BER launches Environmental System Science Program. Visit our new website under construction!

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

BER Research Highlights

Physiologically-Linked Indices of Rainfall Variation Predict Water Stress For Central U.S. Tree Species
Published: December 11, 2015
Posted: May 02, 2016

Multiyear measurements enable researchers to predict impacts of precipitation regimes on central U.S. deciduous forest trees.

The Science
Long-term measurements at an AmeriFlux site in Missouri have enabled researchers to understand and predict how precipitation regimes affect water stress levels for key plant species in a central U.S. deciduous forest.

The Impact
How precipitation regimes affect water stress levels for plant species with contrasting water use strategies is not well understood. This study establishes a simple approach to quantifying plant physiological drought and the ecological impacts of precipitation regimes. This approach will be useful in predictions of forest response to climate change.

Variations in precipitation regimes can shift ecosystem structure and function by altering frequency, severity, and timing of plant water stress. Being able to predictively understand impacts of precipitation regimes on plant water stress is crucial in a changing climate. The research team, led by Oak Ridge National Laboratory (ORNL), formulated complementary, physiologically-linked indices of precipitation variability (PV) and related them to continuous measurements of predawn leaf water potential—a fundamental indicator of plant water status—in six tree species with different water use strategies in a central U.S. forest. These indices explained nearly all interannual variations in water stress levels for all species. These species differed in sensitivities to variations in precipitation regimes with the differences more pronounced in response to PV than to amount. Further, they exhibited stress tradeoffs between low and high PV, suggesting that how different plant species respond to PV is part of species-specific water use strategies in a plant community facing the uncertainty of fluctuating precipitation regimes. The new indices provide simple ways to quantify physiological drought and the ecological impacts of precipitation regimes in a changing climate.


Daniel Stover, SC-23.1,, 301-903-0289; and Jared DeForest, SC-23.1,, 301-903-1678

(PI Contact)
Lianhong Gu
Environmental Sciences Division and Climate Change Science Institute, ORNL, 865-241-5925

This work was supported by the U.S. Department of Energy (DOE), Office of Science, Office of Biological and Environmental Research, Climate and Environmental Sciences Division. ORNL is managed by the University of Tennessee (UT)-Battelle, LLC, for DOE under contract DE-AC05-00OR22725.

Gu, L., S. G. Pallardy, K. P. Hosman, and Y. Sun. 2016. “Impacts of Precipitation Variability on Plant Species and Community Water Stress in a Temperate Deciduous Forest in the Central US,” Agricultural and Forest Meteorology 217, 120–36. DOI: 10.1016/j.agrformet.2015.11.014. (Reference link)

Topic Areas:

  • Research Area: Earth and Environment Systems Data Management
  • Research Area: Terrestrial Ecosystem Science

Division: SC-33.1 Earth 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

Mar 23, 2021
Molecular Connections from Plants to Fungi to Ants
Lipids transfer energy and serve as an inter-kingdom communication tool in leaf-cutter ants&rsqu [more...]

Mar 19, 2021
Microbes Use Ancient Metabolism to Cycle Phosphorus
Microbial cycling of phosphorus through reduction-oxidation reactions is older and more widespre [more...]

Feb 22, 2021
Warming Soil Means Stronger Microbe Networks
Soil warming leads to more complex, larger, and more connected networks of microbes in those soi [more...]

Jan 27, 2021
Labeling the Thale Cress Metabolites
New data pipeline identifies metabolites following heavy isotope labeling.

Analysis [more...]

Aug 31, 2020
Novel Bacterial Clade Reveals Origin of Form I Rubisco

  • All plant biomass is sourced from the carbon-fixing enzyme Rub [more...]

List all highlights (possible long download time)