Tropospheric O3 compromises net primary production in young stands of trembling aspen, paper birch and sugar maple in response to elevated atmospheric CO2

Authors

  • John S. King,

    Corresponding author
    1. Ecosystem Science Center, School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan 49931, USA;
    2. Present address: Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA
      Author for correspondence: John S. King Tel: +1 919 513 7855 Fax: +1 919 515 3169 Email: john_king@ncsu.edu
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  • Mark E. Kubiske,

    1. USDA Forest Service, North-central Research Station, Rhinelander, Wisconsin 54501, USA;
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  • Kurt S. Pregitzer,

    1. Ecosystem Science Center, School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan 49931, USA;
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  • George R. Hendrey,

    1. Brookhaven National Laboratory, Department of Environmental Science, Earth System Sciences Division, Upton, New York 11973, USA;
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  • Evan P. McDonald,

    1. Department of Forest Ecology and Management, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA;
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  • Christian P. Giardina,

    1. USDA Forest Service, North-central Research Station, Houghton, Michigan 49931, USA;
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  • Vanessa S. Quinn,

    1. USDA Forest Service, North-central Research Station, Rhinelander, Wisconsin 54501, USA;
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  • David F. Karnosky

    1. Ecosystem Science Center, School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan 49931, USA;
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Author for correspondence: John S. King Tel: +1 919 513 7855 Fax: +1 919 515 3169 Email: john_king@ncsu.edu

Summary

  • • Concentrations of atmospheric CO2 and tropospheric ozone (O3) are rising concurrently in the atmosphere, with potentially antagonistic effects on forest net primary production (NPP) and implications for terrestrial carbon sequestration.
  • • Using free-air CO2 enrichment (FACE) technology, we exposed north-temperate forest communities to concentrations of CO2 and O3 predicted for the year 2050 for the first 7 yr of stand development. Site-specific allometric equations were applied to annual nondestructive growth measurements to estimate above- and below-ground biomass and NPP for each year of the experiment.
  • • Relative to the control, elevated CO2 increased total biomass 25, 45 and 60% in the aspen, aspen–birch and aspen–maple communities, respectively. Tropospheric O3 caused 23, 13 and 14% reductions in total biomass relative to the control in the respective communities. Combined fumigation resulted in total biomass response of −7.8, +8.4 and +24.3% relative to the control in the aspen, aspen–birch and aspen–sugar maple communities, respectively.
  • • These results indicate that exposure to even moderate levels of O3 significantly reduce the capacity of NPP to respond to elevated CO2 in some forests.

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