| 摘要: |
| 【目的】基于交角的林木竞争指数（CI）简洁，能同时表达出竞争木上方的遮盖和侧翼的挤压。探讨不同林分用胸径（D）或通过胸径-树高（DH）曲线预估树高后替代实测树高计算该竞争指数的可行性，以期给出基于交角的林木竞争指数的最优经验计算途径。【方法】以3个地区共6块样地的天然林和人工林为研究对象，利用全站仪测定并记录林木坐标、树种、胸径、树高、冠幅和健康状况，并计算和分析各样地林木通过胸径得到的竞争指数（CID），通过胸径-树高曲线预估树高后得到的竞争指数（CID-H）与通过实测树高得到的竞争指数（CIH）间的关系。【结果】不同森林类型林分通过胸径和胸径-树高曲线预估树高后计算得到林木竞争指数的2个经验计算途径都是可行的，且都能表达出通过实测树高计算得到林木竞争指数（CIH）结果的95%以上。2个经验计算途径的效果与胸径 树高曲线模型精度呈显著正相关，当胸径-树高曲线模型精度低（R2＜0.53）时，CID-H效果略差。【结论】由于CID-H计算过程较复杂，且当林分胸径-树高曲线模型精度较低时，竞争指数CID-H的应用效果比竞争指数CID略差，因此以胸径替代实测树高可作为该竞争指数的最佳经验计算途径。 |
| 关键词: 基于交角的林木竞争指数 胸径 树高曲线模型 经验计算途径 |
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| 基金项目:国家自然科学基金项目（31370638） |
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| Application of forest competition index based on intersection angle |
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BAI Chao,ZHAO Zhonghua,HU Yanbo,et al
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| Abstract: |
| 【Objective】Forest competition index (CI) based on intersection angle is concise and able to express the over shading and the lateral extruding from the competitive trees.The feasibility of two empirical calculation methods using DBH (D) directly or using estimated tree height from diameter-height (DH) curve model was discussed to provide optimal empirical calculation of forest competition index based on intersection angle.【Method】Six sample plots in natural and artificial forests of 3 regions were selected and trees coordinates,species,DBH,tree height,crown width and health were measured and recorded using electronic total station.Then the relationship between competition index calculated by DBH (CID),tree height estimated with diameter-height curve model (CID-H) and measured tree height (CIH) was analyzed.【Result】It was feasible to use the two empirical calculation methods to calculate competition indexes of different forests with more than 95% identity compared with measured tree height (CIH).The effects of two empirical calculation methods were significantly positively related to the accuracy of tree DBH and tree height model.When the correlation between tree DBH and tree height was low (R2＜0.53),the accuracy of CID-H was slightly worse than that of CID.【Conclusion】Because of complicated calculation process of CID-H,the results of CID-H were slightly better than that of CID when correlation between tree DBH and height was low.Therefore,using DBH directly is the optimal calculation method for forest competition index based on intersection angle. |
| Key words: forest competition index based on intersection angle height-diameter curve model empirical calculation way |
