作者：Shenghua Gao, Jiquan Chen, Yuxi Tang, Jing
Xie, Rui Zhang, Jie Tang, Xudong Zhang*
期刊：Ecology and Management
发表时间：2015年
卷.期.页码：357: 206-219
摘要：Poplar plantations have widely spread around the world
due to its high productivity and adaptability. Clear-cutting is the primary
harvesting method for poplar plantation management in southern China. However,
the effect of harvesting on ecosystem carbon fluxes limits our ability to
estimate its carbon sequestration. A consecutive, three-year observation on
ecosystem CO2 and CH4 flux (FCO2 and FCH4)
of a Populus dettoides plantation on
the floodplain of Yangtze River was made prior and post to the clear cutting using
an eddy-covariance system. We found that clear-cutting turned the ecosystem
from a strong carbon sink to a mediate carbon source only in several months,
July to next January, after the harvest. The ecosystem turned to a net carbon
sink at the beginning of the first growing season following clear-cutting due
to the large productivity of understory vegetation in this region. The annual
carbon budget was -424.3 ± 52.5 g-C
m-2 (95% confidence
interval) in the harvesting year, with 53.6 ± 22.8 g-C m-2 the first year and -290.7 ± 34.2 g-C m-2 the second year after clear-cutting. Clear-cutting
turned the ecosystem from a net CH4 sink to a net CH4
source after the third month, but during the three years the CH4
emission only balanced out a very small portion (0.3%) of FCO2. In
noninundation periods, FCH4 varied from -0.01 to 0.24 mmol m-2 d-1, with a mean
(±SD) of 0.11 ± 0.08 mmol m-2 d-1, while it ranged from 0.33 to 4.39 mmol m-2 d-1 during inundation, with a mean (±SD) of
2.17 ± 1.16 mmol m-2 d-1. Daily and weekly FCH4 during non-inundation
period were highly correlated with ground water table, soil moisture, and
friction velocity, while FCH4 during inundation depended on
inundation depth.