Drought events have been shown to impact species distributions and are predicted to increase in frequency as the climate changes. As this occurs, ecologists predict species distributions will shift dependent upon species ability to track climate. These shifts in species distribution are expected to be particularly acute in arid and...
Tropical island ecosystems have proven to be inordinately vulnerable to invasions by exotic plants and animals. Today these islands only contain small
remnant populations of the original flora and fauna, and these populations are facing increasing pressure from invasive plants. This paper attempts to answer four important questions whose solutions...
Regression equations applicable to biomass components of standsof western hemlock [Tsuga heterophylla (Raf.) Sarg.} were developedby destructive sampling of a thinned and an unthinned stand ofwestern hemlock near Seaside, Oregon. Equations predicted more live-branchbiomass and less dead-branch biomass per tree for the thinnedstand, but equations for biomass of foliage, twigs,...
Climate change and the increase in meteorological drought have generated global concern over the persistence of ecosystems already in decline from decreased moisture. Evidence suggests dryland ecosystems have been more impacted by drought because of their tightly coupled growth-water relationships and high sensitivity to environmental shift. Removal of competing vegetation...
This dissertation investigated potential ecological limitations to seedling regeneration in young, seasonally dry, evergreen forest restoration plantations in northern Thailand. We explored whether recruitment of colonizing tree species in the restoration plantations can be attributed to seed dispersal mode (i.e. abiotic or animal dispersal) and seed size. We did this...
The application of modern land management practices beginning at the turn of the 20th century is widely believed to have dramatically transformed forest landscapes of the inland Pacific Northwest. Restoring historical conditions to make forests resilient to future climate and disturbance regimes is a major goal of federal forest managers....
Changes in climate caused by increased concentrations of carbon dioxide (CO₂) in the Earth’s atmosphere have led land and ocean surface temperatures to increase by 0.85°C and sea level to increase by 19 cm relative to preindustrial times. Global climate change will lead to further alterations in mean temperature and...
Methods for obtaining accurate, spatially explicit estimates of biomass density in tropical forests are required to reduce uncertainties in the global carbon cycle, and to support international climate agreements and emerging carbon markets. Three-dimensional (3-D) remote sensing techniques sensitive to the vertical structure of vegetation provide a unique opportunity for...
Forest management is rapidly undergoing a transformation from a discipline based on efficient commodity production to one for multiple uses, especially on federally managed land in the United States. This new management paradigm has challenged silviculturists to develop and adapt forest management techniques that can deal with increased demands. Using...
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...
Recent climatic warming trends and increases in the frequency and extent of wildfires have prompted much concern regarding the potential for rapid change in the structure and function of forested ecosystems around the world. Episodes of mortality in wildfires and insect outbreaks associated with drought have affected large areas and...
Given the vital role of forest ecosystems in landscape pattern and process, it is important to quantify the effects, feedbacks, and uncertainties associated with forest disturbance dynamics. In western North America, insects and wildfires are both native disturbances that have influenced forests for millennia, and both are projected to increase...
The American beaver (Castor canadensis) was nearly extirpated by the late 1800's due to the fur trade. Due to reintroduction efforts, it now occupies much of its former range. Beavers are a keystone species and ecosystem engineers, greatly influencing riparian and instream habitats through selective harvesting of plant materials and...
Many stakeholders involved with stream restoration in the Pacific Northwest have discussed the potential benefits of using beaver dam construction activities (Castor canadensis) as a management tool to improve degraded stream habitat for anadromous salmon species. In addition, there has been growing interest in using nuisance beavers, primarily controlled by...
Background information is presented that provides historical perspectives on the field of mycology in the Pacific Northwest and its role in forest management. The series of events and decisions that have led to previous studies (or lack of studies) in the field also dictate the directions of current research. Culture,...
Wood modulus of elasticity (MOE), also known as wood stiffness, is one of the most important wood properties. Wood stiffness is a measure of the resistance to deflection, and is important because some products such as laminated veneer lumber, plywood, and dimension lumber require stiff and strong wood. Incorporating wood...
from the summer dry season to the winter wet season. Such movement that connects summer and winter habitats may be particularly important for coho salmon, O. kisutch, because availability of overwintering habitat can limit freshwater survival for this species. Here, I describe basin-scale variability in the spatial pattern of fall...
The structure and composition of mixed-conifer forest (MCF) in central Oregon has been altered by fire exclusion and logging. The resulting increased density, spatial contagion, and loss of fire resistant trees decrease the resiliency of this ecosystem to fire, drought, and insects. The historical and current composition and structure of...
