Research Database
Displaying 121 - 140 of 188
Bridging the divide between fire safety research and fighting fire safely: how do we convey research innovation to contribute more effectively to wildland firefighter safety?
Year: 2017
Creating a safe workplace for wildland firefighters has long been at the centre of discussion for researchers and practitioners. The goal of wildland fire safety research has been to protect operational firefighters, yet its contributions often fall short of potential because much is getting lost in the translation of peer-reviewed results to potential and intended users. When information that could enhance safety is not adopted by individuals, the potential to improve safety – to decipher the wildland fire physical or social environment and to recognise hazards – is lost. We use firefighter…
Publication Type: Journal Article
Cover of tall trees best predicts California spotted owl habitat
Year: 2017
Restoration of western dry forests in the USA often focuses on reducing fuel loads. In the range of the spotted owl, these treatments may reduce canopy cover and tree density, which could reduce preferred habitat conditions for the owl and other sensitive species. In particular, high canopy cover (≥70%) has been widely reported to be an important feature of spotted owl habitat, but averages of stand-level forest cover do not provide important information on foliage height and gap structure. To provide better quantification of canopy structure, we used airborne LiDAR imagery to identify canopy…
Publication Type: Journal Article
Fall and spring grazing influence fire ignitability and initial spread in shrub steppe communities
Year: 2017
The interaction between grazing and fire influences ecosystems around the world. However, little is known about the influence of grazing on fire, in particular ignition and initial spread and how it varies by grazing management differences. We investigated effects of fall (autumn) grazing, spring grazing and not grazing on fuel characteristics, fire ignition and initial spread during the wildfire season (July and August) at five shrub steppe sites in Oregon, USA. Both grazing treatments decreased fine fuel biomass, cover and height, and increased fuel moisture, and thereby decreased ignition…
Publication Type: Journal Article
Climate changes and wildfire alter vegetation of Yellowstone National Park, but forest cover persists
Year: 2017
We present landscape simulation results contrasting effects of changing climates on forest vegetation and fire regimes in Yellowstone National Park, USA, by mid-21st century. We simulated potential changes to fire dynamics and forest characteristics under three future climate projections representing a range of potential future conditions using the FireBGCv2 model. Under the future climate scenarios with moderate warming (>2°C) and moderate increases in precipitation (3–5%), model simulations resulted in 1.2–4.2 times more burned area, decreases in forest cover (10–44%), and reductions in…
Publication Type: Journal Article
Federal fire managers’ perceptions of the importance, scarcity and substitutability of suppression resources
Year: 2017
Wildland firefighting in the United States is a complex and costly enterprise. While there are strong seasonal signatures for fire occurrence in specific regions of the United States, spatiotemporal occurrence of wildfire activity can have high inter-annual variability. Suppression resources come from a variety of jurisdictions and provide a wide range of skills, experience and associated mobility and logistical needs. Dispatch centres and regional and national resource allocation centres move suppression resources to respond to demand. However, little is known about the decision-making…
Publication Type: Journal Article
Characterising resource use and potential inefficiencies during large-fire suppression in the western US
Year: 2017
Currently, limited research on large-fire suppression effectiveness suggests fire managers may over-allocate resources relative to values to be protected. Coupled with observations that weather may be more important than resource abundance to achieve control objectives, resource use may be driven more by risk aversion than efficiency. To explore this potential, we investigated observed percentage of perimeter contained and self-reported containment values, the exposure index, and patterns of resource use during the containment and control phases of fire response. Fireline production capacity…
Publication Type: Journal Article
