Validating estimates of merchantable volume from airborne laser scanning (ALS) data using weight scale data

There is increasing interest in the use of airborne laser scanning (ALS; also referred to as airborne Light Detection and Ranging or LiDAR) for forest inventory purposes in Canada. Timber volume is one of the key inventory attributes that is commonly estimated using ALS data, and estimates of volume can be validated using post-harvest measures. ALS data and the area-based approach were used to develop an enhanced forest inventory for the Hinton Forest Management Area (FMA) in central Alberta. Weight scale measures of coniferous merchantable volume from 272 stands harvested between 2008 and 2010 were used as validation data for both conventional and ALS-based estimates. Overall, conventional estimates of coniferous merchantable volume derived from cover type adjusted volume tables were found to underestimate weight scale volumes by 19.8%. Conversely, estimates generated from the ALS data overestimated weight scale volumes by 0.6%. ALS-based estimates provide wall-to-wall, spatially explicit estimates of merchantable volume, enable within-stand variability in merchantable volume to be characterized, and are beneficial for strengthening linkages between strategic and operational forest planning.