I compared species composition and relative abundance of'small
mammals and herpetofauna between riparian and upslope habitats among 5
forest types. Riparian- and upslope- associated species were identified
based on capture frequency. Small mammal species richness was similar
between stream and upslope habitats and among the 5 forest types. There
were...
Riparian areas that can be used as reference sites on which to base goals of vegetation restoration have not been documented in the Oregon Coast Range. I examined the composition and distribution of unmanaged riparian overstories in the central Oregon Coast Range along nine streams which have experienced minimal disturbance...
Analysis of the long-term spatial pattern and dynamics of hardwood patches in the Coast Range of Oregon provides numerous ecological insights. Natural and anthropogenic disturbances have contributed to the development of a patchy mosaic of vegetation types in the area. Some hardwood patches in the Coast Range may be the...
Riparian zone vegetation can influence terrestrial and aquatic food webs through variations in the amounts, timing, and nutritional content of leaf and other litter inputs. Differences in vegetation composition and density, as well as riparian topography, may modulate the strength and quality of these inputs. Changes in inputs to small...
This study was conducted to describe variation of riparian vegetation in an Oregon Coast Range system according to geomorphic characteristics and in relation to streamflow. Specific objectives of this study were to: I) examine if the vegetation composition and structure of the riparian forest varied among channel-reach morphologies, 2) examine...
This publication is aimed at watershed councils, government agencies, and specialists (foresters, wildlife and fisheries biologists) interested in riparian area silviculture or watershed restoration. It contains information on the ecology of riparian forests and a checklist of recommended practices and common mistakes made in restoring conifers to hardwood-dominated riparian forests....
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...
Forest stands were studied to determine if old-growth
forest structure could be mimicked in younger stands via
overstory manipulation. Cover and species composition of
understory plants were systematically sampled in sixteen
thinned second-growth stands and sixteen adjacent unthinned
second-growth Douglas fir (Pseudotsuga menziesii (Mirabel)
Franco.) stands. The stands were thinned...
In the Coast Range of western Oregon, some natural resource managers are converting red alder-dominated riparian areas to conifers to increase the future source of in-stream large wood for salmonid habitat. However, studies in Alaska have shown red alder-dominated riparian areas support greater invertebrate biomass compared to conifer-dominated areas. In...
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...
The objective of my study was to examine differences in riparian tree and shrub composition associated with adult aquatic emergence and implications for terrestrial spiders in these sites. Seasonal abundance and biomass of adult emergent aquatic insects, riparian arthropod abundances and spider densities were compared between conifer- and hardwood-dominated sites...
Detailed phytosociological and physical data were gathered from six grass-fern balds in the Oregon Coast Range, Monmouth Peak, Grass Mountain, Prairie Peak, Roman Nose Mountain, Tyee Mountain, and Saddle Mountain. Panchromatic and color infrared air photography guided sampling within individual balds. The resultant floristic data was manipulated by a Braun-Blanquet...
During 1988-1989, stream habitat variables were compared between beaver-dam sites and unoccupied-stream sites to identify variables that may have been important for beaver (Castor canadensis) in selecting dam sites in the streams of the Drift Creek basin, Lincoln County, Oregon. Increasing valley floor width and grass/sedge cover and decreasing stream...
Nutrient and particulate matter balances were established for five ecosystems dominated by Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] in the western Cascades, Oregon. Carriers of N and P were particulate matter (dust in precipitation and sediment in streams) and dissolved matter in both precipitation and stream water. The input and outflow...
Fire and other catastrophic disturbance events in the Douglas-fir forests of the Oregon Coast Range have been significant in determining the distribution of stand age classes and, hence, habitat. Except for the past half century, knowledge of fire in the region has largely been local and anecdotal. The Douglas-fir forests...
Ten species of bats occur in the Oregon Coast Range and are hypothesized to be
associated with late-successional forests. The development of characteristics of late-successional
forests in young forest stands can be accelerated through silvicultural
practices such as thinning I examined the effects of thinning on the use of forests...
Fire history and fire regime were interpreted from tree ring analysis of 4320 stumps at 178 sites in a 25 by 55 km area in the central Oregon Coast Range. A total of 27 fire episodes were identified in a 516 year period, with sizes estimated at 18 to 544...
A framework is presented for a more causal explanation and ordering of stream characteristics than traditional means have used. Patterns of stream habitat distribution are related to particular characteristics of the geomorphology of watersheds. Variability in stream characteristics can be explained by the spatial distribution of properties of the watershed...
Streamside buffer strips provide numerous benefits to stream ecosystems. The buffer strips create shade, provide shelter for wildlife, act as barriers to logging debris during and after timber harvest, and serve as a continued source of large woody debris. Quantifying woody inputs resulting from windthrow provides managers with estimates for...
Riparian areas in the Pacific Northwest provide important biotic and abiotic
features, such as down wood, moist microsites, and abundant invertebrate prey that
benefit aquatic and terrestrial amphibians. Reported high densities of amphibians from
streams and riparian areas in the Pacific Northwest highlight their importance in riparian
food webs. Amphibians...
I examined the abundance and habitat associations of terrestrial amphibian species and the species richness of terrestrial amphibian communities in riparian buffer strips, clearcuts, and unmanaged riparian forests. The study was conducted in the western hemlock (Tsuga heteropliylla) vegetation zone of the northern and central Oregon Coast Range. Data were...
Tracer-derived estimates of hydraulic resistance and transient hydraulic
storage were related to measures of pool volume and channel morphometric
variability in small streams of the Oregon coast, U.S.A. Fourteen
100 m study reaches in 3 streams were selected to compare channel
and hydraulic characteristics in streams representing a time series...
