Rainfall interception is a primary control over the moisture input to a forested ecosystem through the partitioning of precipitation into throughfall, stemflow, and an evaporated component (i.e. the interception loss). Rainfall interception is a spatially and temporally varying process at multiple scales, but heterogeneity in interception processes are poorly understood...
This thesis focuses on the identification of ecohydrological processes in nested system of catchments in a tropical alpine (the wet Andean páramo) ecosystem. We accomplish this by conducting a water stable isotopic characterization of water sources, an evaluation of the mean transit time (MTT) of streams waters, and the investigation...
The sustainable use of natural resources, including the goods and services provided by pasturelands and rangelands, is of growing importance due to climatic uncertainty and population growth. Maintaining high productivity in livestock operations is necessary as land availability diminishes and global populations rise. The potential negative impacts to the environment...
Municipal watersheds attempt to balance growing and conflicting demands for water for human use and for ecosystems. The Mill Creek basin, a 295 km2 basin in southeast Washington, exemplifies these conflicts. Since the late 1800s, the City of Walla Walla has withdrawn water from Mill Creek for municipal use. However,...
I compared transpiration among different types of forest stands in the western Cascades of Oregon. The three major questions were: 1) How does transpiration compare between a young and old stand and why? 2) Does diversity of overstory trees affect transpiration? and 3) How is transpiration related to stream flow?...
Understanding how the interactions and feedbacks between plant function, climate, and soils ultimately affects the terrestrial water balance and subsurface flow processes is major challenge in scientific hydrology. This dissertation summarizes the findings of a manipulative climate warming experiment, an observational field study that utilized stable-isotope tracers, and associated modeling...
Exotic ponderosa pine (Pinus ponderosa Doug. ex Lawson) plantations are being planted within the natural distribution area of cordilleran cypress (Austrocedrus chilensis (D.Don) Pic. Ser. et Bizzarri) in Patagonia, Argentina. The productivity of these exotic plantations is much greater than that of native forests, suggesting greater water use. Before these...
Western juniper has rapidly expanded into sagebrush steppe communities in the Intermountain West during the past 120 years. This expansion has occurred across a wide range of soil types and topographic positions. These plant communities, however, are typically treated in current peer-reviewed literature generically. The focus of this research is...
This study quantified the magnitude and timing of summer streamflow deficits in paired-watershed experiments in the Cascade Range of Oregon where mature and old-growth conifer forests were subjected to clearcutting, patch cutting, and overstory thinning treatments in the 1960s and 1970s. Hydrologic effects of clearcutting, small-patch cutting, and overstory thinning...
Rangelands span over 50% of the globe and approximately 70% of the United States. Although livestock production is an important use of rangelands, the benefits of rangelands are highly diverse. Humans find intrinsic value in protecting these unique and variable landscapes for wildlife, vegetation, and recreation enthusiasts. Woodland plant encroachment...
