福建明溪丝栗栲优势群落的结构稳定性

Stability analysis of dominant community structure of Castanopsis fargesii in Mingxi, Fujian

分别设置天然次生林(TCK)、轻度干扰林分(TCR)、强度干扰林分(TCQ)3种处理,通过分析群落的物种组成和径级结构、主要树种的重要值、种群年龄结构与类型、丝栗栲的混交度与角尺度等,探讨了福建省明溪县天然丝栗栲优势群落结构稳定性。结果表明,TCK处理林分表现出典型的中亚热带常绿阔叶林特征,群落结构较为稳定,呈现进展演替趋势,为成熟种群类型;优势树种丝栗栲的混交度均值为0.61,林木为强度混交,角尺度均值为0.528,林木呈团状分布,林木径级结构呈倒"J"型分布,后备资源优势明显。随着干扰强度增大,TCR、TCQ处理优势树种丝栗栲的混交度、角尺度降低,林木为中度混交,呈随机分布或均匀分布,后备资源优势受到削弱,群落遭到一定程度破坏,将威胁常绿阔叶林的生长进程,甚至导致群落出现逆行演替趋势。

Three treatments, i.e., natural secondary forest (TCK), slight disturbance forest (TCR) and strong disturbance forest (TCQ), were set up to analyze the species composition and diameter structure of the community, the important values of main tree species, the age structure and type of the population, the mixed degree and the angular scale of Castanopsis fargesii and to discuss the structural stability of the dominant community of C.fargesii in Mingxi, Fujian. The results showed that the TCK-treated stands showed typical characteristics of the mid-subtropical evergreen broad-leaved forest. The community structure was relatively stable showing a trend of progressive succession and overall performance of a mature population type. The mean mixing degree of C.fargesii was 0.61, the forest was mixed with intensity, trees are strength blending. The average angular scale was 0.528, the trees were cluslered, and the forest-diameter structure showed an inverted J-shap distribution, and the reserve resources had obvious advantages. With the increase of disturbance intensity, the mixed degree and angular scale of the dominant species of TCR and TCQ were decreased, and the trees were moderately mixed, showing a random or even distribution. The advantage of reserve resources was weakened, and the community was destroyed to some extent, which would threaten the growth process of evergreen broad-leaved forest and even lead to a retrograde succession trend of the community.