Research Database
Displaying 121 - 140 of 149
Modifying the Canadian Fine Fuel Moisture Code for masticated surface fuels
Year: 2014
Mechanical mastication is a fuel management technique that disrupts the vertical continuity of forest fuels by shredding of trees and understory vegetation into a highly compacted surface fuel bed. Despite the increasing application of mastication to manage wildfire risk, there is little information to date on fuel moisture in masticated fuels and optimal ignition patterns for prescribed burning. We investigated the applicability of the Fine Fuel Moisture Code (FFMC), a component of the Canadian Fire Weather Index (FWI) System, in tracking the diurnal and day-to-day changes in masticated…
Publication Type: Journal Article
Wildfire and the Future of Water Supply
Year: 2014
In many parts of the world, forests provide high quality water for domestic, agricultural, industrial, and ecological needs, with water supplies in those regions inextricably linked to forest health. Wildfires have the potential to have devastating effects on aquatic ecosystems and community drinking water supply through impacts on water quantity and quality. In recent decades, a combination of fuel load accumulation, climate change, extensive droughts, and increased human presence in forests have resulted in increases in area burned and wildfire severity—a trend predicted to continue. Thus,…
Publication Type: Journal Article
Smoke management of wildfire and prescribed fire: understanding public preferences and trade-offs
Year: 2014
Smoke from forest fires is a serious and increasing land management concern. However, a paucity of information exists that is specific to public perceptions of smoke. This study used conjoint analysis, a multivariate technique, to evaluate how four situational factors (i.e., smoke origin, smoke duration, health impact, and advanced warning) influence public tolerance of smoke in the northern Rocky Mountains and south-central United States. Separate analyses were performed for subgroups, based on community type, level of fire preparedness, demographics, and smoke experience, to explore…
Publication Type: Journal Article
The influence of experimental wind disturbance on forest fuels and fire characteristics
Year: 2014
Current theory in disturbance ecology predicts that extreme disturbances in rapid succession can lead to dramatic changes in species composition or ecosystem processes due to interactions among disturbances. However, the extent to which less catastrophic, yet chronic, disturbances such as wind damage and fire interact is not well studied. In this study, we simulated wind-caused gaps in a Pinus taeda forest in the Piedmont of north-central Georgia using static winching of trees to examine how wind damage may alter fuel characteristics and the behavior of subsequent prescribed fire. We found…
Publication Type: Journal Article
The climate-wildfire-air quality system: interactions and feedbacks across spatial and temporal scales
Year: 2014
Future climate change and its effects on social and ecological systems present challenges for preserving valued ecosystem services, including local and regional air quality. Wildfire is a major source of air-quality impact in some locations, and a substantial contributor to pollutants of concern, including nitrogen oxides and particulate matter, which are regulated to protect public and environmental health. Since climate change is expected to increase total area burned by wildfire and wildfires affect air quality, which is regulated, there is a need to define and study climate, wildfire, and…
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
Relationships between climate and macroscale area burned in the western United States
Year: 2013
Increased wildfire activity (e.g. number of starts, area burned, fire behaviour) across the western United States in recent decades has heightened interest in resolving climate–fire relationships. Macroscale climate–fire relationships were examined in forested and non-forested lands for eight Geographic Area Coordination Centers in the western United States, using area burned derived from the Monitoring Trends in Burn Severity dataset (1984–2010). Fire-specific biophysical variables including fire danger and water balance metrics were considered in addition to standard climate variables of…
Publication Type: Journal Article
Climate Change Quarterly: Summer 2013
Year: 2013
A historical record of Pacific Northwest (defined here as west of the Cascade Mountains in Washington and Oregon) heat waves is identified using the U.S. Historical Climate Network, version 2, daily data (1901–2009). Both daytime and nighttime events are examined, defining a heat wave as three consecutive days above the 99th percentile for the maximum and minimum temperature anomalies separately. Although the synoptic characteristics of the daytime and nighttime heat events are similar, they do indicate some differences between the two types of events. Most notable is a stronger influence of…
Publication Type: Report
Predicting Dry Lightning Risk Nationwide
Year: 2012
Meteorologists developed two formulas to predict the probability of dry lightning throughout the continental United States and Alaska and parts of Canada. Predictions are made daily and are accessible through the web at http://www.airfire.org/tools/daily-fi re-weather/dry-lightning-probability. The emphasis is on the western United States, where dry lightning is a more common occurrence. Predictions are based on identifying days on which lightning is expected and separately determining whether there is likely to be at least 1/10th inch of accompanying rain. The formulas are run with the…
Publication Type: Report
Evidence of Enhanced Freezing Damage in Treeline Plants During Six Years of CO 2 Enrichment and Soil Warming
