Studies were conducted from 1962 to 1966 to investigate the
effectiveness of several practices in manipulating medusahead
(Taeniatherum asperum (Sim. ) Nevski) infested and/or dominated
ecosystems by releasing competition in favor of perennial grasses.
Several herbicide treatments were evaluated for selective
control of medusahead and cheatgrass (Bromus tectorum L. )...
The 2002 Biscuit Fire burned through more than 200,000 ha of mixed conifer/
evergreen hardwood forests in southwestern Oregon and northwestern
California. The remarkable size of the fire and the diversity of conditions through
which it burned provided an opportunity to analyze the correlates of burn severity
across vegetation types...
Following high-severity fire, forest succession may take alternate pathways depending on the pattern of the fire and any secondary disturbances during early stand development, with lasting consequences for ecosystem function. The objectives of this research were to quantify: (1) early postfire regeneration as influenced by the spatial pattern of a...
At the time of the eruptions of Lassen Peak in 1914-1915, an
area of vegetation along the east slope of the mountain approximately
1 1/4 miles wide and four miles long was destroyed. Except for a
few surviving trees, all vegetation was destroyed.
A study of the revegetation of this...
Fire is the dominant disturbance process in western U.S. forests, and although effects of fire in upland forests are relatively well-studied, there is little information about fire effects on riparian forests, critical areas of the landscape for both habitat and water quality. This dissertation examines different aspects of fire effects...
High severity fire is a historical and integral disturbance process in coniferous
forest types. Compounded disturbances such as multiple fires or post-disturbance
management activities are increasingly common, but ecological responses are not well
understood and may represent novel types of disturbances. I studied bird and small
mammal communities in the...
This dissertation seeks to understand Yi farmers’ livelihoods in the midst of an agricultural transition in Yunnan, Southwest China. This dissertation examines a community’s traditional knowledge related to wild edible plants (WEPs), analyzes socio-ecological vulnerability and resilience in the face of agricultural transition from subsistence farming to cash cropping, and...
Phylogeographic studies of six Pacific Northwest forest-associated
salamanders provide insight into historical and contemporary processes on
population genetic structure. Among Larch Mountain Salamanders (Plethodon
larselli), cytochrome b mitochondrial (mtDNA) sequences (381 bp) and random
amplified polymorphic DNA (RAPDs; 34 loci) supported separate Management
Units for northern and southern populations (12...
The use of Native American fire regimes evolved in the Klamath-Siskiyou bioregion over millennia. A mixture of Native American and Euro-American socio-cultural management has developed from adaptations to climate, topography, ecological processes, and land use practices. This research incorporates Traditional Ecological Knowledge (TEK) to partially examine the role of tribal...
Monitoring wildlife habitats has become important to forest ecosystem management because it provides valuable information about the response of forests and their species to harvest practices, impacts from recreational use, conservation efforts, and natural and human-caused disturbances. Monitoring is a complex task that requires a variety of abiotic and biotic...
Small herds of cows were observed and spatially mapped over continuous twenty-four hour periods. Treatments were implemented that investigated the effect of water site and supplementation on animal distribution patterns. A series of six observation periods constituted each observation series. Observation series were repeated winter (January) and summer (July) for...
Accurate taxonomy is essential to preservation and management of native
grasses. Four problems in fescue taxonomy were investigated: the identity of the
native fescue that dominates western Oregon and Washington prairies, the relationship
of native Festuca roemeri to closely related grasses, the status of F. howellii and F.
washingtonica, and...
Pacific whiting (Merluccius productus) is commercially
and ecologically one of the most important fishery resources
in the Pacific coast of the United States. The fishery
is currently going through a period of rapid and profound
transformation that could cause a substantial redistribution
of benefits among domestic users. Benefits from the...
Rising global temperatures are having lasting effects on mountain snow environments in the form of diminishing snowpacks, shorter accumulation seasons, and shifts in meltwater timing. Seasonal snowpack is a vital source of water for natural and human systems. In the forested mountain landscapes of the Pacific Northwest seasonal snowmelt feeds...
Eight species of Lathvrus (Fabaceae, Faboideae) endemic to the
Pacific Coast of North America were the subject of a systematic
investigation. Taxa studied included Lathvrus vestitus, Nutt. ex T.
