茂兰喀斯特森林林隙树种更新及其与环境的相关性分析

Tree Regeneration and Its Relationship with Environment in Gaps of Karst Forest in Maolan Nature Reserve,Guizhou Province

通过对茂兰喀斯特森林林隙更新状况及林隙环境特征的调查,分析了茂兰喀斯特森林主要树种在不同大小和年龄林隙中的更新密度、无性繁殖特征以及林隙特征、立地条件等因素对树种更新密度的影响。结果表明:不同树种的更新密度随林隙大小的变化因树种的耐荫性强弱而存在差异,表现为耐荫性较强的树种在小面积林隙中更新密度较大,而耐荫性较弱树种在大面积林隙中更新密度较大;主要树种的更新密度随林隙年龄的变化曲线有单峰型和双峰型两种类型,可用多项式进行最好的拟合;大部分树种在林隙中的萌枝率较非林隙中的高,无性繁殖的幼苗数量随林隙面积的增大而增多,随林隙年龄的增大而减少,表明林隙的形成对喀斯特森林的无性繁殖也有显著的促进作用,无性繁殖亦是喀斯特森林的重要更新对策;林隙面积、年龄、枯落物厚度及小生境类型等是林隙树种更新的主要影响因子。

On the base of investigation on regeneration of main trees and environmental characters in gaps of karst forest in Maolan,regeneration density,agamogenesis features of trees in gaps of different sizes and developmental stages and the relationship between tree regeneration and gap traits were studied.The results showed that regeneration density of trees in different size gaps were quite different because of their shade tolerance traits,regeneration density of shade tolerance trees was much in small gaps and non-shade tolerance trees was much in large gaps.There were two types of response curves of regeneration density changes of main trees with gap ages.i.e.the unimodal and double modal.They could be simulated with a multinomial.The rate of germs of most trees was much in gaps than in non-gaps and the number of agamogenesis seedlings became much with gap sizes-but became less with gap ages.Calculation and analyses showed that gaps could also promote agamogenesis of karst forest greatly,and agamogenesis was an important regeneration strategy of karst forest to adapt to gap disturbance.Gap size,gap age,coarse debris depth and microhabitat were main factors relation to regeneration of trees in gaps.