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Southern Oregon University

Sciences RM 380

1250 Siskiyou Blvd.

Ashland, OR  97520

(541) 552-6868





B. S. 1977 General Studies Tulane University, cum laude, with Honors in Biology
M. S. 1981 Plant Ecology Colorado State University
Ph.D 1984 Plant Ecology Colorado State University



Principles of Biology Evolution and Diversity (Bi212)

Introductory Ecology (Bi340)

Plant Ecology (Bi454/554)

Fire Ecology (ES 480) 


Research Interests

I am currently working on introduction new teaching methods to my courses and assessing their effectiveness in improving student learning and retention.



Welden, C. W. and R. A. Hossler. 2003..Evolution in the lab: Biocide resistance in E. coli. The American Biology Teacher 65:56-61.

Donovan, T. M. and Welden, C. W. 2001..Spreadsheet Exercises in Ecology and Evolution. 556 pp. Sinauer Assoc.

Donovan, T. M. and Welden, C. W. 2001. Spreadsheet Exercises in Conservation and Landscape Ecology. 464 pp. Sinauer Assoc.

Welden, C. W. 1999.. Using spreadsheets to teach ecological modeling. Bulletin of the Ecological Society of America 80:65-67.

Welden, C. W.,. S. W. Hewett, S. P. Hubbell, and R. B. Foster. 1991. Sapling survival, growth, and recruitment in relationship to canopy height in a neotropical forest. Ecology 72:35-50.

Welden, C. W., W. L. Slauson, and R. T. Ward. 1990.. Spatial pattern and interference in pinon-juniper woodlands of northwest Colorado. Great Basin Naturalist 50:313-319.

Welden, C. W., W. L. Slauson, and R. T. Ward. 1988.. Competition and abiotic stress among trees and shrubs in northwest Colorado. Ecology 69:1566-1577.


Sciences RM 226

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)

Forest Ecology and Management (Bi386)

Biogeochemistry (Bi346)

Plant Form and Function (Bi434/534)

Introductory Ecology Lab (Bi340L)

Stable Isotope Ecology and Biogeochemistry (summer course, University of Utah) 


Research Interests

My fundamental interests are in Plant Physiological Ecology and Biogeochemistry 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.

I am the faculty supervisor of the Southern Oregon University Stable Isotope Facility (SOUSIF), where we measure the stable isotopes of C, O and N from organic matter samples. Stable isotopes have numerous applications in biology and ecology and we have run samples for many different labs and investigators. Recently we had major NSF funded projects looking at the stable isotope variation in coast redwood trees as a proxy for climate variation over the last millennium.  




Roden, J.S. (2008) Cross-dating of tree ring d18O and d13C time series. Chemical Geology. 252: 72-79. doi:10.1016/j.chemgeo.2008.01.007

Roden, J.S. Johnstone J., Dawson TE (2009) Intra-annual variation in the stable oxygen and carbon isotope ratios of cellulose in tree rings of coast redwood (Sequoia sempervirens). The Holocene. 19:189-197.

Roden, JS, Canny, MJ, Huang CX and Ball, MC (2009) Frost tolerance and ice formation in Pinus radiata needles: ice management by the endodermis and transfusion tissues. Functional Plant Biology. 36:180–189.

Roden, J.S. Johnstone J.A. and T.E. Dawson (2011) Regional and watershed coherence in the stable oxygen and carbon isotope ratio time-series in tree rings of coast redwood (Sequoia sempervirens). Tree Ring Research. 67:71-86.

Roden, JS and GD Farquhar (2012) A controlled test of the dual isotope approach for interpretation of stable carbon and oxygen isotope ratio variation in tree-rings. Tree Physiology. 32:490-503. doi:10.1093/treephys/tbs019.

Roden, JS and R. Siegwolf (2012) Is the dual isotope conceptual model fully operational? Tree Physiology 32:1179-1182.

Johnstone JA, J Roden, and TE Dawson (2013) Oxygen and carbon stable isotopes in coast redwood tree rings respond to spring and summer climate signals. Journal of Geophysical Research: Biogeosciences 118:1438-1450.

Voelker SL, JR Brooks, FC Meinzer, J Roden, A Pazdur, S Pawelczyk, P Hartsough,K Snyder, L Plavcova and J Šantrůček (2014) Reconstructing relative humidity from plant δ18O and δD as deuterium deviations from the global meteoric water line. Ecological Applications 24:960-975.

Babst, F, Alexander R, Szejner P, Bouriaud O, Klesse S, Roden J, Ciais P, Poulter B, Frank D, Moore D and Trouet V. (2014) A tree-ring perspective on the terrestrial carbon cycle. Oecologia 176: 307-322. doi:10.1007/s00442-014-3031-6

Tipple BJ, Berke MA, Hambach, B, Roden JS and JR Ehleringer (2015) Predicting leaf wax n-alkane 2H/1H ratios: controlled water source and humidity experiments with hydroponically grown trees confirm predictions of Craig–Gordon model. Plant Cell and Environment 38:1035-1047. Doi:10.1111/pce.12457.

Roden JS, Kahmen A, Buchmann N and R Siegwolf  (2015) The enigma of effective pathlength for 18O enrichment in leaf water of conifers. Plant Cell and Environment 38:2551-2565. doi:10.1111/pce.12568.

Churakova (Sidorova) O, Shashkin A, Launois T, Siegwolf R, Saurer M, Vaganov E, Bryukhanova M, Spahni R, Peylin P, Masson-Delmotte V and J Roden. Application of eco-physiological models to tree-ring parameters. Dendrochronologia (in press).


