基于GIS的常绿阔叶林郁闭度与树冠重叠度分析

Analysis of Canopy Density and Crown Overlap of Evergreen Broad-Leaved Forest Based on GIS

探究常绿阔叶林郁闭度和树冠重叠度特征及其影响因子,可以揭示常绿阔叶林的结构特征,为其科学经营管理提供依据。以浙江省天目山自然保护区常绿阔叶林为研究对象,设置100m×100m大型固定标准地,进行每木调查,采用GIS技术和统计分析方法,分析常绿阔叶林郁闭度、树种郁闭度和树冠重叠度及其与林分因子、林木空间分布格局的关系。结果表明:1)天目山常绿阔叶林1hm^(2)标准地内的树种共有36科83种2625株胸径(DBH)≥5cm的树木,以壳斗科、山茶科、樟科等常绿树种为主;优势树种共有8科13种共计1755株。2)天目山常绿阔叶林林分郁闭度为0.81,树冠重叠度为203.55%,树种郁闭度与株数、树冠面积、胸高断面积之间具有显著的正相关关系。3)优势树种对林分郁闭度的贡献率达90.11%,以细叶青冈为主的壳斗科优势树种对林分冠层的影响最大,对林分郁闭度的贡献度达51.32%。4)林木空间分布格局是影响树冠重叠度的重要因子。

Exploring the canopy density and canopy overlap of the evergreen broad-leaved forest and their influencing factors can reveal the structure characteristics of the evergreen broad-leaved forest and provide basis for its scientific management.Taking the evergreen broad-leaved forest in Tianmu Mountain Nature Reserve of Zhejiang Province as the research object,a large fixed 100m×100m land was set up,and every tree survey was conducted.GIS technology and statistical analysis methods were used for data analysis including canopy density,canopy density of tree species,canopy overlap and their relationships with stand factors and trees distribution pattern.The results showed that:1)the 1hm^(2) standard in-ground tree species of the Tianmu Mountain evergreen broad-leaved forest had 36 families,83 species,and 2625 trees with DBH≥5cm.The dominant tree species were Fagaceae,Camellia,Lauraceae and other evergreen species.The dominant tree had 8 families,13 species,1755 trees in total.2)The canopy density of the evergreen broad-leaved forest in Tianmu Mountain was 0.81,and the canopy overlap was 203.55%.There was a significant positive correlation between the canopy density of tree species,the number of trees,the canopy area,and the cross-sectional area of breast height.3)The dominant tree species contributed 90.11%to the forest canopy density.The dominant tree species of Fagaceae,mainly Cyclobalanopsis glabra,had the greatest impact on the forest canopy,and contributed 51.32%to the forest canopy density.4)The spatial distribution pattern of forest trees wais an important factor that affected the degree of canopy overlap.