竞争与优势木平均高主导驱动闽西北杉木幼龄林单木生物量OA
Competition and Dominant Height as Primary Drivers of Individual-Tree Biomass in Young Cunninghamia lan-ceolata Plantations,Northwestern Fujian
为揭示坡位影响杉木单木生物量的内在驱动机制,以 8 年生杉木(Cunninghamia lanceolata)人工林为研究对象,分析了坡位对林木表型性状、空间结构、竞争强度及生物量的影响.在坡向与坡度保持基本一致的条件下,设置上坡、中坡和下坡 3 个坡位处理,对固定样地开展每木检尺,并结合异速生长方程对生物量进行估算.通过逐步回归和分段结构方程模型,量化各变量因子对杉木人工林生物量的影响.结果表明:①坡位对胸径、枝下高和树冠半径等表型性状具有显著影响(P<0.05),并进一步改变了邻木竞争强度和空间结构,从而影响杉木的生长过程与生物量分配机制.其中,下坡位的单木生物量最大,且其生物量在各器官间的分配模式与上坡和中坡存在明显差异.②逐步回归模型的确定系数、均方根误差和平均绝对误差分别为 0.853、6.554 kg 和 4.882 kg,筛选出的变量包括树冠半径(CR)、竞争指数 CI8、直径大小分化度(T_Udm)和优势木平均高(Hdom).③分段结构方程模型中,各变量对单木生物量的路径系数绝对值从大到小依次为 CI8(-0.945)、Hdom(0.456)、CR(0.055)、T_Udm(-0.029);CI8 和优势木平均高是单木生物量的主导驱动因子.④在后续经营中,可通过合理抚育间伐调控邻木竞争压力,并结合土壤肥力提升措施,有效促进杉木幼龄林的生长发育.
To reveal the intrinsic driving mechanism by which slope position affects individual-tree biomass of Cunninghamia lanceolata,an 8-year-old C.lanceolata plantation was selected as the research material to analyze the effects of slope posi-tion on tree phenotypic traits,spatial structure,competition intensity and biomass.Under nearly identical slope aspect and gradient,three slope position treatments(upper slope,middle slope and lower slope)were established.A full tree inven-tory was implemented in permanent plots,and tree biomass was estimated using allometric growth equations.Stepwise re-gression and piecewise structural equation model were adopted to quantify the effects of various variables on biomass of the C.lanceolata plantation.The results showed that:(1)Slope position exerted significant effects on phenotypic traits inclu-ding diameter at breast height,height to crown base and crown radius(P<0.05).It further altered neighborhood competi-tion intensity and stand spatial structure,thereby regulating tree growth and biomass allocation patterns of C.lanceolata.Individual-tree biomass was the highest at lower slope positions,whose biomass allocation across different organs differed markedly from that on upper and middle slopes.(2)The coefficient of determination,root mean square error and mean absolute error of the stepwise regression model were 0.853,6.554 kg and 4.882 kg,respectively.The screened explana-tory variables contained crown radius(CR),competition index CI8,diameter differentiation index(T_Udm)and domi-nant height(Hdom).(3)In the piecewise structural equation model,the absolute values of path coefficients of all varia-bles on individual-tree biomass ranked in descending order:CI8(-0.945),Hdom(0.456),CR(0.055),T_Udm(-0.029).CI8 and dominant height were the primary driving factors of individual-tree biomass.(4)In subsequent forest management,rational thinning can be carried out to mitigate neighborhood competition pressure,combined with soil fertili-ty improvement measures,so as to effectively boost the growth and development of young C.lanceolata plantations.
潘占冬;王程;罗佳瑶;孙玉军
北京林业大学林学院,北京,100083北京林业大学林学院,北京,100083北京林业大学林学院,北京,100083北京林业大学林学院,北京,100083
农业科技
森林经营杉木生物量坡位结构方程模型
Forest managementCunninghamia lanceolataBiomassSlope positionStructural equation model
《东北林业大学学报》 2026 (10)
63-71,9
国家自然科学基金项目(31870620)林业科学技术推广项目([2019]06).
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