Sharing contracted resources for fire suppression: engine dispatch in the Northwestern United States
Year: 2017
As demand for wildfire response resources grows across the globe, a central challenge is developing new and flexible systems and capacity to ensure that resources needed for fire response arrive when and where they are needed. Private contractors have become increasingly important in providing equipment and services to support agency wildfire suppression needs in the USA. Understanding the capacity of contracted resources for federal agency fire suppression needs is critical for preseason fire planning and response. Using National Resource Ordering and Status System data, we examined…
Publication Type: Journal Article
Long-Term Effects of Burn Season and Frequency on Ponderosa Pine Forest Fuels and Seedlings
Year: 2017
Prescribed fire is widely applied in western US forests to limit future fire severity by reducing tree density, fuels, and excessive seedlings. Repeated prescribed burning attempts to simulate historical fire regimes in frequent-fire forests, yet there is limited long-term information regarding optimal burn season and frequency. In addition, burns are operationally feasible only in the spring and late fall, largely outside the historical wildfire season. This study quantifies the effect of seasonal reburns on woody surface fuels, forest floor fuels, and understory tree regeneration abundance…
Publication Type: Journal Article
A LiDAR-based analysis of the effects of slope, vegetation density, and ground surface roughness on travel rates for wildland firefighter escape route mapping
Year: 2017
Escape routes are essential components of wildland firefighter safety, providing pre-defined pathways to a safety zone. Among the many factors that affect travel rates along an escape route, landscape conditions such as slope, low-lying vegetation density, and ground surface roughness are particularly influential, and can be measured using airborne light detection and ranging (LiDAR) data. In order to develop a robust, quantitative understanding of the effects of these landscape conditions on travel rates, we performed an experiment wherein study participants were timed while walking along a…
Publication Type: Journal Article
Review of the health effects of wildland fire smoke on wildland firefighters and the public
Year: 2016
Each year, the general public and wildland firefighters in the US are exposed to smoke from wildland fires. As part of an effort to characterize health risks of breathing this smoke, a review of the literature was conducted using five major databases, including PubMed and MEDLINE Web of Knowledge, to identify smoke components that present the highest hazard potential, the mechanisms of toxicity, review epidemiological studies for health effects and identify the current gap in knowledge on the health impacts of wildland fire smoke exposure. Respiratory events measured in time series studies as…
Publication Type: Journal Article
Does increased forest protection correspond to higher fire severity in frequent-fire forests of the western United States?
Year: 2016
There is a widespread view among land managers and others that the protected status of many forestlands in the western United States corresponds with higher fire severity levels due to historical restrictions on logging that contribute to greater amounts of biomass and fuel loading in less intensively managed areas, particularly after decades of fire suppression. This view has led to recent proposals—both administrative and legislative—to reduce or eliminate forest protections and increase some forms of logging based on the belief that restrictions on active management have increased fire…
Publication Type: Journal Article
Risk terminology primer: Basic principles and a glossary for the wildland fire management community
Year: 2016
Risk management is being increasingly promoted as an appropriate method for addressing wildland fire management challenges. However, a lack of a common understanding of risk concepts and terminology is hindering effective application. In response, this General Technical Report provides a set of clear, consistent, understandable, and usable definitions for terms associated with wildland fire risk management. The material presented herein is not brand-new or innovative per se, but rather synthesizes the extant science so that readers can readily make a crosswalk to the professional literature.…
Publication Type: Report
Can low-severity fire reverse compositional change in montane forests of the Sierra Nevada, California, USA?
