The purpose of this study is to examine the relationship between land management practices of Indian communities prior to contact with Europeans and the nature or character of subsequent catastrophic forest fires in the Oregon Coast Range. The research focus is spatial and temporal patterns of Indian burning across the...
Forests in the Pacific Northwest receive very little nitrogen through atmospheric deposition and thus studying the nitrogen cycle in this region can provide insights into how the unpolluted nitrogen cycle functions. I examined the fate of organic nitrogen versus inorganic nitrogen and the effect of tamlins on N retention by...
The nomenclatural history of Gomphus sensu lato began with Persoon in
1797. Over 200 years species of Gomphus sensu lato have been variously classified
also under Cantharellus, Craterellus, Chloroneuron, Chlorophyllum,
Gloeocantharellus, Nevrophyllum, and Turbinellus.
Species of Gomphus sensu lato have been historically characterized as
having aboveground fruiting, fleshy basidiomata with...
Sex differentiation in fish is a labile process that allows sex inversion in several species. The inherent capacity of fish germ cells to differentiate into oocytes or spermatocytes constitutes a key factor allowing for functional sex inversion. This thesis set out to determine the mechanism involved in steroid-induced sex differentiation...
Growing societal demand for forest products is pressuring managers to increase productivity from a finite land area, and it is expected that increased supply will come mostly from expansion of intensively managed stands. The USDA Forest Service and numerous collaborators created the Long-Term Soil Productivity (LTSP) network of research sites...
The process of silvicultural thinning has become very controversial recently with regards to fire protection and management for old-growth conditions and biodiversity. Therefore, an unthinned control stand and 3 different thinning intensities were examined for their effects on the abundance, species richness, and diversity of arthropods in thinning treatments of...
This research investigates the direct and downstream impacts of clearcut harvest units on stream temperature as a part of the Hinkle Creek Paired Watershed Study. The Hinkle Creek watershed is located in the foothills of the Cascade Mountains about 30 kilometers northeast of Roseburg, Oregon, is privately owned, and supports...
Balancing resource extraction with protection of Pacific Northwest forest ecosystems requires understanding the population biology of ectomycorrhizal fungi. Design of landscape-scale management and research strategies requires understanding genet size, habitat requirements, and dispersal capabilities. The purpose of this dissertation was to gain knowledge about the distribution of genetic variation, systematics,...
Seasonal and annual patterns of N fluxes and concentrations in streamwater in six conifer-dominated watersheds at the H.J. Andrews Experimental Forest, OR, were studied to gain insight into the factors that influence N retention in this ecosystem. Processes affecting N flux in streamwater differed between organic (DON) and inorganic (DIN;...
This dissertation investigates the problem of uncertainty in complex ecological models. The term "complex" is used to convey both the common and scientific meanings. Increasingly, ecological models have become complex because they are more complicated; ecological models are generally multi-variate and multi-leveled in structure. Many ecological models are complex because...
Maritime cyclonic windstorms cause widespread disturbance to forested ecosystems in southeast Alaska. The consequence of this disturbance process on the movement, storage, and quality of soil carbon, forest hydrology and streamwater chemistry was studied along a windthrow disturbance sequence. Soil profiles were described and the thickness of the major organic...
Beginning in the 1980s, large-scale commercial harvest of Tricholoma magnivelare created a need for management of forests to ensure sustainability, but little was known of the biology or ecology of this species to guide management decisions. Four of the five studies presented here explore the basic synecology of T. magnivelare...
The effects of forest cutting on forested systems and the biotic components of those systems has been at the forefront of scientific research. The inventory and monitoring of biodiversity is one technique used for measuring the effects of forest management. Because bioinventory studies are expensive, indicator species are often sought...
Edge effects resulting from forest fragmentation are likely to alter the distributions and
interactions of resident species. I evaluated changes in species composition, species
turnover, and relative abundance of ground arthropods across replicated transects
extending from regenerating clearcuts into old-growth Douglas-fir forests. Arthropods
were collected from 3-August to 14-September in...
This study was directed to improve our understanding of the ecology of Swiss needle cast (SNC) of Douglas-fir, a disease that produces extensive damage to forests and plantation in the coastal region of Oregon and Washington. A disease prediction model for the coastal area of Oregon was built by establishing...
Feeding rainbow trout 0.3-0.4 mg dieldrinlkg/d for 9-12 weeks stimulated the biliary excretion of a subsequent dose of [¹⁴C]dieldrin by 500% and [³H]7,12- dimethylbenz[a]anthracene (DMBA) by 240%. In vitro work demonstrated that this interaction occurred without induction of the cytochrome P450 system, or other hepatocellular proteins involved in metabolism. The...
The Oregon Long-Term Soil Quality Project was initiated to identify soil
properties that respond rapidly to alternative management practices. Such practices
included winter cover cropping, which was implemented at two experimental research
stations and several grower fields throughout the Willamette Valley. The goal of this
thesis was to identify the...
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,...
As concern over global warming intensifies, sequestration and storage of atmospheric CO2 has become an important scientific and policy issue. Confusion persists, however, over interpretation of forest carbon (C) source-sink dynamics, in part because conclusions drawn depend on temporal and spatial scales of analysis (e.g. day-week
scale vs. successional-scale), type...
Wetlands are widely identified as providing important and fundamental processes valuable for maintaining ecosystem health and diversity. Located in the southern Willamette Valley, the Mt. Pisgah Arboretum contains some valuable remaining wetland habitat along the Coast Fork of the Willamette River. One goal of the Mt. Pisgah Arboretum is "to...