& G., L. laetif lorus Greene, L.. iepsonii Greene, £,. splendens
Kellogg, L. polvphvllus, Nutt. ex T. & G., L. holochlorus...
Identifying appropriate units for conservation requires knowledge of evolutionary
patterns and risks of managing at different geographical and genetic scales. I examined
genetic diversity at different geographical scales among 11,400 rainbow trout
(Oncorhynchus mykiss) from 243 locations in 13 major river basins throughout much of
their range and among coho...
In the United States, many of the thorniest natural resource conflicts occur on private lands. This is especially true in the Willamette Valley of Western Oregon where the hallmark habitat type, Oregon white oak woodland and savanna, is imperiled. Almost exclusively found on private land, Oregon white oak is threatened...
Airborne discrete-return lidar is an active remote sensing technology capable of obtaining accurate, fine-resolution three-dimensional measurements over large areas. Discrete-return lidar data produce three-dimensional object characterizations in the form of point clouds defined by precise x, y and z coordinates. The data also provide intensity values for each point that...
The purpose of this study was to develope a plant community classification
within the Siskiyou mountains, a small range within the Klamath
geological province well known for its geologic and floristic diversity.
Forest land managers have expressed the need for identification of
basic Land classes that will aid in the...
A study was made of the subgenus Genuini of the genus Juncus in the Pacific States, California, Oregon and Washington. Extensive morphological comparisons, geographical distributions, habitat differences and observations of apparent presence or absence of natural hybrids provided the major data sources. Cytological studies were made, but were inconclusive. Eleven...
This research was conducted in the Mamora National Forest of
Morocco to: (1) Evaluate the effect of cork oak (Quercus suber L.)
crown cover on seasonal herbage production, nutritive quality, and
foliar cover on two distinctive sites in each of two years (1982,
1983) and to (2) assess the effects...
The purpose of this study was to examine various host and microclimatic influences affecting the survival and development of the flatheaded fir borer, Melanophila drummondi (Kirby) in Douglas fir, Pseudotsuga menziesii (Mirbel) Franco residues. It also expands current knowledge of the biology, bionomics, life history, ecology, and biotic potential for...
This study was undertaken to determine the
effects of different chilling treatments during the dormant
season upon growth of Douglas-fir seedlings0 In
addition it was planned to determine whether seedlings
native to various geographic areas differ in their chilling
requirements0
The hypotheses were advanced, based on previous
studies, that chilling...
Before the arrival of Euro-Americans, the inland Pacific Northwest was settled by native
people whose frequent intentional burning of the landscape promoted open stands
dominated by large fire-resistant ponderosa pine. Fire suppression for nearly a century,
livestock grazing, and logging of the largest trees has resulted in forests characterized by...
This research was conducted in the Mamora cork oak
forest of Morocco to: (1) Describe the impacts of sheep
grazing (none, 35% use, 70% use) in March, April, May and
June of 1987 and 1988 on seasonal forage production; (2)
evaluate the effects of these factors on annual changes
in...
Mycorrhizal fungi in arid and semiarid rangelands have received little study in southwest Asia and north Africa, although they are important in food production and rangeland productivity. The desert truffles of the genera Terfezia and Tirmania form fruiting-bodies and mycorrhizae with rangeland plants. This thesis treats the taxonomy and the...
Verticicladiella wageneri Kendr. is a vascular wilt pathogen of
Douglas-fir in the Pacific Northwest, The disease is characterized by
black staining of colonized sapwood; crown symptoms are those typical
of a wilting syndrome. Histopathological studies revealed that the
pathogen is limited to the xylem but causes vascular dysfunction in
both...
During summer and fall of 1981 to 1983, mark-recapture was
conducted in riparian and upland habitats within old-growth and
mature forests in the Cascade Range of Oregon. Number of
individuals and species richness were greater in riparian than
upland habitat. For most species, the mean adult weights and
the percentages...
A gene-ecological transplant study was made on populations of
the Crepis nana and C. elegans complex from the Arctic and Alpine of
North America. Transplants were collected from the Brooks Range,
Eagle Summit, and Alaska Range in Alaska, the Rocky Mountains in
Alberta, the Olympic Mountains in Washington, the Wallowa...
