In the Pacific Northwest (PNW), concern about the impacts of climate and land cover change on water resources, flood-generating processes, and ecosystem dynamics emphasize the need for a mechanistic understanding of the interactions between forest canopies and hydrological processes. A detailed measurement and modeling program during the 1999 and 2000 hydrologic years characterized hydrological conditions and processes in a 500-600 year old Douglas fir-western hemlock seasonal temperate rainforest. The measurement program included sub-canopy arrays of radiometers, tipping bucket rain gauges, and soil temperature and moisture probes, to supplement a vertical temperature and humidity profile within the forest canopy. Analysis of the precipitation interception characteristics of the canopy indicated that the mean direct throughfall proportion was 0.36, and the mean saturation storage was 3.3 mm. Evaporation from small storms insufficient to saturate the canopy comprised 19% of the net interception loss, and canopy drying and evaporation during rainfall accounted for 47% and 33% of the net loss, respectively. Results of the measurement program were used to modify the Simultaneous Heat and Water (SHAW) model for forested systems. Changes to the model include improved representation of interception dynamics, stomatal conductance, and within-canopy energy transfer processes. The model effectively simulated canopy air and vapor density profiles, snowcover processes, throughfall, soil water content profiles, shallow soil temperatures, and transpiration fluxes for both a calibration period and for an uncalibrated year. Soil warming at bare locations was delayed until most of the snowcover ablated due to the large heat sink associated with the residual snow patches. During the summer, simulated evapotranspiration decreased from a maximum monthly mean of 2.17 mm day����� in July to 1.34 mm day����� in September, as a result of declining soil moisture and net radiation. Our results indicate that a relatively simple parameterization of the SHAW model for the vegetation canopy can accurately simulate seasonal hydrologic fluxes in this environment. Application and validation of the model in other forest systems will establish similarities and differences in the interactions of vegetation and hydrology, and assess the sensitivity of other systems to natural and anthropogenic perturbations. / Graduation date: 2002

This thesis examines the Schultz Fire as a case study to explain the complex history of fire suppression management in America’s forests, and to gain further understanding of how management practices have affected the increase in fire severity levels and how forests respond to such a disturbance. The thesis objectives were: (1) to analyze the causes of the fire severity of the Schultz Fire, especially: topography, fuels, or weather; (2); to examine the possible correlation between fire severity and tree density; (3) to investigate whether post-fire species richness was related to fire severity two years after the Schultz Fire; (4) to investigate whether post-fire plant species richness, plant cover, and tree regeneration was related to fire severity two years after the Schultz Fire; and (5) to interlink and convey how these factors relate to the history of fire management and policy and public perception. The history of fire related policy and management has significantly changed the dynamics of America's national parks and forests. Understanding the larger context of this history, both of national fire management and of the effects of language and perception on policy and public reaction, is part of understanding the Schultz Fire as a whole. Based on modeling, high winds combined with the presence of high surface fuel load were the main causes of the Schultz Fire's high fire severity levels. As fire severity increased there was a statistically significant increase in species richness. Severity level had little variation on percentage of cover by plants. No statistically significant relationship between tree density and fire severity levels was found. These findings underline the need for fuel treatments in southwest Ponderosa Pine forests, and effective cooperation between communities, managers, and ecologists. The Schultz Fire serves as an example in understanding the intricacies of how history affects the present and future of fire management. How fire has been managed and portrayed in the past has left an indelible mark on how fire is presently viewed. Without a clear understanding of the history of fire management and the role of fire in the ecology, future policies towards fire will be unable to account for and manage for the diversity of ecosystems and fires effects on those ecosystems across the United States. / Graduation date: 2013

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains vii, 109 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 44-50).

Thesis (M.S.)--California State University, Chico. / Includes abstract. "Located in the Chico Digital Repository." Includes bibliographical references (p. 64-69).

No description available.

No description available.

Thesis (M. S. - Renewable Natural Resources)--University of Arizona, 1998. / Includes bibliographical references (leaves 98-103).

Thesis (M.A.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on November 9, 2007) Includes bibliographical references.

Thesis (B.S.)--University of Wisconsin -- La Crosse, 2007. / Also available online. Includes bibliographical references.

Thesis (M.A.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains viii, 55 p. : ill. (some col.), maps. Includes abstract. Includes bibliographical references (p. 44-48).