福建三明马尾松天然林空间结构特征研究

研究福建省三明市马尾松天然林角尺度、混交度、大小比数、开敞度和林层比5个空间结构参数，分析其空间结构特征。结果表明，马尾松天然林树种组成丰富，林分中共出现25个树种，其中马尾松为优势树种。全林分的角尺度均值为0.57，属于聚集分布；混交度均值为0.56，处于中度混交和强度混交之间；以胸径、树高和冠幅计算全林分的大小比数均值分别为0.49、0.48和0.53，均接近于中庸状态；开敞度均值为0.17，生长空间严重不足；林层比均值为0.43，垂直方向上的成层性较为简单。林分的空间稳定性较低。研究结果为该地区马尾松天然林经营提供了依据。

Spatial Structure Characteristics of Pinus massonian Natural Forest

The spatial structure characteristics of Pinus massonian natural forest occurring in Sanming, Fujian was analyzed through its 5 spatial structural parameters: uniform angle index, mingling degree, neighborhood comparison, opening degree, and over story. The results showed that the tree species composition of P. massonian natural forest was abundant, 25 tree species were observed within the forest. The average uniform angle index was 0.57, indicating that the forest was in aggregation distribution. The average mingling degree was 0.56, which was in between moderately and highly mixed plantation. The diameter, tree height and crown of whole forest were 0.49, 0.48, and 0.53, respectively, which approached medium situation. The average opening degree was 0.17, indicating the serious shortage of growth space. The average over story of 0.43 showed that the layered property in vertical direction was simple. In summary, the spatial stability of the forest was low. The results provided the basis for the management of P. massonian natural forest.