The link between aboveground net primary productivity (ANPP) and resource gradients generated by complex terrain (solar radiation, nutrients, and moisture) has been established in the literature. Belowground ecosystem stocks and functions, such as soil organic carbon (SOC), dissolved organic carbon (DOC), and belowground productivity have also been related to the...
Climate exerts considerable control on wildfire regimes, and climate and wildfire are both major drivers of forest growth and succession in interior Northwest forests. Estimating potential response of these landscapes to anticipated changes in climate helps researchers and land managers understand and mitigate impacts of climate change on important ecological...
In terms of production forestry, more often than not any species that is not the crop
species is considered a competitor as they are using finite growing resources that would
otherwise be available to the crop species. With specific regard to Douglas-fir
(Pseudotsuga menziesii (Mirb.) Franco) production in the Pacific...
A growing body of work reveals that animal-mediated pollination is negatively affected by anthropogenic disturbance. Landscape-scale disturbance results in two often inter-related processes: (1) habitat loss, and (2) disruptions of habitat configuration (i.e. fragmentation). Understanding the relative effects of such processes is critical in designing effective management strategies to limit...
Atmospheric carbon dioxide levels have been steadily increasing from anthropogenic energy production, development and use. Carbon cycling in the terrestrial biosphere, particularly forest ecosystems, has an important role in regulating atmospheric concentrations of carbon dioxide. US West coast forest management policies are being developed to implement forest bioenergy production while...
Globally, the forestry sector is the second largest contributor of greenhouse gases, and sustainable forest management is a major target of international environmental policy. However, there is the assumption underlying many policy recommendations that an increase in above-ground carbon stocks correspond to long term increases in ecosystem carbon stocks, the...
Quantifying and modeling processes involved in the global carbon cycle is important to evaluate the temporal and spatial variability of these processes and understand the effect of this variability on future response to changing climate and land use patterns. Biomass accumulation and Net Primary Productivity (NPP) are large components of...
A trait based approach was used to assess impacts of overstory density and thinning on understory vegetation components related to wildlife habitat. The relationship between overstory basal area and understory vegetation for species grouped by traits, such as production of flowers, fleshy-fruit and palatable leaves, was characterized in thinned and...
Bird-vegetation associations are a base for bird conservation and management, as well as for predictions of the effects of resource management and climate change on wildlife populations. A recent shift in forest management priorities from timber production to native species' habitat conservation on federal lands has emphasized the need to...
Calcium (Ca) is an essential macronutrient that is increasingly recognized as a biogeochemical factor that influences ecosystem structure and function. Progress in understanding the sustainability of ecosystem Ca supply has been hampered by a lack of information on the various forms and pools of Ca in forest ecosystems. In particular,...
Improved monitoring of forest biomass is needed to quantify natural and anthropogenic effects on the terrestrial carbon cycle. Landsat's temporal and spatial coverage, fine spatial grain, and long history of earth observations provide a unique opportunity for measuring biophysical properties of vegetation across large areas and long time scales. However,...
Epigenetic mechanisms are important for control of plant development, and may play a particularly important role in trees given their long life cycles and distinctive and stable tissue types. To help understand the role of epigenetics in tree development, we produced transgenic poplars with reduced activity of the DDM1 genes,...
Foresters care about site productivity and stem quality in Douglas-fir plantations for many reasons. The profitability of forest land and the economic returns on silvicultural investments are directly related to site productivity. Thus, understanding the relationships among Douglas-fir productivity, stem form and site characteristics is important economically. My objective was...
In order to investigate potential climate impacts on landscape-scale ecosystem processes, I implemented a dynamic general vegetation model (DGVM) over a large domain in northern California and western Nevada on a rectangular grid of ca. 800-meter spatial resolution. I used 100 years of observed, monthly climate and nine future climate...
Red fir (Abies magnifica) is a high elevation conifer generally growing between an altitude of 1,400 and 2,700 meters. In California, red fir grows in the Sierra Nevada, the Klamath Mountains, the eastern edges of the northern Californian Coast Ranges, and in the southern Cascades. Red fir commonly grows in...
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...
Though the mixed-evergreen forests of the Klamath Siskiyous have a long history of large, mixed-severity fires, most research in this region has concentrated on the impacts of high-severity fire. Knowledge of the ecological effects of low- and moderate-severity areas within mixed-severity fires is important because such areas may account for...
