Successful conservation management requires an understanding of how species respond to intervention. Native and exotic species may respond differently to management interventions due to differences arising directly from their native or exotic origin (i.e., provenance) or from differences in life-history or phylogenetic lineage that are associated with provenance. Thus, selection...
Numerous studies have demonstrated that vegetation canopies affect snow
accumulation and ablation processes. In addition, estimates of remotely sensed snow
covered area can be biased by the presence of an overlying vegetation canopy.
Consequently, any attempts to measure, model, or map the distribution of snow in a
region with heterogeneous...
The Pacific Northwest (Oregon and Washington in the United States and British Columbia in Canada) is one of the major producers of red raspberry (Rubus idaeus L.) and blueberry (Vaccinium corymbosum L.) in the world. The expansion of growing area with these crops has resulted in the emergence of new...
Hypersensitive response-like (HR-like) needle reactions to infection by the white pine blister rust pathogen, Cronartium ribicola, have been reported for several species of five needle pines native to western North America. The best-studied examples are in Pinus monticola and P. lambertiana. In these species a "needle spot" phenotype has been...
Secondary plant succession and the accumulation of biomass and nutrients were documented at seven ruminant exclosures in Abies and Pseudotsuga forests variously disturbed by logging, burning, and grass seeding. Long-term (25 or more years) foraging by Rocky Mountain mule deer (Odocolleus hemionus) and Rocky Mountain elk (Genius elaphus) suppressed the...
I developed a conceptual model of Douglas-fir bark beetle dynamics and associated host mortality across spatial and temporal scales. I proposed that a hierarchy of factors influence host resistance to attack at different spatial scales. I then tested this model by measuring the association between the occurrence of beetle-kill and...
White and grand fir are both valuable components of the mixed-conifer stand structure managed for late-successional reserves in central Oregon. However, they are often short-lived species because of high susceptibility to root diseases, defoliating insects, bark beetles, and wildfire. This study focuses on the effects of root diseases caused by...
The specificity of quantitative host resistance to plant disease has long been a controversial issue. We examined interactions between wheat (Triticum aestivum) and Mycosphaerella graminicola, causal agent of Septoria tritici blotch, to determine whether specific interactions occur between host and pathogen genotypes that could be involved in eroding quantitatively expressed...
Montane meadows comprise less than 5% of the landscape of the western Cascades of Oregon, but they provide habitat for diverse species of plants and pollinators. Little is known about plant-pollinator network structure at these sites. This study quantified plant-pollinator interactions over the summer of 2011, based on six observations...