桂西北杉木成熟林生态系统碳贮量及其分布格局

Carbon Storage and Distribution of Mature unninghamia lanceolata Plantation Ecosystem in Northwestern Guangxi

为了探究桂西北杉木人工林成熟林的碳汇功能,为其生态效益的合理评价和可持续经营提供依据。以广西南丹县杉木成熟林(30年生)为研究对象,通过野外样地调查和室内分析,对其生态系统碳储量及其分布格局进行了研究。结果表明:1) 各器官碳含量介于468.4~502.8 g•kg−1之间,按大小排列次序为干皮 】干材 】树叶 】树枝 】树根,林分中不同层次植物碳含量为乔木层 】灌木层 】草本层,土壤(0~80 cm)平均碳含量为15.16 g•kg−1,随土层加深逐渐下降。2) 杉木成熟林生态系统碳贮量为241.63 t•hm−2,不同部分碳贮量由大到小次序为土壤层(145.61 t•hm−2) 】乔木层(91.36 t•hm−2) 】凋落物层(2.78 t•hm−2 】灌木层(1.38 t•hm−2) 】草本层(0.50 t•hm−2)。乔木层各器官碳贮量与其生物量成正比例关系,干材的生物量最大,其碳贮量也最高,占乔木层碳贮量的68.14%,树枝、树叶、干皮和树根等碳贮量共占31.86%。3) 杉木成熟林乔木层年净生产力为7.84 t•hm−2•a−1,有机碳年净固定量为3.84 t•hm−2•a−1,年净吸收CO2量为14.08 t•hm−2•a−1。因此,桂西北杉木成熟林具有较强的固碳功能,在区域森林生态系统碳循环中发挥着重要的作用。

In order to explore the carbon sequestration of the mature Cunninghamia lanceolata plantation in northwestern Guangxi, and to provide a basis for rational assessment of its ecological benefits and sustainable management, taking the mature C. lanceolata plantation (30-year-old) of Nandan County in northwestern of Guangxi as the research objects, the carbon content, carbon storage, annual carbon sequestration and distribution characteristics of the C. lanceolata plantation ecosystems were studied by the field plot survey and laboratory chemical analysis method. The results showed that 1) Carbon content of each organ ranged between 468.4 and 502.8 g•kg−1, and it was in the order of bark >stem >leaf >branch >root. The carbon content of different layers within the stand was in the order: tree layer >shrub layer >herb layer. The carbon content in the soil (0~80 cm) was 15.16 g•kg−1, and declines with soil depth. 2) The total carbon storage of mature C. lanceolata plantation ecosystems was estimated to be 241.63 t•hm−2, and carbon storage of each component in this ecosystem was in the order as soil layer >(145.61 t•hm−2) tree layer (91.36 t•hm−2) >litter layer (2.78 t•hm−2) >shrub layer (1.38 t•hm−2) >herb layer (0.50 t•hm−2). The carbon storage of different organs was related to the biomass of corresponding organs, stem accumulated the highest carbon storage, comprised 68.14% of carbon storage in tree layer, the rest in branch, leaf, bark and root etc., seized 31.86%. 3) The annual net productivity of C. lanceolata plantation was 7.84 t•hm−2•a−1, and annual carbon fixation was 3.84 t•hm−2•a−1, and the annual net CO2 absorption was 14.08 t•hm−2•a−1. The mature C. lanceolata plantation in Northwest Guangxi has strong and sustainable carbon sink functions, and plays an important role in regional the carbon cycle of the forest ecosystem.