Letter | Published:

Soil fertility limits carbon sequestration by forest ecosystems in a CO2-enriched atmosphere

Nature volume 411, pages 469472 (24 May 2001) | Download Citation



Northern mid-latitude forests are a large terrestrial carbon sink1,2,3,4. Ignoring nutrient limitations, large increases in carbon sequestration from carbon dioxide (CO2) fertilization are expected in these forests5. Yet, forests are usually relegated to sites of moderate to poor fertility, where tree growth is often limited by nutrient supply, in particular nitrogen6,7. Here we present evidence that estimates of increases in carbon sequestration of forests, which is expected to partially compensate for increasing CO2 in the atmosphere, are unduly optimistic8. In two forest experiments on maturing pines exposed to elevated atmospheric CO2, the CO2-induced biomass carbon increment without added nutrients was undetectable at a nutritionally poor site, and the stimulation at a nutritionally moderate site was transient, stabilizing at a marginal gain after three years. However, a large synergistic gain from higher CO2 and nutrients was detected with nutrients added. This gain was even larger at the poor site (threefold higher than the expected additive effect) than at the moderate site (twofold higher). Thus, fertility can restrain the response of wood carbon sequestration to increased atmospheric CO2. Assessment of future carbon sequestration should consider the limitations imposed by soil fertility, as well as interactions with nitrogen deposition.

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This study was supported by the Department of Energy through both the Office of Biological and Environmental Research and the National Institute for Global Environmental Change, Southeast Regional Center at the University of Alabama, and by the US Forest Service through both the Southern Global Climate Change Program and the Southern Research Station. This work contributes to the Global Change and Terrestrial Ecosystems (GCTE) core project of the International Geosphere–Biosphere Programme (IGBP). We thank D. E. Pataki for helping with data acquisition; T. Albaugh for descriptive site data; and C. Körner, C. Field and R. Norby for helpful comments on an early version.

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  1. *Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina 27708, USA

    • Ram Oren
    • , Brent E. Ewers
    • , Karina V.R. Schäfer
    • , Heather McCarthy
    •  & Gabriel G. Katul
  2. †School of Natural Resources and Environment, University of Michigan, Ann Arbor, Michigan 48109, USA

    • David S. Ellsworth
  3. ‡Department of Environmental Sciences, Brookhaven National Laboratory, Upton, New York 11973-5000, USA

    • David S. Ellsworth
    •  & George Hendrey
  4. §Southern Research Station, US Forest Service, Research Triangle Park, North Carolina 27709, USA

    • Kurt H. Johnsen
    •  & Chris Maier
  5. Department of Geography, Boston University, Boston, Massachusetts 02215, USA

    • Nathan Phillips
  6. ¶Southern Global Climate Change Program, US Forest Service, Raleigh, North Carolina 27606, USA

    • Steven G. McNulty


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Correspondence to Ram Oren.

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