Wang Fan, Jia Wei-Wei, Li Feng-Ri, Tang Yi-Ren, Zhang Ying
School of Forestry, Northeast Forestry University, Harbin 150040, China.
Ministry of Education Key Laboratory of Sustainable Forest Ecosystem Management, Northeast Forestry University, Harbin 150040, China.
Ying Yong Sheng Tai Xue Bao. 2025 May;36(5):1309-1318. doi: 10.13287/j.1001-9332.202505.009.
We acquired the terrestrial laser scanning (TLS) point cloud data of five permanent plots of plantations with different thinning intensities [control (CK), four low-intensity thinning treatments (T), two medium-intensity plus one low-intensity thinning treatments (T), two medium-intensity thinning treatments (T), and two high-intensity thinning treatments (T)] in the Mengjiagang Forest Farm. Then, we verified the use of TLS to quantify the individual tree Hegyi competition index (CI) in plantations and analyzed the effect of thinning intensities on stem and crown competition in . The results showed that the thinning treatment reduced the competition among trees, with the average competition indices of T, T, T and T plots being decreased by 0.5%-10.7%, 15.1%-20.6%, 28.6%-34.8% and 39.2%-47.9%, respectively. There were significant differences in the stem-based CI (diameter at breast height, tree height) among different treatments. CI based on crown volume and crown surface area showed significant differences among the thinning treatments. In contrast, the differences in CI based on maximum crown diameter and crown projection area were not significant between the control and low-intensity thinning treatments, though differed significantly between all other treatments. In summary, TLS-based point clouds could quantify individual tree stem and crown competition, and CI based on crown volume and surface area could effectively reflect the competitive relationships within thinned forest stands.
我们获取了孟家岗林场五个不同间伐强度人工林固定样地（对照（CK）、四种低强度间伐处理（T）、两种中强度加一种低强度间伐处理（T）、两种中强度间伐处理（T）以及两种高强度间伐处理（T））的地面激光扫描（TLS）点云数据。然后，我们验证了使用TLS来量化人工林中单株树木的赫吉竞争指数（CI），并分析了间伐强度对[此处原文缺失部分内容]中树干和树冠竞争的影响。结果表明，间伐处理降低了树木之间的竞争，T、T、T和T样地的平均竞争指数分别降低了0.5% - 10.7%、15.1% - 20.6%、28.6% - 34.8%和39.2% - 47.9%。不同处理之间基于树干的CI（胸径、树高）存在显著差异。基于树冠体积和树冠表面积的CI在间伐处理之间存在显著差异。相比之下，基于最大树冠直径和树冠投影面积的CI在对照和低强度间伐处理之间差异不显著，尽管在所有其他处理之间差异显著。总之，基于TLS的点云可以量化单株树木的树干和树冠竞争，基于树冠体积和表面积的CI可以有效地反映间伐林分内的竞争关系。
