Thesis (M.S.)--Oregon State University, 1971. / Partially funded by Oregon Agricultural Experiment Station. Includes bibliographical references (leaves 39-41). Also available on the World Wide Web.

Graduation date: 1999

This thesis documents a period of ecological and cultural change on a Willamette Valley, Oregon landscape. In particular, this study examines the Peavy Arboretum area and the cultural changes that accompanied the transformation of the landscape from an oak savannah in the mid-nineteenth century to a dense Douglas-fir forest in the early twentieth century. Culturally, the inhabitants of this period included late-prehistoric native people, Euro-American based fur industry personnel, and Euro-American settlers. As a student of history and archaeology, I have used a combination of methods and sources for this study including surface surveys for cultural materials and features, archaeological excavations and analysis, and documented materials. Knowledge gained as a result of surveys and excavations are studied within the context of other Willamette Valley archaeology, and likewise, documented materials concerning this landscape and its historic features and people are compared against larger patterns in the history of the American West. Geographically, the study area was in a fortunate position to witness cultural events. Located along the edge of the foothills of the Willamette Valley, its many desirable features attracted both native people and the first white settlers. The study area was also located along a main route of travel that was used by natives, fur company personnel, travelers, and Euro-American settlers. The section of trail has been a part of regional travel routes known at different times as the Hudson's Bay Company Trail, the California Trail, the Southern Route (Scott-Applegate Trail), and the Territorial Road. The objective of this thesis was to see what kind of information could be retrieved for a given landscape using a variety of methods practiced in history and archaeology. I believe such a multi-disciplinary approach allowed me to be more flexible and open to all pertinent sources of information. This type of investigation also provided an example of the type of work that could be done professionally when determining the cultural significance of a property. My fascination with the study of landscapes and their cultural features was also influential in my selection of a thesis topic. / Graduation date: 1999

Typescript. Includes vita and abstract. Includes bibliographical references (leaves 367-382). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.

xvii, 160 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Restoring oak habitats is an emerging conservation priority in Oregon's Willamette Valley. Both private and public landowners face multiple challenges to conservation and restoration of oak habitats, including a lack of knowledge about the potential tradeoffs and constraints for achieving multiple priorities on a given site. This study simulated 25 alternative oak habitat restoration scenarios to develop estimates of outcomes related to six different restoration priorities: costs, income potential, habitat value, scenic quality, fire hazard reduction potential, and time requirements. Model results indicated that initial land conditions strongly influence a landowner's ability to optimize among these different priorities. To assist landowners with decision-making, model estimates were organized into a digital decision matrix that communicates advantages and tradeoffs associated with each alternative scenario. In doing so, it aims to help landowners choose restoration goals that better meet their broader needs and objectives. / Committee in Charge: Dr. Bart Johnson, Chair; Dr. Robert Ribe

xii, 127 p. ： ill. (some col.) / I developed software to incorporate the FlamMap fire model into an agent-based model, Envision, to enable the exploration of relationships between wildfire, land use, climate change, and vegetation dynamics in the Willamette Valley. A dynamic-link library plug-in utilizing row-ordered compressed array lookup tables converts parameters between polygon-based Envision data and grid-based FlamMap data. Modeled fires are determined through Monte-Carlo draws against a set of possible fires by linking historic fire data to future climate projections. I used classification and regression tree (CART) and logistic regression to relate ignitions to human and land use factors in the Willamette Valley above the valley floor from 2000-2009. Both methods showed decreasing distance to major and minor roads as key factors that increase ignition probability for human ignitions but not for lightning ignitions. The resulting statistical model is implemented in the FlamMap plug-in to provide a dynamic ignition probability map over time. / Committee in charge: Dr. Bart Johnson， Co-Chair； Dr. Scott Bridgham ，Co-Chair； Dr. John Bolte； Member

xvii, 382 p. : ill. (some col.), maps. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / The debate concerning the role of natural versus anthropogenic burning in shaping the prehistoric vegetation patterns of the Willamette Valley of Oregon and Washington remains highly contentious. To address this, pollen and high-resolution charcoal records obtained from lake sediments were analyzed to reconstruct the Holocene fire and vegetation history, in order to assess the relative influence of climate variability and anthropogenic activity on those histories. Two sites provided information on the last 11,000 years. At one site at the northern margin of the Willamette Valley, shifts in fire activity and vegetation compared closely with millennial- and centennial-time scale variations in climate, and there was no evidence that anthropogenic burning affected the natural fire-climate linkages prior to Euro-American arrival. In contrast, the fire and vegetation history at a site in the central Willamette Valley showed relatively little vegetation change in response to both millennial- and centennial-scale climate variability, but fire activity varied widely in both frequency and severity. A comparison of this paleoecological reconstruction with archaeological evidence suggests that anthropogenic burning near the site may have influenced middle- to late-Holocene fire regimes. The fire history of the last 1200 years was compared at five sites along a north-south transect through the Willamette Valley. Forested upland sites showed stronger fire-climate linkages and little human influence, whereas lowland sites located in former prairie and savanna showed temporal patterns in fire activity that suggest a significant human impact. A decline in fire activity at several sites in the last 600 years was attributed to the effects of a cooling climate as well as the decline of Native American populations. The impacts of Euro-American settlement on the records include dramatic shifts in vegetation assemblages and large fire events associated with land clearance. The results of this research contribute to our understanding of long-term vegetation dynamics and the role of fire, both natural- and human-ignited, in shaping ecosystems, as well as provide an historical context for evaluating recent shifts in plant communities in the Willamette Valley. / Advisers: Cathy Whitlock, Patrick J. Bartlein