| 摘要: |
| 【目的】探讨采用二元分布描述林分空间结构特征的优越性并应用于实践。【方法】对秦岭中段20和40年生华北落叶松人工林典型样地进行调查，利用林分空间结构分析软件Winkelmass 1.0和Excel 2007计算林分空间结构指标的二元分布，即混交度-大小比数、大小比数-角尺度、角尺度-混交度。【结果】20年生华北落叶松林分中，处于不同优劣程度和混交等级组合的林木株数基本相等；相同优劣程度或相同混交等级的多数林木处于随机分布，而处于相同分布格局且不同优劣程度或不同混交等级的林木株数比例基本相等。40年生华北落叶松林分中，处于不同优劣程度的绝大多数林木周围无其他伴生树种；相同混交状况或相同优劣程度的林木大多处于随机分布；最常见的结构单元为参照树周围相邻木为相同树种且呈随机分布。20和40年生华北落叶松林分中，处于优势、高度混交和随机分布组合的林木相对频率值分布不合理。【结论】通过实例证实二元分布是研究林分空间结构特征较为有效的方法，可为林分结构优化和决策提供借鉴和指导。 |
| 关键词: 华北落叶松 混交度 大小比数 角尺度 秦岭中段 |
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| 基金项目:国家林业公益性行业科研专项“天保工程区天然公益林抚育经营关键技术研究”（201204504） |
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| Bivariate distribution of spatial structure in Larix principis-rupprechtii plantation in the middle section of Qinling Mountains |
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ZHANG Gang-gang,WANG De-xiang,CHAI Zong-zheng,et al
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| Abstract: |
| 【Objective】This study aimed to discuss the superiority of using bivariate distribution to analyze stand spatial structural characteristics and its practical application.【Method】Through typical sample investigation of 20 and 40 years old Larix principis-rupprechtii plantations in the middle section of Qinling Mountains,the bivariate distribution of structural parameters was calculated using Winkelmass 1.0 and Excel 2007.【Result】In 20 years old stand,the frequencies of trees with different dominance degrees and mingling classes were basically the same.Most trees with same dominance degree or mingling class were randomly distributed,and the trees with same distributed pattern and different dominance degrees or mingling classes were almost quantitatively equal.In 40 years old stand,most trees with different advantages had no other tree species surrounded.Trees with same dominance degree or mingling class were almost randomly distributed.The most common structural unit was that reference tree was randomly surrounded by same species trees.In the studied 20 and 40 years old stands,the frequencies of trees with high dominance degree,high mingling class,and random distribution were unreasonable.【Conclusion】The bivariate distribution was confirmed to be an effective method to research stand spatial structure characteristics,which could provide reference and guidance for optimization and decision making of stand structure. |
| Key words: Larix principis-rupprechtii mingling dominance uniform angle index the middle section of Qinling Mountains |
