Study on application of three-dimensional laser scanning technology in forestry resources inventory

Terrestrial laser scanners, as efficient tools, have opened a wide range of application fields within a rather short period of time. Beyond interactive measurement in 3D point clouds, techniques for the automatic detection of objects and the determination of geometric parameters form a high priority research issue. The quality of 3D point clouds generated by laser scanners and the automation potential make terrestrial laser scanning also an interesting tool for forest inventory and management. The paper will first review current laser scanner systems from a technological point of view and discuss different scanner technologies and system parameters regarding their suitability for forestry applications. In the second part of the paper, results of a pilot study on the applicability of terrestrial laser scanners in forest inventory tasks will be presented. The study concentrates on the automatic detection of trees and the subsequent determination of tree height and diameter at breast height. Reliability and precision of techniques for automatic point cloud processing were analysed based on scans of a test region in Harbin Experimental Forest Farm. In the pilot study, which represents an early stage of software development, more than 95% of the trees in a test region could be detected correctly. Tree heights could be determined with a precision of 80 cm, and breast height diameters could be determined with a precision of less than 1.5 cm.