Recent evidence suggests that population declines of some avian species may be driven primarily by reduced quantity and diversity of early-successional habitat on the breeding grounds. Increasing intensity of forest management on private lands and decreased harvest rates on federal lands has resulted in a loss of the diverse early-successional...
Little is known on the importance of riparian areas to birds near small headwater streams in mesic forests. Progress towards understanding limiting factors that affect bird populations has been difficult because of lack of information beyond the breeding period. I compared bird assemblages between headwater riparian and upland areas throughout...
Descriptions of the fire regime in the Douglas-fir/western hemlock region of the Pacific Northwest traditionally have emphasized infrequent, predominantly stand-replacement fires and an associated linear pathway of stand development, where all stands proceed along a common pathway until reset by the next fire. Although such a description may apply in...
In the Pacific Northwest, multiple studies have found negative effects of
timber harvest on stream amphibians, but the results have been highly variable and
region-specific. In this collection of studies, I examined the short term effect of timber
harvest using a field study, and used lab work to examine a...
Variable-retention harvesting was proposed to reduce loss of biodiversity and ecosystem processes associated with late-seral Douglas-fir (Pseudotsuga menziesii) forests in the Pacific Northwest. The Demonstration of Ecosystem Management Options experiment was established to test this hypothesis. Analysis presents various challenges to drawing statistical inferences about treatment effects. This dissertation explored...
The succession of plants over a period of 25 years was analyzed on clearcut areas in the western Cascades of Washington and Oregon. Thirty-three paired burned and unburned plots were reexamined in 1975. Data were combined with records from prior examinations by Morris (1970). Cover trends of six major brush...
The state of Oregon has two distinct climate types bisected by the crest of the Cascade Mountain range. The western side of the Cascades experiences high levels of precipitation and mild temperatures due to the maritime influence of the Pacific Ocean, while the eastern side lies in the rain shadow...
Dry coniferous forests in the western United States are experiencing severe wildfires, insect outbreaks, forest disease epidemics and a growing presence of invasive species. Policies strongly emphasize reducing hazardous fuels at the Wildland Urban Interface (WUI) where communities and forests intersect. However, these areas present restoration challenges as they tend...
The forest alpine tundra ecotone (FTE, also known as alpine treeline or subalpine parkland), is a conspicuous feature of mountain landscapes throughout the world. Climate change-driven increases in temperature are believed to result in FTE movement and tree invasion of subalpine meadows, which have been documented throughout the Northern Hemisphere...
The objectives of this investigation were two-fold: (1) to examine possible seed and cone characteristics and their usefulness as seed maturity indices, and (2) to examine the effects of artificial ripening on seed maturation and germination. Cone fresh weight, cone length, cone specific gravity, cone color, seed fresh weight, seed...
The overall goal of this study was to investigate influences of ectomycorrhizae (EM) and
interspecific carbon transfer on seedling performance in species mixtures. The objectives were to:
(I) determine the potential for EM to link paper birch and Douglas-fir, (ii) quantify gross and net
interspecific carbon transfer, and (iii) evaluate...
Soil respiration, or the combined CO₂ emissions from roots and soil microorganisms, constitutes one of the largest losses of carbon (C) from terrestrial ecosystems. The major drivers of soil respiration, which include soil moisture, temperature, and substrate quality, have been known for some time. Nevertheless,
correlations between these drivers and...
Ecosystems are highly heterogeneous systems subjected to important levels of environmental variability; however, it is common in terrestrial biogeochemical models to assume homogeneous properties of the elements of the system or constant environmental conditions. For some processes, heterogeneity in these models is treated very simplistically, but there is not much...
In western Oregon, hardwood trees occupy 20% of the
timberland but account for less than 1% of the timber
harvest. Information about how to manage them effectively
is limited.
The objective of this study was to examine: 1)
effect of thinning on tree growth, plant moisture stress,
and crown cover...
Understory conifer regeneration needs to occur beneath conifer-dominated
canopies if two-storied or uneven-aged structures are to be considered for western
Oregon Coast Range stand management. To ensure adequate numbers of seedlings
to meet stocking or habitat structure objectives, planting may be a solution. We
undertook a multi-level study to determine...
The broadest goal of the research covered in this thesis was to contribute
to our limited knowledge of high elevation forest soil ecology. Based on the reeds
of funding agencies, specific objectives were to examine 1) how climate-induced
Abies lasiocarpa ([Hook.] Nutt.) forest expansion affects soil nutrient pools, 2) the...
