百山祖北坡中山常绿阔叶林的物种组成和群落结构

在浙江庆元县百山祖北坡常绿阔叶林群落内,设置面积为5 hm2的固定样地,应用相邻格子法划分样地并进行每木调查获得野外资料.通过对群落内物种组成和群落结构的研究表明:①群落内物种丰富,区系复杂,仅含1种的科、属多,常绿树种短尾柯、多脉青冈为建群种,故可称为短尾柯-多脉青冈群落;②从物种的地理分布区类型看,该群落具一定的热带性质,但温带成分仍占较大比例,反映出中亚热带北部亚地带中山常绿阔叶林的植被属性;③从物种多样性看,稀有种丰富,优势种亦十分明显,但多度分布不均;④群落幼苗储备量大,更新良好,但由于竞争激烈,加之台风等自然因素的干扰,胸径超大个体稀少;直径频度呈指数分布,反映出立木在垂直空间上连续分布,且该群落处于演替的成熟阶段;⑤群落层次结构比较复杂,分层不明显:几个优势种分布在不同的两个乔木亚层,一定程度上减少竞争;乔木上层树冠不连续,下层连续郁闭度较高;灌木层密度大,物种丰富,是群落幼苗库;草本层比较稀疏但物种丰富,以蕨类和苔草属植物为主;藤本植物多样,草质木质均有,但大型个体稀少,层间附生植物主要是石韦、瓦韦、膜蕨和一些兰科植物,显示出中亚热带常绿阔叶林的特点.

Floristic composition and community structure of mid-montane evergreen broad-leaved forest in north slope of Baishanzu Mountain

A 5 hm2 permanent plot was established in an evergreen broad-leaved forest,which lies in the north slope of Baishanzu Mountain,Qingyuan of Zhejiang.Using contiguous grid quadrat method,extensive field data were obtained and analysis of floristic composition and community structure showed as following,(i) Two evergreen species,Lithocarpus brevicaudatus and Cyclobalanopsis multinervis are the constructive species within the species-rich community.(ii) Areal-type of species suggests that the forest is highly related to tropic components,while temperate components still occupy fairly high percentage.It indicates that the forest is a mid-montane evergreen broad-leaved forest in the northern subzone of the middle subtropic.(iii) Lots of rare-species exist in the community,and the dominance of the dominant species is high,but the distribution of abundance is uneven.(iv) Large amount of seedlings and saplings exhibit good regeneration,and as a result of the effects of intraspecific and interspecific competition,few individuals have super diameter at breast height(DBH).Distribution of the diameter's frequency is detected as exponential distribution,which indicates the stems are continuous distribution on the vertical space,and the community is on the climax stage of succession process.(v) Community structure is complex,and the delamination is not obvious.The dominant species distribute in different two sub-layers of trees,and it lessens competition on a certain extent.Upper canopy is discontinuous,and it is far from the under-layer.The dense shrub-layer contains many species,and it is the seedling pool of the community.Herb-layer is sparse but with rich species,and liana is various but lack of large individuals.In conclusion,this community is a typical middle subtropical evergreen broad-leaved forest.