Treesearch

Includes 19 papers documenting presentations at the 1991 Forest Service National Silviculture Workshop. Discussions focus on the role of silviculture in New Perspectives (ecosystem management), new approaches to the practice of silviculture, and examples of successful integration of practices into multi resource management.

In addition to thematic maps, remote sensing provides estimates of area in different thematic categories. Areal estimates are frequently used for resource inventories, management planning, and assessment analyses. Misclassification causes bias in these statistical areal estimates. For example, if a small percentage of a common cover type is misclassified as a rare cover type, then the area occupied by the rare type can be severely overestimated. Many categories are rare in detailed classification systems. I present an informal method to anticipate the approximate magnitude of this bias in...

Classifications of remotely sensed data contain misclassification errors that bias areal estimates. Monte Carlo techniques were used to compare two statistical methods that correct or calibrate remotely sensed areal estimates for misclassification bias using reference data from an error matrix. The inverse calibration estimator was consistently superior to the classical estimator using a simple random sample of reference plots. The effects of sample size of reference plots, detail of the classification system, and classification accuracy on the precision of the inverse estimator are...

The 1988 Gates Park Fire, along the North Fork of the Sun River in the Bob Marshall Wilderness, provided an opportunity to explore fire effects on wilderness visitor choices. Recreation visitors along the North and South Fork drainages were interviewed to assess the effects of 1988 fires on their 1989 visits. The Gates Park fire had relatively little impact on the choice to visit the North Fork or the South Fork. Visitors placed more importance on remoteness and naturalness in selecting trails and campsites than on the effects of the fires. The fire effects apparently are not seen as an...

The overall trend in condition on established campsites was one of slight deterioration, with the most deterioration occurring in campsite area, mineral soil exposure, and tree damage. Impacts to ground cover vegetation were relatively stable. Differences in amount of impact between high-use and low-use sites generally increased over time.

Greater knowledge is needed about visitors to federally classified wilderness in the South, the reasons they visit wilderness, and the ways wilderness conditions influence their experiences. This information will allow areas within the region to be compared, and it will improve the potential for tracking future changes that may require management changes. Visitors to the Cohutta Wilderness in Georgia, Caney Creek Wilderness in Arkansas, and Upland island Wilderness in Texas were surveyed to gather baseline data on use and user characteristics. These characteristics included length of...

New techniques in molecular biology can be used to characterize genes whose expression is induced by drought stress. These techniques can be used to understand responses of range plants to environmental stresses at the biochemical and molecular level. For example, they can be used to characterize genes that respond to drought stress conditions in the native shrub Atriplex canescens (Pursh.) Nutt. Complementary DNA (cDNA) libraries constructed from drought-induced messenger RNA (poly A+ RNA) were used to characterize genes which are associated with the stress response. A cDNA library from...

Color photographs show how white pine blister rust can be identified. In addition, the photographs show how pines resistant to the fungus could be identified. Such trees could be used to develop a new variety of whitebark pine that is resistant to blister rust.

Present forest conditions ­ loss of a herbaceous and shrubby understory, reductions in the amount of older forests, and increased areas of dense tree regeneration ­ reflect the extent of human influence on these forests. These changes may also be affecting goshawk populations. Information on goshawk nesting habitat and foraging behavior, and the food and habitats of selected goshawk prey, was therefore synthesized to develop a set of management objectives, desired forest conditions, and management recommendations. Key objectives of the guidelines are to provide (1) nesting, post-fledging,...

The Spotted Owl (Strix occidentalis) is most common in mature and old-growth coniferous forests throughout much of its range (Forsman et al. 1984, Laymon 1988, Ganey and Balda 1989a, Thomas et al. 1990). Proximate factors underlying habitat selection in Spotted Owls are understood poorly. Abundance and availability of food, however, may be a key factor influencing habitat selection in birds in general (Hilden 1965) and in owls in particular (Southern and Lowe 1968).