Research Database
Displaying 121 - 140 of 220
Crowded and Thirsty: Fire exclusion leads to greater drought sensitivity in mixed-conifer forests
Year: 2020
Wildfires were a frequent source of disturbance in forests of the Western United States prior to Euro-American settlement. Following a series of catastrophic wildfires in the Northern Rockies in 1910, the U.S. Forest Service adopted a broad wildfire suppression policy that has resulted in forests thick with small trees. These crowded trees compete for nutrients and water and experience increased drought stress in summer.In recent decades, many trees have died following drought, bark beetle outbreaks, and severe wildfire. A link between this mortality and increasing susceptibility to drought…
Publication Type: Report
Weather, Risk, and Resource Orders on Large Wildland Fires in the Western US
Year: 2020
Our results suggest that weather is a primary driver of resource orders over the course of extended attack efforts on large fires. Incident Management Teams (IMTs) synthesize information about weather, fuels, and order resources based on expected fire growth rather than simply reacting to observed fire growth. Background and Objectives: Weather conditions are a well-known determinant of fire behavior and are likely to become more erratic under climate change. Yet, there is little empirical evidence demonstrating how IMTs respond to observed or expected weather conditions. An understanding of…
Publication Type: Journal Article
Social Vulnerability and Wildfire in the Wildland-Urban Interface: Literature synthesis
Year: 2019
The overall objective of this paper is to clarify areas of debate, clearly define and contrast disparate approaches, and synthesize findings that may help address vulnerability to wildfires and other natural hazards. While land managers and fire personnel might find it pertinent to approach biophysical and social issues separately, addressing both aspects of wildfire hazard can be productive for minimizing risk and empowering communities, neighborhoods, and households to prepare and recover from wildfire events. We aim to provide a practical grasp of social vulnerability research as it…
Publication Type: Report
Cross-boundary wildfire and community exposure: A framework and application in the western U.S.
Year: 2019
In this report we provide a framework for assessing cross-boundary wildfire exposure and a case study application in the western U.S. The case study provides detailed mapping and tabular decision support materials for prioritizing fuel management investments aimed at reducing wildfire exposure to communities located proximal to national forests. The work was motivated by a number of factors, including a request from U.S. Department of Agriculture Undersecretary James Hubbard (Natural Resources and Environment) to assess community wildfire risk specifically from Forest Service lands, language…
Publication Type: Report
Fuel Characteristic Classification System (FCCS) field sampling and fuelbed development guide
Year: 2019
The Fuel Characteristic Classification System (FCCS) was designed to store and archive wildland fuel characteristics within fuelbeds, defined as the inherent physical characteristics of fuels that contribute to fire behavior and effects. The FCCS represents fuel characteristics in six strata including canopy, shrubs, herbaceous fuels, downed wood, litter-lichen-moss, and ground fuels. Each stratum is further divided into one or more categories and subcategories to represent the complexity of wildland and managed fuels. A variety of techniques to measure and summarize fuelbed data are detailed…
Publication Type: Report
The Role of Previous Fires in the Management and Expenditures of Subsequent Large Wildfires
Year: 2019
Previously burned areas can influence the occurrence, extent, and severity of subsequent wildfires, which may influence expenditures on large fires. We develop a conceptual model of how interactions of fires with previously burned areas may influence fire management, fire behavior, expenditures, and test hypotheses using regression models of wildfire size and suppression expenditures. Using a sample of 722 large fires from the western United States, we observe whether a fire interacted with a previous fire, the percent area of fires burned by previous fires, and the percent perimeter overlap…
Publication Type: Journal Article
Social Vulnerability and Wildfire in the Wildland-Urban Interface
Year: 2019
People living in the Pacific Northwest confrontrisks associated with environmentalhazards such as wildfire. Vulnerability towildfire hazard is commonly recognized as beingspatially distributed according to geographic conditionsthat collectively determine the probabilityof exposure. For example, exposure to wildfirehazard is higher for people living in rural, forestedsettings than in a strictly urban neighborhood becauserural housing is built in close proximity tothe threat source, e.g., flammable landscapes suchas forests and chaparral. Yet, even if levels of exposureare held constant, not…
Publication Type: Report
Wildland Fire Science Needs in Oregon and Washington: Local and regional research availability, applications, and gaps
Year: 2019
The Northwest Fire Science Consortium (Consortium) works to accelerate the awareness, understanding, and adoption of wildland fire science by connecting users in the Pacific Northwest with the most useful resources available. These efforts require an ongoing understanding of how users access wildland fire science, the challenges and opportunities that they experience in using different types of research, and topics where more information is needed. Previous research, including a prior assessment by the Consortium in 2011,1 has highlighted the importance of local or regionally-relevant…
Publication Type: Report
Assessing relative differences in smoke exposure from prescribed, managed, and full suppression wildland fire
Year: 2019
A novel approach is presented to analyze smoke exposure and provide a metric to quantify health-related impacts. Our results support the current understanding that managing low-intensity fire for ecological benefit reduces exposure when compared to a high-intensity full suppression fire in the Sierra Nevada of California. More frequent use of fire provides an opportunity to mitigate smoke exposure for both individual events and future emission scenarios. The differences in relative exposure between high-intensity, low-intensity, and prescribed burn were significant (P value < 0.01).…
Publication Type: Journal Article
Factors Associated with Structure Loss in the 2013–2018 California Wildfires
Year: 2019
Tens of thousands of structures and hundreds of human lives have been lost in recent fire events throughout California. Given the potential for these types of wildfires to continue, the need to understand why and how structures are being destroyed has taken on a new level of urgency. We compiled and analyzed an extensive dataset of building inspectors’ reports documenting homeowner mitigation practices for more than 40,000 wildfire-exposed structures from 2013–2018. Comparing homes that survived fires to homes that were destroyed, we investigated the role of defensible space distance,…
