Evidence suggests that western juniper
(Juniperus occidentalis) in Central Oregon affects
understory production and composition. As trees
increase in size and density, understory production is
reduced and composition changes. This study was
designed to identify the relationship between
production and composition of understory vegetation
and various tree canopy sizes of...
This research evaluated the germination and early seedling
development response of two sources of bluebunch wheatgrass (Agropyron
spicatum) to a wide range of environmental conditions. Seeds collected near John Day, Oregon and Secar seed obtained from the Soil
Conservation Service were used in the investigations.
Evaluation of the germination response...
Identifying habitat and spatial requirements of wildlife species across multiple spatial scales is a challenging, yet crucial component of wildlife management. Habitat use of bats is particularly difficult to study, and managing habitat to conserve bats is especially challenging because bats are highly vagile organisms that exploit several different types...
The purpose of this study was to document vegetation on "The Island", a
Research Natural Area at the confluence of the Crooked River and the Deschutes River in
central Oregon's Juniperus occidentalis Zone and to compare the results with an earlier
study reported in 1964 from 1960-'61 data. Present-day comparisons...
Western juniper has increased in density and distribution in the interior Pacific Northwest since the late 1800s. Management
goals for many juniper woodlands are now focused on reducing tree densities and promoting biodiversity, prompting the use of
fuel reduction treatments. Fuel reduction often involves mechanical cutting and disturbances such as...
On piñon-juniper encroached sites that lack the understory fuels to carry a prescribed fire, treatment options are limited to mechanical methods. Cutting with chainsaws and leaving the trees on site has been the primary treatment method for such sites, however this method creates a potential fire hazard, particularly in the...
The Lakes Basin Bibliography consists of over 600 references relating to the natural resources of Oregon’s Lakes Basin. Forty percent of the items listed are available to anyone online though not all links are persistent. The remaining sixty percent are held in at least one library either in print or...
The ability of controlled livestock grazing, in
combination with seeding of palatable forages, to reduce
understory competition and enhance conifer
establishment, was evaluated during 1985 and 1986, on
two adjacent sites in southwestern Oregon. In 1984,
Site 1 was clearcut and broadcast burned to remove
slash, and Site 2 was...
Since the late 1880's western juniper has expanded in range and
increased in density in sagebrush-bunchgrass, riparian, and forested plant
communities of the Pacific Northwest. Succession to western juniper
woodland has been shown to reduce the productivity and diversity of the
understory component, result in concentration of soil nutrients beneath...
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...
Seasonal trends in forage production and environmental parameters
for five plant community types within a northeastern Oregon riparian zone
were described and modeled using correlation and path analysis. Wet
meadows produced the greatest amount of herbage biomass, followed by moist
bluegrass meadows, gravel bars, forests and dry bluegrass meadows. Trends...
The expansion of pion-juniper woodlands the past 100 years in the western United States has resulted in large scale efforts to kill trees and recover sagebrush steppe rangelands. It is important to evaluate vegetation recovery following woodland control to develop best management practices. In this study, we compared two fuel...
The objective of this research was to determine which
environmental resources, light, water, and nutrients,
control understory plant production and composition in a
Pinus ponderosa forest in northeastern Oregon. A split-plot
experimental design, with three blocks, four
treatments, and 44 plots, was established in the summer of
1985. Twenty plots...
Shrub-steppe ecosystems of western North America provide habitat for many wildlife species, are important components of public and private rangelands, and offer recreational opportunities for millions of people. They are some of the most vulnerable ecosystems in the United States and have been altered by human activities such as livestock...
Published June 1985. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Whole tree excavation of 41 western juniper (Juniperus
occidentalis Hook.), ranging in age from 2 to 34 years old,
was used to assess the development and structure of root
systems, to determine biomass allocation patterns, and to
develop mathematical relationships for estimating biomass
and root system dimensions in seedling and...
Western juniper (Juniperus occidentalis) cover has more than doubled within the last century and currently occupies over 9 million acres in the Intermountain West. Encroachment has altered the spatial distribution of soil nutrients and plants in these systems, forming nutrient enriched 'resource islands,' under tree canopies. The purpose of this...
The rapid expansion of western juniper into neighboring plant communities during the past 130 years has caused considerable concern because of increased soil erosion, reduced stream
flows; reduced forage production; altered wildlife habitat; changes in plant community composition, structure, and biodiversity; and the replacement of mesic and semi-arid plant communities...
