立地及密度对杉木林分生长及材种结构的影响
Effects of Site Quality and Stand Density on Growth and Timber Grade Structure of Chinese fir forest
[目的]明确广西融江河流域杉木人工林的立地及密度对林分生长量及材种结构的影响。[方法]以广西融江河流域不同立地条件下的杉木良种林分为研究对象，造林后分别于第 5 年和第 10 年对林分进行间伐抚育，第二次间伐后的林分保留密度分别为1 005、1 380、1 755和2 025 株·hm-2，于 13年生时对林分进行生长量调查和统计分析。[结果]立地质量越好，林分树高、胸径、蓄积量、中径材出材率以及规格材(原条)、薪材和废材出材量越高，且当立地指数级越高时，立地指数提升一级所带来的树高和中径材出材率增幅越大;在该林龄阶段，较高立地指数(20和22)的林分开始出现大径材，说明立地质量越好，大径材形成的时间越早。随林分密度的减小，14 径阶林木株数占比减少，18 和≥20 径阶的林木株数占比增加，小径材出材率减少，中径材出材率增加，林分密度降低有利于中、高径阶林木的产出;林分密度的减小极显著降低了林分蓄积量，但规格材(原条)出材量却呈递增趋势。[结论]立地质量越好，大径材形成的时间越早，高规格材的产出越高，林分密度降低促进规格材产出，提高林分单位面积经济效益。
[Objective]The aim of this study was to investigate the effect of site and density of Chinese fir plantation on stand growth and species structure in Rongjiang River basin of Guangxi.[Method]The Chinese fir plantations under different site conditions in the Rongjiang River valley of Guangxi were thinned twice at 5 years of age and 10 years of age,and the stand densities after the second thinning were 1 005,1380,1755 and 2 025 trees·hm-2,respectively.The growth of stands were investigated and statistically analyzed at 13 years of age.[Result]The results showed that the stands with better site quality obtained higher stand height,DBH,stand volume,medium-diameter timber yield,as well as dimension timber(original trunk),fuelwood and waste timber yield,When the site index level is higher,the increase of tree height and medium diameter timber yield will be greater.In this age stage,the stands with higher site index(20 and 22)began to show large diameter wood,indicating that the better the site quality,the earlier the formation of large diameter wood.With the decrease of stand density,the proportion of 14 diameter trees decreased,the proportion of 18 and≥20 diameter trees increased,the output rate of small-diameter timber decreased,the output rate of medium-diameter timber increased,and the decrease of stand density was beneficial to the yield of middle and high diameter trees.The decrease of stand density significantly reduced the stand volume,but the output of dimension timber(original trunk)showed an increasing trend.[Conclusion]The better the quality of the site,the earlier the formation time of large-diameter material,the higher the output of high-specification material.The decrease of stand density was beneficial to dimension timber(original trunk)output and increased the economic benefit per unit area.
陈琴;董利军;黄开勇;段爱国;戴俊;胡建军;余代渊;林丽;
广西壮族自治区林业科学研究院,广西 南宁 530002##中南速生材繁育国家林业和草原局重点实验室,广西 南宁 530002##广西优良用材林资源培育重点实验室,广西 南宁 530002;融水苗族自治县国营贝江河林场,广西 融水5453003;广西壮族自治区林业科学研究院,广西 南宁 530002##中南速生材繁育国家林业和草原局重点实验室,广西 南宁 530002##广西优良用材林资源培育重点实验室,广西 南宁 530002;中国林业科学研究院林业研究所,北京,100091;广西壮族自治区林业科学研究院,广西 南宁 530002##中南速生材繁育国家林业和草原局重点实验室,广西 南宁 530002##广西优良用材林资源培育重点实验室,广西 南宁 530002;融水苗族自治县国营贝江河林场,广西 融水5453003;融水苗族自治县国营贝江河林场,广西 融水5453003;融水苗族自治县国营贝江河林场,广西 融水5453003;
artificial forest Chinese fir output site index stand density
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