Journal of Hunan Ecological Science

【Objective】This study aims to evaluate the spatial structure characteristics of a Taxodium ascendens plantation by integrating terrestrial and airborne LiDAR point cloud data, providing scientific basis and theoretical support for the quality improvement and sustainable management of the plantation. 【Method】Data sources included UAV LiDAR, terrestrial LiDAR, and field survey data from two 30 m × 30 m Taxodium ascendens plots in Xiannv Forest Farm. After merging the point cloud data, individual tree segmentation and parameter extraction were performed. Seven parameters—angular scale, size ratio, spatial density index, openness, growth space index, growth space competition index, and simple compe- tition index were selected to construct a comprehensive evaluation model. The comprehensive evaluation model was used to perform simulated logging, and the optimal logging intensity was selected to evaluate the optimization strategy of the forest spatial structure. 【Result】Compared with the measured data, the extraction accuracy of diameter at breast height (DBH) and tree height from terrestrial and airborne Li- DAR data had average R2 values of 0. 988 3 and 0. 985 3, with mean squared error values of 0. 493 9 cm and 0. 125 5 m, respectively. The comprehensive spatial structure index of plots A and B was 0. 526 and 0. 349, respectively. Through simulated logging, the optimal logging intensity for plots A and B was found to be 6% and 8% of the total volume, respectively. This logging intensity, without excessive log- ging, increased the comprehensive spatial structure index by 0. 067 and 0. 132, respectively, effectively improving the growth environment within the forest and reducing resource competition pressure. 【Conclu- sion】The integration of terrestrial and airborne LiDAR can efficiently digitize and refine stand structure information, and overcome the limitations of single LiDAR systems and traditional manual methods. This approach has significant practical implications for the survey and monitoring of plantation resources. Utili- zing a comprehensive evaluation model to assess the spatial structure of Taxodium ascendens plantations and simulate logging can guide the optimization of stand spatial structure, providing a scientific basis and practical reference for stand transformation and forest quality improvement.

Taxodium ascendens;plantation;airborne LiDAR;stand spatial structure; simulation log- ging