Research Database
Displaying 1 - 20 of 215
Temporal and spatial pattern analysis of escaped prescribed fires in California from 1991 to 2020
Year: 2025
Background: Prescribed fires play a critical role in reducing the intensity and severity of future wildfires by systematically and widely consuming accumulated vegetation fuel. While the current probability of prescribed fire escape in the United States stands very low, their consequential impact, particularly the large wildfires they cause, raises substantial concerns. The most direct way of understanding this trade-off between wildfire risk reduction and prescribed fire escapes is to explore patterns in the historical prescribed fire records. This study investigates the spatiotemporal…
Publication Type: Journal Article
Fine Particulate Matter From 2020 California Wildfires and Mental Health–Related Emergency Department Visits
Year: 2025
Importance: A growing body of research suggests that exposure to fine particulate matter (PM2.5; particle size 2.5 microns or smaller) may be associated with mental health outcomes. However, the potential impact of wildfire-specific PM2.5 exposure on mental health remains underexplored.Objective: To investigate whether wildfire-specific PM2.5 exposure may be associated with emergency department (ED) visits for mental health conditions, including all-cause and for psychoactive substance use, nonmood psychotic disorders, anxiety, depression, and other mood-affective disorders during the…
Publication Type: Journal Article
Review of thermal behaviour of firebrands and their role in fuel bed and structure ignition
Year: 2025
Firebrands or embers are a crucial phenomenon in wildfire behaviour. Firebrands – small, burning or smouldering pieces of wood or other flammable materials – can be carried by wind considerable distances, leading to ignition of new fires ahead of the main fire front. This process, called spotting, significantly contributes to the rapid spread of fires, particularly in wildland–urban interface (WUI) areas. Spot fires pose a severe threat to people and properties. Better understanding the thermal behaviour of firebrands and their ability to ignite various natural fuel beds and structural…
Publication Type: Journal Article
Can ‘‘Fire Safe’’ Cigarettes (FSCs) Start Wildfires?
Year: 2025
Over the last 20 years, all states within the US have required all cigarettes sold to be ‘‘fire safe’’ or ‘‘fire standards compliant’’ meaning that they must pass ASTM standard E2187. Though these cigarettes are designed to self-extinguish, there have been recent studies suggesting that these ‘‘fire safe’’ cigarettes (FSCs) can still ignite mattresses and other furnishings, but there has been no guidance for fire investigators whether FSCs can ignite natural fuels, such as duff and needles, that can be the source of a wildland fire. This work sets out to investigate whether FSCs can indeed be…
Publication Type: Journal Article
Compounding effects of climate change and WUI expansion quadruple the likelihood of extreme-impact wildfires in California
Year: 2025
Previous research has examined individual factors contributing to wildfire risk, but the compounding effects of these factors remain underexplored. Here, we introduce the “Integrated Human-centric Wildfire Risk Index (IHWRI)” to quantify the compounding effects of fire-weather intensification and anthropogenic factors—including ignitions and human settlement into wildland—on wildfire risk. While climatic trends increased the frequency of high-risk fire-weather by 2.5-fold, the combination of this trend with wildland-urban interface expansion led to a 4.1-fold increase in the frequency of…
Publication Type: Journal Article
Unpacking the pluralism paradox: collaborative governance outcomes in jurisdictionally complex environments
Year: 2025
Background: In collaborative governance, many of the factors that give rise to the need for collaboration are also identified by scholars as undermining its effectiveness. Complex task environments mean that multiple and varied interests are necessary to address problems, but this inherent pluralism may also increase conflict. This suggests a pluralism paradox.Aims: Our article advances theory and provides evidence about pluralism associated with jurisdictional affiliation and their relationship to collaborative governance outcomes during wildfires.Methods: We analyzed data…
Publication Type: Journal Article
Methods to assess fire-induced tree mortality: review of fire behaviour proxy and real fire experiments
Year: 2025
Background: The increased interest in why and how trees die from fire has led to several syntheses of the potential mechanisms of fire-induced tree mortality. However, these generally neglect to consider experimental methods used to simulate fire behaviour conditions.Aims: To describe, evaluate the appropriateness of and provide a historical timeline of the different approaches that have been used to simulate fire behaviour in fire-induced tree mortality studies.Methods: We conducted a historical review of the different actual and fire proxy methods that have been used to…
