间伐和套种对尾叶桉人工林物种多样性的影响

The Effect on Species Diversity of Eucalyptus urophylla Plantation by Thinning and Interplanted with Broad-leaved Tree

在东莞大岭山实验场对12年生的尾叶桉(Eucalyptus urophylla)人工林进行间伐和套种改造,设3种间伐强度(30%、70%、100%)处理,间伐后均套种阔叶树种,以不间伐纯林为对照;改造7 a后,比较不同间伐强度套种改造模式对群落物种组成、物种多样性和林分生长状况的影响。结果表明:与对照林分相比,乔木层的物种数明显增加,灌草层物种数差异不大,但其优势种有所变化;改造后各处理乔木层物种丰富度、Shannon-Wiener指数和草本层Pielous指数均高于对照,灌木层Shannon-Wiener指数和Pielous指数有所下降。整体来看,以间伐100%处理组的物种多样性指数最高,间伐70%处理组次之。林分套种树种的平均树高、胸径和胸高断面积均随着间伐强度的增大而增大;高强度改造(间伐100%)的尾叶桉人工林适合套种米老排和亮叶猴耳环等树种,该间伐套种模式能促进套种树种生长和林分天然更新能力。

The experiment sites are Eucalyptus urophylla plantations stands under thinning and interplanted transformation,with three thinning density（30%,70% and 100%） and un-thinning stand was served as the control（CK） in Daling Mountain of Dongguan.Many broad-leaved species were inter-planted into the stands.The impact of different thinning densities and interplanted on community composition,species diversity and growth status were studied.The results showed that after seven years of transformation,compared to CK site,the species numbers in overstory layer was highly increased,and these was no significant different in understory layer and herb layer,while the dominant species in understory layer and herb layer varied after thinning between treatments and CK.The richness index and Shannon-Wiener index in overstory and Pielous evenness index in the herb layer were higher than that of CK,while Shannon-Wiener index and Pielous evenness index were decreased.Overall,the species diversity was highest in the 100% thinning intensity treatment,followed by 70% thinning density.The mean height,DBH and basal area were significantly increased with the thinning intensities.Mytilaria laosensis and Pithecellobium lucidum were good for inter-planted in the high thinning intensity during transformation of Eucalyptus urophylla plantation.That model could promote the tree growth and accelerating forest vegetation.