A microclimatology study was conducted on a high elevation clearcut
near the summit of Mt. Ashland in southwest Oregon to evaluate the effects
of frost on Douglas-fir seedling growth and survival. Frost and low
temperatures cause seedling stress through frost damage, frost desiccation,
increased root resistance, and decreased rates of...
Since European American settlement of the Intermountain Region, dramatic changes in vegetation composition and structure have occurred in the sagebrush steppe ecosystem. Western juniper (Juniperus occidentalis spp. occidentalis Vasek), although indigenous to the Intermountain Region, has increased since the late 1800s. Considerable work has been done documenting juniper woodland expansion...
We examined how the experiences of World War II and Korean War veterans,
including prewar, warzone, and postwar factors, affected PTSD symptoms in later life.
This dissertation consists of two studies. In Study 1, four different hypotheses from a
lifespan approach were examined (King et al., 1996): stress evaporation (only...
During the last century, fire suppression, grazing, and climate change have caused sagebrush grasslands to be altered in both function and form; juniper and sagebrush dominate the landscape at the expense of herbaceous plants. Management efforts to reduce juniper and sagebrush overstory in order to enhance herbaceous components of the...
Western juniper (Juniperus occidentalis) encroachment has been associated with negative ecological and hydrological consequences including reductions in herbaceous production and diversity, deterioration for wildlife habitat, and higher erosion and runoff potentials. As a result, western juniper removal is a common and accepted rangeland management practice. Although studies evaluating the ecological...
Revised edition of the author's "Vegetation of Oregon and Washington", originally published by the U.S. Forest Service in 1973. Reprinted with new bibliographic supplement by the OSU Press in 1988.
Published June 1998. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published June 1994. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Central Oregon has attracted attention as a potential location for a biomass industry based on a locally fixed source of western juniper (Juniperus occidentalis Hook) feedstock. This study identifies a supply of juniper from private lands to determine how much of the available juniper is economically supplied at alternative prices...
Folic acid and ascorbic acid status have been assessed in
twenty non-institutionalized elderly subjects with respect to both
hematological and dietary aspects.
The hemoglobins, hematocrits, and serum ascorbic acid
concentrations were within the normal range. A few subjects had
total serum protein concentrations which were less than the acceptable
level....
Logging and forest thinning operations generate large amounts of residues in the form of small trees, branches and foliage that are usually left on the ground to decay or are burned. These resources are readily available, but it is uneconomical to remove them from the forest. The potential utilization of...
An improved understanding of ecohydrologic connections is critical for improving land management decisions in water-scarce regions of the western United States. For this study, conducted in a semiarid (358 mm) rangeland location in central Oregon, we evaluated precipitation-interception-soil moisture dynamics at the plot scale and characterized surface water and groundwater...
Published June 1986. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
I conducted a field study using gray wolf and mountain lion urine to investigate white-tailed deer and mesopredator behavioral responses to novel predator cues in a natural setting and to see if any changes in wildlife activity correspond to changes in the local biodiversity of a wetland environment. I created...
In order to develop three models for use in quantifying the
environmental conditions of reforestation, extensive measurements
required for energy balance calculations were taken for a
reforestation site in southwest Oregon. The models are used to
decrease the number of measurements required to properly evaluate
the potential for heat or...
Understanding the effects of disturbance and restoration on a species’ habitat is essential for understanding the demographic rates and population trends observed in a species. Sufficient habitat provides the space and resources required for survival and successful reproduction, such as food availability, access to water, protection from predators, protection from...
The electrical properties of ion-implanted GaAs FET channels
are investigated by two methods. First, the channel current (I) as
a function of voltage (V) is examined at different temperatures and
using different voltage ramp rates. The standard FET I-V curve,
which can be observed on a commercial curve tracer, is...
Two experiments were conducted to investigate the effects of
gonadotropin-releasing hormone (GnRH), administered twice during
the same estrous cycle, on bovine luteal function. Eight mature
beef cows, each cow serving as her own control, were injected
intravenously (i.v.) with saline on days 2 and 8 of the cycle (day of...
Published June 1999. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Juniper is a native species to Oregon and confers ecological benefits to wildlife when it is at savannah and transitional densities. Its range and extent have fluctuated with climatic change, but the current range expansion is unprecedented in its extent. The range expansion has been associated with the degradation of...
Current research indicates that the expansion of
western juniper can inhibit soil water retention, storage
and prolonged releases from watersheds. This phenomenon
is of great importance in eastern Oregon, as western
juniper is encroaching into sagebrush/grass communities
with a correlated reduction in herbaceous ground cover,
resulting in reduced infiltration rates...