National Forest management in the Pacific Northwest is shifting
from a focus on commodity production to ecosystem management, in which
the health of the entire forest ecosystem is considered, rather than that
of a few key species. Ecosystem management includes retention of some
live trees following timber harvest (green-tree retention)...
Falls are a common problem among older adults, including those who are relatively healthy and living independently. Exercise has been recommended as an intervention to reduce falls by slowing and/or reversing age-related declines in balance, strength, and mobility. However, it remains unclear which types or combinations of programs are most...
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Samuel T. Johnson
Falls are a common problem among older adults, including those who are
To study the combined effects of seedling quality and fertilization at the time of planting, three experiments were established in western Oregon during the winter of 2000. The first experiment investigated the effect of preplanting rootvolume and fertilization rate on the field performance of 1+1 Douglas-fir seedlings during two growing...
Coastal Douglas-fir (Psuedotsuga menziesii (Mirb.) Franco) 1 + 1 seedlings were fertilized with two types of fertilizers (NB4NO3+K2SO4 and (NH.4)2 SO4+KC1) at four rates (0, 80, 160, 320 kg N and K/ha) split over 3 application dates (September 19, October 13, November 1, 1996). By January 10, total Kjeldahl nitrogen...
A series of studies and replicated field sites were implemented in the Oregon Coast Range within Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) sapling plantations infected with varying levels of Swiss needle cast (SNC) caused by the fungus, Phaeocryptopus gaeumannii (Rhode) Petrak (PG). This research was conducted to understand the effects of...
Concern over the increasing proportion of juvenile wood grown in second growth plantations has led to a large amount of research on the effects of common silvicultural practices on wood quality. Lacking is research on the effect of timing and
duration of vegetation control on wood quality near the pith...
Douglas-fir (Psudotsuga menziesii (Mirb.) Franco) seedlings were outplanted on eight dates (every three weeks from mid-August 2005 through mid-January 2006). On each plant date, seedlings from a conventional dormancy (CONV) induction treatment, including moisture and nutrient stress, and a shortened daylength (SD) treatment were outplanted on three western Oregon sites...
In this report, three studies are presented that utilize computations to predict transformations, identities, and properties of environmental organic molecules. Each study shows how computations can lead to models of chemical behavior. The importance of this research is rooted in the need for understanding how human behavior and health intersect...
Methane derived authigenic carbonate (MDAC) precipitation occurs within marine sediments as a byproduct of the microbial anaerobic oxidation of methane (AOM). While these carbonates form in chemical and isotopic equilibrium with the fluids from which they precipitate, burial diagenesis and recrystallization can overprint these signals. Plane polarized light (PPL) and...
Studies were conducted on pathogenic specialization and
heterothallism in Sphaerotheca pannosa var. rosae, causal agent of
rose powdery mildew.
Methods were developed for isolation and identification of
Sphaerotheca pannosa var. rosae races on rose. Monoconidial isolates were initiated on detached leaves, increased on host plants,
and inoculated to rose cultivars...
The purpose of the study was to develop a system and procedure for classifying and cataloguing the textile, costume, and slide collections of the Clothing, Textile, and Related Arts (CTRA) Department at Oregon State University. Investigation was made by letter, personal visit, interview with faculty and curators, and literature research...
Biological di-nitrogen (N₂) fixation is a key process in open-ocean ecosystems, where the new nitrogen (N) provided by marine diazotrophs can support a large fraction of primary productivity and carbon (C) drawdown. Recent laboratory studies have shown that elevated pCO₂ enhances the rate of N₂ fixation by select laboratory isolates...
Full dynamic control of physically simulated characters is the holy grail of video
games and other interactive applications. Recent advances in the field have
presented controllers that can handle the balance and fall response after a
collision. This thesis addresses the development of a controller that handles the
response before...
The Cook-Austral island chain has been the center of debate for many years. Contrary to the classical hotspot hypothesis, this volcanic island chain does not exhibit a linear age progression with a single node of active volcanism, but instead shows evidence of young volcanism at several points along the chain....
In this work, I developed a six degree of freedom flight simulator specific to liquid engine launch vehicles. This flight simulator improves upon available software by accounting for liquid engine specific phenomena such as tank pressurization, liquid engine performance, and center of gravity modeling. Additionally, I implemented methods for optimization...
This research assessed the effect of western juniper (Junlperus
occldentalls) removal on understory plant production and cover and
ponderosa pine (Pinus ponderosa) growth and plant water status.
A complete randomized block design, with four blocks and four
treatments was established in the summer of 1984 near Prineville,
Oregon. The four...
Chinook salmon returns to the Columbia River basin have declined due to impacts of a growing human population, despite significant mitigation expenditures. Consequently, fisheries managers have become focused on recovery and long-term viability of at-risk populations. A viable population depends, in part, on the connectivity and quality of diverse habitat...
From July, 1982 to August, 1983 I had the privilege of serving an internship
as an oceanographer at the National Marine Fisheries Service Beaufort
Laboratory. During the period of my appointment I assisted in a preliminary
assessment of the potential fishery impacts of ocean thermal energy conversion
(OTEC) power plants....