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研究林木个体间竞争关系,建立以保留木为对象的单木邻体竞争模型对于人工林的抚育经营具有重要的作用。本研究以北京西山试验林场油松人工林为研究对象,采用改进的Hegyi竞争指数分析林木的竞争强度;以对象木胸径和空间相对位置为参数构造加权Voronoi图,选择S_i=n∑j = 1λ(α_(ij)-α_i)~a/L~b作为模型表达式,分析对象木与邻近的少数林木(3株或4株)之间的竞争关系并建立邻体竞争模型。结果表明,油松人工林林木间竞争较剧烈,密度越大、坡位越低的林分中林木间的竞争越强。以胸径和冠幅作为自变量构造的单木竞争模型具有较低的标准误,3-邻体竞争模型和4-邻体竞争模型的相关性分别为0.83和0.84。本研究基于Voronoi图和林冠面积建立单木邻体竞争模型,为优化林分空间结构、提高森林质量的单株木抚育择伐经营技术提供参考。
Studying the competition among individuals in forest and establishing a competition model of single-tree neighborhood with reserved wood plays an important role in the management of plantations. In this study, the Pinus tabulaeformis plantation in Beijing Xishan experimental farm was used as the research object. The competitive Heinz index was used to analyze the competition intensity of forest trees. The weighted Voronoi diagram was constructed by taking the DBH and the relative spatial position as the parameters, and S_i = nΣj = 1λ (α_ (ij) -α_i) ~ a / L ~ b were used as model expressions to analyze the competition relationship between the target wood and a few neighboring forest trees (3 or 4) and to establish the neighbor competition model. The results showed that the competition among trees in Pinus tabulaeformis plantation was more intense and the density was higher. The single-tree competition model constructed by using the diameter at breast height and the crown as the independent variable has a lower standard error, and the correlations between the 3-adjacent competition model and the 4-adjacent competition model are 0.83 and 0.84, respectively. Based on Voronoi diagram and canopy area, this study established a single-neighbor competition model to provide reference for optimization of forest spatial structure and improvement of forest quality.