Prediction of tree height, basal area and stem volume in forest stands using airborne laser scanning

The aim of this study was to develop prediction models using laser scanning for estimation of forest variables at plot level, validate the estimations at stand level (area 0.64 ha) and test the effect of different laser measurement densities on the estimation errors. The predictions were validated using 29 forest stands (80 x 80 m(2)), each containing 16 field plots with a 10 in radius. For the best tested case, mean tree height, basal area and stem volume were predicted with a root mean square error of 0.59 in (3% of average value), 2.7 m(2) ha(-1) (10%, of average value) and 31 m(3) ha(-1) (11% of average value), respectively, at stand level. There were small differences in terms of prediction errors for different measuring densities. The results indicate that mean tree height, basal area and stem volume can be estimated in small stands with low laser measurement densities producing accuracies similar to traditional field inventories.