Old-Growth Forests Can Accumulate Carbon in Soils.pdf

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Old-Growth Forests Can Accumulate Carbon in Soils

Guoyi Zhou,^1* Shuguang Liu,^2* Zhian Li,¹ Deqiang Zhang,¹ Xuli Tang,¹ Chuanyan Zhou,¹ Junhua Yan,¹ Jiangming Mo¹

Old-growth forests have traditionally been considered negligible as carbon sinks because carbon uptake has been thought to be balanced by respiration. We show that the top 20-centimeter soil layer in preserved old-growth forests in southern China accumulated atmospheric carbon at an unexpectedly high average rate of 0.61 megagrams of carbon hectare-1 year-1 from 1979 to 2003. This study suggests that the carbon cycle processes in the belowground system of these forests are changing in response to the changing environment. The result directly challenges the prevailing belief in ecosystem ecology regarding carbon budget in old-growth forests and supports the establishment of a new, nonequilibrium conceptual framework to study soil carbon dynamics

¹ South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
² SAIC, U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science, Sioux Falls, SD 57198, USA.

^* These authors contribute equally to this work.

To whom correspondence should be addressed. E-mail: gyzhou@scib.ac.cn