Estimation of forestry stand parameters using laser scanning data in temperate, structurally rich natural European beech (Fagus sylvatica) and Norway spruce (Picea abies) forests

The purpose of this study was to investigate how well forestry stand parameters can be estimated with statistical methods from lidar data. The study material included small-footprint time-of-flight laser scanner data acquired in the spring and summer of 2002 using a TopoSys II airborne laser system over the montane mixed forests dominated by Norway spruce (Picea abies L.) and European beech (Fagus sylvatica L.) of the Bavarian Forest National Park near Passau, Germany. With the method presented here - through stratification into deciduous, coniferous and mixed forest classes - it was possible to obtain satisfactory results for the estimation of forestry stand parameters at plot level. The best estimations were for height (root mean square error (RMSE) 5 per cent) and for the diameter at breast height parameters (RMSE 10 per cent). The RMSEs of all the other stand parameters, such as volume, basal area and the various stand density indices, lay between 10 and 20 per cent. In contrast to these good results were the values for the number of trees per hectare (RMSE 60 per cent). It could be shown that the results were influenced by the structural diversity of the forests, such as the substantial mixture of tree species and the presence of deadwood.