造林密度对科尔沁沙地奈曼沙区小叶杨防护林林下植被的影响

Influence of Populus Simonii Planted Forest Density on Understory in Naiman Banner of the Horqin Sandy Land

[目的]探明科尔沁沙地南缘的奈曼旗沙区小叶杨(Populus simonii)防护林造林密度对林下植被的影响,提出适宜植被群落多样性恢复与稳定性发展的造林密度。[方法]以自然恢复状态下,林龄相近的3种典型造林密度类型(867~1022株/hm^(2),1444~1667株/hm^(2),2177~2322株/hm^(2))的小叶杨防护林为研究对象,开展每木检尺、物种组成与多样性、植被群落结构等调查,对野外采集数据进行统计分析。[结果]造林可以显著提高植被恢复与演替速度,造林密度的大小对林下植被多样性与群落稳定有显著影响,随着造林密度的减小,林下草本生物量、物种组成丰富度、物种多样性指数增大,植物恢复程度、群落稳定性上升;造林密度与林下物种多样性指数、物种数量、林下植被盖度、林下草本生物量等植被特征指标均呈现极显著负相关关系(p<0.01)。[结论]当小叶杨防护林造林密度为867~1022株/hm^(2)时,群落与未经开垦的草地样地的群落相似性最高,植被群落演替逐渐向地带性植被发展,与其他造林密度相比更有利于研究区物种多样性与群落恢复发展。

[Objective]In order to explore the influence of afforestation density of Populus simonii shelterforest in the Naiman Banner Sand area of the southern margin of the Horqin Sandy Land on the vegetation under the forest,the afforestation density suitable for the restoration and stable development of vegetation community diversity was proposed.[Methods]The shelter forest of Populus poplar with similar forest age(867~1022 plants/hm^(2),1444~1667 plants/hm^(2),2177~2322 plants/hm^(2))was taken as the research objects.The survey of each wood ruler,species composition and diversity,vegetation community structure was carried out,and the collected data in the field were statistically analyzed.[Results]Afforestation can significantly improve the rate of vegetation recovery and succession.The size of afforestation density has a significant impact on understory vegetation diversity and community stability.With the decrease of afforestation density,understory herbaceous biomass,species composition richness,species diversity index increase,plant recovery degree and community stability increase.There is a significant negative correlation between afforestation density and vegetation characteristics such as species diversity index,species number,understory vegetation cover,and understory herbaceous biomass(p<0.01).[Conclusion]The plantation with density of 867~1022 plants/hm^(2) has the highest community similarity with the uncultivated grassland site.The vegetation community gradually succeeds towards zonal climax vegetation.