Publication Type: Journal Article
Future enhanced threshold effects of wildfire drivers could increase burned areas in northern mid- and high latitudes
Year: 2025
Wildfires exhibit extensive nonlinear characteristics and threshold effects in response to environmental changes. However, how threshold effects affect wildfire responses and their future changes remains unclear. Here we identified thresholds where wildfire-driver relationships shift and estimated the impact of threshold effects on wildfire dynamics in the 21st century in northern mid- and high latitudes (>30°N). Wildfire-driver thresholds, coregulated by gradient differences in heat and moisture conditions, vegetation productivity, and human activities, effectively explain the spatial…
Publication Type: Journal Article
Multifactor Change in Western U.S. Nighttime Fire Weather
Year: 2025
Reports from western U.S. firefighters that nighttime fire activity has been increasing during the spans of many of their careers have recently been confirmed by satellite measurements over the 2003–20 period. The hypothesis that increasing nighttime fire activity has been caused by increased nighttime vapor pressure deficit (VPD) is consistent with recent documentation of positive, 40-yr trends in nighttime VPD over the western United States. However, other meteorological conditions such as near-surface wind speed and planetary boundary layer depth also impact fire behavior and exhibit…
Publication Type: Journal Article
Wildland Firefighters Suffer Increasing Risk of Job-Related Death
Year: 2025
Wildland firefighting is a niche specialization in the fire service - inherently dangerous with unique risks. Over the past decade, fatalities amongst all firefighters have decreased; however, wildland firefighter fatalities have increased. This subject has only been described in the grey literature, and a paucity of medical literature exists. The United States Fire Administration's online fatality database was queried for on duty mortality between 1990 and 2022. The year 2001 was excluded due to the 340 deaths that occurred on September 11th. Data collected included demographics, incident…
Publication Type: Journal Article
Evaluating a simulation-based wildfire burn probability map for the conterminous US
Year: 2025
Background: Wildfire simulation models are used to derive maps of burn probability (BP) based on fuels, weather, topography and ignition locations, and BP maps are key components of wildfire risk assessments.Aims: Few studies have compared BP maps with real-world fires to evaluate their suitability for near-future risk assessment. Here, we evaluated a BP map for the conterminous US based on the large fire simulation model FSim.Methods: We compared BP with observed wildfires from 2016 to 2022 across 128 regions representing similar fire regimes (‘pyromes’). We…
Publication Type: Journal Article
Lightning ignition efficiency in Canadian forests
Year: 2025
Background: Lightning-caused fires have a driving influence on Canadian forests, being responsible for approximately half of all wildfires and 90% of the area burned. We created a climatology (2000–2020) of daily lightning efficiency (i.e., the ratio of cloud-to-ground lightning flashes to lightning-caused wildfires that occurred) over the meteorological summer for four ecozones and a subset of British Columbia (BC) ecoprovinces. We estimated lightning efficiency using data from the Canadian Lightning Detection Network and the Canadian National Fire Database. We used the ERA5…
Publication Type: Journal Article
Global Synthesis of Quantification of Fire Behaviour Characteristics in Forests and Shrublands: Recent Progress
Year: 2025
Purpose of ReviewThe behaviour of wildland fires, namely their free spreading nature, destructive energy fluxes and hazardous environment, make it a phenomenon difficult to study. Field experimental studies and occasional wildfire observations underpin our understanding of fire behaviour. We aim to present a global synthesis of field-based studies in forest and shrublands fuel types published since 2003 with a focus on the most commonly measured fire behaviour attributes, namely rate of fire spread, ignition and spread sustainability, flame characteristics, fuel consumption…
Publication Type: Journal Article
Compounding effects of climate change and WUI expansion quadruple the likelihood of extreme-impact wildfires in California
Year: 2025
