晋西山杨和油松生物量分配格局及异速生长模型研究

山杨和油松是晋西地区重要的建群树种,采用整株收获法分析了山杨和油松各器官生物量以及地上地下生物量分配格局.采用胸径(DBH)、树高(H)、树木因子(D2H)、平均冠幅(CW)和冠长(CL)等变量建立了叶、枝、干、根、地上部分及整株生物量模型,并选取了最优模型.结果表明:(1)山杨的叶、枝、干、根生物量分配比例分别为3.42％,11.23％,64.30％和21.06％,油松的叶、枝、干、根生物量分配比例分别为13.44％,19.86％,47.52％和19.18％；山杨和油松地上生物量和地下生物量比值分别为3.32∶1和3.99∶1.(2)山杨和油松的地上生物量与地下生物量之间呈极显著线性相关(p＜0.001).(3)山杨和油松各器官生物量拟合的最优模型形式均为CAR类型,模型解释量均超过92％.(4)基于树木胸径D的山杨和油松各器官单变量模型可解释量除叶(解释量＞83％)外均达到或超过了90％,树高不宜单独对各器官生物量进行预测.综合考虑模型的可解释量和生产实践中的需要,胸径是预测山杨和油松不同器官生物量的可靠变量.

Biomass Allocation Patterns and Allometric Models of Populus Davidiana and Pinus Tabulaeformis Carr.in West of Shanxi Province

Populus davidianaand Pinus tabulaeformis Carr.are two important tree species in western Shanxi Province.Biomass of each component and above and below-ground biomass of Populus davidianaand Pinus tabulaeformis Carr.were obtained by harvesting 40trees with various diameters at breast height(DBH),and furthermore,their allocation patterns were analyzed.Allometric models for each component(leaves,branch,stem,root,aboveground and the whole tree)of Populus davidiana and Pinus tabulaeformis Carr.were then developedbased on independent variables including DBH,tree height(H),trees factor(D2 H),average crown width(CW),and crown length(CL),and the best fitting models were identified.The results showed that relativeproportions of leaves,branch,stem and root to the total tree biomass were 3.42%,11.23%,64.30%and21.06%for Populus davidiana,and 13.44%,19.86%,47.52% and 19.18%for Pinus tabulaeformisCarr.,respectively.The ratio of aboveground biomass and belowground biomass were 3.32:1and 3.99:1for Populus davidiana and Pinus tabulaeformis Carr.,respectively.The two variables were correlated linearly forboth Populus davidiana and Pinus tabulaeformis Carr.(p<0.001).The best fitting models of two species wereCAR models.The allometric models explained more than 92%of the variance in the data,biomass allometricmodels based on DBH explained more than 90%,while leaves biomass allometric model explained more than83%.Tree height should not be used alone to predict the biomass of each component.Considering the variance explainability and the practical need,it can be concluded that DBH is a reliable predictor for estimatingthe biomass of each component for both Populus davidiana and Pinus tabulaeformis Carr.