 Sciences RM 384

1250 Siskiyou Blvd.

Ashland, OR  97520

(541) 552-6799





B.S. Physics (1985) Stanford University

Ph.D. Biology (2001) University of Colorado, 2001

Santa Fe Institute Complex Systems Summer School, 1997



Genetics (Bi341)

Evolution (Bi348)

Molecular Biology (Bi425)

The New Sciences of Complexity (Bi381)


Research Interests:

Dr. Oline's research interests are in using molecular tools to address ecological questions. Currently he is participating in an NSF Dimensions of Biodiversity project investigating the dynamical interactions between temperate forest trees and their oomycete pathogens. Our field site is the Wind River Forest Dynamics Plot in southern Washington, and collaborators are a diverse group of ecologists, genomicists, and plant pathologists from Oregon State, Utah State, and Lewis and Clark college. We are using the resources of the SOU Biotechnology Center and SOU student researchers to take two approaches - characterizing allelic diversity of the PR4 plant resistance genes in the tree species at the Wind River site, and also investigating the diversity of native oomycetes present in the soil. Additionally, Dr. Oline is involved in projects including the molecular documentation of two different hybrid zones within the genus Abies (true firs) which interestingly co-occur in the local forests of southern Oregon and northern California - one between noble and red fir, and another between grand and white fir.



Oline, D.K.  2008. Geographic variation in chloroplast haplotypes in the California red fir-noble fir species complex and the status of Shasta red fir.  Can. J. For. Res. 38:2705-2710.

Oline, D.K. 2006. Phylogenetic comparisons of microbial communities from serpentine soils.  Appl. Environ. Microbiol. 72(11):6965-6971.

Oline, D.K., S.K. Schmidt, and M.C. Grant.  2006.  Biogeography and landscape-scale diversity of the dominant Crenarchaeaota of soil.  Microbial Ecology 52(3):480-490.

Oline, D.K., and M.C. Grant. 2002. Scaling properties of biomass and soil properties: an empirical analysis. Landscape Ecology 17:13-26.

Oline, D.K., J.B. Mitton, and M.C. Grant. 2000. Population and subspecific genetic differentiation in the Foxtail Pine (Pinus balfouriana). Evolution 54(5):1813:1816.


Sciences RM 386

1250 Siskiyou Blvd.

Ashland, OR  97520

(541) 552-6788





B.A. Biochemistry, University of California, Berkeley, 1978

M.A. Biology, University of California, Santa Barbara, 1981

Ph.D. Microbiology and Immunology, University of California, Los Angeles, 1988


Elementary Microbiology (Bi214)

Microbiology (Bi351, Bi353)

Our Microbial World (Bi383)

Cell Biology (Bi342)

Immunology (Bi456/556)

Research Interests

Dr. Page's research is focused on Environmental Microbiology. She is isolating and characterizing novel bacterial species from diverse environmental sites such as Crater Lake and an abandoned copper mine. She is also interested in assessing microbial pollution problems that occur in regional waterways. 



English, F., K. Coffelt, J. Daomn-Tollenaere, J. Heglie, M. Plankenhorn, and K. Page.  2011.  Ashland Creek E. coli Study.  Rogue Riverkeeper, Ashland, OR.

Page, K. A., S.A. Connon, and S. J. Giovanoni.  2004.  Representative Freshwater Bacterioplankton Isolated from Crater Lake, Oregon.  Appl. Environ. Microbiol. 70:6542-6550.

Page, K.A., Liegler, T, and M.B. Feinberg. 1997. Use of a green fluorescent protein as a marker for human immunodeficiency virus type 1 infection. AIDS Res. and Hu. Retro. 13:1077-1083

Page, K.A., W. van Schooten, and M.B. Feinberg. 1997. Human immunodeficiency virus type 1 Nef does not alter T-cell sensitivity to antigen-specific stimulation. J. Virol. 71:3776-3787.

Miller, M.D., M.T. Warmerdam, K.A. Page, M.B. Feinberg, and W.C. Greene. 1995. Expression of the human immunodeficiency virus type 1 (HIV-1) nef gene during HIV production increases progeny particle infectivity independent of gp160 or viral entry. J. Virol. 69:579-584.


Sciences RM 371

1250 Siskiyou Blvd.

Ashland, OR  97520

(541) 552-6867




Ph.D. Biological Anthropology, Kent State University (1998)

M.A.  Anthropology, Kent State University (1992)

B. A. Anthropology, University of California, Berkeley (1989)



Human Anatomy and Physiology (Bi231, Bi232, Bi233)

Advanced Human Anatomy and Physiology (Bi361, Bi362, Bi363)


Research interests

My research has involved studies of early childhood growth and development in collaboration with the Women, Infants, and Children (WIC) program. These projects have identified patterns of infant growth associated with later obesity and has identified demographic factors related to inappropriate maternal weight gain during pregnancy. More recently, my research has focused on effects of psychosocial stress on the neuroendocrine system. In collaboration with undergraduate students in Biology, we have addressed effects of chronic stress on daily cortisol patterns. These projects have recruited undergraduate students in Anatomy and Physiology courses as participants. Our research has identified individual factors such as coping and emotion regulation that moderate effects of stress on endocrine responses.



May RL, Kim D, and D Mote-Waton (2013) Change in weight-for-length status during the
first three months: relationships to birth weight and implications for metabolic risk.
American Journal of Physical Anthropology 150:5-9.

May RL (2009) Maternal factors associated with smoking and inappropriate weight gain
during pregnancy. Open Epidemiology Journal 2:20-25.

May RL (2007) Pre-pregnancy weight, inappropriate gestational weight gain, and
smoking: relationships to birthweight. American Journal of Human Biology 19:305-310.