基于Voronoi图和Delaunay三角网的杉木游憩林空间结构

Stand Spatial Structure of Cunninghamia lanceolata Recreational Forest Based on Voronoi Diagram and Delaunay Triangulated Network

基于Voronoi图和Delaunay三角网建立空间结构单元的方法,采用聚集指数、混交度、大小比数、竞争指数和开敞度5个指数分析福建将乐国有林场典型游憩林的林分空间结构特征。结果表明:杉木游憩林以1株对象木周围6株最近邻木的构成形式最为常见,林分平均聚集指数R为1.05;林木空间分布格局呈均匀分布;林分平均混交度M-为0.48,树种空间相互隔离程度不高,处于中等混交状态;林分平均胸径和树高大小比数分别为0.49和0.51,林木胸径、树高分化不太明显,林分处于中等竞争状态;优势树种中,杉木竞争指数CI为346.27,具有较强竞争力;林分平均开敞度K-为0.21,林分内林木生长空间不足。在维持现有林分条件的基础上,应增大林内开敞度以便进一步优化林分空间结构,提升游憩林的游憩价值。

In this paper, spatial structure （including aggregation index, mingling, neighborhood comparison, competition index and open degree） of a typical recreation forest in Jiangle state-owned forest farm of Fujian was analyzed by using the method of Voronoi diagram and the Delaunay triangulation to establish the spatial structure unit. The results indicated that： It was a common form with one subject tree with 6 nearest neighbor trees in Cunninghamia lanceolata recreational forest. The average aggregation index of the stand was 1.05. The spatial pattern of forest trees was uniformly distributed. The average mingling of the stand was 0.48. The degree of spatial segregation among tree species was not high with the intermediate mixed state. The average neighborhood comparisons based on DBH and tree height were 0. 49 and 0.51. The differentiation of DBH and height was not significant, indicating a middle level of competition. Among superiority species, the competition index of Cunninghamia lanceolata was 346.27. The competitiveness was strong. The average open degree of the stand was 0.21. Thus, there is insufficient space for the trees＇ growing. On this basis, stand spatial structure and recreation value can be optimized through increasing open degree of the stand.