Field surveys in 2006 confirmed that the
exotic rust fungus Phragmidium violaceum was widespread
on Rubus armeniacus and Rubus laciniatus in
the Pacific Northwest of the USA. The origin and
dispersal pattern of this obligate biotrophic pathogen in
the USA were investigated by comparing the genetic
diversity and structure of...
Tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.] is an important forage and turf grass seed crop in Oregon. Use of the stem-shortening plant growth regulator (PGR) trinexapac-ethyl (TE) has gained broad acceptance by tall fescue seed producers in Oregon and elsewhere world-wide as an economical agent of seed yield enhancement through...
The purpose of this dissertation was to increase understanding of adolescent school counseling groups including a literature review of the quantitative outcome research on group work with adolescents in the schools and a qualitative exploration of the adolescent experience of cohesion in rural school counseling groups. Outcome research on group...
Net uptake of carbon from the atmosphere (net ecosystem production, NEP) is dependent on climate, disturbance history, management practices, forest age, and forest type. To improve understanding of the influence of these factors on forest carbon flux in the western U.S., a combination of federal inventory data and supplemental ground...
Cavity trees contribute to diverse forest structure and wildlife habitat. For a given stand, the size and density of cavity trees indicate its diversity, complexity, and suitability for wildlife habitat. Size and density of cavity trees vary with stand age, density, and structure. Using Forest Inventory and Analysis (FIA) data...
Regional estimation of potential forest productivity is important to diverse applications, including biofuels supply, carbon sequestration, and projections of forest growth. Using PRISM (Parameter-elevation Regressions on Independent Slopes Model) climate and productivity data measured on a grid of 3356 Forest Inventory and Analysis plots in Oregon and Washington, we evaluated...
Management of grape powdery mildew (Erysiphe necator) and other polycyclic diseases often relies on calendar-based pesticide application schedules that assume the presence of inoculum. An inexpensive, loop-mediated isothermal amplification (LAMP) assay was designed to quickly detect airborne inoculum of E. necator to determine when to initiate a fungicide application programme....
As global climate changes over the next century, forest productivity is expected to change as well. Using PRISM climate and productivity data measured on a grid of 3356 plots, we developed a simultaneous autoregressive (SAR) model to estimate the impacts of climate change on potential productivity of Pacific Northwest (PNW)...
Many growth and yield simulators require a stand table or tree-list to set the initial condition for projections in time. Most similar neighbour (MSN) approaches can be used for estimating stand tables from information commonly available on forest cover maps (e.g. height, volume, per cent canopy cover and species composition)....
Information on current forest condition is essential to assess and characterize resources and to support resource management and policy decisions. The 1998 Farm Bill mandates the US Forest Service to conduct annual inventories to provide annual updates of each state's forest. In annual inventories, the sample size of I year...