吉林省汪清林业局云冷杉天然林结构特征研究

以云冷杉天然林为研究对象，利用固定标准地1986—2011年间13次调查数据，对其树种组成、直径结构、年龄结构、立木空间结构以及对林分结构有重要影响的天然更新等进行研究。结果表明:针阔混交比稳定在5∶5，林分株数径阶分布曲线呈倒“J”型，林分属于成过熟林。平均混交度为083，即不同树种呈现强度混交结构状态，群落结构非常复杂。根据林层划分条件，乔木层可分为上林层(树高≥17 m)、中林层(12 m＜树高＜17 m)和下林层(树高≤12 m)。历年更新调查的结果显示:平均更新幼苗株数为4 328株/hm2，能够满足更新需要，但1988—2011年更新苗株数呈减少趋势；更新树种主要为冷杉、红松和云杉。 

Structural characteristics of natural spruce-fir forest in Wangqing Forestry Bureau of Jilin Province, northeastern China.

This study focused on the 0.2 hm2 plot of natural spruce-fir forest in Wangqing Forestry Bureau of Jilin Province,northeastern China,and the investigation data from 1986 to 2011 were used to analyze the forest structural characteristics by composition of species,diameter structure,age structure,spatial structure and natural regeneration.Results showed that the species composition of conifer and broadleaf with the proportion of 5:5 was stable.The diameter grade and number distribution were expressed in a reverse letter "J" and the forest was mature and over-mature.The forest community structure was complex with different species mixed strongly,and its mingling degree was 0.83.The tree storey was divided into upper storey (tree height≥17 m),middle storey (12 m