This analysis is the study of Oregon's wildlife resources from
the period prior to white settlement up to the present time, including
critical projections, based on present trends and expected conditions
for both human and wildlife populations in the state up to the year 2010.
Prior to white settlement Oregon...
This thesis research consists of an investigation of the human
influences on wildlife in Belize. The study was accomplished by the
collection and analysis of data with respect to land use, habitat
characteristics, and wildlife status in Belize. Requirements and
status of many species are tabulated in order to give...
Species interactions and their effect on the use of habitat by benthic fishes were examined in a guild composed of Cottus perplexus, C. rhotheus, and C. beldingi in the Marys River above Philomath, Oregon, and in a constant environment provided by an artificial stream. In the Marys River system, the...
Inoculations of white fir, Shasta red fir, Douglas fir and
ponderosa pine with Pisolithus tinctorius spores when outplanted
failed to produce P. tinctorius mycorrhizae at the end of the first
growing season. In the third year a few P. tinctorius mycorrhizae
were formed on white fir. Inoculations reduced seedling survival...
Imaging spectra of plant tissues yield considerable potential and useful information
for basic studies and agriculture practice. We constructed an imaging spectrophotometer
with spectral range from 400 nm to 1100 nm, which was used to study various
physiological events of plant germplasm: location of bundle sheath and mesophyll cells in...
A classical biological control project was undertaken
against the filbert aphid, Myzocallis coryli (Goetze), in
western Oregon. Hazelnut orchards in Spain, France, and
Italy were searched for natural enemies of the aphid, and
a parasitic wasp, Trioxys pallidus Haliday, was imported,
quarantined, mass-reared, and released in Oregon orchards.
The wasp...
Several empirical formulas that may be used to estimate available
chilling are presented in this study. Many climatic parameters
were considered in the derivation of these formulas. One equation
employing only maximum and minimum temperatures had a coefficients
of correlation (R) and R² values of .978 and .957, respectively. This...
There are about 80 million single-family dwellings (SFD) in the United States, predominantly of wood-frame construction. Of these, 68% are owner occupied. A home is typically the largest single investment of a family, and is often not covered by earthquake insurance, even where it is available. Of all SFD in...
In an effort to describe the plant communities and
succession of the Oregon coastal grasslands, vegetation
and environmental data were collected from 75 stands at
24 separate locations ranging from Cape Falcon in Tillamook
County to Cape Ferrelo in Curry County. The vegetation
data consisted of cover and frequency values...
North America, with over 400 species of Astragalus (Fabaceae), is one of three major centers of diversity, all of which comprise the majority of the nearly 1750 species of Astragalus worldwide. One of the most diverse species, Astragalus lentiginosus of Section Diphysi, is a polymorphic complex of over 40 varieties,...
Diseases can be a substantial threat to woody plant production, a major industry in Oregon. Boxwood (Buxus spp.) and rhododendron (Rhododendron subgenus Rhododendron and Hymenanthes) represent the top two broadleaf evergreen woody plants by farmgate value in Oregon. Historically, Phytophthora root rot has been considered the most destructive disease of...
A pest management program for variegated cutworm (VC), Peridroma
saucia (Hubner), in Oregon peppermint was developed based on studies
of pheromone trapping, sampling methods, and economic thresholds.
Pheromone traps effectively trapped VC males and were used to
reflect development and oviposition trends. Trap height was linearly
correlated to moth catch...
Developmental requirements were determined for both larva and pupa as 503 and 176 degree-days (dd) above a lower threshold of 5°C. Adult emergence occurred from 300 to 700 dd accumulated from January 1st. Cumulative male emergence preceded female's by 50 - 80 dd. A PETE phenology model modified to include...
Statistically, travel by air is one of the safest forms of transportation. Yet we
continue to experience aviation tragedies. Do we fully understand flight safety or is
there another way of looking at the problem? In this work a new way of approaching
the question of flight safety is developed,...
Three provisional species are described as new: Leucogaster
couchii, L. gelatinosus, and L. microsporus. Leucophlebs candida
is transferred to Leucogastef, completing the transfer of all
Leucophlebs species to Leucogaster. L. columellatus is transferred
to Sclerogaster. L. longisterigmatus is synonymized with
L. rubescens, L. foveolatus with L. odoratus, and L. fulvimaculatus...