抚育采伐对吉林蛟河针阔混交林幼苗更新的影响

Effects of tending thinning on seedling regeneration in a mixed conifer-broadleaf forest in Jiaohe, Jilin Province of northeastern China

【目的】探究不同抚育采伐强度下吉林蛟河针阔混交林幼苗更新状况,为进行科学合理的森林经营提供理论依据和科学指导。【方法】以吉林蛟河4 hm^2采伐样地为基础,将100个2 m×2 m的幼苗样方中所有乔木树种幼苗作为研究对象,基于2018年7月至9月每月上旬的幼苗监测数据,比较不同采伐强度下样地内幼苗的物种组成、数量特征以及月际动态,采用单因素方差法分析抚育采伐对林下幼苗更新的影响。【结果】(1)调查期间共监测到幼苗948株,隶属10科12属19种。对照、轻度、中度和重度采伐下样地的物种丰富度分别为8、13、14、16,采伐后样地内幼苗的物种丰富度、辛普森指数、香农-威纳指数和均匀度指数都有显著提高。(2)不同采伐强度下样地内幼苗数量差异较大,轻度采伐样地和重度采伐样地的幼苗数量明显高于对照样地和中度采伐样地。采伐后幼苗不同龄级和高度级上数量的分布趋于均匀,随着采伐强度的增大,较大龄级和较大高度级上幼苗数量的比重逐渐增多。(3)采伐后样地内幼苗死亡率降低,增补率上升。不同采伐强度下幼苗的死亡率和增补率存在较大差异,其中重度采伐样地内幼苗的死亡率较低,轻度和中度采伐样地内幼苗的增补率较高。【结论】抚育采伐影响了林下幼苗更新。采伐后物种多样性指数显著提高。从林下幼苗更新数量来看,轻度采伐和重度采伐下幼苗更新数量较多。从林下幼苗生长状况来看,重度采伐下幼苗龄级分布和高度级分布更均匀,生长较好。

[Objective]This paper aims to explore the seedling regeneration status of a mixed coniferbroadleaf forest in Jiaohe,Jilin Province of northeastern China,and to provide a better guidance and theoretical basis for scientific and reasonable management.[Method]Based on 4 ha thinning sample land in Jiaohe,Jilin Province,with the seedlings of all tree species in 100 seedling plots(2 m×2 m)as the research object,we compared the species composition,quantity characteristics and monthly dynamics according to the seedling monitoring data from early June to early August in 2018.We used single factor anova to analyze the effect of thinning on undergrowth seedling regeneration.[Result](1)A total of 948 seedlings were found,belonging to 10 families,12 genus and 19 species.The species richness of the control,light,moderate and heavy thinning plots were 8,13,14 and 16,the Simpson’s diversity index,ShannonWeiner index and Pielou index of the seedlings were significantly increased after thinning.(2)The number of seedlings in the sample plot varied greatly under different thinning intensities,and the number of seedlings in the light thinning plot and the heavy thinning plot was significantly higher than control and the moderate thinning plot.After thinning,the number of seedlings in different age grades and height grades tended to be evenly distributed.With the increase of thinning intensity,the proportion of the number of seedlings in older age grades and higher height grades gradually increased.(3)The mortality rate of seedlings reduced and the supplementation rate increased after thinning and it had difference under different thinning intensities.The mortality rate of seedlings in heavy thinning sample plots was lower,while the supplementation rate in light and moderate thinning sample plots was higher.[Conclusion]Thinning affected the regeneration of undergrowth seedlings.The species diversity index was significantly increased after thinning.From the seedling number under the forest,the regeneration status was better under light and heavy thinning intensities.From the seedling growth under the forest,the distribution of seedling age grade and height grade was more uniform and the seedling growth was better.