Research Database
Displaying 181 - 200 of 228
Capturing Fire: RxCadre Takes Fire Measurements to a Whole New Level
Year: 2013
Models of fire behavior and effects do not always make accurate predictions, and there is not enough systematically gathered data to validate them. To help advance fire behavior and fire effects model development, the Joint Fire Science Program is helping fund the RxCADRE, which is made up of scientists from the U.S. Forest Service and several universities who orchestrate and collect data on prescribed burns in the southeastern United States. The RxCADRE-prescribed burns are yielding a comprehensive dataset of fire behavior, fire effects, and smoke chemistry and dynamics, with measurements…
Publication Type: Report
Examination of the wind speed limit function in the Rothermel surface fire spread model
Year: 2013
The Rothermel surface fire spread model includes a wind speed limit, above which predicted rate of spread is constant. Complete derivation of the wind limit as a function of reaction intensity is given, along with an alternate result based on a changed assumption. Evidence indicates that both the original and the revised wind limits are too restrictive. Wind limit is based in part on data collected on the 7 February 1967 Tasmanian grassland fires. A reanalysis of the data indicates that these fires might not have been spreading in fully cured continuous grasslands, as assumed. In addition,…
Publication Type: Journal Article
ArcFuels10 System Overview
Year: 2013
Fire behavior modeling and geospatial analyses can provide tremendous insight for land managers as they grapple with the complex problems frequently encountered in wildfire risk assessments and fire and fuels management planning. Fuel management often is a particularly complicated process in which the benefits and potential impacts of fuel treatments need to be demonstrated in the context of land management goals and public expectations. The fuel treatment planning process is complicated by the lack of data assimilation among fire behavior models and weak linkages to geographic information…
Publication Type: Report
Assessing forest vegetation and fire simulation model performance after the Cold Springs wildfire, Washington, USA
Year: 2013
Given that resource managers rely on computer simulation models when it is difficult or expensive to obtain vital information directly, it is important to evaluate how well a particular model satisfies applications for which it is designed. The Forest Vegetation Simulator (FVS) is used widely for forest management in the US, and its scope and complexity continue to increase. This paper focuses on the accuracy of estimates made by the Fire and Fuels Extension (FFE-FVS) predictions through comparisons between model outputs and measured post-fire conditions for the Cold Springs wildfire and on…
Publication Type: Journal Article
Analysis of Meteorological Conditions for the Yakima Smoke Intrusion Case Study, 28 September 2009
Year: 2013
On 28 September 2009, the Naches Ranger District on the Okanogan-Wenatchee National Forest in south-central Washington State ignited an 800-ha prescribed fire. Later that afternoon, elevated PM2.5 concentrations and visible smoke were reported in Yakima, Washington, about 40 km east of the burn unit. The U.S. National Weather Service forecast for the day had predicted good dispersion conditions and winds that would carry the smoke to the less populated area north of Yakima. We undertook a case study of this event to determine whether conditions leading to the intrusion of the smoke plume into…
Publication Type: Report
Estimating Critical Climate - Driven Thresholds in Landscape Dynamics Using Spatial Simulation Modeling: Climate Change Tipping Points in Fire Management
Year: 2013
Climate projections for the next 20-50 years forecast higher temperatures and variable precipitation for many landscapes in the western United States. Climate changes may cause or contribute to threshold shifts, or tipping points, where relatively small shifts in climate result in large, abrupt, and persistent changes in landscape patterns and fire regimes. Rather than simulate potential climate-fire interactions using future climate data derived from Global Climate Models (GCMs), we developed sets of progressively warmer and drier or wetter climate scenarios that span and exceed the range of…
Publication Type: Report
Modelling conditional burn probability patterns for large wildland fires
Year: 2013
We present a technique for modelling conditional burn probability patterns in two dimensions for large wildland fires. The intended use for the model is strategic program planning when information about future fire weather and event durations is unavailable and estimates of the average probabilistic shape and extent of large fires on a landscape are needed. To model average conditional burn probability patterns, we organised historical fire data from Yellowstone National Park, USA, into a set of grids; one grid per fire. We captured various spatial relationships inherent in the gridded data…