Effects of small-scale disturbances on fecundity and growth rates of Linnaea
borealis L., Tiarella trifoliata L. var. unifoliata, and Trillium ovatum Pursh. were studied in
old-growth forests in the Tsuga heterophylla Zone on the west slope of the Cascade
Mountain Range of Oregon. Performance of each species was compared in...
Western redcedar (Thuja plicata Donn.) is a valuable commercial species found in
the northwestern United States and southwestern Canada. This dissertation includes four
papers focused on wood and stem characteristics of second-growth western redcedar, and
how those characteristics vary within the stem or how they are influenced by cultural
practices....
This study was conducted to investigate why root disease centers east of the
Cascade crest tend to be larger in diameter and more abundant than their counterparts to
the west, within subalpine forest stands of central Oregon. The trend in a 290 km² study
area appeared opposite of what was...
Knowledge about vegetation patterns and ecological processes in unmanaged, late-successional
watersheds is needed to provide a foundation for forest management strategies
aimed at conserving native biodiversity. I examined influences of environmental variability
and disturbance history on forest structure and composition in the Cummins Creek
Wilderness, located on the central Oregon...
Fire history and fire regimes were reconstructed for a 450 km² area in the central
western Oregon Cascades, using tree-ring analysis of fire scars and tree origin years at
137 sampled clearcuts. I described temporal patterns of fire frequency, severity, and size,
and interpreted topographic influences on fire frequency and...
Ten herbicides (atrazine, azafenidin, chlorsulfuron, clopyralid, hexazinone, imazapic, imazapyr, metsulfuron, pendimethalin, and sulfometuron) were evaluated for phytotoxicity in first-year seedlings of eight conifer species (Douglas-fir, grand fir, noble fir, redwood, Sitka spruce, western hemlock, western red cedar, and western white pine). Six of these herbicides (atrazine, clopyralid, hexazinone, imazapyr, metsulfuron,...
Because of their small genomes, facile clonal propagation, fast growth, and
susceptibility to Agrobacterium transformation, poplars (genus Populus) are widely
considered model systems for the application of molecular genetics and biotechnology
in forestry. However, a major concern over commercial use of genetically engineered
trees is the release of transgenes into...
Soil effects from mountain beaver (Aplodontia rufa ) burrowing were
investigated in Oregon Coast Range soils formed from Tyee sandstone. The potential
for observed changes in soil to affect productivity was assessed. Soil horizons from
mountain beaver mound soil and adjacent unmounded profiles were collected with a
monolith-type quantitative sampler....
Forest roads constructed in steep mountain landscapes have been associated with a
number of effects on hydrologic and geomorphic processes. This research examined the
effects of forest roads on the flow of water and sediment in drainage basins in the Cascade
range of western Oregon. A study conducted at the...
Selective suppression of crown and root sprouting of
non-coniferous cover are the keys to effective forest
vegetation management. This study 1) develops insight into
mechanisms of controlling root suckering and top regrowth of
bear clover (Chamaebatia foliolosa), and develops a broad
data base for controlling broad groups of vegetation
chemically....
Stem defects, including sinuosity, large branches, and the occurrence of steep-angled
branches (e.g., forks and ramicorns) can occur with high frequency in young
plantations of Coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco).
The importance of including these stem defects as criteria in early selection depends, in
great part, on...
There has been an increased interest in the
quantification of pattern in ecological systems over the past
years. This interest is motivated by the desire to construct
valid models which extend across many scales. Spatial methods
must quantify pattern, discriminate types of pattern, and
relate hierarchical phenomena across scales. Wavelet...
Green-tree retention is being implemented on state and
federal lands in Oregon. Silvicultural prescriptions with
tree and snag retention are thought to mimic natural
disturbance patterns in the Pacific Northwest more closely
than traditional silvicultural practices, which reduce
structural complexity. The effects of green-tree retention
on native bird species in...
Evaluation of meta-sedimentary bedrock as a source of stored water available
to plants in a mediterranean climate is presented based on: root length distribution
(RLD), root morphology, rock water holding capacity and seasonal pattern of water
depletion. Studies were performed in southwestern Oregon under young stands of
whiteleaf manzanita, ponderosa...
The effects of prescribed burning on the rates of recent litter
decomposition, nitrogen and phosphorus release from litter, soil total and
inorganic nitrogen pools, and net nitrogen mineralization were determined in
ponderosa pine sites that had been burned 0.3, 5 or 12 years earlier. Prescribed
burning decreased litter decomposition rates...
The purpose of this study was to assess how growth of young to mature Douglas-fir
(Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sar.)
in mixed stands was influenced by the presence of residual trees. Fourteen paired plots with
and without residual trees were examined in a retrospective...
