桂西北秃杉人工林不同年龄阶段的固碳功能

目的 探究秃杉人工林生长过程中的固碳功能及其变化趋势，为合理评价其生态效益提供依据。 方法 以桂西北秃杉人工林为研究对象，采用野外调查与室内分析相结合的方法，研究广西南丹县4个年龄阶段秃杉林（9、17、25、37年生）生态系统碳含量、碳储量、年净固碳量及其分配特征。 结果 （1）秃杉不同器官碳含量为425.3～507.2 g·kg−1；灌木层碳含量为446.9～461.3 g·kg−1；草本层碳含量为387.0～412.5 g·kg−1；凋落物层碳含量为410.5～438.2 g·kg−1；土壤层(0～80 cm) 碳含量为5.72～45.79 g·kg−1，且随土层加深而下降，同时随林龄增加而增大。（2）不同年龄阶段（9、17、25、37年生）秃杉林生态系统碳储量分别为180.39、223.24、254.65、314.59 t·hm−2，其中，乔木层依次占20.15%、33.72%、38.31%、46.70%，灌草层依次占0.37%、0.66%、0.88%、0.84%，凋落物层依次占0.51%、0.93%、1.17%、1.41%，土壤层依次占78.98%、64.69%、59.69%、51.06%。（3）9、17、25、37年生秃杉林年净固碳量分别为5.42、7.15、7.32、7.03 t·hm−2·a−1，其中，乔木层依次占85.24%、73.85%、70.41%、68.58%，年凋落物依次占14.76%、26.15%、31.42%、29.59%。 结论 桂西北秃杉人工林生态系统碳储量随生长过程增加的变化规律明显，碳汇潜力巨大，研究结果为桂西北地区碳汇林业的经营与发展提供了依据。

Carbon Sequestration of Different Aged Taiwania flousiana Plantations in Northwestern Guangxi

Objective To study the carbon sequestration and its change during the growth of the Taiwania flousiana plantations, and to provide reference for rational assessment of its ecological benefits. Method Taking T. flousiana plantations at Nandan Forest Farm, Northwestern of Guangxi, as the research samples, the carbon content, carbon storage, annual carbon sequestration and distribution characteristics of T. flousiana plantation at four stand ages (9-, 17-, 25- and 37-years-old) were studied by field investigation and laboratory analysis. Result (1) The carbon content in different organs of T. flousiana ranged from 425.3 g·kg−1 to 507.2 g·kg−1. The content of shrub, herb, litter layers ranged from 446.9 g·kg−1 to 461.3 g·kg−1, from 387.0 g·kg−1 to 412.5 g·kg−1, and from 410.5 g·kg−1 to 438.2 g·kg−1, respectively. The carbon content of soil layer (0−80 cm) ranged from 5.72 g·kg−1 to 45.79 g·kg−1, which increased with stand age but decreased with the soil depth. (2) The total carbon storage in the 9-, 17-, 25- and 37-year-old T. flousiana plantations were 180.39, 223.24, 254.65 and 314.59 t·hm−2, respectively, of which the arbor layer accounted for 20.15%, 33.72%, 38.31% and 46.70%, the shrub layer for 0.37%, 0.66%, 0.88% and 0.84%, the litter layer for 0.51%, 0.93%, 1.17% and 1.41%, and the soil layer for 78.98%, 64.69%, 59.69% and 51.06%, respectively. (3) Annual carbon sequestrations of T. flousiana plantations with the four age classes were up to 5.42, 7.15, 7.32 and 7.03 t·hm−2·a−1, respectively, of which the arbor layer accounted for 85.24%, 73.85%, 70.41% and 68.58%, and the annual litter accounted for 14.76%,26.15%, 31.42% and 29.59%, respectively. Conclusion The carbon storage of T. flousiana plantation in Northwest Guangxi obviously varies with growth, and has huge carbon storage potential. This study can be used as reference for the forest management aiming at carbon sequestration in northwestern Guangxi.