Treesearch

We determined food habits of Red-tailed Hawks (Buteo jamaicensis) for comparison with published information for Northern Goshawks (Accipiter gentilis) to evaluate potential competition on the Kaibab Plateau, Arizona. We collected prey remains and pellets from 42 Red-tailed Hawk nests at the end of the nesting season between August-October 1998-2001, and opportunistically from below nest trees during site visits, May-July 2000-01. We identified 478 prey items, including 17 mammal, 7 bird, and 2 reptile species. Prey species frequency did not vary among years (P = 0.3), across habitat types...

Cronartium ribicola (J. C. Fischer ex Rabh.), the causal agent of white pine blister rust (WPBR), was introduced to western North America via infected nursery stock imported from France to Point Grey near Vancouver, British Columbia (Mielke 1943). Primary infection of white pines occurs on the needles where fungal spores land, enter through stomata, grow within the vascular tissue, and then enter branches and stems. The fungus grows in the intercellular spaces within the bark of white pines where the production of spores breaks apart the bark causing the girdling of branches and stems; the...

The ability to assess the potential for a severe infestation of white pine blister rust is an important management tool. Successful hazard rating requires a proper understanding of blister rust epidemiology, including environmental and genetic factors. For the blister rust caused by Cronartium ribicola, climate and meteorology, and the ecology, distribution, and pathology of ribes and other telial hosts affect spread and intensification of rust on white pine hosts (several sections in subgenus Strobus of genus Pinus). The importance of ribes (genus Ribes) for supporting effective inoculum...

The Random Forests multiple-regression tree was used to model climate profiles of 25 biotic communities of the western United States and nine of their constituent species. Analyses of the communities were based on a gridded sample of ca. 140,000 points, while those for the species used presence-absence data from ca. 120,000 locations. Independent variables included 35 simple expressions of temperature and precipitation and their interactions. Classification errors for community models averaged 19%, but the errors were reduced by half when adjusted for misalignment between geographic data...

There is an increasing need for spatial wildland fire analysis in support of incident management, fuel treatment planning, wildland-urban assessment, and land management plan development. However, little guidance has been provided to the field in the form of training, support, or research examples. This paper provides guidance to fire managers, planners, specialists, and analysts in the use of "models" (FARSITE, FlamMap, RERAP-Term), tools/programs (KCFAST, RAWS, FireFamily Plus, WindWizard), and procedures for spatial fire analysis. The approach includes a brief discussion about models...

Reliable predictions of the effects changing climate and disturbance regimes will have on forest ecosystems are crucial for effective forest management. Current fire and climate research in forest ecosystem and community ecology offers data and methods that can inform such predictions. However, research in these fields occurs at different scales, with disparate goals, methods, and context. Often results are not readily comparable among studies and defy integration. We discuss the strengths and weaknesses of three modeling paradigms: empirical gradient models, mechanistic ecosystem models,...

In recent years, the young dense forests of northern Arizona have suffered extreme droughts, wildfires, and insect outbreaks. Improving forest health requires reducing forest density by cutting many small-diameter trees with the consequent production of large volumes of residual biomass. To offset the cost of handling this low-value timber, additional marketing options for current operations are urgently needed to recover more value as wood products, energy, and chemicals. Northern Arizona forests are predominantly composed of ponderosa pine (Pinus ponderosa) which, besides producing...

The Malpai Borderlands study area is in those portions of southeastern Arizona and southwestern New Mexico that have been biogeographically described as the Madrean Archipelago (DeBano and others 1994: 580). The area covers approximately 1,600 square miles of the Basin and Range Physiographic Province south of the Rocky Mountains and north of the Sierra Madre Occidental (fig 1.1). Arbitrarily bounded on the south by the international border with Mexico, it includes large sections of the San Bernardino, San Luis, Animas, and Playas Valleys.

The Landscape Fire and Resource Management Planning Tools Prototype Project, or LANDFIRE Prototype Project, required a system for classifying vegetation composition, biophysical settings, and vegetation structure to facilitate the mapping of vegetation and wildland fuel characteristics and the simulation of vegetation dynamics using landscape modeling. We developed three separate, fully integrated vegetation and biophysical settings map unit classifications that quantified, categorized, and described vegetation and environmental conditions; these include: cover type (CT), potential...

Erosion in the first year after a wildfire can be up to three orders of magnitude greater than the erosion from undisturbed forests. To mitigate potential postfire erosion, various erosion control treatments are applied on highly erodible areas with downstream resources in need of protection. Because postfire erosion rates generally decline by an order of magnitude for each year of recovery, effective erosion mitigation treatments are most needed during the first year or two after a fire. Postfire treatments include broadcast seeding, scarification and trenching, physical erosion barriers...