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Letters to Nature

Nature 411, 466-469 (24 May 2001) | doi:10.1038/35078060; Received 3 January 2001; Accepted 2 April 2001

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Limited carbon storage in soil and litter of experimental forest plots under increased atmospheric CO2

William H. Schlesinger1 & John Lichter2

  1. Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina 27708, USA
  2. Biology Department and Environmental Studies Program, Bowdoin College, Brunswick, Maine 04011, USA

Correspondence to: William H. Schlesinger1 Correspondence and requests for materials should be addressed to W.H.S. (e-mail: Email: schlesin@duke.edu).

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The current rise in atmospheric CO2 concentration is thought to be mitigated in part by carbon sequestration within forest ecosystems1, 2, where carbon can be stored in vegetation or soils. The storage of carbon in soils is determined by the fraction that is sequestered in persistent organic materials, such as humus. In experimental forest plots of loblolly pine (Pinus taeda) exposed to high CO2 concentrations3, 4, nearly half of the carbon uptake is allocated to short-lived tissues, largely foliage. These tissues fall to the ground and decompose, normally contributing only a small portion of their carbon content to refractory soil humic materials5. Such findings call into question the role of soils as long-term carbon sinks, and show the need for a better understanding of carbon cycling in forest soils. Here we report a significant accumulation of carbon in the litter layer of experimental forest plots after three years of growth at increased CO2 concentrations (565 microl l-1). But fast turnover times of organic carbon in the litter layer (of about three years) appear to constrain the potential size of this carbon sink. Given the observation that carbon accumulation in the deeper mineral soil layers was absent, we suggest that significant, long-term net carbon sequestration in forest soils is unlikely.

  1. Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina 27708, USA
  2. Biology Department and Environmental Studies Program, Bowdoin College, Brunswick, Maine 04011, USA

Correspondence to: William H. Schlesinger1 Correspondence and requests for materials should be addressed to W.H.S. (e-mail: Email: schlesin@duke.edu).