河北省孟滦林场华北落叶松白桦混交林空间结构分析

合理的林分空间结构是决定林分生产力和生态功能的重要基础。本研究以河北省围场县木兰林管局孟滦林场典型林分类型华北落叶松白桦混交林为研究对象,通过混交度、密度指数和竞争指数、空间分布格局三个定量指标分析了林分的空间结构特征。结果表明,(1)林分的平均混交度为0.37,处于弱度混交与中度混交之间。(2)林分密度指数为841.2,林分密度较低(一般林分密度指数在1 200～1 600比较合适);竞争指数为2.704,竞争不激烈。(3)当模拟尺度d在0～0.6m时,林分呈现聚集分布;当模拟尺度d在0.6～1.0m和8.5～10.0m时林分呈现随机分布;当模拟尺度d在1.0～8.5m时,林分呈现均匀分布。

Spatial structure analysis of Larix Principis-rupprechtii Mayr. and Betula spp. mixed forest in the Mengluan Forest Farm in Hebei Province

Reasonable spatial structure is the important foundation of the stand productivity and ecological function.By studying the typical forest type-Larix principis-rupprechtii Mayr. and Betula spp. mixed forest in the Mengluan Forest Farms in Weichang of Hebei,and using the three quantitative indices of mingling degree,density index and competitiveness index,and space distribution pattern,the spatial structural characteristics of mixed forest were analyzed.Results showed that：（1） The average mingling degree of the stand is 0.37,which is between weak mingling degree and moderate mingling degree.（2） The density index of the stand is 841.2 and the competitiveness index is 2.704,indicating that the stand density is low and the competition is not fierce.As we know,stand density index is commonly in 1 200～1 600.（3） The stand presents a gathered distribution when the analog scale is between 0～0.6 m a random distribution when between 0.6～1.0 m and 8.5～10.0 m,and a homogeneous distribution when between 1.0～8.5 m.