新疆杨不同林龄农田防护林的碳储量

Carbon storage of Populus alba var. pyramidalisa Bunge farmland shelter forest with different ages

【目的】了解新疆杨各组分生物量和碳储量的差异,为新疆农田防护林生态效益评估提供参考依据。【方法】以新疆和田地区4个龄级新疆杨农田防护林为对象,基于样地生物量调查与室内分析,探讨其碳储量的时空变化规律,比较分析各龄级和各组分的生物量及碳储量。【结果】随林龄增大,新疆杨农田防护林林木及各组分生物量增加,树干所占比例呈明显的逐年增加趋势,树叶、树枝和树根所占比例呈不同程度下降趋势,各组分所占比例表现为树干〉树枝〉树根〉树叶;随林龄的增大,新疆杨农田防护林林木根系直径〈2.0 cm和2.1-5.0 cm根的生物量基本呈递减规律,而5.1-10.0 cm根的生物量呈增大趋势;不同龄级林分土壤碳储量基本上随着土层深度的增加逐渐降低,表层土的碳密度均高于其他土层;林木碳储量随着林龄增加而增大的趋势很明显,成熟林的碳储量约是幼龄林的17.41倍,不同龄级林分的年碳储量大小为成熟林（142.88 t/ha）〉近熟林（67.93 t/ha）〉中龄林（34.66 t/ha）〉幼龄林（9.80 t/ha）。【结论】新疆杨农田防护林固碳能力较强,碳储量主要分布在林木层。新疆杨可作为其适种区固碳林的优良树种继续发展种植。

【Objective】The present experiment was conducted to investigate differences in biomass and carbon storage between every two components of Populus alba var. pyramidalisa Bunge, in order to provide references for evaluating ecological benefit of farmland shelter forest in Xinjiang. 【Method】The P. alba var. pyramidalisa Bunge farmland shelterbelts at four different age classes in Hetian region of Xinjiang were used as objects. Based on biomass investigation and laboratory analysis, the spatio-temporal variation of carbon storage was analyzed, and the biomass and carbon storage of every component of P. alba var. pyramidalisa Bunge at different age classes were investigated. 【Result】The results showed that the biomass of tree and its each component were increased with the increase of forest age, and the proportion of trunk significantly increased year by year, however, the proportions of leaves, branches and roots decreased to varying degrees. Thus,based on proportions, the components of tree were in order as follows： trunkbranchesrootsleaves. With the increase of forest age, the biomass of less than 5 cm root in diameter decreased gradually, and the biomass of 5.1-10.0 cm root in diameter increased gradually. Moreover, the soil carbon storage of forests at different age classes decreased gradually with the increase of soil depth, and the carbon density of topsoil was higher than that of other soil. Besides the carbon storage of forest increased obviously with the increase of forest age, the carbon storage of mature forest was 17.40 times that of young forest. According to carbon storage, the order of forests at different age classes was as follows： mature forest（142.88 t/ha）near-mature forest（67.93 t/ha）〉half-mature forest（34.66 t/ha）〉young forest（9.80 t/ha）. 【Conclusion】P. alba var. pyramidalisa Bunge farmland shelterbelt has better carbon sequestration capacity, and the carbon storage is distributed mainly in tree layer. Therefore, P. alba var. pyramidalisa Bunge can be used as carbon-sequestration tree species to plant and develop.