Treesearch

Erosion from forest roads is an important contribution to the sediment budget of many forested basins, particularly over short time scales. Sediment production from 74 road segments was measured over three years to examine how road slope, segment length, cutslope height, and soil texture affect sediment production and how these relationships change with time. In the first year, differences in sediment production between plots could be explained by differences in sediment transport capacity of the plots. With time, differences between plots of different slope, length, cutslope height, and...

Accurate modeling of the energy balance of a snowpack requires good estimates of the snow surface temperature. The snow surface temperature allows a balance between atmospheric heat fluxes and the conductive flux into the snowpack. While the dependency of atmospheric fluxes on surface temperature is reasonably well understood and parameterized, conduction of heat from the snow surface into the snowpack depends on a complex history of previous heat exchanges and surface temperatures and can be somewhat more difficult to model. A variety of schemes ranging from multiplayer finite difference...

Observations of sediment yield from road segments in the Oregon Coast Range show that either heavy traffic during rainfall or blading the road ditch will increase erosion from forest roads. For the fine soils and high quality aggregate surfacing on the study plots, ditch blading increased sediment yield more than traffic equivalent to 12 log trucks per day. The combination of ditch blading and heavy traffic did not produce significantly more sediment than simply blading the ditch, a finding with important implications for sediment modeling and erosion control design. Increases in sediment...

Aquatic species throughout the interior Columbia River basin are at risk. Evaluation of the potential effects of federal land management on aquatic ecosystems across this region is an important but challenging task. Issues include the size and complexity of the systems, uncertainty in important processes and existing states, flexibility and consistency in the analytical framework, and an ability to quantify results. We focused on salmonid fishes and their habitats as indicators of conditions in aquatic ecosystems and used Bayesian belief networks as a formal, quantitative framework to...

In this paper a physically based snow transport model (SnowTran-3D) was used to simulate snow drifting over a 30 m grid and was compared to detailed snow water equivalence (SWE) surveys on three dates within a small 0.25 km2 subwatershed, Upper Sheep Creek. Two precipitation scenarios and two vegetation scenarios were used to carry out four snow transport model runs in order to (1) evaluate the blowing snow model, (2) evaluate the sensitivity of the snow transport model to precipitation and vegetation inputs, and (3) evaluate the linearity of snow accumulation patterns and the utility of...

Monitoring of salmonid populations often involves annual redd counts, but the validity of this method has seldom been evaluated. We conducted redd counts of bull trout Salvelinus confluentus in two streams in northern Idaho to address four issues: (1) relationships between adult escapements and redd counts; (2) interobserver variability in redd counts; (3) sources of interobserver variability; and (4) temporal and spatial variation in spawning activity. We found that estimated adult escapements and redd counts were strongly correlated on a logarithmic scale, but both sources of data...

Animals react not only to immediate changes in their environment but also to cues that signal long-term changes to which they must adapt to survive. A proximate factor stimulates an animal’s immediate behavioral response, whereas what is known as an ultimate factor causes an animal to adjust its behavior to evolving conditions, thereby increasing its fitness and chances of long-term survival. The Salmonid family are cold-blooded organisms that can respond to an uncomfortable water temperature by moving from one spot to another to maintain thermal comfort. If the reason they move is because...

Wilderness conflict research has mostly followed the direction of recreation research in the U.S. An interpersonal recreation conflict model proposed in the late 1970s has guided much of the conflict research in wilderness, with emphasis on determining the amount of interpersonal conflict resulting from goal interference and how much one or more hypothesized contributors actually influence the occurrence of conflict. This approach is heavily rooted in expectancy-valence theory explanations of human recreation behavior and may contribute to an understanding of how social densities influence...

In the years following a major forest disturbance, such as fire, the erosion rate is greatly influenced by variability in weather, in soil properties, and in spatial distribution. This paper presents a method to incorporate these variabilities into the erosion rate predicted by the Water Erosion Prediction Project model. It appears that it is not necessary to describe both the soil and the vegetation effects of the disturbance. Incorporating the vegetation effects on soil erodibility, and its associated variability, is sufficient-when combined with weather and spatial variability-to...

How we resolve two management dilemmas will determine the future nature and value of wilderness. The first dilemma is providing for use and enjoyment while protecting wilderness conditions. The second is whether wilderness ecosystems should be left wild and “untrammeled” or, paradoxically, be manipulated toward a more natural state. Alternative solutions are explored. Because compromises between value systems will tend to homogenize wilderness areas, such that no area will fully meet any goal, we should consider allocating separate lands to each goal. Expanding our conception of wilderness...