Terrestrial Laser Scanning in Forestry: Accuracy and Efficiency in Measuring Individual Tree Structural Parameters

Abstract

Tree position, tree height and diameter at breast height are extremely important structural parameters in forest sample plot surveys. Compared with traditional manual measurement methods, the advantages of terrestrial laser scanning (TLS) in terms of data acquisition efficiency and accuracy have led to its gradual and widespread use, but the research on the accuracy of TLS in extracting forest structural parameters is still insufficient. This paper analyzes the accuracy and effectiveness of TLS in extracting structural parameters (tree height, diameter at breast height, and location) using poplar and Styphnolobium as examples, using TLS, airborne lidar system (ALS), and combining with field measurements. The results show that TLS has significant shortcomings in measuring tree height due to observation viewpoint limitations and forest obstruction, but is more efficient and accurate for breast diameter within the observation range (radius < 50m): the detection rate of single-station TLS reaches 50–60%, while the maximum measurement error (RMSE) of DBH is 1.6cm; Furthermore, even with RTK support, the single tree location bias (M) of two independent TLS measurements is 0.11m. TLS is of great value in obtaining forest sample parameters efficiently, and this study provides a reference for evaluating the accuracy and reliability of TLS technology in forest sample measurements.