木兰围场山杨次生林空间结构分析研究

Analysis on the spatial structure of aspen forest in Mulan-Weichang

林分空间结构是森林经营管理过程中的重要因子之一。基于木兰围场国有林场管理局植被群落调查,利用林分空间结构参数角尺度、混交度和大小比数分析研究该区山杨次生林林分空间结构特征。结果表明:木兰围场林场次生林乔木层共有10个种群,山杨在种群密度和蓄积量方面占有明显优势,是林分乔木层的建群种。林分混交程度较低,混交形式以零度混交和弱度混交为主;次生林内山杨大小比数频率分布较为均匀,但伴生树种大小分化程度差异较大;角尺度频率分布呈单峰状,林分水平分布格局为团状分布。林分内伴生种华北落叶松、白桦优势地位较高,大多为优势木和亚优势木,生长、发展潜力巨大,在群落演替过程中占有重要地位,但具体演替过程还需进一步研究。

Stand spatial structure was one of the most important factors in the process of forest management.Based on the vegetation community survey in Mulan-Weichang National Forestry Administration,and using the stand structure parameters including mingling degree,neighborhood comparison and uniform angle index,this paper analyzed the spatial structure characteristics of Populus davidiana secondary forests in Mulan-Weichang.The results showed as the followings： there were 10 populations in the tree layer of the forest,among which P.davidiana had the obvious advantages in population density and stock volume,being the constructive species of the tree layer.The average mingling degree of the forest was low,and the mainly mixed forms were none-mixed or less-mixed;neighborhood comparison of P.davidiana was uniform,but the differentiation of associated tree species was significant;the frequency distribution of uniform angle index was a single peak and showed that the distribution pattern of the overall stand trees was of aggregative distribution.Much of Larix principis-rupprechtii and Betula platyphylla,the associated species,were dominant or sub-dominant trees in a huge potential for growth and development,and would play important roles in the community succession,but the specific process needed further studies.