Treesearch

This is the fourth in a series of studies to evaluate perceptions of U.S. Department of Agriculture Forest Service law enforcement personnel of the roles, responsibilities, and issues related to their jobs. An e-mail survey was administered to the 89 Forest Service special agents, assistant special agents in charge, senior special agents, and supervisory special agents (SAs) across the United States. Seventy completed and returned the questionnaire. Communication with others in the Forest Service was important to the SA respondents, as evidenced by their efforts to communicate at group...

Individual cuttings from eight plant species native to California chaparral or Utah were burned in a well-controlled, well-instrumented facility. Gas temperatures above a flat-flame burner were controlled at 987 ± 12°C and 10 ± 0.5 mol% O2, resulting in a heat flux at the leaf surface varying from 80-140 kw/m2. High moisture leaves were observed to burst due to the rapid escape of vapor from the leaf interior. Bubbles in or on the leaf surface were observed for leaves with moderate moisture contents. A large number of leaf temperature measurements were made, along with measurements of the...

This paper presents a combined study of laboratory scale fire spread experiments and a three-dimensional large eddy simulation (LES) to analyze the effect of terrain slope on marginal burning behavior in live chaparral shrub fuel beds. Line fire was initiated in single species fuel beds of four common chaparral plants under various fuel bed configurations and ambient conditions. An LES approach was developed to model fire spreading through a fuel bed with a subgrid scale turbulent combustion model based on a flame surface density concept. By examining two fuel bed slope configurations, it...

Recent advances in molecular techniques have provided new tools for confirming species identities, however they can be expensive and results are not immediately available. Myotis lucificugus and M. yumanensis are morphologically cryptic species of bats sympatric in western North America that can be difficult to distinguish in the field. We valuated a set of models that used morphological and echolocation call characters obtained in the field to predict species identity as determined by DNA analysis. We constructed models using data from 98 M. lucifugus and 100 M. yumanensis captured...

Little quantitative information exists about the survey effort necessary to inventory temperate bat species assemblages. We used a bootstrap resampling lgorithm to estimate the number of mist net surveys required to capture individuals from 9 species at both study area and site levels using data collected in a forested watershed in northwestern California, USA, during 1996–2000. The mean number of simulated surveys required to capture individual species varied with species’ rarity and ranged from 1.5 to 44.9. We retrospectively evaluated strategies to reduce required survey effort by...

Even as they increase the beauty of our surroundings, trees provide us with a great many ecosystem services, including air quality improvement, energy conservation, stormwater interception, and atmospheric carbon dioxide reduction. These benefits must be weighed against the costs of maintaining trees, including planting, pruning, irrigation, administration, pest control, liability, cleanup, and removal. We present benefits and costs for representative small, medium, and large deciduous trees and coniferous trees in the Interior West region derived from models based on indepth research...

This is the third in a series of studies to evaluate perceptions of USDA Forest Service law enforcement personnel of the roles, responsibilities, and issues entailed in their jobs. An e-mail survey was administered to the 79 Forest Service patrol captains and patrol commanders (PCs) across the United States. Seventy completed and returned the questionnaire. Communication with others in the Forest Service was important to the PC respondents, as evidenced by their efforts to communicate at group meetings, talking face-to-face with others, their use of e-mail and the phone, and being available...

Even as they increase the beauty of our surroundings, trees provide us with a great many ecosystem services, including air quality improvement, energy conservation, stormwater interception, and atmospheric carbon dioxide reduction. These benefits must be weighed against the costs of maintaining trees, including planting, pruning, irrigation, administration, pest control, liability, cleanup, and removal. We present benefits and costs for representative small, medium, and large deciduous trees and coniferous trees in the Temperate Interior West region derived from models based on indepth...

Outcomes from the 22nd meeting for Specialists in Air Pollution Effects on Forest Ecosystems "Forests under Anthropogenic Pressure – Effects of Air Pollution, Climate Change and Urban Development", September 10–16, 2006, Riverside, CA, are summarized. Tropospheric or ground-level ozone (O3) is still the phytotoxic air pollutant of major interest. Challenging issues are how to make O3 standards or critical levels more biologically based and at the same time practical for wide use; quantification of plant detoxification processes in flux modeling; inclusion of multiple environmental stresses...

Chaparral watersheds associated with Mediterranean-type climate are distributed over five regions of the world. Because brushland soils are often shallow with low water holding capacities, and are on slopes prone to erosion, disturbances such as fire can adversely affect their physical properties. Fire can also increase the spatial coverage of soil water repellency, reducing infiltration, and, in turn, increasing overland flow and subsequent erosion. We studied the impacts of fire on soil properties by collecting data before and after a prescribed burn conducted during Spring 2001 on the...