择伐对尖峰岭马占相思和杉木次生林林分空间结构的影响

Effects of selective cutting on stand spatial structure of Acacia mangium and Cunninghamia lanceolata secondary forest in Jianfengling

为探索尖峰岭次生林林分空间结构,研究择伐对马占相思和杉木次生林林分空间结构的影响,文章利用混交度、大小比数和角尺度等3种空间结构指标,分析尖峰岭马占相思、杉木次生林10块标准地的林分空间结构,并分别选取具有代表性的马占相思和杉木试验样地,择伐样地中的马占相思和杉木,分析择伐对次生林林分空间结构的影响。结果表明:(1)马占相思和杉木次生林混交度处于强度和极强度混交水平;从大小比数来看,林分以中庸状态为主;从角尺度来看,林分以团状分布为主。(2)两个试验样地均表明择伐可促进林分空间结构优化,林分空间结构比较不合理的,人为措施干预后,优化效果明显;林分空间结构较为稳定的,人为措施干预效果较弱。在生产实践中可根据不同林分的空间结构状态,针对性地采取措施促进林分结构优化和向顶级群落演替。

In order to explore the spatial structure of the secondary forest in Jianfengling,Hainan Province,and study the effect of selective cutting on the spatial structure of the secondary forest of Acacia mangium and Cunninghamia lanceolata,this paper analyzed the spatial structure of 10 standard plots of Acacia mangium and Cunninghamia lanceolata secondary forest in Jianfengling Branch of Tropical Rainforest National Park by using three spatial structure indexes,such as mixing degree,size ratio and angular scale.In addition,the effects of selection on the stand spatial structure of secondary forest were analyzed by selecting Acacia mangium and Cunninghamia lanceolata in one test plot respectively.The results showed that:(1)the mixing degree of Acacia mangium and Cunninghamia lanceolata secondary forest was at the level of intensity and extreme intensity mixing;From the point of view of size ratio,the stand was mainly in the middle state;From the Angle scale,the stands are mainly distributed in clumps.(2)Both experimental plots showed that selective cutting could promote the optimization of stand spatial structure.When the stand spatial structure was unreasonable,the optimization effect was obvious after human intervention.When the stand spatial structure was stable,the effect of human in-tervention was weak.In production practice,measures can betaken to promote the optimization of stand structure and the succession to the top community according to the spatial structure of different stands.