华北土石山区天然次生林空间结构特征分析

Spatial Structural Characteristics of Natural Secondary Forest in Rocky Mountain Area of Northern China

以河北省木兰围场国有林场内1hm2标准地植被群落调查数据为基础,利用角尺度、混交度和大小比数这3个林分空间结构参数分析了华北土石山区天然次生林林分空间结构特征。结果表明,优势种白桦混交程度较低,林木空间隔离状况较差,亚优势种和伴生树种混交程度普遍较高,林分混交形式以零度和弱度混交为主,平均混交度为0.400。林木个体大小分化明显,各树种平均大小比数排序为:华北落叶松>花楸>蒙古栎>棘皮桦>白桦>青杄>山杨>油松>华北五角枫。群落内多数林木处于随机分布状态,但林分平均角尺度为0.562,属团状分布。依据天然次生林空间结构特征,分析预测了群落演替趋势,并提出森林经营的相关建议。

Based on the vegetation community survey of a 1 hectare plot in Forest Farm of Mulanweichang,and by using the mingling degree,neighborhood comparison and uniform angle index,the spatial structure characteristics of nature secondary forest in rocky mountain area of Northern China were analyzed.The results showed that Betula platyphlla was the dominant and constructive species of the tree layer,its mingling degree was low,but the mingling degrees of sub-dominant and associated trees were big.The mainly mixed forms of the stand were none-mixed or less-mixed,the average mingling degree was 0.400.The order of tree species neighborhood comparison was as follow： Larix principis-rupprechtii,Sorbus pohuashanensis,Quercus mongolica,Betula dahurica,B.platyphlla,Picea wilsonii,Populus davidiana,Pinus tabulaeformis and Acer truncatum.In the vegetation community,most of the trees were in the random distribution,but the average uniform angle index of the stand was 0.562,so the distribution pattern of the overall stand was aggregative distribution.According to the spatial structure characteristics of nature secondary forest,the tendency of community succession and some management advices were proposed.