Treesearch

Although the quality of water draining forested watersheds is typically the best in the Nation, some forest management practices can seriously impair streamwater quality. Sediment is the main concern. High suspended sediment levels, and adverse changes in stream channels, are potential problems in several regions, especially after road construction, and some harvesting and grazing practices. Impacts are most serious where fish reproduction is affected. Nitrate and water temperature are less serious problems. Harvesting can increase nitrate levels markedly, in some locations and removal of...

Current management guidelines for the Northern Goshawk (Accipiter gentilis) in the Southwest call for a mosaic habitat consisting of approximately 10 percent of the forest area in grass-forb/ shrubs, 10 percent in 2.5-12.7 cm trees, 20 percent in 12.7-30.5 cm trees, 20 percent in 30.5-45.7 cm trees, 20 percent in 45.7-61.0 cm trees, and 20 percent in 61.0 cm and greater trees. This habitat mosaic was conceived as convenient categories to describe a generally balanced, ecologically sustainable, forest ecosystem. In reality, however, the vegetative structural percentages vary. We describe...

The flammulated owl (Otus jlammealus) is an insectivorous species (Marshall 1957, Ross 1969) that breeds in dry, montane conifer forests of western North America. In Colorado , this owl fed primarily on small lepidopterans, although its diet included a variety of arthropods (e.g., Orthoptera, Diptera, and Arachnida) as summer progressed (Reynolds and Linkhart 1987). Some authors (Bent 1938, Bailey and Niedrach 1965) have reported that flammulated owls occasionally prey on small mammal s and birds. However, none of these authors provided direct evidence of flammulated owls feeding on...

Recent wetland area trends were estimated from the National Resources Inventory (NRI) for nonfederal rural lands for the period 1982-1987. NRI-based estimates of wetland area for states comprising the conterminous United States were highly correlated with estimates made by the US Fish and Wildlife Service and with estimates of coastal salt marsh wetlands made by the National Oceanic and Atmospheric Administration. Net wetland area declined by 1.1% (~363,200 ha) during the five-year study period. Conversion to open water, primarily caused by natural flooding in western inland basins, was...

The cedar (Thuja plicata) -hemlock (Tsuga heterophylla) -white pine (Pinus monticola) forests are some of the most productive in North America. Silvicultural practices used in these forests originated in Europe and usually concentrated on producing high-value commercial products.Beginning in the 1960s society's interest in the management of natural resources, especially forests, increased, and a component of society no longer desired forests managed exclusively for timber production. But a significant portion of the public still expect a high level of wood products. As society changed in...

Fluctuations in atmospheric carbon dioxide is influenced by carbon storage and cycling in terrestrial forest ecosystems. Currently, only gross estimates are available for carbon content of these ecosystems and reliable estimates are lacking for Rocky Mountain forests. To improve carbon storage estimates more information is needed on the relationship between carbon and organic matter, carbon concentrations of forest components, and how carbon storage varies among vegetation types. Therefore, this study used four different vegetation types (habitat types) to supply a portion of this informati...

Natural resource management in the United States is in a state of flux now more than any time in history. Many of the concerns about forest management are related to the enforcement of the Endangered Species Act. This act focuses forest management on preserving the habitat of a single species. But, for the northern goshawk (Accipiter gentilis) because it is a habitat generalist and a predator of over 50 birds and mammals, a multiple species approach was used for developing management recommendations. Even with this approach, however, several animal and plant species were not explicitly...

Western white pine (Pinus monticola Dougl. ex D. Don) continues to be one of the most important coniferous tree species growing in Northern Rocky Mountain forests. Because large wildfires occurred early in the 1900s, many plantations of western white pine with varying levels of resistance to blister rust (Cronartium ribicola Fisch.) were established. Thinning these stands cannot only produce high value lumber products, but can maintain other resource values important to sustaining forest ecosystems. In 1982, a 53-year-old western white pine plantation was thinned to three different...

Instream flow is valuable to recreationists who rely on flows for fishing, boating, and other forms of river recreation. Instream flow is also valuable to many members of society, whether they visit the rivers or not, because flows maintain ecosystem stability and associated fish and wildlife habitat. This study estimates the economic value of these recreation and preservation benefits along the Big Hole and the Bitterroot Rivers in Montana. Valuation and participation information was obtained from recreationists who were interviewed along the rivers, and from households that were sampled...

Environmental protection strategies often rely on environmental impact assessments. As part of the assessment process biologists are routinely asked to evaluate the effects of management actions on plants and animals. This evaluation often requires that biologists make judgments about the viability of affected populations. However, population viability analyses that are analytically comprehensive require extensive ecological data. Such data are usually unavailable and impossible for wildlife managers to collect given limitations of time and money. In this paper we present a conceptual...