Debris flows, common disturbances in many mountainous areas, initially scour or bury stream habitats; however, debris flows deliver vast amounts of wood, boulders, and gravel that may ultimately form complex stream habitat to potentially support a diverse salmonid assemblage. The materials deposited by debris flows would otherwise be inaccessible to...
This study is part of the effort to quantify sediment budgets and understand the geomorphic evolution of steep mountains where debris flows are the dominant agent of upland erosion. Observations indicate that headwater basins in the Oregon Coast Range (OCR) can store a large amount of sediment, mostly from debris...
Debris flows in the Pacific Northwest play a major role in routing wood and sediment stored on hillslopes and in first- through third-order channels to higher order channels and valley floors. Forest practices on steep, unstable slopes and removal of riparian trees along low-order streams can affect the frequency, magnitude,...
This study examined debris flows occurring in a 125 km² study area in the Blue River watershed in the western Cascade Mountains of Oregon over a 50-year period. Debris flow occurrence was found to be concentrated in a distinct zone of high activity occupying approximately half of the study area,...
This study investigated the long-term consequences of timber stand removal on the recruitment, physical characteristics, and
spatial distribution of coarse woody debris in small (second- and third-order) streams of the Oregon Coast Range. A chronosequence of stream-stand systems, ranging from 21- to 140-years since disturbance (YSD), were sampled to determine...
Western forests have become increasingly fragmented landscapes dominated by young stands. Given that western Oregon forests largely consist of headwater systems, there is a need to better understand how headwater forest taxa and their habitats are impacted by forest management practices. Several amphibian species associated with forested headwater systems have...
Large wood (LW) pieces are recognized as an important habitat component for salmon freshwater habitat. As such, they are often used in stream habitat restoration practices despite a lack of knowledge about their impacts on spatial and temporal hydraulic characteristics relevant to fish habitat. In this thesis we present results...
The abundance and spatial heterogeneity of coarse woody debris (CWD) on the forest floor is a prominent feature of Pacific Northwest (PNW) forest ecosystems. The effect of CWD on soil solution chemistry, nutrient cycling and availability, soil physical structure and formation of soil organic matter, however, remains unknown. Therefore, studies...
Mountain glaciers are receding worldwide with numerous consequences including changing hydrology and geomorphology. This study focuses on changes in glacier area on Mt. Hood, Oregon and Mt. Rainier, Washington where damaging debris flows have occurred in glaciated basins. Landsat imagery is used to map debris-free ice on a decadal time...
In November of 2006 an intense rainstorm of tropical origin, known colloquially as the "Pineapple Express," inundated the Pacific Northwest region of the United States, initiating numerous periglacial debris flows on several of the
stratovolcanoes in the Cascade Range of Oregon and Washington. These debris flows rapidly aggrade channels, deposit...
A study was conducted to evaluate the properties of soils in
the fog belt area of the Oregon Coast Range. Soils in the study
were chosen to include only those belonging to Andepts or to andic
subgroups. Samples were collected from eleven sites that were
formed mostly from colluvial deposits...
Daily and seasonal habitat use by Roosevelt elk was investigated
in the Oregon Coast Range on managed, public forestland. Over 3,700
locations of 6 radio-collared cow elk were recorded during 12 consecutive
months. Two elk formed part of a north band and 4 elk were
part of a south band....
A study of the temporal and spatial variability of stream gravel bed
composition and the factors affecting the amount of fine sediment within
the bed was conducted in the streams of the Oregon Coast Range.
Streambed samples were obtained by frozen core techniques and the
amount of sediment smaller than...
Sediment cores were retrieved from a landslide-dammed lake, recording events back to the 5th century AD in a forested, mountainous catchment. These cores provide an opportunity to compare the impacts of known recent perturbations, including floods and timber harvesting with those of the early period of the core, flood, fire,...
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....
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,...
In the Pacific Northwest ecoregion of North America, sculpins represent a major constituent of freshwater assemblages in coastal rivers. Based on their prevalence and abundance, sculpins are likely important ecologically, yet little is known of their interactions with co-occurring species, such as widely studied salmon and trout (salmonines). In this...
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...
Forest landowners are interested in practicing alternative silviculture methods on their property without having to clearcut. This publication describes a case study on shelterwood harvest and two-aged stand management of a forest in the Oregon Coast Range. The landowner’s core management philosophy is to create forests that are both ecologically...