measurements.