U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights


Elevated CO2 and Extreme Drought Too Much for a Temperate Forest To Handle
Published: April 18, 2011
Posted: April 29, 2011

In 2007, an extreme drought and acute heat wave impacted ecosystems across the southeastern U.S., including a 19-year-old sweetgum (Liquidambar styraciflua L.) plantation exposed experimentally to long-term elevated or ambient CO2 treatments. Stem sap velocities (i.e., tree water use) were analyzed to assess plant response to potential interactions between CO2 and these weather extremes. Canopy conductance and net carbon assimilation were modeled based on patterns of sap velocity to estimate the indirect impacts of observed reductions in transpiration under elevated CO2on premature leaf senescence. Elevated CO2 reduced sap flow by 28% during early summer, and by up to 45% late in the drought during record-setting temperatures. Elevated CO2 reduced the capacity of leaves to exchange gases with the atmosphere (i.e., stomatal conductance) and reduced photosynthetic carbon gain. Premature leaf loss also increased rapidly during this period, and was 30% greater under elevated CO2 conditions. While elevated CO2 can reduce leaf-level water use under drought conditions, acute drought may induce excessive stomatal closure that could offset the overall productive capacity of temperate forest species during extreme weather events.

References: Warren J. M., R. J. Norby, and S. D. Wullschleger. 2011. “Elevated CO2 Enhances Leaf Senescence During Extreme Drought in a Temperate Forest,” Tree Physiology 31, 117–130. DOI: 10.1093/treephys/tpr002.

Contact: Mike Kuperberg, SC-23.1, (301) 903-3281, Daniel Stover, SC-23.1, (301) 903-0289
Topic Areas:

  • Research Area: Terrestrial Ecosystem Science
  • Research Area: Carbon Cycle, Nutrient Cycling
  • Research Area: Free Air CO2 Enrichment (FACE)

Division: SC-23.1 Climate and Environmental Sciences Division, BER

 

BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

May 10, 2019
Quantifying Decision Uncertainty in Water Management via a Coupled Agent-Based Model
Considering risk perception can improve the representation of human decision-making processes in age [more...]

May 09, 2019
Projecting Global Urban Area Growth Through 2100 Based on Historical Time Series Data and Future Scenarios
Study provides country-specific urban area growth models and the first dataset on country-level urba [more...]

May 05, 2019
Calibrating Building Energy Demand Models to Refine Long-Term Energy Planning
A new, flexible calibration approach improved model accuracy in capturing year-to-year changes in bu [more...]

May 03, 2019
Calibration and Uncertainty Analysis of Demeter for Better Downscaling of Global Land Use and Land Cover Projections
Researchers improved the Demeter model’s performance by calibrating key parameters and establi [more...]

Apr 22, 2019
Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles
Representation of warm temperature events varies considerably among global climate models, which has [more...]

List all highlights (possible long download time)