Cold hardiness and phenology are important adaptive
traits for perennial plant species in temperate climates.
Timing of growth, dormancy, and associated cold acclimation
and deacclimation represents a delicate balance between
maximizing growth under favorable conditions and minimizing
frost damage under unfavorable conditions. Geographic
patterns of genetic variation in adaptive traits,...
The main objective of this study was to evaluate the interaction between
herbaceous competition, fertility, and seed source on Douglas-fir survival and
growth. A secondary objective was to evaluate the effect of these various factors
on the production of lammas shoots and the selectivity of deer browse. Finally,
the role...
The purpose of this study was to develop a plant
association classification for the mature coniferous
forests of the McDonald and Paul M. Dunn Research Forests.
A secondary objective was to quantify diversity within the
plant associations. This Forest is approximately 11,000
acres and is located 6 miles to the...
The coniferous forests of the Pacific Northwest are
affected by a variety of endemic fungal root pathogens. Forest
disease surveys have noted the presence of two or more of
these root pathogens infecting the same stump or root, and it
has been suggested that these fungi may be interacting
synergistically....
Chloroplast DNA (cpDNA) variability and phylogeny were
studied via analysis of restriction site mutations and DNA
sequencing in a complex of three closely related species of
pines: Pinus radiata D. Don, P. attenuata Lemm., and
muricata D. Don. Genomic DNA from 384 trees representing
20 populations in the complex were...
Allochthonous litter inputs are a primary source of organic matter in low-order
forested streams. A major component of this litter moves through small streams as fine
particulate organic matter (FPOM). Litter decomposition has been well studied, but few
studies have examined benthic FPOM (FBOM) dynamics. The purpose of this study...
I studied species' abundances and habitat relationships
of breeding and winter birds in commercially thinned and
unthinned Douglas-fir (Pseudotsuga menziesii) stands from May
1989 to June 1991. The study was conducted in 40- to 55-year old
stands in the Central Oregon Coast Ranges and the
Tillamook State Forest. Total abundance...
This thesis examines the 8-year growth trend of
Douglas-fir (Pseudotsuga menziesii (mirb.)Franco), ponderosa
pine (Pinus ponderosa Dougl. ex laws.), and whiteleaf
manzanita (Arctostaphylos viscida Parry). Manzanita stands
ranging from 1700/ha to 27000/ha density were grown among
mixed conifers of the same age, which were planted in 1981
at 250x250 cm...
Two-year-old ponderosa pine (Pinus ponderosa Laws.)
from two seed sources were grown at two nurseries. The
Fremont seed source was raised at Bend and Stone Nursery;
the Ochoco was grown at only the Bend Nursery. The
seedlings were fertilized in late September-early October
with nitrogen (N) or nitrogen plus potassium...
Regeneration of salal (Gaultheria shallon Pursh.) in the
Coast Range of western Oregon was examined over two growing
seasons in a three part study consisting of seedling
establishment, clone excavation, and population sampling
experiments. The effects of study site location, overstory
stand density, and substrate on seedling emergence and
survival...
I used greenhouse and field studies to investigate how intraspecific and
interspecific competition, soil disturbance, and fertilization affect the biomass and
reproductive output of Senecio sylvaticus and Epilobium paniculatum, common winter
annuals which invade and dominate western Cascades forests during the first two seasons
after clearcutting and slashburning.
Field work...
Xylem conducting tissue or sapwood is an important storage organ
for water, carbohydrates, and nutrients, and this storage helps trees
accommodate environmental change. However, the living ray parenchyma
cells in sapwood, which store the carbohydrates and nutrients,
require energy for maintenance. I examined how sapwood maintenance
costs vary among species,...
Bioassays using red alder and snowbrush plants grown in soils collected
from a clearcut, a young Douglas-fir plantation, and an old-growth stand were
conducted. Sites are located at the Andrews Experimental Forest, Oregon. In
the first bioassays, more alder than snowbrush plants survived and nodulated.
Of the plants that survived,...
This study assessed the effects of thinning on arthropod communities on understory plants in the Central Oregon Coast Range. Arthropods were sampled from five understory plants in five pairs of thinned and unthinned, young (50-80 yrs), managed Douglas-fir stands, from late May to mid-July of 1998. Vine maple (Acer circinatum),...