Year: 2012
Climate change and elevated atmospheric CO 2 levels could increase the vulnerability of plants to freezing. We analyzed tissue damage resulting from naturally occurring freezing events in plants from a longterm in situ CO 2 enrichment (+ 200 ppm, 2001-2009) and soil warming (+ 4°C since 2007) experiment at treeline in the Swiss Alps (Stillberg, Davos). Summer freezing events caused damage in several abundant subalpine and alpine plant species in four out of six years between 2005 and 2010. Most freezing damage occurred when temperatures dropped below -1.5°C two to three weeks after snow melt…
Publication Type: Journal Article
Research Perspectives on the Public and Fire Management: A Synthesis of Current Social Science on Eight Essential Questions
Year: 2012
As part of a Joint Fire Science Program project, a team of social scientists reviewed existing fire social science literature to develop a targeted synthesis of scientific knowledge on the following questions: 1. What is the public’s understanding of fire’s role in the ecosystem? 2. Who are trusted sources of information about fire? 3. What are the public’s views of fuels reduction methods, and how do those views vary depending on citizens’ location in the wildland-urban interface or elsewhere? 4. What is the public’s understanding of smoke effects on human health, and what shapes the public’…
Publication Type: Report
Harmful filamentous cyanobacteria favoured by reduced water turnover with lake warming
Year: 2012
Anthropogenic-induced changes in nutrient ratios have increased the susceptibility of large temperate lakes to several effects of rising air temperatures and the resulting heating of water bodies. First, warming leads to stronger thermal stratification, thus impeding natural complete water turnover (holomixis), which compensates for oxygen deficits in the deep zones. Second, increased water temperatures and nutrient concentrations can directly favour the growth of harmful algae. Thus, lake-restoration programmes have focused on reducing nutrients to limit toxic algal blooms. Here we present…
Publication Type: Journal Article
Atmospheric Interactions with Wildland Fire Behaviour I. Basic Surface Interactions, Vertical Profiles and Synoptic Structures
Year: 2012
This paper is the first of two reviewing scientific literature from 100 years of research addressing interactions between the atmosphere and fire behaviour. These papers consider research on the interactions between the fuels burning at any instant and the atmosphere, and the interactions between the atmosphere and those fuels that will eventually burn in a given fire. This first paper reviews the progression from the surface atmospheric properties of temperature, humidity and wind to horizontal and vertical synoptic structures and ends with vertical atmospheric profiles. (The companion paper…
Publication Type: Journal Article
The push and pull of climate change causes heterogeneous shifts in avian elevational ranges
Year: 2012
Projected effects of climate change on animal distributions primarily focus on consequences of temperature and largely ignore impacts of altered precipitation. While much evidence supports temperature-driven range shifts, there is substantial heterogeneity in species' responses that remains poorly understood. We resampled breeding ranges of birds across three elevational transects in the Sierra Nevada Mountains, USA, that were extensively surveyed in the early 20th century. Presence absence comparisons were made at 77 sites and occupancy models were used to separate significant range shifts…
Publication Type: Journal Article
Health Effects of Wildland Fire Smoke: Insight from Public Health Science Studies
Year: 2012
Due to the composition and dispersion of wildland fire smoke, particulate matter is the principal pollutant of public health concern. Effects will vary based on the source of smoke but predominantly impact local communities in the same way. Studies of the effects of PM from non-fire sources show that long-term exposure can reduce lung function and cause the development of chronic bronchitis. Short-term exposure (hours or days), typical of wildland fire events, can aggravate lung disease, leading to asthma attacks and acute bronchitis. These effects can also increase the susceptibility to…
Publication Type: Report
Afternoon Rain More Likely Over Drier Soils
Year: 2012
Land surface properties, such as vegetation cover and soil moisture, influence the partitioning of radiative energy between latent and sensible heat fluxes in daytime hours. During dry periods, soil-water deficit can limit evapotranspiration, leading to warmer and drier conditions in the lower atmosphere. Soil moisture can influence the development of convective storms through such modifications of low-level atmospheric temperature and humidity, which in turn feeds back on soil moisture. Yet there is considerable uncertainty in how soil moisture affects convective storms across the world,…
Publication Type: Journal Article
Simulating effects of climate change and ecological restoration on fire behaviour in a south-western USA ponderosa pine forest
Year: 2012
Global climate change has the potential to affect future wildfire activity, particularly in south-western USA ponderosa pine forests that have been substantially altered by land-use practices and aggressive fire suppression. Using two regional general circulation models for the A1B greenhouse gas emission scenario, Australia's CSIRO:MK3 and Germany's MPIM:ECHAMS, we predicted fire behaviour under the 80th, 90th and 97th percentiles of future fire-weather conditions at a study site on the Kaibab National Forest, Arizona. We then altered the fuel structure by simulating alternative ecological…
Publication Type: Journal Article
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