福寿林场天然次生林空间结构分析与评价

分析天然次生林空间结构并对其评价，为制定合理的林分空间结构优化措施提供理论依据，同时也为人工林林分的空间结构优化和生态功能提高提供参照模板。以湖南省平江县福寿林场天然次生林为对象，选取角尺度、混交度和林层指数3个林分空间结构指标分析其林分空间结构特征，运用乘除法原理构建空间结构评价参数对其空间结构进行评价。结果表明，林分平均角尺度为0.45，林木的水平分布状况较为理想，接近随机分布；林分的平均混交度0.73，接近强度混交，林分树种丰富，具有良好的树种混交程度，林分稳定性较强；林分平均林层指数为0.42，林分垂直结构上成层性较高，空间利用性较好；天然次生林林分空间结构评价指数为0.624 8、0.554 1和0.569 3，评价等级分属3、4等级，林分空间结构较理想。

Analysis and Evaluation of Spatial Structure of Natural Secondary Forest in Fushou Forest Farm

This paper analyzed and evaluated the spatial structure of natural secondary forest to provide theoretical basis for formulating reasonable measures of forest spatial structure optimization and reference template for spatial structure optimization and ecological function improvement of artificial forest.Taking the natural secondary forest occurring in Fushou Forest Farm of Pingjiang County of Hunan Province as the research object,indices such as angle scale,mingling degree and forest layer index were selected to analyze the spatial structure characteristics of the stand.The results showed that the average angle scale of stand was 0.45,the horizontal distribution of the trees was satisfactory,close to random distribution; the average mingling degree of the stand was 0.73,close to intensity mixing; the stand was rich in tree species,with good tree species mixing degree and strong stand stability; the average forest layer index was 0.42,the vertical structure of the stand had high stratification and good spatial utilization.The values of the stand spatial structure evaluation index of three sampled natural secondary forests were 0.624 8,0.554 1 and 0.569 3,respectively,which were within the ranges of level 3 and 4,and the stand spatial structure was ideal.