Advancing Forest Inventory in Tropical Rainforests: A Multi-Source LiDAR Approach for Accurate 3D Tree Modeling and Volume Estimation

Abstract

This study proposes an Automatic Branch Modeling (ABM) framework that combines AdTree and AdQSM algorithms to reconstruct individual tree models and estimate timber volume from fused Hand-held Laser Scanners (HLS) and Unmanned Aerial Vehicle Laser Scanners (UAV-LS) point cloud data. The research focuses on two 50 × 50 m primary tropical rainforest plots in Hainan Island, China, characterized by dense and vertically stratified vegetation. Key steps include multi-source point cloud registration and noise removal, individual tree segmentation using the Comparative Shortest Path (CSP) algorithm, extraction of diameter at breast height (DBH) and tree height, and 3D reconstruction and volume estimation via cylindrical fitting and convex polyhedron decomposition. Results demonstrate high accuracy in parameter extraction, with DBH estimation achieving R2 = 0.89–0.90, RMSE = 2.93–3.95 cm and RMSE% = 13.95–14.75%, while tree height estimation yielded R2 = 0.89–0.94, RMSE = 1.26–1.81 m and RMSE% = 9.41–13.2%. Timber volume estimates showed strong agreement with binary volume models (R2 = 0.90–0.94, RMSE = 0.10–0.18 m3, RMSE% = 32.33–34.65%), validated by concordance correlation coefficients (CCC) of 0.95–0.97. The fusion of HLS (ground-level trunk details) and UAV-LS (canopy structure) data significantly improved structural completeness, overcoming occlusion challenges in dense forests. This study highlights the efficacy of multi-source LiDAR fusion and 3D modeling for precise forest inventory in complex ecosystems. The ABM framework provides a scalable, non-destructive alternative to traditional methods, supporting carbon stock assessment and sustainable forest management in tropical rainforests. Future work should refine individual tree segmentation and wood-leaf separation to further enhance accuracy in heterogeneous environments.

Plant phenotyping relevance

マルチソースLiDAR融合、個体樹木セグメンテーション、3D再構成によってDBH・樹高・材積を抽出する手法を開発し、精度検証まで行っており、植物形質計測が研究の中心である。

Code and data availability

The supplied blocks describe HLS/UAV-LS point cloud acquisition, field measurements, and an ABM (AdTree+AdQSM) analysis pipeline, but contain no public deposit of the paper's point clouds, field measurements, code, or models. CloudCompare is cited only as a generic third-party tool, not an authors' asset. No data or代码-

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