不同混交度指数的比较分析

Comparative Analyses on Different Mingling Indices

混交度是近年来提出的描述林分树种相互隔离程度的指数,包括简单混交度、树种多样性混交度和物种空间状态; 但现有混交度的指数对空间结构单元的树种隔离关系表达不完整,存在不同混交结构具有相同混交度的问题。本文在分析简单混交度、树种多样性混交度和物种空间状态及其存在问题的基础上,提出全混交度。以天目山常绿阔叶林数据为例,采用基于 GIS 的 Voronoi 图分析方法对不同混交度指数进行比较分析。结果表明: 由于树种多样性混交度、物种空间状态和全混交度都是对简单混交度的改进,所以各混交度既有区别又有联系,证明它们之间存在数学关系。全混交度增加考虑最近邻木相互之间的树种隔离关系,并引入生物多样性 Simpson 指数,可明显提高对不同混交结构的分辨能力。

Mingling has recently been presented as an index describing tree species separation in a stand including simple mingling, tree species diversity mingling, and tree species spatial status. However, current mingling indices incompletely express the separation relationship among tree species in a spatial structure unit, there is a problem of different mixed structure with equal mingling. This paper proposes complete mingling based on analyzing simple mingling, tree species diversity mingling and tree species spatial status, and their existing problems. Comparative analyses of different mingling indices were carried out based an example of the evergreen broadleaved forest in Tianmu Mountain National Nature Reserve and Voronoi diagram method of GIS. The results show that tree species diversity mingling, tree species spatial status and complete mingling are improved from simple mingling, so differences and relationships exist among them, and mathematical relationships between different mingling indices have been testified. Complete mingling additionally involves tree species separation relationship of the nearest neighbors, and biodiversity Simpson index is introduced into complete mingling. As a result, complete mingling significantly increases resolving power for different mixed structures.