Forest managers of public lands in western Oregon and Washington have become increasingly interested in creating additional conifer cohorts in young, even-aged, second-growth Douglas-fir stands. The purpose of our research was to assess the establishment, survival, and growth of naturally-regenerated and underplanted conifers 10-13 years after overstory thinning and understory...
Previous research examining the influences of post-fire salvage logging on abundances of birds has focused primarily on the response of cavity-nesting species. There is limited research in regard to the impact of salvage logging on a broader range of bird species. In addition, little is known about how different intensities...
Bale Mountains National Park (BMNP) is currently considered the most important conservation area in Ethiopia. BMNP was established over forty years ago to protect Ethiopian endemic fauna and to preserve an array of habitat types including Afroalpine, Afromontane, and the second largest natural humid forest (Harenna forest) left in Ethiopia....
Two case studies of 5 ecosystems were used to examine the nitrogen fixation rate of red alder (Alnus rubra Bong.), varnishleaf (Ceanothus velutinus var. laevigatus (Hook.) T. & G.), deerbrush (C. i ntegerrimus H. & A.), and snowbrush (C. velutinus var. velutinus Dougl. Ex Hook). The first case study assayed...
Intensive forest management (IFM, dense conifer plantings and herbicide applications) may alter the characteristics of early seral plant communities that function as major habitat resources for a host of wildlife species, including cervid herbivores such as Cervus elaphus and Odocoileus hemionus. Such large herbivores can also substantially affect plant community...
Investigations of the Pleistocene peopling of the New World require archaeologists to establish an understanding of the paleoenvironmental conditions that would have affected early foraging peoples. Other studies have focused on the timing and route of migration and the peopling of the Americas. This project contributes to the body of...
This collection of three manuscripts serves to improve methods for collecting, interpreting, and utilizing autocorrelated data from headwater stream networks. Each stream network is comprised of linear segments. These segments lie within a unique branching structure that connects the segments via flowing water, and the connectivity provided by water varies...
Tree species directly and indirectly affect soil nutrient cycles. I sought to characterize soils and foliage associated with four common canopy tree species (Douglas-fir, western hemlock, western redcedar, and bigleaf maple) in mixed-species old-growth forests of the Oregon Coast Range and to determine whether and how soils differ among the...
Native America tribes and community members throughout Oregon have asserted a strong opposition to the fossil fuel industry’s attempt to expand railways, build pipelines, and construct refineries, holding facilities, and export terminals. Despite the limited presence of fossil fuel infrastructure in the state, however, the industry is actively pursuing permits...
Small pelagic fishes (SPF), such as anchovies and sardines, are ecologically important due to their large abundance and intermediate trophic position that links plankton production to upper trophic levels. They are also economically important, supporting large fisheries that contribute to one fourth of the world fish landings. Reproductive success in...
Ungulates comprise some of the most well researched and intensely managed wildlife populations on earth. As such, they are recognized as ideal study subjects for developing and modifying management tools or theories (Danell et al. 1994, Shipley 2010). An introduced moose (Alces alces gigas) population on the Copper River Delta...
Large areas of non-coniferous communities in southwestern Oregon are thinned to reduce fire hazard and accomplish ecosystem restoration, under the assumption that current fuel loads are unnaturally high. Although Oregon white oak (Quercus garryana) woodlands are a characteristic landscape component in this region, little is known about their current or...
I studied presence, relative abundance, and resource selection of bats in managed Douglas-fir (Pseudotsuga menziesii) forests in western Oregon from May through September, 1999–2001. Species richness was not related to elevation, density of snags, or length of edge or perennial streams in sampled landscapes. I captured bats more frequently in...
We conducted capture and acoustic surveys for bats in six areas along a latitudinal gradient in Southeast Alaska from mid-May to September in 2005 and we continued surveys on Prince of Wales Island from mid-May to September in 2006. We determined the level of effort required to catch each species...
Vegetation provides food for many insects, and many insects serve as food for bats. We investigated the linkages among these three trophic levels in riparian areas throughout the Oregon Coast Range by examining the influence of vegetation cover, composition, and structure on the activity of nocturnal insects and bats, the...
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E. Macro-moths captured in conifer- and deciduous-dominated stream reaches..... 212
F
The diverse lichen flora of the Pacific Northwest is being impacted by
population growth and by forest management practices. Accumulating information
about our lichen flora will improve our conservation strategies. This dissertation first
collects information to improve our understanding of how lichen communities vary
among forests of differing structure, and...
Mixed-severity fire occurrence is increasingly recognized in Pseudotsuga forests of the Pacific Northwest, but questions remain about how tree mortality varies, and forest structure is altered, across the disturbance gradient observed in these fires. Therefore, we sampled live and dead biological legacies at 45 one ha plots, with four 0.10...
Fundamental objectives in the field of conservation biology involve understanding the processes that influence small and declining populations and applying that knowledge to develop appropriate monitoring strategies and targeted management and conservation actions. Critical first steps in determining the relative role of factors that drive population declines involves estimation of...
The genus Phytophthora contains some of the most destructive pathogens of forest trees, including the most destructive pathogen of alder in recent times, Phytophthora alni. Alder trees were reported to be suffering from canopy dieback in riparian ecosystems in western Oregon, which prompted a survey of alder health and monitoring...
Prairie-oak ecosystems in the Willamette Valley, Oregon have experienced habitat loss and degradation; most of these ecosystems are fragmented into smaller patches. Prairie-oak butterfly species, in the Willamette Valley, have decreased dramatically due to loss or degradation of habitat. More research is needed on sustaining the populations of butterflies in...
Fuels management on Bureau of Land Management lands in SW Oregon, USA, is motivated by the needs to reduce fire hazard and restore ecosystems thought to be impacted by fire suppression. Chaparral is one of the most characteristic vegetation communities of SW Oregon's interior valleys, and extensive acreages within this...
There is renewed interest in agroforestry as a management strategy for marginal agricultural lands in western Oregon. Silvopastoral systems combine tree and
forage production, which involve crops and practices familiar to the area. The objective of this study was to determine how
management influences the physiology and ecological interactions of...
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...
Deforestation, accelerated soil erosion, and land degradation are serious problems in Ethiopia. The uncontrolled removal of natural forests, demographic pressures and cyclical drought has aggravated the situation, resulting in massive environmental degradation and a serious threat to sustainable agriculture and forestry. To overcome these problems efforts have been made to...
Canopy gap formation is a major factor contributing to maintenance of overstory species diversity and stand structure in forests and may be integral to development of understory shrub and herb layers as well. Acknowledgement of gap formation as a fundamental feature of natural forests has led to consideration of gaps...
Fire is a major disturbance process in many forests. Long-term studies of the biogeochemical effects of fires, especially on soils, are very rare.
Consequently, long-term effects of fire on soils are often hypothesized from
short-term effects. In a chronosequence study, I studied 24 western Cascades
(Oregon) forest stands thought to...
Previous studies of bird communities in the mid-Willamette Valley, Oregon, indicated that Oregon white oak (Ouercus garryana) stands supported more cavity-using bird
species than sympatric stands of Douglas-fir (Pseudotsuga menziesii). Mature Oregon oak stands are being harvested and few are regenerating. I compared cavity availability for hole-using fauna among 10...
Chlorinated and non-chlorinated solvents are used in a variety of industrial processes and as a consequence, they have become environmental contaminants as well. Because of this, they lead to both occupational and environmental exposures. Exposure to these compounds can potentially result in various forms of neurological damage with a wide...
Ecosystem nitrogen (N) supply strongly influences the availability and cycling of other essential nutrients in temperate forests, especially calcium (Ca). Short-term additions of N that exceed ecosystem demands often increase dissolved nitrate fluxes and decrease soil pH, which can stimulate soil Ca loss. However, the long-term effects of high N...
Various methods have been used to estimate the amount of above ground forest biomass across landscapes and to create biomass maps for specific stands or pixels across ownership or project areas. Without an accurate estimation method, land managers might end up with incorrect biomass estimate maps, which could lead them...
Several studies of herbaceous perennials have addressed the effects of environmental factors during and after production, inherent cold hardiness, and post-harvest handling procedures to enhance flowering and growth during establishment. The regrowth of both woody and herbaceous forage plants following establishment is reported to be directly related to reserve-nitrogen content....
Stem rust, caused by the fungus Puccinia graminis subsp. graminicola, can cause yield reductions exceeding 90% on perennial ryegrass (Lolium perenne L.) crops grown for seed if not treated with fungicide in the spring. There is evidence that late-spring stem rust epidemics are initiated by populations that survived the winter....
In response to concerns about excessive stand densities and high-severity wildfires, land managers in the western United States are carrying out extensive programs of fuel reduction thinning. How will these sudden reductions in canopy cover and associated changes in habitat affect native and exotic herbaceous vegetation and canopy species regeneration?...
This study examines the long-term role of interference on stand development of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) and red alder (Alnus rubra Bong.) planted mixtures in the Central Cascades of Oregon, USA. The two species are common associates in naturally regenerated and planted conifer stands in the Pacific Northwest. Due...
Silvicultural canopy gaps are emerging as an alternative management tool to accelerate development of complex forest structure in young, even-aged forests of the Pacific Northwest. I investigated patterns of nitrogen (N) availability along transects through 0.1 and 0.4 ha silvicultural gaps in three 50-70 year old Douglas-fir forests of western...
Sagebrush steppe ecosystems are one of the most widespread but endangered ecosystems in North America. A diverse array of human-related stressors has gradually compromised these ecosystems' resilience to disturbance and invasion by Bromus tectorum (cheatgrass). The role of the foundational shrub Artemisia as a driver of herbaceous community structure and...
Disaggregative and individual-tree/distance-independent modeling methods are
compared and contrasted. Differences between the two are related to differences in functional
and apparent resolution and may be illustrated using aggregation theory. When considering
models of different levels of resolution describing a given phenomenon, invariance with respect
to the aggregation implied (symmetry) may...
Pollination is an essential ecosystem service that sustains functioning ecosystems and aids in food production. In response to recent, widespread declines of managed and native bee populations, many land managers have shown interest in developing conservation and restoration plans for enhancing native bee habitat. However, there is a lack of...
Population trends and patterns in species distributions are the major currencies used to examine responses by biodiversity to changing environments. Effective conservation recommendations require that models of both distribution dynamics and population trends accurately reflect reality. However, identification of the appropriate temporal and spatial scales of animal response, and then...
Models of weed communities aid in the development of
weed management strategies and elucidate the processes
and mechanisms that regulate plant populations and
communities. A conceptual weed community model was
developed to organize key regulatory life-history
processes. Specific investigations focused on the
processes of plant growth and competition, and
relationships...
Fire severity is hypothesized as an important driver of bird responses to wildfire. For those species that typically respond negatively to increasing severity, Accessibility of high-severity burned forest may be dependent on the proximity of unburned or low-severity burned forest to meet all of the needs of breeding bird species...
Headwater streams are generally small, first-order streams that can comprise up to 80% (by stream length) of the drainage network in mountainous areas of the Pacific Northwest. These streams are intimately connected with downstream reaches, serving as a source of sediment, woody debris, organic matter and nutrients. The surrounding forests...
This thesis examines the competitive aspects of Douglas-fir trees growing with two commonly associated competitors--red alder and grass--at varying densities. Two Nelder plots in three different environments in the Oregon Coast Range were studied. The sites represented the warm, dry climate of the Willamette Valley; the warm, moist climate of...
This thesis research examines the effects of film-forming antidesiccants applied to dormant pondexosa pine (Pinus ponderosa Dougl.) seedlings after being lifted and to actively growing seedlings. The basic proposition was that antidesiccants would have a positive effect on reducing water loss in ponderosa pine seedlings. In order to evaluate the...
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...
Since 2007, electronic cigarette (e-cigarette) sales in the U.S. have surpassed those of tobacco cigarettes. This is due, in part, to manufacturer’s claims that they are a safer alternative to tobacco cigarettes. However, formaldehyde, acrolein, and diacetyl have been detected in e-cigarettes and public knowledge of e-cigarette composition and potential...
We studied the feasibility of using end-grain characteristics to match individual boards and cants back to their parent Douglas-fir (Pseudotsuga menziesii) logs. After reviewing marking/reading and biometric automated identification systems, we focused on end-grain biometrics because they appear to have the most promise for sawmills. Biometric identification requires that every...
Forest management is an important mechanism that provides social, ecological, and economic benefits to the community. On public lands, management is often initiated for multi-use objectives. However, both history and research have proven that the level of acceptance for harvesting on public lands varies both temporally and spatially. Public perceptions...
Surface water and groundwater are intimately connected by a two-way flux between the stream and the underlying aquifers; a complicated yet crucial relationship to represent in models. However, the National Water Model currently only considers a one-way flux, where groundwater can enter a stream but cannot return to the aquifer....
HOE 23408 [methyl 2-[ 4-( 2, 4- dichlorophenoxy )phenoxy]propanoate]
is a herbicide used to selectively-control Italian ryegrass
(Lolium muitiflorum Lam.) and wild oats (Avena fatua L.) in wheat.
The objective of this research was to compare the relative importance
of foliar and root uptake of the herbicide in these two...
To understand the influence of selective harvesting on
the adaptive capacity of fish populations in changing
environments, a computer simulation model was developed. In
the model, hypothetical populations were composed of five
different life histories, which were genetically determined.
Each life history type had its own rate of survival and...
Reducing the cover of non-native species is one of the challenges of ecosystem restoration. The goal of this study is to identify native species traits that will increase native species cover and reduce non-native species cover in the first growing season at upland and wetland prairie restoration sites. Native and...
Cellooligosaccharides are the reaction intermediates produced during the hydrolysis of cellulose to glucose. Hence, they have the same chemical structure as cellulose, just shorter chain lengths. Cellooligosaccharides up to DP eight are soluble in water. The soluble cellooligosaccharides can be used "as is" in the food industry as non-digestible oligosaccharides...
Many streams in eastern Oregon are listed as water quality impaired on the basis of water temperature. However, it is often difficult to predict water temperature for these streams even if there are no anthropogenic impacts. We measured air and water temperature and stream characteristics on three Type C and...
This dissertation describes arthropod responses to and effects on decay processes in ponderosa pine, a dominant forest canopy tree in northern California. We used both descriptive and experimental field techniques to establish how arthropod assemblages depend on and are important to the disintegration of woody structures in forests of this...
Land use alters the physical and biological structure of stream ecosystems and potentially alters their capacity to process nitrogen (N), an essential nutrient that has nearly doubled in abundance on the biosphere
during the past century from human activities. In this dissertation, I quantified uptake and transformation of nitrate (NO₃⁻)...
Anthropogenic induced climate change is predicted to alter distribution of existing plant populations. As plants migrate over space and time, populations often fragment and contract, affecting basic elements of population dynamics (e.g., population size, gene flow, genetic diversity, etc.). Little is known, however, how these impacts on plant species will...
Snow is a critical component of global climate regulation and provides water resources to over one billion people worldwide. Yet current measurement methods and modeling techniques lack the ability to fully capture snow characteristics such as snow water equivalent (SWE), snow depth, and density variable landscapes. In recent years, the...
Aquatic and riparian systems in the western United States have been highly modified by anthropogenic impacts since Euro-American settlement. Ecological restoration is a practice that has been widely conducted around the world to mitigate the degradation of these systems. The majority of stream restoration efforts have focused on improving in-stream...
The salt marshes of the Salmon River Estuary, Oregon have been of interest for decades due to their disturbance and restoration history, as well as the presence of long-term vegetation transects that were established as early as the 1970s. Vegetation abundance data have been gathered in the four sites of...
Though numerous drought metrics have been developed by the research community, adoption of these metrics by water managers has been limited. The reasons for this vary, but some include mismatches in time scales and spatial scales between the metric supplied and the operational decisions (e.g. water managers often work within...
Self-regulation in early childhood encompasses higher-order executive function processes and lower-order emotional responses that enable children to navigate the classroom environment. Although self-regulation and executive functions are overlapping constructs, self-regulation represents a broad assessment of children’s ability to call upon executive function processes in order to meet contextual demands. Prior...
Cyanolichens, lichens with a cyanobacterial photobiont, benefit our ecosystems by the fixation of atmospheric nitrogen into a usable form for other organisms. They are highly sensitive to air pollution and require liquid water for photosynthesis. Many cyanolichen species frequently occur on the ground in the Pacific Northwest, however, most macrolichen...
Large ensembles of regional climate simulations were generated from the weather@home distributed volunteer computing project over the western US domain. Weather@home uses the U.K. Met Office Hadley Centre’s regional climate model HadRM3P (~0.22°) nested within the atmospheric global model HadAM3P (1.875 longitude° by 1.25 latitude°). Simulations from HadRM3P were evaluated...
Rhizopogon vesiculosus is a common ectomycorrhizal (EM) symbiont of Pseudotusga menziesii (Douglas-fir) in the coast range of the Pacific Northwest. The species has been studied for its systematics, genet size, population structure, and competitive ability in several field and experimental studies. This thesis seeks to provide a more thorough characterization...
Discussions around adapting water management systems to climate change often express the need to increase the flexibility and adaptive capacity of current systems, and to implement robust strategies going forth. While these topics lie at the center of many climate change discussions, transforming adaptation recommendations into tangible tools and information...
A sequence of soils derived from tuffaceous rocks was sampled
on the H. J. Andrews Experimental Forest and adjacent U. S. Plywood
land to determine some genetic and stability relationships. The
less than two micron size fraction from each sample was characterized
by x-ray diffraction with respect to crystalline clay...
After nearly 20 years of commercial use in orchards without
apparent tree injury in Oregon and Washington, 2,4-D [(2,4-dichlorophenoxy)
acetic acid] was reported in 1970 to cause injury to apple
and pear trees in Washington. In the early 1970's, there was widespread
concern among growers, researchers, and processors in the...
In the last decade regulatory bodies have begun to implement standards to protect populations of non-human biota (NHB) from the consequences of radiation exposure. This is a departure from previous regulatory frameworks which were concerned only with protecting man. The implementation of these new standards has started an ongoing discussion...
This investigation was motivated by the introduction of the new
nearest neighbour analyses which reportedly provided a better control
of soil gradients than conventional experimental methods.
Three nearest neighbour analyses and six other analyses were
compared with the completely randomized design or the randomized
complete block design in reducing the...
The pharmacokinetics of two antimicrobials were investigated in alpacas. Six healthy alpacas were each administered a single dose of 10 mg/kg of oxytetracycline by IV injection and IM injection. In addition, a single dose of 20 mg/kg of florfenicol by IV administration was given to alpacas in a separate study....
Previous studies have shown that rainbow trout exposed to dieldrin via diet for 9 to 12 weeks increased biliary excretion of a subsequent dose of [¹⁴C]dieldrin by 500%. This was not explained by induction of the cytochrome P-450 (CYP) system involved in oxidative metabolism of these compounds. We hypothesized that...
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...
A triple layer phoswich detector was designed and assembled in the advanced radiation instrumentation lab at Oregon State University. The detector had three scintillation layers: the first one was a BC-400 for beta and conversion electron detection, the second layer was a CsI(Tl) for x-ray and gamma detection, and the...
Natural fibers such as wood, flax, and hemp are frequently used as fillers in natural fiber-plastic composites (NFPCs). At present, wood fiber is the most commonly used filler in the production of wood-plastic composites (WPCs). The advantages of these fibers compared to conventional inorganic fibers such as glass fiber is...
The purpose of this research project was to provide a resource for
individuals doing historic restoration and preservation of buildings
built between 1850 and 1900 in Oregon. The research attempted to determine
the styles, patterns, and colors of wallpaper that were used, who
applied the wallpaper, the methods of application,...
An energy balance analysis was performed on each of four
transplanted Douglas-fir [Pseudotsuga menziesii (Mirb.) Francol
seedlings growing on two cutover sites in southwestern Oregon. The
two sites were a clearcut and a partial-cut (shelterwood) side by
side, with a pair of seedlings used on each site. One seedling of...
Island biogeography has strongly influenced the study of biodiversity because
archipelagos provide natural model systems for investigating patterns of diversity and the
processes that shape ecological communities. I investigated the influence of area and
isolation of islands (n = 32) in the Gulf of California, Mexico on patterns of richness,...
Forests play an integral role in the global carbon cycle, regulating the atmospheric CO₂ concentration by sequestering nearly one third of anthropogenic carbon emissions and storing carbon for centuries. Forest ecosystems are integrated into the culture, ecology, and economy of western North America, supporting wildlife habitat, local economies, recreation, and...
Twenty-six Holstein and 18 Jersey multiparous cows in a randomized block design were assigned by calving date and breed to a non-anionic prepartum diet (CTRL) or a treatment diet containing a commercial anionic salt supplement (Animate®). Control and treatment diets were formulated to a dietary anion-cation difference (DCAD) of 21.3...
The Safe Drinking Water Act ensures that public systems provide water that meets health standards. However, no such protection exists for millions of Americans who obtain water from private wells. Concern for safety is warranted as most wells draw from underground aquifers, and studies demonstrate that groundwater is affected by...
Escalating demand for organic blueberries has driven a significant expansion of northern highbush blueberry (NHB; Vaccinium corymbosum L.) production area. This expansion is particularly pronounced in regions of the Pacific Northwest where native soil conditions are sub-optimal for NHB, notably east of the Cascade Mountain Range of Oregon and Washington,...
The environmental health science community recognizes polycyclic aromatic hydrocarbons (PAHs) as a re-emerging class of environmental pollutants due to their persistence and prominence in mixtures of concern. Due to their widespread distribution in the environment, exposure to PAHs often occur as complex chemical mixtures. Exposures are linked to numerous adverse...
Mathematical modeling plays a pivotal role in understanding the mechanism of radiation-induced cellular effects, and also in quantifying the radiation risk to the cell. However, there are still compelling challenges facing the conventional modeling in radiobiology, such as lacking a generalized theory structure of quantifying target effect and non-target effect...
Over the past century, life expectancy in the United States has dramatically increased leading to an increasingly aging population with people reaching, and spending more years in ‘old age’. While this unprecedented shift in population demographics represents great strides for humanity, it is not without cost. One consequence of longer...
Chlamydia is a genus of obligate intracellular bacteria that undergo a unique, biphasic developmental cycle. The infectious and metabolically inert Elementary Bodies (EBs) begin the cycle of infection by attaching and invading a host cells. Once inside, the EBs differentiate into the metabolically active, dividing Reticulate Bodies (RBs) within their...
Research has established that poor outcomes are the future for those without a
high school diploma--yet students continue to drop out and become members of
that population. The purpose of this qualitative study was to investigate the
experiences and perceptions of individuals who did not complete high school
within the...
Sulforaphane is an isothiocyanate derived from cruciferous vegetables and has been under investigation as a cancer chemopreventive agent for over two decades. The compound is well tolerated and has been shown to slow cancer progression in several different pre-clinical models of carcinogenesis, such as of the lung, breast and colon....
The purpose of the thesis is to design, construct,
program, and test an automatic integrated circuit test
system. The class of integrated circuits tested was restricted
to digital integrated circuits. The general concept
of testing a digital integrated circuit is based on
the truth table of that circuit. A combination...
The objectives of this study were: 1) to identify and map the
experimental area of Meadow Creek watershed by existing vegetation,
and 2) to identify and map the experimental area of Meadow Creek
watershed by habitat types. The classification system adopted for
this study was based on the habitat type...
The major focus of this research was to examine the factors, both
instructional factors and student factors, that influence student
gains in economic knowledge in economic education. This study sampled
twelfth grade students from randomly selected high schools in the
Williamette Valley of Oregon. The stepwise regression analysis was
used...