Airborne laser scanning-based prediction of coarse woody debris volumes in a conservation area

The importance of dead wood (coarse woody debris, CWD) for biodiversity in boreal forests is high that is mainly due to its role in nutrient cycling and species habitation. Recognition of its importance in storing carbon has also raised an interest in developing new methods for assessing the quantity and quality of CWD. Since the traditional measuring techniques are often expensive to apply for the estimation of volume characteristics in the field, more attention is currently being paid to remote-sensing techniques that could provide lower cost data for forest inventories over large areas. The aim of this study was to investigate the potential of airborne laser scanner (ALS) data for estimating downed and standing dead wood volumes. The analysis was based on field measurements from 33 sample plots which were evaluated against the ALS-derived height-intensity metrics obtained from the Koli National Park in eastern Finland. The accuracy of the ALS data proved adequate for predicting the downed dead wood volume (RMSE 51.6%), whereas the standing dead wood volume estimates were somewhat poorer (RMSE 78.8%). The ALS-based volume estimates for downed dead wood were found to be substantially more accurate than the estimates based on field-measured characteristics of living trees.