Live western larch, Larix occidentalis Nutt., a tree species resistant to the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, produces the monoterpene 3-carene in higher concentrations compared to Douglas-fir, the preferred host of D. pseudotsugae (Reed et al. 1986). The inhibitory effects on attraction to aggregation pheromones and toxicity of 3-carene to...
The Chugach National Forest has been using prescribed fire as a wildlife habitat management tool since l977. Between 1977 and 1997 about 4,000 hectares have been burned on the Kenai Peninsula to promote regeneration of woody plant species used by moose (Alces alces). Browse species include paper birch (Betula papyrifera),...
The MODIS NBAR (M0D43B4) data space is explored in terms of biophysical variables with the objective of formulating a MODIS transformation relevant to global vegetation studies. The basic ideas of transform formulation were borrowed from the development of the TM Tasseled Cap transformation, but with differences in sampling strategy and...
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...
To increase our understanding of the timber harvesting behavior of family forest owners, I developed theoretical and empirical timber harvesting models for family forest owners in the southeastern United States. An individual-choice model was the basis for the models. Family forest owners were modeled as utility-maximizers who made harvesting decisions...
Stream systems in the Pacific Northwest have come to be understood in the absence of beaver (Castor canadensis). To understand the effect of beaver upon riparian plant communities, four basins in the lower Alsea drainage were examined to determine the effect of beaver and their impoundments on streamside herbaceous/shrub and...
Field studies were conducted from 1996 to 1998 in three villages in a Highland watershed in Mae Hong Son Province, northern Thailand. The objectives of the study were to classify and define the fruit-based agroforestry cropping system and investigate
management activities used by villagers. In the first part of the...
To effectively manage for biodiversity at broad, ecosystem scales, the influences of habitat structure at multiple spatial scales on vertebrate species must be understood. There are few studies on the broad-scale habitat requirements of stream amphibians despite their importance in streams in forest ecosystems in the Pacific Northwest (PNW) as...
Thinning of young Douglas-fir forests has the potential to enhance structural diversity and improve habitat for wildlife. I examined the effects of thinning and thinning intensity on abundance and demographic characteristics of forest-floor small mammals in the Coast Range of Oregon 5 and 6 years after thinning had occurred. Thinning...
My objectives were to investigate the correlation of height and diameter growth in young Douglas-fir (Pseudotsuga menziesii) plantations with stand density, and to determine the effects of stand density on the canopy boundary layer conductance (g[subscript]ac) and microclimate characteristics of young Douglas-fir plantations. I measured annual height (h) and diameter...
Two experiments were conducted on the invasive plant species Potentilla recta in northeastern Oregon to investigate both biological and ecological characteristics of the species. Growth analysis was conducted on the plant at three sites over a period of two years (2002 and 2003). Relative growth rate (RGR) was calculated for...
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...
The tree species and size structure of 9l old-growth forests dominated by Douglas-fir
in central western Oregon was characterized using complete inventories of all trees larger than 20cm dbh over a mean area of 17.1ha at each site. Douglas-fir accounted
for over 75% of the total average basal area (39.1...
Viability analysis of well-selected focal species can complement other types of conservation planning by revealing thresholds in habitat area and landscape connectivity that may not be evident from ecosystem-level evaluations. I used focal species analysis of five carnivores to suggest conservation planning guidelines for the Rocky Mountains and adjacent areas...
The Amazon Tropical Rain Forest is the largest tropical rain forest system, comprising approximately 65% of such forests on earth. Since the 1960's, human populations in the Brazilian Amazon have increased from two to over 20 million. Concomitant urbanization, forest conversion, and economic dependence on resource extraction have exerted severe...
The goal of this dissertation was to improve our understanding of age-related constraints on aboveground production of forest trees. Previous research suggesting that carbon uptake of old trees is hydraulically constrained by tree size was used as the
springboard for this research. Three specific working hypotheses were investigated: 1) compensation...
Prescribed burning is increasingly being used as a management tool to reduce potential fuels on the forest floor and promote stand vigor through removal of dense, crowded vegetation. Because fire affects both the standing vegetation and the amount of downed wood in the ecosystem, it is imperative to examine how...
Human activities are causing profound changes to the global environment, yet the potential consequences of these changes on rising atmospheric carbon dioxide and climate change are not well understood. Improving our understanding of these processes requires an enhanced awareness of how global ecosystems are changing and how these changes affect...
I conducted two separate studies, both related to the impacts of spring and fall prescribed fire on ponderosa pine (Pinus ponderosa Dougl. ex Loud.) forest soils in Eastern Oregon. The studies were either conducted at or linked to four stands of ponderosa pine, in the Malheur National Forest. Each stand...
Delayed tree mortality is an unpredictable occurrence when prescribed burning is implemented. Fire scorched trees may die as the result of crown scorching, stem charring, root injury, bark beetle attack, or through a combination of these factors. This study examined ponderosa pine mortality and the incidence of two bark beetle...