青冈常绿阔叶林群落动态研究

DYNAMICS OF AN EVERGREEN BROAD-LEAVED FOREST DOMINATED BY CYCLOBALANOPSIS GLAUCA IN SOUTHEAST CHINA

研究了分布于浙江建德林场和黄山西北坡４ 个不同发育阶段青冈常绿阔叶林（７ 龄林、２０ 龄林、４０龄林和近熟林） 的动态特征。青冈林在不同发育阶段的种类组成体现出以青冈和其它常绿种类占优势，并伴有一定比例落叶成分的特征。群落的叶面积７ 龄时比２０ 龄高，２０ 龄后逐渐增大，近熟林中达１２－８ 。个体密度和物种数在林木层、藤本植物和草本层中以７ 龄时为最高，７ 龄林中缺乏的下木层则在后３ 个阶段中呈上升态势。４ 个阶段林木层、下木层和草本层的Ｓｈａｎｎｏｎ － Ｗｉｅｎｅｒ 指数分别为３－３２ ～４－８８ 、３－５９ ～４－１４ 、１－１４ ～２－３６ ，其动态与结构和物种数相似。优势种青冈能在采伐迹地上萌生，使群落以压缩演替的方式快速步入常绿阔叶林阶段。由于年龄较小、种子库遭破坏、种子萌发和幼苗生长需一定的光照条件等原因，没及时产生充足的幼苗和幼树，青冈种群在４０ 龄左右尚缺低龄级个体，其基株的大小级结构往往为纺锤形，使之以产生克隆分株和萌生枝作为对空间占有的补充。此后，根据生境状况，它可能通过有性和无性两种方式进行繁殖，以巩固其优势地位。林木层生物量和生长量随着群落的发育而增加。

Dynamics of evergreen broad-leaved forests dominated by \%Cyclobalanopsis glauca\% in Zhejiang, China was studied. Species composition of the forests indicated that it was dominated by evergreen species with fairly proportion of deciduous species in all four stages. LAI of the forest tree layers was bigger in 7 years forest than that of 20 years forest, and it increased gradually after 20 years. Diversity of the individuals and amount of species of trees, subtrees, liana and herbs were highest in 7 years. Shannon-Wiener index of tree, subtree, and herb layer in four stages was respectively 3 32～4 88\,3 59～4 14\,1 14～2 36,and its dynamic characteristics was similar to that of the community structure and species numbers. \%C.glauca\% can germinate fast in the cutover land, it is dominant in the 7 years young forest. Because of this, the community demonstrates condensed succession to go to the phase of evergreen broad-leaved forest quickly. \%C.glauca\% population was short of seedlings and saplings and its size class structure shows as spindle shape in 40 years, the reasons for this were: the population age was young, the seed pool was destroyed by animals and microbes, sprouting of seeds and growing of seedlings needed certain conditions such as light, temperature, and humidity' etc.. To fill up the vacancy of seedlings and saplings, mother ramets can grow a lot of daughter ramets and sprouted branches. In the later stages, it may be propagated by sexual and/or asexual ways according to the habitat to consolidate its dominant position. Biomass, growth-yield of tree and subtrees layers increased with the development of community.