甘肃大野口青海云杉种群的空间分布格局

Spatial distribution pattern of Picea crassifolia population in Dayekou,Gansu Province

为掌握青海云杉的空间分布特征和大面积遥感定量反演青海云杉结构提供关键参数,以及为青海云杉种群保护和祁连山水源涵养林的可持续经营提供基础数据,根据甘肃大野口1hm2青海云杉林大样地的调查结果,首次应用点格局方法开展青海云杉种群空间格局的研究,并且将研究区内树木分龄级计算,得到不同龄级的树木在不同尺度下的空间分布格局。首先,应用Weibull分布对样地内青海云杉的胸径分布进行拟合;然后分别采用点格局分析法和聚集指标测定法,对样地内各龄级的树木在不同尺度下的空间分布格局进行研究;最后应用纽曼A型分布对研究区内的青海云杉种群空间分布格局进行拟合。结果表明:青海云杉林胸径分布基本符合Weibull分布;研究区内种群密度较大,空间格局呈集群分布;幼树、小树、中树和大树在各研究尺度下均呈集群分布;青海云杉随着年龄的增长,聚集强度逐渐降低;研究区内青海云杉种群空间分布格局符合纽曼A型分布。集群分布的原因主要是自然和人为干扰、环境条件及青海云杉的生物学特性共同作用的结果。

The purpose of this study is to obtain an understanding of the spatial distribution pattern of Picea crassifolia population,deduce the key parameters for a quantitative remote sensing inversion of largescaled P.crassifolia population and provide a basis for the protection of P.crassifolia populations and sustainable management of the forest for conservation of water supply in the Qilian Mountains,northwestern China.Based on the inventory data of a 1 hm2 sample plot in Dayekou of Gansu Province,we studied the spatial distribution patterns of a P.crassifolia population using an analytical point pattern method and investigated the spatial patterns of trees at different age classes under different spatial scales.First,a Weibull function was used to analyze the distribution of DBH （diameter at breast height）.Then,the methods of point pattern analysis and aggregation indices were employed to study the spatial distribution patterns of trees at different age classes under different spatial scales.Finally,a Neymans type A distribution was used to simulate the spatial distribution pattern of P.crassifolia population.The results show that： 1） the DBH distribution of P.crassifolia conforms to the Weibull function;2） the distribution of the population is dense and follows an aggregation pattern;3 ） the spatial distribution patterns of young,small,middle and big trees all obey the aggregation distribution under different scales;4） the aggregation intensity decreases with the growth of P.crassifolia population and 5） the spatial distribution pattern of P.crassifolia conforms to the Neyman  s type A distribution.The aggregation distribution of the population could result from natural and human disturbance,environmental conditions and biological characteristics of P.crassifolia.