Carbon balance of afforested peatland in Scotland
Carbon balance of afforested peatland in Scotland
复制标题
苏格兰绿化泥炭地的碳平衡
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
M. Cannell
中科院分区：
文献类型：
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作者：
K. Hargreaves;R. Milne;M. Cannell
摘要使用涡动协方差法连续22个月测量了苏格兰未受干扰的深层泥炭地的年度净CO2交换。每年的CO2交换泥炭地已排水，犁和针叶树造林1，2，3，4，8，9和26年前估计外推2至4周的测量，使用白天通量和太阳辐射和夜间通量和空气温度之间的关系。树木的整体净CO2通量的贡献估计使用碳核算模型，校准，以适应针叶树体积产量数据。泥炭和地面植被的碳交换是指总的碳通量与树木和枯落物中积累的碳量之差。未受扰动的泥炭累积约0.25 t C ha-1 a-1。新排水的泥炭地（翻耕后2 - 4年）排放2 - 4 t C ha-1 a-1，但当地面植被酸化时，泥炭地再次成为汇，在植树后4 - 8年吸收约3 t C ha-1 a-1。此后，树木占了预算的主导地位，绿化泥炭地吸收了高达5 t C ha-1 a-1的碳。假设树木以与产量等级10 m3 ha-1 a-1相当的速率积累碳，则树冠关闭后树木下方的泥炭估计仅以~1 t C ha-1 a-1或更少的速度分解。这比以前认为的要慢，并表明苏格兰的绿化泥炭地在树木、凋落物、森林土壤和产品比从泥炭失去了90 - 190年。
Summary The annual net CO2 exchange over undisturbed deep peatland in Scotland was measured continuously for 22 months using eddy covariance. Annual CO2 exchanges over peatlands that had been drained, ploughed and afforested with conifers 1, 2, 3, 4, 8, 9 and 26 years previously were estimated by extrapolating two to four weekly measurements, using relationships between daytime fluxes and solar radiation and night-time fluxes and air temperature. The contribution of the trees to the overall net CO2 flux was estimated using a carbon accounting model, calibrated to fit conifer volume yield data. The carbon exchange of the peat and ground vegetation was then the difference between the overall carbon flux and the amount accumulated in trees and tree litter. The undisturbed peat accumulated ~0.25 t C ha ‐1 a ‐1 . Newly drained peatland (2‐4 years after ploughing) emitted between 2 and 4 t C ha ‐1 a ‐1 , but when ground vegetation recolonized, the peatland became a sink again, absorbing ~3 t C ha ‐1 a ‐1 4‐8 years after tree planting. Thereafter, the trees dominated the budget and afforested peatlands absorbed up to 5 t C ha ‐1 a ‐1 . Assuming that the trees accumulated carbon at rates commensurate with yield class 10 m3 ha‐1 a‐1, the peat beneath the trees after canopy closure was estimated to be decomposing at only ~1 t C ha‐1 a‐1 or less. This is slower than previously thought and suggested that afforested peatlands in Scotland accumulate more carbon in trees, litter, forest soil and products than is lost from the peat for 90‐190 years.