Despite the critical ecological roles of structural features in forests, ecologically
relevant quantitative measures of structure that allow comparisons among forest stands
are still limited. A new index, the structural complexity index (SCI), was developed to
characterize and compare the structural complexity of different forests. Point patterns
of stem-mapped trees...
Despite the importance of rain and snowmelt in causing peakflows in the Pacific
Northwest, the interactive effects of a snowpack and watershed physiography on
streamflow are largely undocumented. This study investigated the influence of soil and
snowpack moisture on peakflow hydrograph shape in three small (< 60 ha) control sub-watersheds...
To improve the efficiency of herbicide
applications, each stage of the spray application
process must be considered. Two of these stages, the
process of spray deposition within plant canopies and
the influence of the form of the spray deposit on
efficacy were investigated.
The effect of droplet size, spray volume,...
Analysis of import trade since 1976 shows that forests of the Pacific Northwest provide
Japan with the largest share of pine mushrooms (Tricholoma spp.) outside of East Asia.
To determine whether North American pine mushrooms (Tricholoma magnivelare (Peck)
Redhead) merit more intensive management in the southern Cascade Range, a major...
Computer simulations and experiments were used to determine
the basis for skewness and inequality in size structures
(frequency distributions of Individual plant sizes) prior to
self-thinning mortality. In simulated stands, density-dependent
neighborhood heterogeneity caused variability in the growth rate
of individuals with the same size, and such variability caused
skewness...
A field study was established to explore stand structure and development patterns of
mature, mixed-species forests in the Interior Cedar-Hemlock (ICH) zone: moist cold
subzone of northwestern British Columbia. The species of interest in the study area
were: western hemlock (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Thuja
plicata Donn), lodgepole...
To determine whether shading increases drought-induced
root mortality by changing the chemical
composition of roots, I conducted an experiment in which
high and low light treatments in combination with high
and low soil moisture treatments were applied to
seedlings of Douglas-fir (Pseudotsuqa menziesii Mirb.
Franco). Because synthesis of suberin (a...
Hysterangium, a genus of hypogeous Basidiomycotina (false truffles) is
commonly placed in the Hysterangiaceae and ascribed affinities to the Phallales. It
is a large genus among hypogeous taxa and is commonly collected in large
numbers in eastern and western North America, Australasia and Europe. Some
Hysterangium species are dominant components...
Salmonberry community structure was examined in alder-dominated
riparian buffer strips in the Oregon Coast Range. Salmonberry growing on slopes
was found to respond differently, to both characteristics of the buffer strips and
to environmental factors, than salmonberry growing on terraces.
Salmonberry, as measured by total height, number of ramets or...
Natural Douglas-fir stand development is the result of
many types of disturbance, both natural and management
induced. The magnitude and timing of these disturbances
have profound effects on the structure and composition of
both the overstory and understory plant communities. Vine
maple responds to disturbance by basal sprouting, layering,
producing...
A sustainable resource development plan framework was prepared for the
Neskonlith Indian Band, who are located in the interior of British Columbia, Canada.
The framework intends to address issues involving; integrated resource management,
traditional native land management, ecosystem management, and community-based
resource management.
A soft systems (Wilson & Morren, 1990)...
The growth of western hemlock during the first four
years of seedling establishment was examined in a competitive
environment in which seedlings were exposed to various types
of animal damage and salmonberry and/or alder competition.
The study utilized an existing Nelder/replacement series
experiment which focused on the competitive effects among...
A simple debris-slide model, employing a digital elevation model (DEM) and geological data, was used in a geographic information system (GIS) to map slope stability in the Andrews Experimental Forest, located in the western Cascade Range in Oregon, USA. To evaluate the contribution of error in elevation to the uncertainty...
A guild of three and possibly five tip moths
(Rhyacionia spp.) occurs on ponderosa pine (Pinus ponderosa)
in southeastern Montana, northwestern South Dakota, and
southwestern North Dakota. Trapping results indicated that
many of these species may be flying simultaneously, and
individual species relative abundances showed west-to-east
trends.
Tip moth larvae...
I studied the relationship of environmental variables
to six plant associations on McDonald and Paul M. Dunn
Forests. Indirect gradient analysis was used to determine
relationships. The plant associations were developed in a
companion study by C.J. Hubbard (1991).
McDonald-Dunn Forests are located north and northwest
of Corvallis, Oregon. The...
The objective of this study was to determine how the
balance of carbon to nitrogen in a grand fir ecosystem affects
the chemistry of emerging grand fir foliage and the growth of
western spruce budworm larvae. Forest plots in the grand fir
zone of eastern Oregon were thinned, thinned and...