Abstract:In order to solve the problems of low efficiency, high risk and insufficient accuracy of traditional tree surveys in expressway reconstruction and expansion, the efficient and accurate technical methods are explored. Taking the Guangzhou - Shenzhen Expressway Reconstruction and Expansion Project as the research object, the “unmanned aerial vehicle + Airborne LiDAR” survey method is adopted to generate high-precision orthophoto images and 3D point clouds. Combined with semantic segmentation, single-tree extraction, tree species identification and parameter interpretation are realized, and a tree background database is established. The result shows that (1) the average accuracy rate of tree quantity survey and tree species identification reaches 97%, and the survey of over 100,000 trees in Dongguan City and Shenzhen City has been completed efficiently within two months. (2) Based on the survey results, the approval process is optimized, and the declared quantity is reduced from 100,000 to 60,000 trees, which significantly improves the approval efficiency. (3) The relevant permits have been approved to effectively reduce the safety risks of road-related operations on expressways, providing replicable practical references for similar projects.