基于Voronoi图的侧柏游憩林空间结构分析

为了探究侧柏游憩林的林分结构调控途径，采用聚集指数、混交度、大小比数及开敞度4个指数，基于Voronoi图空间结构单元分析了北京西山国家森林公园典型侧柏林的林分空间结构特征。结果表明:1）林分平均聚集指数为1.31，林木总体上呈均匀分布格局；2）林分平均混交度为0.427，树种空间隔离程度较低，且空间配置较为简单；3）林分平均胸径和树高大小比数分别为0.512和0.497，林木胸径及树高分化均不太明显，说明林分处于中等竞争状态；4）林分平均开敞度为0.320，林内空间较为开阔，林木生长空间基本充足。侧柏游憩林的林分空间结构基本合理，建议通过少量间伐或补植乡土阔叶树种等措施优化林分空间结构，进一步提升该地区侧柏林的游憩价值。 

Analysis of stand spatial structure of Platycladus orientalis recreational forest based on Voronoi diagram method

To explore the approaches to regulate its stand structure, spatial structure (including aggregation index, mingling, neighborhood comparison, and open degree) of typical forest stand in Xishan National Forest Park of Beijing was analyzed by using Voronoi diagram method. Results indicated that: 1) the average aggregation index of stand was 1.31. The individuals of tree displayed an uniform distribution pattern. 2) The average mingling of stand was 0.427. The degree of segregation among tree species was low and the spatial configuration was relatively simple. 3) The average neighborhood comparison based on DBH and tree height was 0.512 and 0.497, respectively. The differentiation of DBH and height was not significant, which indicated a middle level of competition. 4) The average open degree of stand was 0.320. Thus, the stand was relatively open and had adequate growing spaces. In conclusion, spatial structure of this recreational forest was basically reasonable. For the purpose of improving recreational value, stand spatial structure can be optimized through little thinning or adding native broadleaved trees.