ESTIMATION OF FOREST TREES DIAMETER FROM TERRESTRIAL LASER SCANNING POINT CLOUDS BASED ON A CIRCLE FITTING METHOD

In forest monitoring and management, any rational decision needs to be based on forest parameters. The diameter at breast height (DBH) of a tree is considered to be the most significant parameter among them. This paper presents a novel method for extracting tree stems and estimating DBH of trees in a forest environment from 3D point clouds data acquired by a terrestrial laser scanning (TLS) system. In the proposed method, a downward-growing algorithm is used to extract individual tree stems and DBH of trees are estimated by the circle fitting algorithm. This proposed method can avoid errors caused from tilted trees by estimating a plane perpendicular to the tree stem. With this method, 17 trees were extracted from single-scan point cloud data consisting of 21 trees. The estimated DBH had a bias of 0.38 cm and a root mean squared error of 1.76 cm. These experiment results show the feasibility of the proposed method.