Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Brief Communications Arising
  • Published:

Keenan et al. reply

Nature volume 507, pages E2–E3 (2014)Cite this article

Subjects

Abstract

replying to C. D. Holmes Nature507,http://dx.doi.org/10.1038/nature13113(2014)

Forests have become more efficient at using water over the past two decades1. A series of hypotheses exist to explain this trend, but the only credible explanation to date is a response to rising atmospheric CO2. Keenan et al.1 show that the observed trend is physiologically plausible, but is much larger than expected from conventional theory and experimental evidence. This has led to suggestions that processes other than increased atmospheric CO2 may have contributed to the observed trend2. One such process that has yet to be examined is the effect of tropospheric ozone on forest water-use efficiency (WUE). In the accompanying Comment3, Holmes reports that ozone concentrations have declined in the northeastern and midwestern USA by about 50% from 1995 to 2010. Using empirical relationships, he estimates that this decline could explain roughly 15% of the reported increase in WUE over North America, and a significantly lower proportion of the trend in Europe.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Ozone and WUE at Harvard Forest.

Similar content being viewed by others

References

  1. Keenan, T. F. et al. Increase in forest water-use efficiency as atmospheric carbon dioxide concentrations rise. Nature 499, 324–327 (2013)

    Article  ADS  CAS  Google Scholar 

  2. Medlyn, B. E. & De Kauwe, M. Carbon dioxide and water use in forest plants. Nature 499, 287–289 (2013)

    Article  ADS  CAS  Google Scholar 

  3. Holmes, C. D. Air pollution and forest water use. Nature 507, http://dx.doi.org/10.1038/nature13113 (2014)

    Article  ADS  CAS  Google Scholar 

  4. Lombardozzi, D., Sparks, J. P. & Bonan, G. Integrating O3 influences on terrestrial processes: photosynthetic and stomatal response data available for regional and global modeling. Biogeosciences 10, 6815–6831 (2013)

    Article  ADS  CAS  Google Scholar 

  5. Parrish, D. D. et al. Long-term changes in lower tropospheric baseline ozone concentrations at northern mid-latitudes. Atmos. Chem. Phys. 12, 11485–11504 (2012)

    Article  ADS  CAS  Google Scholar 

  6. Cooper, O. R. et al. Increasing springtime ozone mixing ratios in the free troposphere over western North America. Nature 463, 344–348 (2010)

    Article  ADS  CAS  Google Scholar 

  7. Cooper, O. R., Gao, R.-S., Tarasick, D., Leblanc, T. & Sweeney, C. Long-term ozone trends at rural ozone monitoring sites across the United States, 1990–2010. J. Geophys. Res. 117, D22307 (2012)

    ADS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Biological Sciences, Macquarie University, North Ryde, 2109, New South Wales, Australia

    Trevor F. Keenan

  2. USDA Forest Service, Northern Research Station, Durham, 03824, New Hamphire, USA

    David Y. Hollinger

  3. Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, Columbus, 43210, Ohio, USA

    Gil Bohrer

  4. Department of Geography, Indiana University, Bloomington, 47405, Indiana, USA

    Danilo Dragoni

  5. School of Engineering and Applied Sciences and Department of Earth and Planetary Sciences, Harvard University, Cambridge, 02138, Massachusetts, USA

    J. William Munger

  6. Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, IMK-IFU, Garmisch-Partenkirchen 82467, Germany,

    Hans Peter Schmid

  7. Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, 02138, Massachusetts, USA

    Andrew D. Richardson

Authors
  1. Trevor F. Keenan
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. David Y. Hollinger
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Gil Bohrer
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Danilo Dragoni
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. J. William Munger
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Hans Peter Schmid
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Andrew D. Richardson
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Trevor F. Keenan.

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Cite this article

Keenan, T., Hollinger, D., Bohrer, G. et al. Keenan et al. reply. Nature 507, E2–E3 (2014). https://doi.org/10.1038/nature13114

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature13114

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing