This report presents a nested gauging study of streamflow variability from three sub-catchments (150-200 ha in area) of the Burns Creek catchment (565 ha) in the Entiat Experimental Forest of central Washington State. We test and reject the hypothesis that headwater catchments of this size are composed of physically and...
Understanding how the interactions and feedbacks between plant function, climate, and soils ultimately affects the terrestrial water balance and subsurface flow processes is major challenge in scientific hydrology. This dissertation summarizes the findings of a manipulative climate warming experiment, an observational field study that utilized stable-isotope tracers, and associated modeling...
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JeffreyJ. McDonnell
Understanding how the interactions and feedbacks between plant
This dissertation integrates a process-based hydrological investigation with an
ongoing paired-catchment study to better understand how forest harvest impacts
catchment function at multiple scales. We do this by addressing fundamental questions
related to the stocks, flows and transit times of water. Isotope tracers are used within a
top-down catchment intercomparison...
Bedrock groundwater dynamics in headwater catchments are poorly understood and
poorly characterized. Direct hydrometric measurements have been limited due to the
logistical challenges associated with drilling through hard rock in steep, remote and
often roadless terrain. Here we develop and use an inexpensive, portable bedrock
drilling system to explore bedrock...
This dissertation re-examines the now standard perceptual model of hillslope
hydrological response to rainfall, which includes the growth of a saturated wedge at the soil-bedrock interface or impeding layer. It also challenges the notion of bedrock impermeability and the assumption that the pattern of subsurface stormflow is determined by the...
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JeffreyJ. McDonnell
This dissertation re-examines the now standard perceptual model of
The age, or residence time of water is a fundamental descriptor of catchment hydrology, revealing information about the storage, flow pathways and source of water in a single integrated measure. While there has been tremendous recent interest in residence time to characterize catchments, there are few studies that quantify residence...
The specific objectives of this dissertation are to determine subsurface flow
behaviors across different antecedent wetness conditions from a top-down perspective
and to mechanistically assess the hydrological controls on DOC and N transport at the
hillslope and catchment scale. The study area is a small catchment where hillslopes
issue directly...
The physical controls of snowmelt in the Pacific Northwest (PNW) are poorly
understood. While there have been numerous field and modeling investigations at the
plot and watershed scale, few studies have identified how the snow energy balance
(EB) components vary in importance both spatially and temporally. The identification
of how...
Rainfall interception is a primary control over the moisture input to a forested ecosystem through the partitioning of precipitation into throughfall, stemflow, and an evaporated component (i.e. the interception loss). Rainfall interception is a spatially and temporally varying process at multiple scales, but heterogeneity in interception processes are poorly understood...
Stream discharge is a key water balance component and important factor in global change evaluations. Nevertheless, the mechanisms for streamflow generation are poorly understood. Near- stream surface saturation during precipitation events is one of the most iconic, visible indicators of rapid runoff production in upland humid catchments around the world....
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JeffreyJ. McDonnell
Stream discharge is a key water balance component and important factor in
The dominant controls on flow generation in steep, forested hillslopes are poorly understood. This dissertation examined the dominant flow processes operating at the hillslope scale, using a combined macroscale measurement and model development and analysis framework. Irrigation experiments at two steep forested hillslopes were conducted to isolate individual hillslope flow...
Members of the family Sciomyzidae, known as snail-killing or marsh flies, are unique amongst insects in that the vast majority of reared species feed exclusively on mollusks and as a result their biological control potential has been well documented in the scientific literature. However, in North America there is a...
The links between forests, streamflow, and climate are poorly understood. Despite hundreds of studies over the past 60 years, fundamental questions of forests' effects on the hydrologic cycle remain unanswered. The hydrological cycle involves mutually-dependent biological and physical processes that operate at multiple scales of time and space, and this...
Fungi are the primary biological agents of wood deterioration and cause major economic losses of wood products globally. Wood in outdoor applications tends to remain wet for extended time periods, making it susceptible to fungal attack. Understanding the factors involved in fungal colonization of wood is important for developing improved...
Chlorpyrifos (CPF) is a widely used broad-spectrum organophosphate insecticide. Following exposures, CPF and its more toxic oxon metabolite (CPFO) elicit neurotoxic effects by inhibiting the activity of the acetylcholinesterase enzyme (AChE), resulting in altered fitness and death at high doses. Following exposure, organisms bioactivate CPF to CPFO through the Cytochrome...
This research examined the potential for using peanut husk as a fiber alternative to wood in the production of melamine-formaldehyde (MF) particleboard. MF resin was used to produce panels with one, three, six, nine or 12 percent resin contents. Modulus of Rupture (MOR), Modulus of Elasticity (MOE), Internal Bond (IB)...
The sustainable use of wood for rail ties requires chemical treatment to increase service life and maintain structural integrity. Treatment can only be applied after lengthy air-seasoning to reduce moisture content in wood, but seasoning leaves ties exposed to attack by decay fungi for up to a year. One factor...
The vast majority of U.S. farm bill spending goes to nutrition assistance, on the one hand, and farm safety net programs, on the other. Although these programs are a major part of federal government expenditures, controversial and governed by a common bill, they have rarely been quantitatively analyzed together. To...
Boron and boron compounds have been long used for pressure treatment, dip-diffusion, and remedial treatments of wood because of their proven efficacy against fungi and insects. These materials are especially attractive because their high water solubility promotes deeper penetration into wood. Other useful properties of boron include its neutral pH,...
Pacific Northwest and California freshwater resources are key elements in the life history and ecology of Pacific salmon and steelhead listed as threatened or endangered under the Endangered Species Act. Risk to listed Pacific salmonid species can be assessed by evaluating the spatial and temporal co-occurrence of salmonid species at...
Small manufacturing firms often serve a domestic market but would like to expand their sales overseas. It is difficult for a small firm to develop overseas contracts and relationships, however, in part because of their small size, and because the advantages of their products may not always be obvious. The...
Resistance to moisture uptake is an important attribute of some wood preservatives and can help reduce moisture cycling that leads to the development of deep checks. While the potential for preservative treatments to help improve wood/moisture interactions is acknowledged, there are no tests that specifically evaluate this performance parameter. Checking...
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JeffreyJ. Morrell
Resistance to moisture uptake is an important attribute of some wood
Copper is the most common ingredient in waterborne preservatives and provides excellent activity against most fungi and insects. However, issues associated with copper migration from treated wood have created increasing concerns about potential risks to non-target organisms in surrounding environments, especially those in sensitive aquatic environments. Various Best Management Practices...
Both red (Trifolium pratense L.) and white (Trifolium repens L.) clover
seed yields can be highly variable and low in western Oregon. The objectives of
this study were to: i) determine crop water requirements and supplemental
irrigation timing, and ii) quantify the effects of soil and water status on
inflorescence...
Kura clover (Trifolium ambiguum M. Bieb.) is slow to establish and
has low seed yields the year after establishment. Intercropping a cereal
grain during clover seed field establishment could provide additional
revenue to seed growers, provided that intercropping did not jeopardize
future clover seed yields. Factorial combinations of spring- and...
Birdsfoot trefoil (Lotus corniculatus L.) is a popular perennial, non-bloating forage legume used for pasture, hay and silage throughout the temperate regions of Europe, Asia Minor, North Africa and North and South America. It is regarded as the most morphologically and biochemically variable species in the genus. Research investigating the...
There is no information available on water management of birdsfoot
trefoil grown for seed. Information is also not available describing how to
minimize seed losses due to shattering in order to obtain consistently high
birdsfoot trefoil seed yields. The objectives of this research are to: (i) quantify
crop water use,...
Volatile loss rates of pesticides from turfgrass were measured using the Backward-Time Lagrangian Stochastic Dispersion model (Flesch et al., 1995). Solar radiation, ambient temperature, surface temperature, relative humidity, wind direction, and wind speed were monitored continuously. Growth regulator was applied to the turf plot several days before pesticide application to...
Postmenopausat women on hormone replacement therapy (HRT) have been reported to be stronger when compared to women who are not using HRT. The first goal of this study was to investigate whether muscle morphology was altered in women who use HRT when compared to women who do not use HAT....
The goals of this research were to a) characterize the protein-function relationships of skeletal muscle single fibers from the mouse hindlimb b) examine mouse-strain related differences in myosin heavy chain composition (MHC) and single fiber contractile function, and c) quantify changes in fiber size and contractile function in response to...
The purpose of this work was to determine if environmentally-relevant concentrations of chlorpyrifos and copper, two commonly detected chemicals in Western surface waters, can negatively impact the biological health of salmonids. Both compounds are highly neurotoxic to fish, but each with distinct biological target sites and mechanisms of action. We...
Resistance training is widely prescribed for rehabilitation of injuries and as a method to improve athletic performance. It is accepted that resistance training increases the maximal force production of whole muscle and it has been suggested that the velocity of shortening can increase as well. However, little is known about...
Skeletal muscle damage induced by lengthening ("eccentric" or
"pliometric") contractions cause an immediate loss in maximal tetanic force (P₀) and an increase in protein degradation by unidentified endogenous mechanisms.
We hypothesized that increased proteolysis following active lengthening injury is
mediated by the Ca²⁺ dependent protease calpain. To test this hypothesis...
The goal of this project was to develop an integrated pest management strategy
for the control of a powder-post beetle (Dinoderus minutus F.). This species causes
serious damage in Philippine bamboo. Developmental threshold and thermal constants
were examined and natural enemies and ftmgi associated with beetles were investigated.
Finally, the...
Supercritical fluid (SCF) impregnation is a promising preservative treatment method, however, the development of SCF processes has been slowed by a limited understanding of the process. Developing a better understanding of the effects of various process parameters on treatment results would allow for a more rational development of SCF impregnation....
Copper is an excellent biocide which has a long history of usage for protecting wood from deterioration, but some organisms have developed tolerance for this chemical. Copper tolerance among wood decay fungi is a poorly understood phenomenon that is gaining importance as cofactors such as arsenic and chromium are removed...
Moisture intrusion in residential structures can lead to substantial fungal decay and this damage costs billions in repair/replacement costs. The extent of damage and the rate at which it occurs are primarily dependent on the wood moisture content and temperature in the structure. Determining the risk of decay for various...
Small size wood assays were utilized to study the
effect of added nutrients to the wood on the interactions
of Trichoderma harzianum Rifai and two wood decay fungi,
Trametes versicolor (white rot) and Gloeophyllum trabeum
(brown rot). Weight losses related to time of exposure
were monitored as a measure of...
Biological stain (blue stain) reduces wood value and
prevents its use in many structural applications. Increasing
environmental concerns have restricted the chemicals
available for controlling this damage. As a result,
biological control has received more interest. The
application of these systems to wood has been limited due to
their inability...
The fungi that cause mold and stain of freshly sawn lumber result in millions of dollars in losses to the forest products industry. Stain and mold are typically prevented by either kiln drying or by application of a topical fungicide. While these treatments are effective, kiln drying is costly and...
The biocontrol potential of Trichoderma harzianum strains
B-2A, B-8A, B-4B, B-15B, and B-41 and Serratia plymuthica was
evaluated using agar plates and wood wafers of unseasoned
ponderosa pine (Pinus ponderosa laws). All five isolates of
Trichoderma harzianum and Serratia plymuthica could inhibit
stain fungi growth in agar plates and exhibited...
Pest control operators in Oregon were surveyed to examine the occurrence of carpenter ants and other wood destroying organisms in structures. Carpenter ants frequently occurred in the coast and Willamette valley regions of the state and were associated with wetter, mesic habitats. To examine the effects of substrate and moisture...
Two approaches to improving wood treatability include the modification of pressure
schedules during conventional liquid treatments and the use of supercritical fluids (SCFs). In
both of these techniques, pressure differences are important for transporting materials into
wood. The level of pressure and its change during SCF treatments are also important...
Basamid^R (3,5-dimethy1-1,3,5,2H-tetrahydrothiadiazine-
2-thione) is a crystalline powder used as a soil sterilant.
This fumigant acts in soil by decomposing to methylisothiocyanate
(MITC), the primary active ingredient, as well as
hydrogen sulfide, methylamine, and formaldehyde. In wood,
Basamid decomposes too slowly to be efficacious against
decay fungi unless amended with various...
Metham sodium or NaMDC is one of the four major soil
fumigants that are currently registered for controlling
internal decay of wood products in use. Fumigants are used
primarily in utility poles but are also applied to piling,
timbers and other large wood members.
NaMDC must decompose to fungitoxic compounds...
Natural and synthetic estrogenic compounds detected in surface waters have
been linked to endocrine signaling disruption in several species. Endogenous
estrogen contributes to cartilage and bone deposition during development in
vertebrates, and is susceptible to perturbation from xenoestrogens. The goals of
this work were to develop a teleost model to...