Publication Type: Journal Article
Social Vulnerability and Wildfire in the Wildland-Urban Interface - Annotated Bibliography
Year: 2019
Publication Type: Report
Historical patterns of fire severity and forest structure and composition in a landscape structured by frequent large fires: Pumice Plateau ecoregion, Oregon, USA
Year: 2019
Context Lack of quantitative observations of extent, frequency, and severity of large historical fires constrains awareness of departure of contemporary conditions from those that demonstrated resistance and resilience to frequent fire and recurring drought. Objectives Compare historical and contemporary fire and forest conditions for a dry forest landscape with few barriers to fire spread. Methods Quantify differences in (1) historical (1700–1918) and contemporary (1985–2015) fire extent, fire rotation, and stand-replacing fire and (2) historical (1914–1924) and contemporary (2012) forest…
Publication Type: Journal Article
Designing Operationally Relevant Daily Large Fire Containment Strategies Using Risk Assessment Results
Year: 2019
In this study, we aim to advance the optimization of daily large fire containment strategies for ground-based suppression resources by leveraging fire risk assessment results commonly used by fire managers in the western USA. We begin from an existing decision framework that spatially overlays fire risk assessment results with pre-identified potential wildland fire operational delineations (PODs), and then clusters PODs into a response POD (rPOD) using a mixed integer program (MIP) model to minimize expected loss. We improve and expand upon this decision framework through enhanced fire…
Publication Type: Journal Article
Embracing Complexity to Advance the Science of Wildland Fire Behavior
Year: 2018
Wildland fire behavior research has largely focused on the steady-state interactions between fuels and heat fluxes. Contemporary research is revealing new questions outside the bounds of this simplified approach. Here, we explore the complex interactions taking place beyond steady-state assumptions through acknowledging the manufactured separation of research disciplines in fire science and the dynamic interactions that unfold when these separations are removed. Through a series of examples spanning at least four research disciplines and three ranges of spatial scale, we illustrate that by…
Publication Type: Journal Article
The influence of fire history on soil nutrients and vegetation cover in mixed-severity fire regime forests of the eastern Olympic Peninsula, Washington, USA
Year: 2018
The rain shadow forests of the Olympic Peninsula exemplify a mixed-severity fire regime class in the midst of a highly productive landscape where spatial heterogeneity of fire severity may have significant implications for below and aboveground post-fire recovery. The purpose of this study was to quantify the impacts of wildfire on forest soil carbon (C) and nitrogen (N) pools and assess the relationship of pyrogenic carbon (PyC) to soil processes in this mixed-severity ecosystem. We established a 112-year fire chronosequence with nine similar forest stands ranging in time since lastfire (TSF…
Publication Type: Journal Article
The Weather Conditions for Desired Smoke Plumes at a FASMEE Burn Site
Year: 2018
Weather is an important factor that determines smoke development, which is essential information for planning smoke field measurements. This study identifies the synoptic systems that would favor to produce the desired smoke plumes for the Fire and Smoke Model Evaluation Experiment (FASMEE). Daysmoke and PB-Piedmont (PB-P) models are used to simulate smoke plume evolution during the day time and smoke drainage and fog formation during the nighttime for hypothetical prescribed burns on 5–8 February 2011 at the Stewart Army Base in the southeastern United States. Daysmoke simulation is…
Publication Type: Journal Article
Rapid growth of the US wildland-urban interface raises wildfire risk
Year: 2018
The wildland-urban interface (WUI) is the area where houses and wildland vegetation meet or intermingle, and where wildfire problems are most pronounced. Here we report that the WUI in the United States grew rapidly from 1990 to 2010 in terms of both number of new houses (from 30.8 to 43.4 million; 41% growth) and land area (from 581,000 to 770,000 km2; 33% growth), making it the fastest-growing land use type in the conterminous United States. The vast majority of new WUI areas were the result of new housing (97%), not related to an increase in wildland vegetation. Within the perimeter of…
Publication Type: Journal Article
Defining extreme wildfire events: Difficulties, challenges, and impacts
Year: 2018
Every year worldwide some extraordinary wildfires occur, overwhelming suppression capabilities, causing substantial damages, and often resulting in fatalities. Given their increasing frequency, there is a debate about how to address these wildfires with significant social impacts, but there is no agreement upon terminology to describe them. The concept of extreme wildfire event (EWE) has emerged to bring some coherence on this kind of events. It is increasingly used, often as a synonym of other terms related to wildfires of high intensity and size, but its definition remains elusive. The goal…
Publication Type: Journal Article
Pyro-Ecophysiology: Shifting the Paradigm of Live Wildland Fuel Research
Year: 2018
The most destructive wildland fires occur in mixtures of living and dead vegetation, yet very little attention has been given to the fundamental differences between factors that control their flammability. Historically, moisture content has been used to evaluate the relative flammability of live and dead fuels without considering major, unreported differences in the factors that control their variations across seasons and years. Physiological changes at both the leaf and whole plant level have the potential to explain ignition and fire behavior phenomena in live fuels that have been poorly…
Publication Type: Journal Article
A comparison of the US National Fire Danger Rating System (NFDRS) with recorded fire occurrence and final fire size
Year: 2018
Most previous research has assessed the ability of the National Fire Danger Rating System (NFDRS) to portray fire activity at either single sites or on small spatial scales, despite it being a nation-wide system. This study seeks to examine the relationships between a set of NFDRS fire danger indices (Fire Danger Ratings, Staffing Level and the Ignition Component) and measures of fire activity (fire occurrence and final fire size) across the entire conterminous US over an 8-year period. We reveal that different regions of the US display different levels of correspondence between each of the…
Publication Type: Journal Article