老龄林林分空间的点格局分析

采用TOPCON全站仪,在吉林省蛟河市林业实验区管理局施业区内设置1块500 m×600 m固定监测样地,并进行群落调查,在Arc GIS平台上采用Ripley’s K函数进行不同尺度的空间聚集度研究,采用空间自相关方法对研究区内的种群进行空间自相关性分析。结果表明:老龄林中数量最多的前6个种群分别是簇毛槭、白牛槭、千金榆、色木槭、裂叶榆和花楷槭;不同的起测胸径对林木的空间格局分布有重要的影响,起测胸径5 cm时,发现6个个体数量最多的种群显示出了不同的空间格局,其中白牛槭的空间聚集性最高;优势木在空间尺度较小时,生长得比较密集,在空间尺度较大时,则呈现出离散的分布特点,不同的起测胸径对研究结果也有一定的影响,因此,在研究空间格局分布时,起测胸径是首先需要考虑的因素;优势木在种群间还是不同空间距离下,优势木间均显示正向的空间自相关性,只是相关性程度略有差异,优势木的相关性受空间尺度的影响较大。

Spatial Point Pattern of An Old Growth Forest

TOPCON total station was used in an old growth forest in Jilin Province Jiaohe Forestry Administration of Experimental Area to set up a 500 m×600 m fixed monitoring plot and community survey was conducted.The Ripley' s K function on ArcGIS platform was used to study the spatial aggregation of tree species in different scales in the sample plot.The spatial autocorrelation method was applied to study the spatial dependence of different species in the study plot.The top six tree species in terms of population size were Acer barbinerve,A.mandshuricum,Carpinus cordata,A.mono,Ulmus laciniata,and A.ukurunduense.The minimum measured diameter had important impact on the spatial pattern of stands.When the minimum measured diameter was 5 cm,the top six largest populations all showed spatial clustering in varying degrees and the spatial aggregation of A.mandshuricum was the largest among them.The dominant tree species in the old growth forest were determined and the spatial aggregation of dominant trees was analyzed.The dominant trees showed dense distribution in smaller spatial scales and showed scattered distribution in larger spatial scales.Different minimum measured diameter also had certain impact on the study results,therefore,this factor should be considered firstly while studying the spatial pattern of individual trees.Among different tree species and under different spatial scales,the dominant tree species all showed positive spatial autocorrelation with varying correlation degrees,and the spatial autocorrelation was greatly affected by the spatial scales.