中文摘要：

可变竞争区域类竞争指标根据对象木某个描述型指标函数确定竞争区域；而树冠在树木的生长过程中具有重要的作用，并且反映了树木的长期竞争水平，根据这两种思想提出一种新的竞争可变区域类竞争指标——树冠影响度。采用典型选样法设置研究样地，并对样地内树种的各个测树因子进行调查统计，应用树冠影响度对数据进行分析讨论，结果显示：样地树种平均树冠影响度为0．3594，样地中群落竞争相对较弱，群落结构相对稳定，其中马尾松（Pinus massoniana）的树冠影响度最小，为0．2613；枫香（Liquidambar formosana）的树冠影响度最大，为0．5101。优势种群树种平均树冠影响度小于非优势种群树种，优势种群受到的竞争较小，竞争能力较强，针叶树种平均树冠影响度小于阔叶树种树种，针叶树在群落中处于优势地位。

英文摘要：

Variable competitive region （VCR） is determined by exponential function based on a description indicator of the objects. Crown has an important role in tree growth, and reflects the level of tree competition in the long term. A new competitive index of VCR was proposed： competition degree of crown. Using typical sampling method to establish sample plot, and each factor of tree species was investigated. Analysis by competition dgree of crown showed that the average competition degree of crown in the plot was 0.3594, the competition of populations in the plot was relatively weak, indicating that the community structure was relatively stable. Competition degree of the crown ofPinus massoniana （0.2613） was the smallest and that of Liquidambarformosana （0.5101）.was the largest. The average competition degree of the crown of dominant species was less than that of non-dominant species. Competitive ability of dominant species was stronger. The average competition degree of the crown of coniferous trees was less than that of broad-leaved trees, coniferous trees were in a dominant position in the commuriity.