Thesis (M.S.)--Oregon State University, 2004. / Printout. Includes bibliographical references (leaves 74-78). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 101-107). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1993. / Typescript (photocopy). Includes bibliographical references (leaves 118-122). Also available online.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 38-40). Also available on the World Wide Web.

Stemflow creates biogeochemical hotspots at tree bases. Few studies examine bark structure effects on stemflow generation via stable isotopes. Stemflow volume and isotopic composition (δD, δ18O) were measured over 15 months to address three main objectives: to determine origins and pathways of stemflow, to identify differences in stemflow generation mechanisms between tree species, and to identify differences in stemflow generation mechanisms between meteorological events. Laser ablation spectroscopy showed that, compared to throughfall and precipitation, stemflow was isotopically enriched, signifying isotopic fractionation. A bark-wetting experiment showed bark water storage capacity to be greatest in species with thick, continuous bark. Isotopic composition of precipitation was significantly more enriched in convective storms compared to that of continental or oceanic origin. Therefore, isotopic fractionation of stemflow and stemflow generation mechanisms vary from that of throughfall and precipitation, by interspecific differences in bark, and by meteorological event, potentially influencing existing canopy water storage models.

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 211-223). Also available on the World Wide Web.

No description available.

Understanding the controls on water movement on forested uplands is critical in predicting the potential effects of disturbance on the sustainability of water resources. I examined the controls on vertical and lateral water movement on forested uplands on a range of landforms (coarse textured outwash, fine textured moraine) and time periods (individual events, during snowmelt, through the growing season, annually, and long-term) at the Utikuma Region Study Area (URSA) on the sub-humid Boreal Plains of Alberta, Canada. To quantify vertical and lateral water movement, hydrometric and tracer measurements were made under natural and experimental conditions at plot and hillslope scales. Vertical flow and unsaturated zone storage dominated hydrologic response to snowmelt and rainfall at the plot and hillslope scales. Plot-scale snowmelt infiltration was greater than near-surface runoff, and when runoff occurred it was limited to south-facing outwash hillslopes underlain by concrete frost. Rainfall simulation studies showed that even under the extreme conditions tested, vertical flow and storage dominated the hydrologic response. Soils at field capacity and precipitation inputs of 15-20 mm or greater at high intensities were required to generate lateral flow via the transmissivity feedback mechanism. The threshold soil moisture and precipitation conditions are such that lateral flow will occur infrequently under natural conditions. Seasonal vertical water movement under natural conditions was greater on outwash than moraine uplands. The maximum downward vertical movement occurred in response to snowmelt, with little subsequent movement over the growing season. Recharge following snowmelt was similar for outwash and moraine sites and was followed by declining water tables through the growing season. Tracer estimates of long-term root zone drainage were low, while estimates of recharge for the moraine were high, raising questions about the appropriateness of this method for these sites. These results emphasize the dominance of vertical relative to lateral water flow on Boreal Plain uplands. Detailed understanding of the controls on water movement can be used to predict the potential effects of disturbance on hydrology and water resources. / Ecology

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 154-164). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Alaska Fairbanks, 2005. / "May 2005." Includes bibliographical references. Also available in electronic format via Internet.