桂西南连续年龄序列尾巨桉人工林碳储量及其分布特征

Carbon Storage and Distribution of Eucalyptus urophylla × E.grandis Plantations in Continuous Age Sequences in Southwest Guangxi

采用固定标准地法对广西宁明县连续年龄系列(1~4年)生尾巨桉人工林的碳储量和年碳素固定量进行了研究。结果表明:尾巨桉各器官中碳素含量范围在455.4~502.4 g/kg之间,不同器官碳素含量高低的排列顺序为树叶、树干、树皮、树枝、树根。林分中不同结构层次碳素平均含量高低的排列顺序乔木层、地表凋落物层、灌木层、草本层;0~80 cm土壤碳素含量均随林龄的增长而增加。1、2、3和4年生尾巨桉人工林生态系统碳储量依次为88.42、106.84、122.76和135.30 t/hm^2,其中乔木层碳储量占4.84%~35.04%,灌草层占0.38~1.14%,现存凋落物层占为1.85%~2.48%、土壤层占61.77%~92.90%.4个林龄杉尾巨桉人工林乔木层净生产力依次为9.02、23.26、24.56和24.30 t/(hm^2·a),碳素年净固定量分别为4.30、11.12、11.92和11.84 t/(hm^2·a).

The standard plot method was used to study the carbon storage and annual net carbon fixation of 1-year-old to 4-year-old Eucalyptus urophylla x E.grandis plantations in Ningming county of Guangxi, China. The results showed that carbon content in different organs orE. urophylla x E.grandis plantation ranged from 455.4 g/kg to 502.4 g/kg, and was in the order as： leaf〉stem〉bark〉branch〉root. Carbon content in different layers within stand was in the following order： tree 〉ground litter〉shrub 〉herb.＇ Carbon content in the 0-80 cm of soil declines with increased soil depth. The total carbon storage of 1, 2, 3 and 4 year old E. urophylla x E.grandis plantation ecosystem were 88.42 t/hm^2, 106.71 t/hm^2, 122.63 t/hm^2 and 135.08 t/hm^2, respectively. Of the total storage of carbon, 4.84 %-35.04 % was distributed in arbor layer, 0.38 %-1.14 % at herb and shrub layer, 1.85 %-2.48 % at standing litter layer,61.00 %-92.90 % at soil layer. Annual net productivity at 1-year-old to 4-year-old of the E. urophylla x E.grandis plantation in the tree layer were 9.02 t·hm^-2·a^-1, 23.26 t·hm^-2·a^-1, 24.56 t·hm^-2·a^-1 和 24.30 t/（hm^2·a）, respectively. Annual net carbon fixation were up to 4.30 t/（hm^2·a）, 11.12 t/（hm^2·a）, 11.92 t/（hm^2·a） and 11.84 t/（hm^2·a）, respectively.