大树在东北云冷杉混交林地上生物量的主导作用

Dominant Role of Big Trees in Aboveground Biomass of Spruce-fir Mixed Forests in Northeast China

为精准评估大型树木对森林地上生物量的影响及其重要性,进一步探究森林的碳循环作用。通过对东北金沟岭林场224块固定样地(20 m×20 m)进行每木检尺,采用随机森林算法和结构方程模型,探究物种多样性、林分密度、大型树木、气候因子对地上生物量的影响。结果表明:随机森林算法得出,所选因素共解释了地上生物量42.68%的方差,其中大树生物量是森林地上生物量的重要影响因素。对地上生物量构建结构方程模型发现,物种丰富度与地上生物量呈负相关,林分密度及大树生物量均促进地上生物量生长。考虑变量间的相互作用后发现,大树生物量对地上生物量的影响稍大于林分密度。

In order to accurately assess the influence of large trees on aboveground forest biomass and its significance in elucidating the forest carbon cycling dynamics,an investigation was conducted with 224 permanent plots(20 m×20 m)within the Jingouling Forest Farm in Northeast China.Individual tree measurements were taken,and the effects of species diversity,stand density,large tree abundance,and climatic factors on aboveground biomass were explored using the Random Forest algorithm and Structural Equation Modeling.The selected factors collectively explained 42.68%of the variance in aboveground biomass,with large tree biomass emerging as a crucial determinant of aboveground biomass.The Structural Equation Model revealed a negative correlation between species richness and aboveground biomass,while stand density and large tree biomass both positively influenced aboveground biomass.Considering the interplay among variables,the impact of large tree biomass on aboveground biomass slightly exceeded that of stand density.