基于G/H极值约束的马尾松人工林自稀疏规律  

Self-thinning law of Pinus massoniana plantation based on G/H constraint

作　　者：杨盛扬 曾思齐[1] 张会儒[2] 谌红辉[3] 龙时胜 YANG Shengyang;ZENG Siqi;ZHANG Huiru;CHEN Honghui;LONG Shisheng(College of Forestry,Central South University of Forestry&Technology,Changsha 410004,Hunan,China;Experimental Center of Forestry in North China,Chinese Academy of Forestry,Beijing 102300,China;Experimental Center of Tropical Forestry,Chinese Academy of Forestry,Pingxiang 532600,Guangxi,China)

机构地区：[1]中南林业科技大学林学院,湖南长沙410004 [2]中国林业科学研究院华北林业实验中心,北京102300 [3]中国林业科学研究院热带林业实验中心,广西凭祥532600

出　　处：《中南林业科技大学学报》2022年第5期1-10,共10页Journal of Central South University of Forestry & Technology

基　　金：国家林业公益性行业科研专项(201504301)。

摘　　要：【目的】研究马尾松人工林的自稀疏规律,为构建林分最大密度线模型、研制林分生长过程表等经营数表、实现人工林的科学经营管理提供理论依据。【方法】以马尾松人工林为研究对象,对不同造林密度试验数据进行统计分析,建立郁闭状态下林分平均断面积与平均高、平均直径与平均高的相关模型,根据试验数据及所建模型中断面积生长率(P_(G))、树高生长率(P_(H))、直径生长率(P_(D))的变化趋势分析,提出郁闭林分达到一定阶段时存在两个极值的推论,并据此分析了在极值约束条件下的马尾松人工林自稀疏规律。【结果】林分在郁闭状态至自稀疏前马尾松林分断面积与平均高呈直线相关关系(G=a+bH),根据其生长过程中P_(G)>P_(H)>P_(D)的规律,进一步分析得出林分中存在两个极值:G/H与H/D。林分从郁闭至开始自稀疏的生长阶段,G/H比值是增加的,当达到自稀疏起点时,G/H达到极值点,此后林分会在极值状态下继续生长,自稀疏方向满足P_(G)=P_(H),按断面积比例计算的自稀疏率为β=2P_(D)-P_(H)。林分郁闭后,树高生长加快,树高生长率大于直径生长率,其H/D值增加,由树木的生物学特性所决定,H/D值在某一阶段会达到极值点,此后,林木在极值状态下继续生长,树高和直径的生长率相等,即P_(D)=P_(H),达到同速生长状态。【结论】林分之所以产生自稀疏是由于其G/H值的极值约束所决定的,不同初植密度的林分具有不同的G/H极值,初植密度越大,其G/H比值越大,达到自稀疏的时间越早;林分的H/D比值达极值点后,林木直径与树高由异速生长进入同速生长阶段,树木干形保持稳定。【Objective】The self-thinning law of Pinus massoniana plantation was studied to provide a theoretical basis for the construction of stand maximum density line model,the development of stand growth process table and other management tables,and realizing the scientific management of Pinus massoniana plantation.【Method】Taking Pinus massoniana plantation as the research object,the experimental data of forests with different planting densities was statistically analyzed,and the correlation models between the average cross-sectional area and the average height,average diameter and average height of trees were established.According to the experimental data and the analysis of the changing trend of basal area growth rate(P_(G)),the tree height growth rate(P_(H))and the DBH growth rate(P_(D))in the model,it was inferred that there are two extremes when the closed stand reached a certain stage.Based on this,the self-thinning law of Pinus massoniana plantation under extreme constraints was analyzed.【Result】From the canopy state to the beginning of sparseness,the stand basal area of the Pinus massoniana stand was linearly related to the average tree height:G=a+bH.According to the law of P_(G)>P_(H)>P_(D) during the growth process,it was further analyzed that there were two extreme values in the stand:G/H and H/D.The ratio of G/H increased from canopy closure to the self-thinning stage and reached an extreme point at the beginning of self-thinning.After that,the stand continued to grow in the extreme state.The self-thinning direction satisfied P_(G)=P_(H),and the self-thinning rate calculated according to the proportion of sectional area wasβ=2P_(D)-P_(H).After the stand was closed,the growth of tree height accelerated,which growth rate was greater than the DBH growth rate,and the H/D value increased.Determined by the biological characteristics of the tree,the H/D value will reach an extreme point at a certain stage.After that,the tree continued to grow in the extreme state,and the growth rates of tree height and

关 键 词：马尾松 人工林 极值 自稀疏 

分 类 号：S791.248[农业科学—林木遗传育种]