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Southern Oregon University


Sciences 206

1250 Sisikiyou Blvd.

Ashland, OR  97520

(541) 552-6798





Ph.D., Botany, University of California, Davis. 1992

M.S., Botany, University of California, Davis. 1989.

B.S., Forest Management, University of Washington. 1987.


Plant Physiology, (Bi 331)

Principles of Biology, (Bi211)

General Biology (Bi103)

Forest Ecology and Management (Bi386)

Biogeochemistry (Bi346)

Plant Form and Function (Bi434/534)

Introductory Ecology Lab (Bi340L)


Research Interests

My fundamental interests are in Plant Physiological Ecology with special reference to trees and forest ecosystems. The theme that binds my interests together is an interest in how the microenvironment of a plant influences its form and function. In particular, I have been interested in how plants acclimate and adapt to environmental heterogeneity with an emphasis on how those physiological and morphological characteristics affect survival and growth.  Recent projects have included stable isotopes in tree ring cellulose as indicators of plant water use and climate change, the effects of wind and leaf movements (leaf flutter) on canopy light dynamics and its impact on photosynthesis, the effects of elevated CO2 and temperature extreme events (global change) on tree seedling physiology, and the genotype/phenotype interactions of conifers in common garden experiments.     



Roden JS and JR Ehleringer (2000) Biochemical fractionation of hydrogen and oxygen isotopes in tree-ring cellulose is not temperature dependent. Isotopes in Environmental and Health Studies 36:303-317.

Roden JS, G Lin and JR Ehleringer (2002) Response to the comment of V.J. Terwilliger on "A mechanistic model for the interpretation of hydrogen and oxygen isotope ratios in tree-ring cellulose," by J.S. Roden, G. Lin, and J.R.Ehleringer 2000 Geochimica et Cosmochimica Acta 64:21-35. Geochimica et Cosmochimica Acta 66:733-734.

Helliker BR, JS Roden, C Cook and JR Ehleringer (2002) A rapid and precise method for sampling and determining the oxygen isotope ratio of atmospheric vapor. Rapid Communication in Mass Spectromotry 16:929-632.

Roden JS. (2003) Modeling the light interception and carbon gain of individual fluttering aspen (Populus tremuloides) leaves. Trees 17:117-126.

Barbour MM, JS Roden, GD Farquhar and JR Ehleringer (2004) Expressing leaf water and cellulose oxygen isotope ratios as enrichment above source water reveals evidence of a Péclet effect. Oecologia 138:426-435.