Feasibility for estimation of single tree characteristics using laser scanner

The most advanced laser scanners and intelligent algorithms today are capable to detect single trees. In boreal forest zone, significant amount of laser pulses reflect directly from the ground due to gaps in the canopy layer. The use of high-pulse-rate laser scanners allows detailed investigation of forest areas and the creation of a 3-dimensional tree height model. By extracting the height, location, tree species and crown dimension of the trees from the 3-dimensional tree height model obtained from laser scanner data, important tree attributes, such as stem volume, basal area, and age, can be estimated for single trees. By knowing the characteristics of single trees, forest characteristics for sample plots, stands and larger areas, such as stem volume per hectare [m³/ha], basal area per hectare [m² /ha], mean height, dominant height, mean age, number of stems [pc/ha] and development class, can be calculated. The automatic extraction of crown dimensions from 3-dimensional tree height models is based on segmentation. This paper describes the method in detail and gives the first indication of the performance of the novel developed method. The following standard errors were obtained for mean height, basal area and stem volume at stand level: 2.3 m (13.6%), 1.9 m² /ha (9.6%), and 16.5 m³/ha (9.5%), respectively, even without using the full power of the described method. The accuracy was better than the accuracy of conventional standwise field inventory