Euro-American settlement and organized fire suppression have been associated with structural and compositional changes in many upland forests of the western United States, but little is known about the impacts on riparian forests, portions of the landscape protected for habitat and water quality. In this study, we used dendro-ecological methods...
Beetle diversity and habitat associations of five
prevalent riparian plant communities were examined along
the lower reaches of Big Beaver Creek Research Natural
Area, North Cascades National Park, Washington. These
communities were defined by dominant tree species, and
included Alder Swamps, Cedar-Hemlock Forests, Douglas-fir
Forests, Gravel Bars, and Willow-Sedge Swamps....
I evaluated fire occurrence, growth and recruitment and determined the fire history of 21 old and 20 young 8ha stands in Cascade, Siskiyou and mid-Coast mixed conifer and evergreen forests in southwestern Oregon. The rates and patterns of growth were measured and analyzed on 1,079 old-growth and 2,111
young stand...
During the last century, fire suppression, grazing, and climate change have caused sagebrush grasslands to be altered in both function and form; juniper and sagebrush dominate the landscape at the expense of herbaceous plants. Management efforts to reduce juniper and sagebrush overstory in order to enhance herbaceous components of the...
The 1994 Northwest Forest Plan (NWFP) shifted federal lands management from a focus on timber production to ecosystem management and biodiversity conservation. The plan established a network of conservation reserves and an ecosystem management strategy on ~10 million hectares from northern California to Washington State, USA, within the range of...
Project AFS-58 Final Report (part 3). The final of three reports on a 15-year study to determine the effects of logging on the aquatic resources of three tributaries of the lower Alsea River. The study took place from 1959-1973. Primary objectives included in-depth study of population characteristics of fish species...
In the Northwest Great Basin, aspen (Populus tremuloides) communities uniquely contribute to the biodiversity of a semi-arid, sagebrush-dominated landscape. In this same region, western juniper (Juniperus occidentalis) is encroaching into aspen stands. This study determined the timing, extent, and some of the effects of this expansion. Aspen stands below 2,133...
This study examined debris flows occurring in a 125 km² study area in the Blue River watershed in the western Cascade Mountains of Oregon over a 50-year period. Debris flow occurrence was found to be concentrated in a distinct zone of high activity occupying approximately half of the study area,...
In the last decade, many U.S. parks and protected areas (PPA) experienced record breaking visitation levels. Managers of these PPAs face the challenging task of providing a range of quality and accessible outdoor experiences without compromising the integrity and health of surrounding ecosystems. Understanding how PPA visitors move and interact...
Remote sensing techniques have long been useful in quantifying changes in ecosystems and the field of remote sensing is constantly evolving to better assess and describe changes, both spatially and temporally. In this thesis I explored the novel use of two remote sensing methods to quantify ecosystems; repeat photograph to...
The United States is the third-largest producer of raspberries in the world. Washington
State leads the nation in red raspberry (Rubus idaeus L.) production. 'Meeker', the
most grown red raspberry cultivar in the Pacific Northwest (Washington, Oregon and
British Columbia, Canada) is highly susceptible to Raspberry crumbly fruit, a virusinduced...
Ectomycorrhizal fungi (EmF) form symbioses with trees. These symbioses profoundly influence forest ecology. Certain EmF form specialized profusions of hyphae, known as ectomycorrhizal fungal mats (mats) which are visible to the naked eye, alter forest soil biogeochemistry, substantially contribute to soil microbial biomass/respiration and support unique microbial communities. Piloderma and...
Project AFS-58 Final Report (part 2).
The second of three reports on a 15-year study to determine the effects of logging on the aquatic resources of three tributaries of the lower Alsea River. The study took place from 1959-1973. Primary objectives included in-depth study of population characteristics of fish species...
A microclimatology study was conducted on a high elevation clearcut
near the summit of Mt. Ashland in southwest Oregon to evaluate the effects
of frost on Douglas-fir seedling growth and survival. Frost and low
temperatures cause seedling stress through frost damage, frost desiccation,
increased root resistance, and decreased rates of...
A model of agricultural decision making is developed and tested in this thesis. The expected value of utility evaluated under alternative outcomes is directly maximized in a nonlinear programming model. Two features of the model distinguished it from traditional risk programming models. First, alternative attitudes towards the assumption of risk...
A trait based approach was used to assess impacts of overstory density and thinning on understory vegetation components related to wildlife habitat. The relationship between overstory basal area and understory vegetation for species grouped by traits, such as production of flowers, fleshy-fruit and palatable leaves, was characterized in thinned and...
Wild fish populations are typically infected with a variety of micro- and macroparasites that may affect fitness and survival, however, there is little published information on parasite distribution in wild juvenile salmonids in three upper tributaries of the Willamette River, OR. The objectives of this survey were to document (1)...
Debris flow initiation is controlled by a complex interaction of geology, geomorphology, climate, and weather. In the Cascade Range of Pacific Northwest and mountainous areas globally, patterns of temperature and precipitation are being altered by climate change, which may in turn impact debris flow initiation. Temperature has increased and patterns...
Several streams in the mixed conifer cover type of the Ochoco and Blue Mountains of central Oregon were studied to determine what effects selective harvesting of the riparian timber stand had on the amounts and distribution of coarse woody debris (CWD) in the stream. Pristine streams were measured to develop...