华北落叶松混交林林下植物群落特征对间伐的响应

The Effects of Different Thinning Intensities on the Understory Vegetation Characteristics of Mixed Forests of Larix principis-rupprechtii

为探究提高华北落叶松混交林生物多样性的抚育措施,通过对北京市京西林场对照区(Ⅰ)、弱度间伐(Ⅱ)、中度间伐(Ⅲ)和强度间伐(Ⅳ)4种间伐强度下的华北落叶松混交林林下植物群落调查和监测,分析其林下植被变化特征。结果表明,4种间伐强度下,林下灌木种类分别为5、7、7、6种,草本种类分别为11、11、10、12种,共有物种包括山楂叶悬钩子、榛、绣线菊、溲疏、野青茅、苔草和假还阳参;随着林分郁闭度减小,灌木和草本数量增加,中度抚育强度样地(Ⅲ)中灌木数量最多,强度间伐样地(Ⅳ)中草本数量最多;随着间伐强度增加,喜光灌木如六道木、接骨木、连翘增多,凸显阳光对植被影响;不同抚育强度下灌木和草本植被重要值排序不同;灌木层中,绣线菊、牛叠肚在4种间伐强度样地中重要值均排前三,荆条仅在对照区(Ⅰ)中重要值排前三,连翘仅在强度间伐样地(Ⅳ)中重要值排前三,草本层中,野青茅在弱度、中度间伐强度均重要值排前三,尤其在强度间伐样地(Ⅳ)中,重要值达到37.16;物种多样性、群落相似性和林下物种多样性评估表明,不同抚育强度影响物种组成和多样性,高强度间伐有助于提高多样性,尤其是在草本层。研究结果为优化华北落叶松混交林抚育策略以提升生物多样性的保护效果提供重要参考。

In order to explore the management measures to improve the biodiversity of mixed forest of Larix principis-rupprechtii,through investigations and monitoring of understory plant communities in mixed forests of Larix principis-rupprechtii subjected to four different thinning intensities-control group(Ⅰ),light(Ⅱ),moderate(Ⅲ)and heavy(Ⅳ)-within the Beijing Forest Farm,this study analyzed variations in understory vegetation.Results revealed that under the four thinning intensities,the number of understory shrub species were 5,7,7,6 respectively,while herbaceous species were 11,11,10,12,respectively.Shared species encompass species included Rubus crataegifolius,Corylus heterophylla,Spiraea salicifolia,Deutzia scabra,Deyeuxia pyramidalis,Carex tristachya Thunb.,and Crepidiastrum lanceolatum.As the forest canopy closure decreased,the number of shrubs and herbaceous plants increased.In the moderate thinning intensity plots(Ⅲ),the number of shrubs was the highest,while in the heavy thinning intensity plots(Ⅳ),the number of herbaceous plants was the highest.Increased thinning intensity prompted a rise in light-loving shrubs such as Zabelia biflora,Sambucus williamsii,and Forsythia suspensa,underscoring the sunlight's impact on vegetation.Significant variations were observed in the ranking of importance values of shrubs and herbs across different thinning intensities.Notably,species like Spiraea salicifolia and Rubus crataegifolius consistently ranked among the top three in all intensities.However,Corylus heterophylla only appeared in the top three at control group(Ⅰ),while Forsythia suspensa was exclusive to heavy thinning(Ⅳ).In the herbaceous layer,Deyeuxia pyramidalis ranked among the top three in light and moderate intensities,with a particularly high value of 37.16 in the heavy intensity(Ⅳ).Analysis of species diversity,community similarity,and understory diversity suggested that different thinning intensities influence species composition and diversity,increased thinning intensity positively impacted diversity,especially in the herbaceous layer.The results of this study provide an important reference for optimizing the management strategy of mixed larch forest of Larix principis-rupprechtii to improve the conservation effect of biodiversity.