Publication Type: Journal Article
Comparative Hazard Assessment for Protected Species in a Fire-Prone Landscape
Year: 2012
We conducted a comparative hazard assessment for 325,000 ha in a fire-prone area of southwest Oregon, USA. The landscape contains a variety of land ownerships, fire regimes, and management strategies. Our comparative hazard assessment evaluated the effects of two management strategies on crown fire potential and northern spotted owl (Strix occidentalis caurina) conservation: (1) no action, and (2) active manipulation of hazardous fuels. Model simulations indicated that active management of sites with high fire hazard was more favorable to spotted owl conservation over the long term (75 years…
Publication Type: Journal Article
Climate Change, Forests, Fire, Water, and Fish: Building Resilient Landscapes, Streams, and Managers
Year: 2012
Fire will play an important role in shaping forest and stream ecosystems as the climate changes. Historic observations show increased dryness accompanying more widespread fire and forest die-off. These events punctuate gradual changes to ecosystems and sometimes generate stepwise changes in ecosystems. Climate vulnerability assessments need to account for fire in their calculus. The biophysical template of forest and stream ecosystems determines much of their response to fire. This report describes the framework of how fire and climate change work together to affect forest and fish…
Publication Type: Report
Delayed Phenology and Reduced Fitness Associated with Climate Change in a Wild Hibernator
Year: 2012
The most commonly reported ecological effects of climate change are shifts in phenologies, in particular of warmer spring temperatures leading to earlier timing of key events. Among animals, however, these reports have been heavily biased towards avian phenologies, whereas we still know comparatively little about other seasonal adaptations, such as mammalian hibernation. Here we show a significant delay (0.47 days per year, over a 20-year period) in the hibernation emergence date of adult females in a wild population of Columbian ground squirrels in Alberta, Canada. This finding was related…
Publication Type: Journal Article
Commonalities of Carbon Dioxide Exchange in Semiarid Regions with Monsoon and Mediterranean Climates
Year: 2012
Comparing biosphereatmosphere carbon exchange across monsoon (warm-season rainfall) and Mediterranean (cool-season rainfall) regimes can yield information about the interaction between energy and water limitation. Using data collected from eddy covariance towers over grass and shrub ecosystems in Arizona, USA and Almeria, Spain, we used net ecosystem carbon dioxide exchange (NEE), gross ecosystem production (GEP), and other meteorological variables to examine the effects of the different precipitation seasonality. Considerable crossover behavior occurred between the two rainfall regimes. As…
Publication Type: Journal Article
Pattern and process of prescribed fires influence effectiveness at reducing wildfire severity in dry coniferous forests
Year: 2012
We examined the effects of three early season (spring) prescribed fires on burn severity patterns of summer wildfires that occurred 1–3 years post- treatment in a mixed conifer forest in central Idaho. Wildfire and prescribed fire burn severities were estimated as the difference in normalized burn ratio (dNBR) using Landsat imagery. We used GIS derived vegetation, topography, and treatment variables to generate models predicting the wildfire burn severity of 1286–5500 30- m pixels within and around treated areas. We found that wildfire severity was significantly lower in treated areas than in…
Publication Type: Journal Article
A Comprehensive Guide to Fuel Management Practices for Dry Mixed Conifer Forests in the Northwestern United States
Year: 2012
This guide describes the benefits, opportunities, and trade-offs concerning fuel treatments in the dry mixed conifer forests of northern California and the Klamath Mountains, Pacific Northwest Interior, northern and central Rocky Mountains, and Utah. Multiple interacting disturbances and diverse physical settings have created a forest mosaic with historically low- to mixed-severity fire regimes. Analysis of forest inventory data found nearly 80 percent of these forests rate hazardous by at least one measure and 20 to 30 percent rate hazardous by multiple measures. Modeled mechanical…
Publication Type: Report
Projected range shifting by montane mammals under climate change: implications for Cascadia's National Parks
Year: 2012
