论文部分内容阅读
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,其中青冈的比例趋于增大
The dynamic characteristics of the evergreen broad-leaved forests (7-year-old, 20-year-old, 40-year-old and nearly mature forests) were investigated in four different developmental stages of Jiande Forest Farm in Zhejiang Province and northwest slope of Huangshan Mountain. The species composition of Cyclobalanopsis glauca forest at different developmental stages is characterized by the dominant Cyclobalanopsis glauca and other evergreen species with a certain proportion of deciduous components. The leaf area of the community was higher than the 20th instar at the 7th instar, and gradually increased after the 20th instar, reaching 12-8 in the near-mature forest. Individual density and species number were highest at 7th instar in tree layer, vines and herbaceous layer, while the understory layer lacking in 7th instar layer showed an upward trend in the latter 3 stages. The Shannon - Wiener index of tree layer, wood layer and herb layer in the four stages were 3-32 ~ 4-88, 3-59 ~ 4-14, 1-14 ~ 2-36, respectively. The dynamics and structure and species number similar. The dominant species, Cyclobalanopsis glauca, can initiate on the cutting tracks and make the community quickly enter the stage of evergreen broad-leaved forest by means of compressional succession. Due to the age, the seed bank was destroyed, seed germination and seedling growth need certain light conditions and other reasons, did not produce enough seedlings and saplings in time, the population of the genus Cyclobalanopsis at age 40 still lack age-class individuals, the size of its base The class structure is often spindle-shaped, allowing for the production of clonal ramets and shoots as a complement to space occupancy. Thereafter, depending on the status of habitats, it may reproduce both sexually and asexually to consolidate its dominance. The biomass and growth of forest layer increased with the development of community, and the proportion of Cyclobalanopsis glauca tended to increase