天山林区6种优势种灌木林生物量比较及估测模型

采用平均标准木收获法测定了天山东、中、西部林区6种优势种灌木,多刺蔷薇(Rosa spinosissima L.)、黑果小檗(Berberis heteropoda Schrenk.)、刚毛忍冬(Lonicera hispida Pall.)、天山绣线菊(Spiraea.tianschanica Pojark.)、新疆方枝柏(Juniperus pseudosabina Fisch.et Mey.)和黑果栒子(Cotoneaster melanocarpus Lodd.)的地上和地下生物量并构建基于D~2H变量的个体生物量模型。结果表明:(1)天山西部林区灌木林的总生物量大于中部和东部的;(2)6种灌木的平均生物量大小排序为刚毛忍冬黑果栒子黑果小檗新疆方枝柏天山绣线菊多刺蔷薇;(3)6种灌木的生物量贡献主要源于根和枝生物量,不同器官生物量的大小排序根枝叶;6种灌木叶生物量的大小与枝的生物量之间呈极显著相关(P0.01);(4)以D2H为自变量建立6种灌木不同器官及个体生物量估测模型24个,除黑果小檗和新疆方枝柏叶生物量模型达到显著水平(P0.05),其他各组成生物量模型均达到极显著水平(P0.01),模型模拟结果达到了较高的准确度,可用于推算灌木生物量。研究结果可为定量评估天山森林生态系统的固碳功能提供数据支撑,也可为深入开展森林生态系统服务功能评价提供依据。

Biomass comparison and estimation models for six dominant species of woody shrubs in the forest zones of the Tianshan Mountains

The woody shrub layer in the Tianshan Mountains comprises a large proportion of the plant biomass of the entire forest ecosystem, significantly affecting estimates of the total forest biomass. Therefore, using an average wood-harvesting method, this study measured both the aboveground and belowground biomasses of six species of dominant woody shrubs (Rosa spinosissima L., Berberis heteropoda Schrenk., Lonicera hispida Pall., Spiraea tianschanica Pojark, Juniperus pseudosabina Fisch. et Mey., and Cotoneaster melanocarpus Lodd.) in eastern, central, and western areas of the Tianshan Mountains. A series of individual biomass models inferred from the variable D²H were established. The results are as follows: (1) The total biomass of the forest in the western areas of the Tianshan Mountains was larger than that in the central and eastern areas. The average biomass of an individual plant of the six woody shrubs was in the order of Lonicera hispida > Cotoneaster melanocarpus > Berberis heteropoda > Juniperus pseudosabina > Spiraea tianschanica > Rosa spinosissima. (2) In the western areas of Tianshan Mountains, the ratio of aboveground biomass to belowground biomass was greater than 1 for all six species; in the central area, it was less than 1 for all species except R. spinosissima and L. hispida; and in the eastern area, it was less than 1 for all species except B. heteropoda. (3) In all species, roots and branches were the major contributors to the biomass. The plant organ biomass was in the order of root < branch < leaf. The biomass of different root sizes was in the order of thick root > large root > medium root > small root > fine root. The variation in biomass distribution among different nutritive organs and diameter-class roots reflects the strategies that species employed to adapt to selected habitats. (4) Twenty-four biomass estimation models, with D²H as an independent variable, were established to evaluate organ biomass and individual biomass in the six species. The established models included 10 linear models, eight power function models, four polynomial models, and two logarithmic models. Except for B. heteropoda and J. pseudosabina, which reached only the significant level, the biomass models for all species reached the extremely significant level. The results indicate that the models can provide highly accurate estimates that could be used to evaluate the biomass of woody shrubs. This study provides supporting data for quantitative assessment of carbon fixation capacity of the Tianshan Mountains forest ecosystem. In addition, it provides strong evidence for further evaluation of the service capacity of forest ecosystems.