Year: 2016
Throughout the Sierra Nevada, nearly a century of fire suppression has altered the tree species composition, forest structure, and fire regimes that were previously characteristic of montane forests. Species composition is fundamentally important because species differ in their tolerances to fire and environmental stressors, and these differences dictate future forest structure and influence fire regime attributes. In some lower montane stands, shade-tolerant, fire-sensitive species have driven a threefold increase in tree density that may intensify the risk of high-severity fire. In upper…
Publication Type: Journal Article
Socioecological transitions trigger fire regime shifts and modulate fire–climate interactions in the Sierra Nevada, USA, 1600–2015 CE
Year: 2016
Large wildfires in California cause significant socioecological impacts, and half of the federal funds for fire suppression are spent each year in California. Future fire activity is projected to increase with climatechange, but predictions are uncertain because humans can modulate or even override climatic effects on fire activity. Here we test the hypothesis that changes in socioecological systems from the NativeAmerican to the current period drove shifts in fire activity and modulated fire–climate relationships in the Sierra Nevada. We developed a 415-y record (1600–2015 CE) of fire…
Publication Type: Journal Article
Drivers of Wildfire Suppression Costs: A Review
Year: 2016
As federal spending on wildland fire suppression has increased dramatically in recent decades, significant policymaking has been designed, at least in part, to address and temper rising costs. Effective strategies for controlling public spending and leveraging limited wildfire management resources depend on a comprehensive understanding of the drivers of suppression costs. Problematically, frequently noted drivers often do not explain variability between similar wildfires or comparable wildfire seasons. As speculation and scrutiny around rising costs have increased, so too have scholarly…
Publication Type: Report
Toward a more ecologically informed view of severe forest fires
Year: 2016
We use the historical presence of high-severity fire patches in mixed-conifer forests of the western United States to make several points that we hope will encourage development of a more ecologically informed view of severe wildland fire effects. First, many plant and animal species use, and have sometimes evolved to depend on, severely burned forest conditions for their persistence. Second, evidence from fire history studies also suggests that a complex mosaic of severely burned conifer patches was common historically in the West. Third, to maintain ecological integrity in forests born of…
Publication Type: Journal Article
Areas of Agreement and Disagreement Regarding Ponderosa Pine and Mixed Conifer Forest Fire Regimes: A Dialogue with Stevens et al.
Year: 2016
In a recent PLOS ONE paper, we conducted an evidence-based analysis of current versus historical fire regimes and concluded that traditionally defined reference conditions of low-severity fire regimes for ponderosa pine (Pinus ponderosa) and mixed-conifer forests were incomplete, missing considerable variability in forest structure and fire regimes. Stevens et al. (this issue) agree that high-severity fire was a component of these forests, but disagree that one of the several sources of evidence, stand age from a large number of forest inventory and analysis (FIA) plots across the western USA…
Publication Type: Journal Article
Quantifying the influence of previously burned areas on suppression effectiveness and avoided exposure: a case study of the Las Conchas Fire
Year: 2016
We present a case study of the Las Conchas Fire (2011) to explore the role of previously burned areas (wildfires and prescribed fires) on suppression effectiveness and avoided exposure. Methodological innovations include characterisation of the joint dynamics of fire growth and suppression activities, development of a fire line effectiveness framework, and quantification of relative fire line efficiencies inside and outside of previously burned areas. We provide descriptive statistics of several fire line effectiveness metrics. Additionally, we leverage burn probability modelling to examine…
Publication Type: Journal Article
Average Stand Age from Forest Inventory Plots Does Not Describe Historical Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America
Year: 2016
Quantifying historical fire regimes provides important information for managing contemporary forests. Historical fire frequency and severity can be estimated using several methods; each method has strengths and weaknesses and presents challenges for interpretation and verification. Recent efforts to quantify the timing of historical high-severity fire events in forests of western North America have assumed that the “stand age” variable from the US Forest Service Forest Inventory and Analysis (FIA) program reflects the timing of historical high-severity (i.e. stand-replacing) fire in ponderosa…
Publication Type: Journal Article
Dormant season grazing may decrease wildfire probability by increasing fuel moisture and reducing fuel amount and continuity
Year: 2015
Mega-fires and unprecedented expenditures on fire suppression over the past decade have resulted in a renewed focus on presuppression management. Dormant season grazing may be a treatment to reduce fuels in rangeland, but its effects have not been evaluated. In the present study, we evaluated the effect of dormant season grazing (winter grazing in this ecosystem) by cattle on fuel characteristics in sagebrush (Artemisia L.) communities at five sites in south-eastern Oregon. Winter grazing reduced herbaceous fuel cover, continuity, height and biomass without increasing exotic annual grass…
Publication Type: Journal Article