桉树是我国南方重要的速生树种,在保障国家木材安全和增强森林碳汇能力方面发挥着重要作用,但目前尚无可靠的立木生物量模型。从我国桉树林的主要分布区广西分别采集了183株和124株代表性样木的地上生物量(含干、皮、枝、叶各个分量)和地下生物量数据,采用最新的综合哑变量方法和误差变量联立方程组方法的联合估计技术,建立了相容性可加性一元和二元立木生物量模型系统。结果表明,地上、地下生物量模型的确定系数R²均在0.95以上,平均预估误差MPE分别在3%和6%以下。通过对3组已发表的桉树地上、地下生物量模型的估计结果进行对比分析,发现仅1组模型能达到相关技术规程的精度要求,另外2组模型的估计结果明显有偏差,其中偏差最大的地下生物量模型其相对误差甚至超出了100%。此次研建的桉树相容性可加性立木生物量模型系统,为准确估计广西乃至全国桉树林的生物量及碳储量提供了计量依据。

Eucalyptus is an important fast-growing tree species in southern China,which plays a significant role in ensuring national timber safety and enhancing forest carbon sequestration capacity.However,there are still no reliable tree biomass models for Eucalyptus.In this study,based on the data of above-ground biomass (including the components of stem wood,stem bark,branches and forages) from 183 sample trees and underground biomass from 124 sample trees of Eucalyptus spp.in Guangxi which was the key distribution region of Eucalyptus plantations in China,one- and two-variable biomass model systems with compatibility and additivity were developed using the new combined estimation technique integrating dummy variable modeling approach and error-in-variable simultaneous equations approach.The results showed that the determination coefficients (R²) of above- and underground biomass models were all more than 0.95,and the mean prediction errors (MPEs) were less than 3% and 6%,respectively.From the comparison of estimates resulted from 3 sets of above- and underground biomass models for Eucalyptus published before,it was found that only one set of the models could met the precision needs of relevant technical regulation,and other two sets of the models resulted in significant biased estimates,where the highest estimate error of underground biomass model had even more than 100% of relative error.The compatible and additive tree biomass models systems for Eucalyptus developed in this study would provide a basis for accurately estimating the biomass and carbon storage in Guangxi,even in the whole country.