林隙对小兴安岭阔叶红松林树种更新及物种多样性的影响

Effects of forest gap on tree species regeneration and diversity of mixed broadleaved Korean pine forest in Xiaoxing'an Mountains

研究了小兴安岭阔叶红松林不同林隙梯度（林隙中心、林隙近中心、林隙边缘）中主要树种的数量特征,以及林隙大小对树种更新的影响.结果表明：不同梯度林隙内灌木树种的密度均明显高于非林隙,同种灌木密度的比值在1.08~18.15之间;随林隙面积增加,乔木幼苗更新密度逐渐增大,幼树Ⅰ（高度H≥1 m,胸径DBH≤2 cm）和幼树Ⅱ（H≥1 m,2 cm〈DBH≤5 cm）的更新密度呈多峰曲线.林隙灌木总体更新密度主要随幼苗和幼树Ⅰ数量而变化.林隙内不同位置幼苗的平均树高、平均基径、种密度和个体密度有所差异.从林隙中心到非林隙,更新层乔木幼苗重要值的大小顺序为：林隙中心〉林隙近中心〉林隙边缘〉非林隙;物种均匀度呈高-低-高的变化,物种多样性的变化为早期林隙〉中期林隙〉晚期林隙.

This paper studied the quantitative characteristics of main tree species along a forest gap gradient（gap center-near gap center-gap border） of mixed broadleaved Korean pine forest in Xiaoxing＇an Mountains,as well as the effects of forest gap size on the regeneration of the tree species.In forest gap,the density of shrub species was obviously larger than that in non-gap,and the density ratio of the same shrub species in forest gap to in non-gap ranged from 1.08 to 18.15.With the increase of gap size,the regeneration density of tree seedlings increased,and that of saplingⅠ（H≥1 m,DBH≤2 cm） and saplingⅡ（H≥1 m,2 cmDBH≤5 cm） exhibited multiple peak curve.The overall regeneration density of shrubs in forest gaps varied mainly with the amounts of tree seedlings and saplingⅠ.The mean height,mean basal diameter,species density,and individual density of trees in different locations of forest gaps were all different.From gap center to non-gap,the importance value of tree species seedlings in regeneration layer was ranked in gap center near gap center gap border non-gap,the tree species evenness presented a variation of high-low-high,and the species diversity decreased in the order of early phase gap mid phase gap late phase gap.