间伐强度对白龙江林区云杉人工林下植物多样性及其更新的影响

调查了粗枝云杉(Picea asperata)人工林间伐后和未间伐的林分生长、林下植物和幼苗种类、数量、盖度及高度，采用物种丰富度、Shannon-Wiener指数、Simpson指数和Pielou均匀度指数进行多样性分析，以探讨间伐强度对云杉人工林下植物多样性及其更新的影响。结果表明，随着间伐强度的增大，保留木的生长显著优于对照区(P0.05)，林下植物种类和数量明显增加;不同间伐强度的林下植物多样性、丰富度、生物量和盖度等都显著高于对照区，且随间伐强度的增强而增大;幼苗密度、多样性、丰富度及其高度也随着间伐强度的增强而增大，且幼苗在各个径级都有分布。幼苗与生境条件的相关分析结果显示，光照和枯枝落叶层厚度是影响间伐林地幼苗生长的主要因素。

Effects of thinning intensity on diversity of undergrowth vegetation and regeneration in artifical spruce forest

In order to explore the effects of pre-and post-thinning intensity on undergrowth vegetation and regeneration in artificial spruce (Picea asperata) forest,species number,coverage,height of vegetation and seedling were investigated.Species richness,indices including Shannon-Wiener,Simpson and Pielou were analyzed to study plant diversity in this study.The results showed that the reserve trees growth with thinning were better than those control ones (without thinning) and species number of undergrowth vegetation with thinning plots increased significantly.With thinning intensity increased,the species richness,biomass and coverage of undergrowth vegetation also increased,and the most heavy thinned stands (450 stem·ha-1) showed the highest value of each index.The density,species richness,and height of seedling increased with thinning intensity.In heavy thinning intensity plots,tree seedling with all size classes distributed which did not observed in other plots.There was significant positive correlation between light and seedling diversity,density and richness,while the thin layer may have negative effects on them in thinning intensity plots.In this study,herbaceous coverage was observed to be the important factor in seedling richness and seedling density.