自然与人工恢复对川西高山采伐迹地植物群落特征的影响

以天然林为对照,选取自然恢复(40年)与人工恢复(30、40和50年)下川西高山采伐迹地,研究不同恢复途径下川西高山采伐迹地的植物群落特征。结果表明: 采伐迹地经过40年的自然恢复演替成为高山绣线菊次生灌丛,人工恢复后成为川西云杉林,与天然林群落相似性分别为极不相似(0.19)和中等不相似(0.28~0.49)。自然与人工恢复采伐迹地的灌木层物种多样性均低于天然林,而草本层高于天然林。随着恢复年限的增加,人工林胸高断面积、蓄积量、径级幅度、物种多样性指数及与天然林群落的相似性均呈现增加的趋势,而林分密度逐渐减小。人工林面临林分密度较高、结构不合理、同龄纯林和林下更新差等问题。

Effects of natural and artificial restoration on plant community characteristics of alpine cutting blank in Western Sichuan,China

To investigate the plant community characteristics of alpine cutting blanks under different restoration approaches,we conducted a field survey on cutting blanks experienced either natural restoration(40 years)or artificial restoration(30,40 and 50 years)in western Sichuan,with natural forests as the reference.Our results showed that after 40 years natural succession,cutting blank was replaced by the secondary shrub of Spiraea alpina,while artificial restoration plantation was dominated by Picea likiangensis var.rubescens.The similarity indices between these communities and natural forests were low(0.19)and medium(0.28-0.49),respectively.Cutting blank through natural and artificial restoration had lower species diversity in the shrub layer but higher diversity in the herb layer than that of natural forests.With the increases of recovery time,total cross-sectional area at breast height,wood volume,index of species diameter class distribution,diversity indices,and similarity indices between plantations and natural forests gradually increased,while stand density gradually decreased.Compared with natural forests,plantations were facing with problems including high stand density,unreasonable structure,pure stands of cohorts and poor regeneration.