We examined potential impacts of climate change over the next century on eight mammal species of conservation concern in western Washington State, under four warming scenarios. Using two species distribution models, including a logistic regression-based model and the "maximum entropy" (MaxEnt) model, we predicted the location and extent of the potential current and future range of each species based on a suite of environmental and geographical variables. Both models projected significant losses in range size within the focal area over the next century across all warming scenarios. Projections…
Publication Type: Journal Article
Eco-Evolutionary Responses of Biodiversity to Climate Change
Year: 2012
Climate change is predicted to alter global species diversity, the distribution of human pathogens and ecosystem services. Forecasting these changes and designing adequate management of future ecosystem services will require predictive models encompassing the most fundamental biotic responses. However, most present models omit important processes such as evolution and competition. Here we develop a spatially explicit eco-evolutionary model of multi-species responses to climate change. We demonstrate that both dispersal and evolution differentially mediate extinction risks and biodiversity…
Publication Type: Journal Article
Climatic, Landform, Microtopographic, and Overstory Canopy Controls of Tree Invasion in a Subalpine Meadow Landscape, Oregon Cascades, USA
Year: 2012
Tree invasions have been documented throughout Northern Hemisphere high elevation meadows, as well as globally in many grass and forb-dominated ecosystems. Tree invasions are often associated with large-scale changes in climate or disturbance regimes, but are fundamentally driven by regeneration processes influenced by interactions between climatic, topographic, and biotic factors at multiple spatial scales. The purpose of this research was to quantify spatiotemporal patterns of meadow invasion; and how climate, larger landforms, topography, and overstory trees have interactively influenced…
Publication Type: Journal Article
Climate and Weather Influences on Spatial Temporal Patterns of Mountain Pine Beetle Populations in Washington and Oregon
Year: 2012
Widespread outbreaks of mountain pine beetle in North America have drawn the attention of scientists, forest managers, and the public. There is strong evidence that climate change has contributed to the extent and severity of recent outbreaks. Scientists are interested in quantifying relationships between bark beetle population dynamics and trends in climate. Process models that simulate climate suitability for mountain pine beetle outbreaks have advanced our understanding of beetle population dynamics; however, there are few studies that have assessed their accuracy across multiple outbreaks…
Publication Type: Journal Article
The Age of Western Wildfires
Year: 2012
The 2012 wildfire season isn’t over yet, but already this year is shaping up to be the one of the worst on record in the American West. According to the National Interagency Fire Center, with nearly two months still to go in the fire season, the total area already burned this year is 30 percent more than in an average year, and fires have consumed more than 8.6 million acres, an area larger than the state of Maryland. Yet, what defines a “typical” wildfire year in the West is changing. In the past 40 years, rising spring and summer temperatures, along with shrinking winter snowpack, have…
Publication Type: Report
Fuels and Fire Behavior Dynamics in Bark Beetle-Attacked Forests in Western North America and Implications for Fire Management
Year: 2012
Declining forest health attributed to associations between extensive bark beetle-caused tree mortality, accumulations of hazardous fuels, wildfire, and climate change have catalyzed changes in forest health and wildfire protection policies of land management agencies. These changes subsequently prompted research to investigate the extent to which bark beetle-altered fuel complexes affect fire behavior. Although not yet rigorously quantified, the results of the investigations, in addition to a growing body of operational experience and research, indicates that predictable changes in surface,…
Publication Type: Journal Article
Changes to Dryland Rainfall Result in Rapid Moss Mortality and Altered Soil Fertility
Year: 2012
Arid and semi-arid ecosystems cover ~40% of Earth's terrestrial surface, but we know little about how climate change will affect these widespread landscapes. Like many drylands, the Colorado Plateau in southwestern United States is predicted to experience elevated temperatures and alterations to the timing and amount of annual precipitation. We used a factorial warming and supplemental rainfall experiment on the Colorado Plateau to show that altered precipitation resulted in pronounced mortality of the widespread moss Syntrichia caninervis. Increased frequency of 1.2mm summer rainfall events…
Publication Type: Journal Article