Treesearch

Reviews mining laws and regulations and their application to mining in Western States. Describes prospecting, exploration, mine development and operation, and reclamation factors.

Disturbance profiles, indices based on both spatial and non-spatial statistics, are used to examine how small-scale disturbances and the resulting canopy gaps disrupt ecosystem patterns and processes in selected stands in the Blue Mountains of Oregon. The biological meaning of many indices remains undefined for small scale disturbance phenomena, but their disturbance profiles could eventually be used to assess current and desired forest conditions and suggest actions to meet specific management objectives. These profiles can be determined for plots representing desired conditions associated...

Forest health issues include the effects of fire suppression and grazing on forest stands, reduction in amount of old-growth forests, stand structural changes associated with even-aged management, .changes in structure of the landscape mosaic, loss of habitat for threatened species, and the introduction of exotic species. The consequences of these impacts can be evaluated using an ecological approach based on conservation biology and several subdivisions of ecology. These disciplines provide a basis for assessing how the forested landscape has been altered from, earlier conditions and for...

Forest health is an increasingly important concept in natural resource management. However, definition of forest health is difficult and dependent on human perspective. From a utilitarian perspective, forest health has been defined by the production of forest conditions which directly satisfy human needs. From an ecosystem-centered perspective, forest health has been defined by resilience, recurrence, persistence and biophysical processes which lead to sustainable ecological conditions. Definitions and understanding of forest health are also dependent on spatial scale, with increasing...

Provides an overview of extant desert tortoise literature, summarizing literature on taxonomy, morphology, genetics, and paleontology and paleoecology of the desert tortoise, as well as its general ecology. Literature on desert tortoise ecology encompasses distribution and habitat, burrows and dens, reproduction, growth, physiology, feeding and nutrition, mortality factors, and behavior. Information on habitat deterioration, management of tortoises, their legal status and tortoise husbandry is also included. The manuscript is a complete overview of existing literature, including peer-review...

The fastest growth in outdoor recreation participation is projected for activities that are popular with older adults, and the slowest growth for those activities popular with younger adults. Nationally, changing age distribution is the main reason for change in participation; but, in some areas of the U.S., changing racial and ethnic structure and urban residence also are very important. Cohort component projection models estimate that participants be older and will include more racial and ethnic minorities, with minorities a substantial portion of increases in participants. Changes in...

Rainfall simulation is a commonly used approach for studying runoff and erosion from forest roads, and a method is needed to estimate infiltration parameters from these experiments. We used two algorithms, the Simplex and Shuffled Complex Evolution, to estimate parameters for a physically based infiltration and overland flow model. Each algorithm was tested by estimating parameters for 92 field-measured hydrographs from forest roads. Nine of the field-measured hydrographs allowed us to further test whether estimated parameters could be extended to other antecedent conditions and plot...

The single-species approach to conserving threatened and endangered species in the United States is insufficient, given the number of species (more than 700) officially considered at risk of extinction (i.e., formally listed under the Endangered Species Act of 1973), the rate at which new species are being listed (more than 50 species a year), and the number of species awaiting listing (more than 3,500 candidate species). Regions supporting many endangered species were located in the humid Southeast and the arid Southwest, and tended to be unique with respect to taxonomic composition,...

This report provides analysis of long-range trends in paper recylcling and impacts on the timber outlook for the 1993 RPA Assessment Update. Paper recycling is projected to increase substaintially in the next decade. Increased recylcing will extend timber resources and fiber supply.

Biological diversity in the United States is summarized in three categories: genetic diversity, species diversity, and community/ecosystem diversity. Major changes have occurred in the distribution and abundance of native diversity in the United States over the past 300 years. Native plant and animal diversity has declined over teh past three decades, and is likely to continue to decline because of human population growth and associated development.