马占相思优势木择伐对林下灌木多样性的影响  

Impact of selective logging of dominant Acacia mangium trees on understory shrub diversity

作　　者：杨佳 彭文成 廖立国 王如 段左俊 YANG Jia;PENG Wencheng;LIAO Liguo;WANG Ru;DUAN Zuojun(Hainan Academy of Forestry,Haikou 571100,Hainan,China)

机构地区：[1]海南省林业科学研究院(海南省红树林研究院),海南海口571100

出　　处：《中南林业科技大学学报》2024年第4期18-27,共10页Journal of Central South University of Forestry & Technology

基　　金：海南省省属科研院所技术开发专项技术创新类项目(SQKY2022-0028);国家自然科学基金地区科学基金项目(32260106)。

摘　　要：【目的】择伐是促进林下灌木生长与更新的有效手段,分析马占相思优势木择伐对林下灌木多样性影响效果与范围,构建影响范围预估模型,对制定科学合理的马占相思林择伐技术具有重要指导意义。【方法】以海南省南崖林场76株马占相思优势木为研究对象,开展优势木择伐试验(监测年限为2014—2021年)。通过设置不同样圆大小(0.6倍冠幅、0.8倍冠幅、1.0倍冠幅、1.2倍冠幅、1.4倍冠幅)的优势木影响半径,比较与确定马占相思优势木的最大影响范围,分析不同恢复年限对林下灌木多样性的影响,构建马占相思优势木的影响范围预估模型。【结果】马占相思优势木影响灌木Shannon指数和Pielou指数的最大影响范围分别为1.0倍实测冠幅和1.2倍实测冠幅;马占相思优势木择伐能显著提高林下灌木多样性(P<0.05),通常灌木Shannon指数和Pielou指数在择伐后的5年内显著增加(P<0.05),5年以后的增幅不明显(P>0.05);影响灌木Shannon指数和Pielou指数的范围预估模型均以理查德式为最优,其决定系数均为0.702,相对均方根误差均为14.341%。【结论】从单木影响范围的角度分析马占相思优势木择伐对林下灌木多样性的影响,优势木择伐在一定范围和一定年限内可以显著改善林下灌木多样性,且最大影响范围与马占相思优势木的胸径大小密切相关。研究结论可以为后续马占相思林的密度控制以及林分改造提供有效指导。【Objective】Selective cutting is a powerful tool to promote the growth and regeneration of understory shrubs.Analyzing the effect and extent of selective cutting of dominant Acacia mangium trees on shrub diversity,and constructing a predictive model for the influence range,can provide significant guidance for establishing scientifically sound selective cutting techniques for A.mangium forests.【Method】76 dominant A.mangium trees in Nanya Forestry Farm,Hainan province,were studied through a selective cutting experiment(monitored from 2014 to 2021).By setting up different plot sizes(0.6 times crown radius,0.8 times crown radius,1.0 times crown radius,1.2 times crown radius,1.4 times crown radius),the maximum influence range of A.mangium trees was determined,and the influence on understory shrub diversity across different recovery periods was analyzed,so as to construct a predictive model for the influence range of dominant A.mangium trees.【Result】The maximum influence range of dominant A.mangium trees on shrub Shannon index and Pielou index were 1.0 times measured crown width and 1.2 times measured crown width,respectively.Selective cutting of A.mangium trees significantly increased understory shrub diversity(P<0.05),with usual shrub Shannon index and Pielou index significantly increasing within 5 years after cutting(P<0.05),and the increase rate being not obvious after 5 years(P>0.05).The predictive models for the influence range of the shrub Shannon index and Pielou index are best represented by Richards’curves,with their respective determination coefficients amounting to 0.702,and root-mean-square percent errors being 14.341%.【Conclusion】The selective cutting of a single A.mangium tree significantly improves understory shrub diversity within a certain range and over a certain period,and its maximum influence range is closely related to the breast height diameter of the A.mangium trees.These findings can provide effective guidance for subsequent density control and reformation of A.mangium forests

关 键 词：冠幅 物种多样性 择伐 预估模型 马占相思 

分 类 号：S718.54[农业科学—林学]