混交度在不同相邻木选取方案下的差异性研究

Research on the Difference of Mingling Degree under Different Selection Schemes of Adjacent Trees

为了厘清林分混交度在不同相邻木选择方案下的差异,寻找不同相邻木选取方案适用于哪种林分类型的混交度求解证据,为林分空间结构相关问题的研究提供参考。依据聚集分布林分、随机分布林分、均匀分布林分及稀疏分布林分类型,在南洞庭湖区的龙虎山设置了31块样地,分别使用基于“1+4”最邻近相邻木、基于半径R(R=3.05m)圆及基于Voronoi图的方法求解了各样地的单株相邻木数、单株林木混交度及林分平均混交度值,并探究了不同方案在不同林木类型之间的相关性。1)从总体林分平均混交度的角度上看,实验样地中除了稀疏分布中基于半径R圆的相邻木选择方案求得林分平均混交度的值偏低之外,其它几种林分的平均混交度值差别均不大。2)从单株的角度上看,不同林分类型中对象林木的混交度值在不同相邻木选择方案下存在差异。3)基于“1+4”最邻近相邻木与基于Voronoi图的相邻选取方案在不同林分类型中的相关性相对较高。不同的相邻木选择方案在不同的林分类型下虽各有优势,但从总体上看,使用基于“1+4”最邻近相邻及基于Voronoi图的相邻选取方案在求解不同类型林分混交度的稳定性和精确性相对较高。

In order to clarify the difference of stand mingling degree under different adjacent tree selection schemes,and find the evidence of which stand type is suitable for different adjacent tree selection schemes,this paper can provide reference for the research of stand spatial structure related issues.31 sample plots were set up in Longhu Mountain of South Dongting Lake area according to the types of aggregated distribution stand,random distribution stand,uniform distribution stand and sparse distribution stand.The methods based on"1+4"nearest adjacent trees,radius R(R=3.05 m)circle and Voronoi diagram were used to solve the number of adjacent trees per plot,the mingling degree of single tree and the average mingling degree of stand in various places,and explore the correlation between different schemes in different forest types.1)From the point of view of the overall stand average mingling degree,the average mingling degree values of the other stands in the experimental plots were not greatly different,except that the average mingling degree value of the adjacent trees based on the radius R(R=3.05 m)circle in the sparse distribution was low.2)From the point of view of individual tree,the mingling degree values of target trees in different stand types were different under different adjacent tree selection schemes.3)The correlation between"1+4"nearest adjacent tree and Voronoi diagram was relatively high in different stand types.Different selection schemes of adjacent trees had their own advantages under different stand types,but on the whole,the stability and accuracy of the adjacent selection schemes based on"1+4"nearest adjacent tree and Voronoi diagram were relatively high in solving mingling degrees of different stand types.