Treesearch

A computer simulation model, FARSITE, includes existing fire behavior models for surface, crown, spotting, point-source fire acceleration, and fuel moisture. The model's components and assumptions are documented. Simulations were run for simple conditions that illustrate the effect of individual fire behavior models on two-dimensional fire growth.

This report briefly describes the main vegetation types and lists the vascular plant species that are known to occur in and near the Pawnee National Grassland, Weld County, Colorado. A checklist includes the scientific and common names for 521 species. Of these, 115 plant species (22 percent) are not native to this region. The life forms, habitats, and geographic distribution of native and introduced plants are summarized and discussed.

We studied 347 nesting attempts on 107 nesting territories of northern goshawks (Accipiter gentilis) on 1,732 km2 of the Kaibab Plateau, Arizona from 1991-1996. Mark and recapture methodology was used to estimate survival probabilities, territory and mate fidelity, turnover on territories, and dispersal. Territories were regularly spaced at a mean nearest neighbor distance of 3.88 krn (n = 100, P = 0.98, Cramer-von-Mises). An estimate of the total breeding population on the study area (146 territories) suggested that about 73 percent of the breeding population was located during the study....

This conference provided an arena for identifying common key issues that are shaping wildland fire research. Commonly identified desired outcomes include: research, integrated across disciplines, and management form partnerships; communication between management and research is effective and continuous; responsive and proactive research balances long-term scientific goals with rapidly changing management issues; the success of research and development is measured by on-the-ground implementation; and fire research is responsive to national goals and receives long-term, stable political...

Quaking aspen (Populus tremuloides) are unique because, in contrast to most western forest trees, they reproduce primarily by suckering from the parent root system. Generally disturbance or dieback is necessary to stimulate regeneration of aspen stands. These self-regenerating stands have existed for thousands of years. If they are lost from the landscape, they will not return through normal seeding processes as do other tree species.

Riparian zones are key areas of most western landscapes. The kinds and amounts of natural and human activity occurring on these sites are often in dispute as many riparian areas in the mountain West are remote or have limited seasonal access. Impacts by wild ungulates, domestic livestock, or recreationists can result in relatively similar damages to streamside environments. Competing interests often blame other uses for perceived resource damage. These questions of use can become serious management issues.Time-lapse photography is proposed as a use documentation method to help guide...

The prevailing assumption, that for Poisson sampling the adjusted estimator "Y-hat a" is always substantially more efficient than the unadjusted estimator "Y-hat u" , is shown to be incorrect. Some well known theoretical results are applicable since "Y-hat a" is a ratio-of-means estimator and "Y-hat u" a simple unbiased estimator. We formalize an additional realistic situation for high-value timber estimation for which "Y-hat u" is more efficient. (Please note: equations are spelled out inside quotation marks. Please see PDF for symbols.)

We measured noise levels of four logging trucks as the trucks passed within approximately 500 m of two active northern goshawk (Accipiter gentilis) nests on the Kaibab Plateau in northern Arizona in 1997. Neither a brooding adult female nor a lone juvenile exhibited any discernable behavioral response to logging truck noise, which peaked at 53.4 and 50.3 decibels (dBA). Spectral analysis showed most of the truck sound energy was in the vicinity of 80 Hz.

The allocation of recreation use is a task that has challenged wilderness managers throughout the National Wilderness Preservation System for nearly two decades. This note reviews and evaluates approaches for allocating wilderness recreation use between commercially outfitted, institutionally outfitted, and nonoutfitted visitors to wildlands. Of the 17 identified approaches to allocation, 11 of those are sufficiently defined to allow a comparative evaluation to determine how these approaches are able to address eight wilderness recreation allocation goals. The analysis results in a...

A key product of both Forest Inventory and Analysis (FIA) of the USDA Forest Service and the Natural Resources Inventory (NRI) of the Natural Resources Conservation Service is a scientific data base that should be defensible in court. Multiple imputation procedures (MIPs) have been proposed both for missing value estimation and prediction of non-remeasured cells in annualized forest inventories such as the Southern Annual Forest Inventory System (SAFIS). MIPs generate clean-looking data bases that are easily used but hide a serious weakness: under different assumptions made by reasonable...