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Ram Oren

Nicholas Distinguished Professor of Earth Systems Science
Earth and Climate Sciences
Box 90328, Durham, NC 27708-0328
A246A Lev Sci Res Ctr, Durham, NC 27708

Overview


With his graduate students, Oren quantifies components of the water cycle in forest ecosystems, and their responses to biotic and abiotic factors. Relying on the strong links between the carbon and water cycles, he also studies the components of the carbon flux and their response to these factors. Climate variability, including variations in air temperature, vapor pressure deficit, incoming radiation and soil moisture, and environmental change, including elevated atmospheric carbon dioxide, affect the intra- and inter-annual dynamics, and amounts of water used by forest ecosystems, and their spatial distribution, as well as carbon uptake and sequestration. In turn, the variation of water flux influence the temporal and spatial partitioning of incoming radiation between latent and sensible heat. The flow of water from soil through plant leaves into the atmosphere, and the exchange of water for CO2 absorbed from the atmospheric, are among the processes theoretically best understood in plant and ecosystem physiology. Using these theories, local mass balance approaches, and detailed measurements of water and carbon flux and driving variables in the soil, plants, and the atmosphere, Oren has been attempting to predict the likely responses of forest ecosystems, from the equator to the arctic circle, to environmental change and management.

Current Appointments & Affiliations


Nicholas Distinguished Professor of Earth Systems Science · 2009 - Present Earth and Climate Sciences, Nicholas School of the Environment
Professor in the Division of Earth and Climate Science · 2024 - Present Earth and Climate Sciences, Nicholas School of the Environment
Professor in the Department of Civil and Environmental Engineering · 2024 - Present Civil and Environmental Engineering, Pratt School of Engineering
Professor in the Environmental Natural Science Division · 2024 - Present Environmental Natural Science, Nicholas School of the Environment

In the News


Published November 19, 2019
Global List of Highly Cited Puts Duke in Top Ten
Published November 27, 2018
Duke Faculty Plentiful On ‘Highly Cited’ List

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Recent Publications


Increasing pathlength resistance and within-canopy shading similarly attenuate transpiration in accruing collocated stands of five pine species

Journal Article Agricultural and Forest Meteorology · February 15, 2026 In forested regions dominated by management for timber production, quantifying biosphere-atmosphere exchange of mass and energy over accruing forests is essential for accurate estimates of water yield and carbon sequestration. Environmental conditions driv ... Full text Cite

Regulation of tree water use by biophysical factors: Insights based on multi-layer hierarchical residual analysis

Journal Article Journal of Hydrology · October 1, 2025 The complex impact of biophysical factors on tree water use in changing environments has been an important topic in the ecohydrological studies. However, understanding how to model tree water use based on key biophysical factors requires an in-depth analys ... Full text Cite

Xylem Hydraulic Properties of Five Pinus Species Grown in Common Environment Vary From Needles to Roots With Needle Length and Native-Range Climate.

Journal Article Plant, cell & environment · October 2025 Plant hydraulics govern water transport linking root to mesophyll surfaces, affecting gas-exchange, survival and growth. Xylem and leaf structural and functional characteristics vary widely among Pinus species, even when growing under similar conditions. W ... Full text Cite
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Recent Grants


Can Variation in Hydraulic Conductance Explain Isohydric and Anisohydric Stomatal Behavior?

ResearchPrincipal Investigator · Awarded by US-Israel Binational Science Foundation · 2011 - 2016

Duke Forest FACE Experiment: Forest-Atmosphere Carbon Transfer and Storage

ResearchPrincipal Investigator · Awarded by Department of Energy · 2001 - 2015

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Education, Training & Certifications


Oregon State University · 1984 Ph.D.
Oregon State University · 1980 M.S.
Humboldt State University · 1978 B.S.