Previous research has examined individual factors contributing to wildfire risk, but the compounding effects of these factors remain underexplored. Here, we introduce the “Integrated Human-centric Wildfire Risk Index (IHWRI)” to quantify the compounding effects of fire-weather intensification and anthropogenic factors—including ignitions and human settlement into wildland—on wildfire risk. While climatic trends increased the frequency of high-risk fire-weather by 2.5-fold, the combination of this trend with wildland-urban interface expansion led to a 4.1-fold increase in the frequency of…
Publication Type: Journal Article
Influence of Time‐Averaging of Climate Data on Estimates of Atmospheric Vapor Pressure Deficit and Inferred Relationships With Wildfire Area in the Western United States
Year: 2025
Vapor pressure deficit (VPD) is a driver of evaporative demand and correlates strongly with wildfire extent in the western United States (WUS). Vapor pressure deficit is the difference between saturation vapor pressure (es) and actual vapor pressure (ea). Because es increases nonlinearly with temperature, calculations of time‐averaged VPD vary depending on the frequency of temperature measurements and how ea is calculated, potentially limiting our understanding of fire‐climate relationships. We calculate eight versions of monthly VPD across the WUS and assess their differences. Monthly VPDs…
Publication Type: Journal Article
Prescribed fire, managed burning, and previous wildfires reduce the severity of a southwestern US gigafire
Year: 2025
In many parts of the western United States, wildfires are becoming larger and more severe, threatening the persistence of forest ecosystems. Understanding the ways in which management activities such as prescribed fire and managed wildfire can mitigate fire severity is essential for developing effective forest conservation strategies. We evaluated the effects of previous fuels reduction treatments, including prescribed fire and wildfire managed for resource benefit, and other wildfires on the burn severity of the 2022 Black Fire in southwestern New Mexico, USA. The Black Fire burned over 131,…
Publication Type: Journal Article
Role of Forensic Anthropology in the Search and Recovery of Fatal Wildland Fire Victims
Year: 2025
The search and recovery process of fatal fire victims is one of the greatest challenges in forensic anthropology, especially in large-scale wildland fire disasters. Burned human remains can exhibit significant variation in their degree of preservation depending on the temperature of the fire, the length of exposure to the heat source, and intrinsic characteristics of the victim (e.g., body size, age, and bone density). Wildland fire victims typically exhibit characteristics of the final stages of burning (i.e., nearly complete to complete calcination). The search for burned human remains is…
Publication Type: Journal Article
Perspectives: Six opportunities to improve understanding of fuel treatment longevity in historically frequent-fire forests
Year: 2025
Fuel-reduction and restoration treatments (“treatments”) are conducted extensively in dry and historically frequent-fire forests of interior western North America (“dry forests”) to reduce potential for uncharacteristically severe wildfire. However, limited understanding of treatment longevity and long-term treatment effects creates potential for inefficient treatment maintenance and inaccurate forecasting of wildfire behavior. In this perspectives paper, we briefly summarize current understanding of long-term effects of three common treatment types (burn-only, thin-only, and thin-plus-burn)…
Publication Type: Journal Article
Changing fire regimes in the Great Basin USA
Year: 2025
Wildfire is a natural disturbance in landscapes of the Western United States, but the effects and extents of fire are changing. Differences between historical and contemporary fire regimes can help identify reasons for observed changes in landscape composition. People living and working in the Great Basin, USA, are observing altered fire conditions, but spatial information about the degree and direction of change and departure from historical fire regimes is lacking. This study estimates how fire regimes have changed in the major Great Basin vegetation types over the past 60 years with…
Publication Type: Journal Article
Wildland fire entrainment: The missing link between wildland fire and its environment
Year: 2025
Wildfires are growing in destructive power, and accurately predicting the spread and intensity of wildland fire is essential for managing ecological and societal impacts. No current operational models used for fire behavior prediction resolve critical fire-atmospheric coupling or nonlocal influences of the fire environment, rendering them inadequate in accounting for the range of wildland fire behavior scenarios under increasingly novel fuel and climate conditions. Here, we present a new perspective on a dominant fire-atmospheric feedback mechanism, which we term wildland fire entrainment (…
Publication Type: Journal Article