Thinning of young Douglas-fir forests has the potential to enhance structural diversity and improve habitat for wildlife. I examined the effects of thinning and thinning intensity on abundance and demographic characteristics of forest-floor small mammals in the Coast Range of Oregon 5 and 6 years after thinning had occurred. Thinning...
This study estimates a range of opportunity costs associated with three land
management alternatives for a site in the Oregon Coast Range. A 35,000 acre site was
selected which includes a mix of federal and private land ownership and provides
significant biological resources. The first alternative examines a plan for...
This study investigates patterns of physical structure organization in stream
networks. In particular, it seeks to describe patterns of wood, boulders, pools and slope
that are evident in stream channels and to determine whether patterns of these elements
are influenced by network-level controls. The four in-stream parameters were
combined 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,...
The purpose of this study was to determine the effect of clearcut logging on stormflow by analysis of characteristic parameters of individual storm hydrographs. Parameters considered included height-of-rise, peak discharge, volume and time-to-peak. The hydrologic data were derived from experimental watersheds of the Alsea Study located in the Oregon Coast...
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...
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...
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...
Molybdenum is an essential component of biogeochemical cycling, most notably as a component of the nitrogenase enzyme used in biological nitrogen (N) fixation. While the important role of phosphorus (P) in limiting N fixation in ecosystems has been well documented, occurrence and prevalence of molybdenum (Mo) limitation is largely unknown....
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...
Understanding the tradeoff between water use and productivity is critical for modeling growth of intensively managed Douglas-fir forests in the Pacific Northwest. Evapotranspiration is closely linked to carbon dioxide intake during the process of photosynthesis. However, summer drought characterizing the growing season in this region imposes a limit on carbon...
One of the goals of ecosystem management is to integrate management of many species and processes across a range of temporal and spatial scales. I investigated the relationship between small mammals and amphibians at 3 spatial scales. My objective
was to identify, habitat associations of forest floor vertebrates at the...
Human-induced fragmentation of forests is increasing, yet the consequences of these landscape changes to vertebrate communities are poorly understood. Despite progress in our understanding of how bird communities
respond to forest fragmentation caused by agricultural or urban development, we have little understanding of these dynamics in landscapes undergoing intensive forest...
Western hemlock forests in the coastal areas of Oregon are some of the most productive and diverse forests in the world. This rich diversity represents both a challenge and an opportunity for woodland owners interested in managing western hemlock on their property.
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...
The work upon which this publication is based was supported by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized under the Water Resources Research Act of 1964 and by the United States Department of Agriculture, Forest Service, Pacific Northwest Forest...
Channels that were scoured to bedrock by debris flows provided unique opportunities to calculate the rate of sediment and wood accumulation, to make inferences about processes associated with input and transport of sediment, and to gain insight into the temporal succession of channel morphology following disturbance. In an intensive investigation...
Improving vegetation management decisions in Pacific Northwest forests requires a better understanding of the interactions between
planted conifers and associated vegetation. A practical index of interspecific competition, and quantitative models predicting conifer performance from such an index are particularly needed. To meet this
need, neighborhood models of interspecific competition were...
General outcomes of this study show that early growth of planted red alder is often slowed in the presence of neighboring vegetation, and overwhelmingly by salmonberry, a common associate in disturbed Oregon Coast Range habitats. Additionally, young red alder plantations located in
riparian areas may be highly susceptible to frost...
Three studies were conducted to characterize and present early-seral
competition between Douglas-fir seedlings and the surrounding vegetation
communities during Pacific Northwest forest establishment. The first experiment
served as the foundation for this dissertation and was designed to quantify tradeoffs
associated with delaying forest establishment activities by introducing a fallow year...
Nutrient losses of the biologically responsive anions, nitrate and bicarbonate together with the major cations, were monitored on 14 small watersheds in Oregon's Coast Range and evaluated in relation to management-induced disturbance. Mixed forests of Douglas-fir and red alder had dominated these high-nitrogen sites prior to treatment. A paired-watershed experimental...
In this study, biological and chemical characteristics were determined for two high-elevation meadow-to-forest transitions located in the Central Oregon Cascades. The chloroform fumigation incubation method (CFIM) was used to determine microbial biomass C(MBC) and the N flush due to fumigation (NF), and meadow values were compared to forest values for...
This study examined the effect of fire regime on coarse woody debris (CWD) mass using a combination of field data and modeling. The objectives were to use field sampling to determine how CWD differs between two areas that have had different fire regimes, and investigate how fire frequency and severity,...
History is an invaluable source of information to understand and evaluate management influences on contemporary ecosystems and landscapes. The first two chapters (Chapters 2 and 3) explored the concept of historical range of variability (HRV) in landscape structure and stand structure using a stochastic fire simulation model to simulate presettlement...
This study focuses on the tradeoffs that exist for managing forested landscapes for biodiversity and timber production. Tradeoff evaluation is important to natural resource managers so they can understand the benefits and costs of alternative management prescriptions. The study examines three watersheds in the Oregon Coast Range and 166 terrestrial...
Forest roads alter hillslope hydrologic processes by intercepting, concentrating, and rerouting storm runoff. Current road drainage guidelines are based on minimizing erosion and do not take into account the impact of forest roads on hillslope hydrology. This work monitors ditch flow and rainfall for 10 road segments over the course...
Understanding the impact of low volume road networks on forested watersheds is important for future forest management and watershed restoration. This study characterized the hydrology of five segments of forest road in the Oregon Coast Range. Rainfall, infiltration, road surface runoff, and intercepted subsurface flow were measured at each road...
This thesis examines factors limiting understory herb presence and flowering in young second-growth Douglas-fir (Pseudotsuga menziesii) forests on the west side of the Cascade Mountains, Oregon, USA. I studied the belowground effects of canopy trees on understory herbs and shrubs in old-growth forests using trenched plots from which tree roots...