Mass wasting events are a principal form of erosion that occurs on steep forest land throughout the Pacific Northwest. Numerous studies have reported that tree roots help stabilize steep forest land. A complete
understanding of the mechanism by which roots strengthen soil would enable modeling to more closely approximate field...
Two hilislope sites in the central Oregon Coast Range were instrumented and monitored for winter precipitation and saturated and unsaturated subsurface conditions. The study sites were near-ridge depressions typically known as headwalls. Based on results of the monitoring, two existing mathematical models
were adapted to predict piezometric levels in headwalls...
An 18-year record of nitrate (NO₃), orthophosphate, total nitrogen and total phosphorus in four streams of the Bull Run
watershed, Oregon, was examined to determine its precision and time resolution. Of these four species, only NO₃ was found to be known to a sufficient level of detail for modeling and...
The forest products industry often uses intermediate-support cable logging systems to transport logs from the harvest site to a staging area. A method is presented to assist in the analysis and design of these cable systems. The method determines tensions in individual cables, forces on and stresses in the support...
Forest roads produce fine sediment with traffic during wet weather. If the forest road is connected to a stream it can be a source of turbidity and fine sediment that may be detrimental to aquatic organisms especially salmonids.
The goal of this work was to investigate turbid runoff during wet-weather...
The objective of this study was to provide first order observations of bed level changes occurring in streambed simulated culverts throughout an annual period. To accomplish this, 30 culvert sites were selected in Oregon and Washington, and monitored over, at least, a 2 year period. Streambed scour and redeposition data...
:
_____________________________________________________________________
Marvin Pyles
The objective of this study was to provide first order observations of bed
Many miles of roads are built in the Pacific Northwest Forests to provide access for logging and fire protection. Logging roads often cross steep mountainous terrain. Logging roads and the associated cut and fill slopes represent a discontinuity in the natural stress state in the soil mantle. These conditions result...
Research was conducted to study the behavior and
load carrying capacity of stump anchors. A field testing
program was undertaken to determine the response and
strength characteristics of second growth Douglas-fir
(Pseudotsuga menziesii) stumps ranging in diameter from
6 to 17 inches. Horizontal and vertical stump movements
due to an...
Twenty eight countersunk culverts in Oregon were evaluated to assess current conditions and hydraulic performance. The culverts were also assessed with respect to their stability, particularly when subjected to high flows. In general, the culverts were
found to be resistant to erosion and effective at conveying large discharges. Based on...
This thesis describes the results of a project conducted to determine the economics of forest road maintenance alternatives
between periods of timber harvesting. An open road and a closed road alternative will be compared to the economics of clearcutting an
entire area and obliterating the road system until reentry at...