Treesearch

Recreational use of backcountry inevitably impacts environments intended for preservation. Where use is light or where management programs provide adequate protection, impacts need not be unacceptably severe. However, where use is heavy and protective actions are inadequate, impacts may be severe and widespread. Trails may become deeply eroded trenches or mudholes and crisscross the landscape like a spider web (Figure 1). Campsites, viewpoints and other destination areas may be stripped of all groundcover vegetation and standing trees may be scarred and killed. Mineral soil may be exposed,...

The wolverine (Gulo gulo) is the largest-bodied terrestrial mustelid. Its distribution is circumpolar; it occupies the tundra, taiga, and forest zones of North America and Eurasia (Wilson 1982). North American wolverines are considered the same species as those in Eurasia. They are usually thought of as creatures of northern wilderness and remote mountain ranges. In fact, wolverines extend as far south as California and Colorado and as far east as the coast of Labrador, although low densities are characteristic of the species.

We examined responses of Northern Goshawks (Accipter gentilis) to taped broadcast calls of conspecifics in tree-harvest areas and around alternate goshawk nests on Kaibab National Forest, Arizona, in 1991 and 1992. Forest areas totaling 476 km2 were systematically surveyed for goshawks. Ninety responses by adult and juvenile goshawks were elicited and 15 active nests were located. No difference in response rates between sexes was detected. Adult males, however, tended to approach the broadcaster without vocalizing, whereas adult females approached while vocalizing. Our success in finding...

Recommendations for managing coarse woody debris after timber harvest were developed for 14 habitat types, ranging from ponderosa pine (Pinus ponderosa) habitat types of Arizona to subalpine fir (Abies lasiocarpa) habitat types of western Montana. Ectomycorrhizae were used as a bioindicator of healthy, productive forest soils. Undisturbed stands were studied to determine the optimum amounts of organic material for ectomycorrhizal activity. The management recommendations are intentionally conservative to ensure that enough organic matter is left after timber harvest to maintain long-term...

Feeding ecology of 11 Sharp-skinned Hawk (Accipiter striates) pairs nesting in aspen (Populus tremuloides), conifer (Abies, Picea spp.), and mixed aspen-conifer habitats in southwest Colorado was investigated during 1988-1989. Small birds (x-bar = 20.9 g, SE = 0.8 g) and mammals (x-bar = 41.1 g, SE = 3.3 g) comprised 91 and 9% of 513 prey identified at nests that fledged at least one young, respectively. Sixty percent of the birds eaten during the hawks' nestling and fledgling stages were nestlings or fledglings. Accordingly, median mass of birds eaten decreased from 17.4 g during incubatio...

Three species of wild cats (felids) occur in the temperate forests of North America: the cougar (Fells concolor), bobcat (Lynx rufus), and lynx (Lynx canadensis). The cougar is found in both temperate and tropical forests from the mountains of southern British Columbia to the southern tip of South America, whereas the bobcat and lynx are restricted to the temperate zone of North America. Bobcats are common throughout a variety of habitats in the conterminous United States, southernmost Canada, and northern Mexico. The lynx, in contrast, occurs primarily in the boreal forests of Alaska and...

Controversy over managing public lands is neither an unexpected nor recent development. In the 1970's, debate over land management began to focus on the effects of timber management practices on wildlife. This was most evident in the Pacific Northwest where the public was beginning to express strong concerns about the effects of timber harvest in late-successional forests on northern spotted owls and other vertebrates. The focus on all vertebrates and not just "game animals" distinguished these concerns from earlier wildlife-related issues. In 1976, Congress passed the National Forest...

This guide describes underwater methods using snorkeling gear to study fish populations in flowing waters of the Intermountain West. It outlines procedures for estimating salmonid abundance and habitat use and provides criteria for identifying and estimating the size of fish underwater.

Photographic guides are presented to help estimate grazing utilization of important riparian grasses and grasslike plants. Graphs showing the percent of a plant's weight that has been consumed based on the percent of its height left after grazing allow utilization estimates to be refined further.

Tree ring chronologies from 24 mixed-conifer stands were used to reconstruct the long-term history of western spruce budworm (Choristoneura occidentalis) in northern New Mexico. Temporal and spatial patterns of budworm infestations (within-stand occurrences) and outbreaks (more-or-less synchronous infestations across many stands) were investigated to identify local-scale to regional-scale forest disturbance patterns. Nine regional-scale outbreaks were identified from 1690 to 1989. One ancient stand of Douglas-fir trees (Pseudotsuga menziesii) exceeding 700 yr in age revealed that budworms...