Research Database
Displaying 1 - 20 of 260
Canadian forests are more conducive to high-severity fires in recent decades
Year: 2025
Canada has experienced more-intense and longer fire seasons with more-frequent uncontrollable wildfires over the past decades. However, the effect of these changes remains unknown. This study identifies driving forces of burn severity and estimates its spatiotemporal variations in Canadian forests. Our results show that fuel aridity was the most influential driver of burn severity, summer months were more prone to severe burning, and the northern areas were most influenced by the changing climate. About 6% (0.54 to 14.64%) of the modeled areas show significant increases in the number of days…
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
Assessing wildland fire suppression effectiveness with infrared imaging on experimental fires
Year: 2025
Background: Suppression effectiveness is often evaluated by measuring the extent to which it slows fire spread and reduces fireline intensity. Although studies have used infrared (IR) imaging methods to explore suppression effectiveness, most do not measure or assess the influence of water application on energy release.Aims: This preliminary analysis uses IR imagery to quantify the impact of suppression on fire behaviour and the reduction in energy released from a flaming fire.Methods: We conducted a series of small-scale experimental burns…
Publication Type: Journal Article
Assessing fuel treatments and burn severity using global and local analyses
Year: 2025
BackgroundWildfires in western U.S. dry forest ecosystems have increased in size and severity during recent decades due primarily to more than a century of fire suppression, exclusion of Indigenous fire, and a rapidly warming climate. Fuel treatments have been employed to restore historical forest conditions and mitigate burn severity. However, their influence on burn severity in the context of other environmental variables and firefighting operations has not been extensively explored. The 2021 Bootleg Fire in south-central Oregon provided an opportunity to evaluate the effectiveness of…
Publication Type: Journal Article
Fatigue in wildland firefighting: relationships between sleep, shift characteristics, and cognitive function
Year: 2025
BackgroundWildland firefighting requires exposure to long shifts and poor sleep, which may pose a risk to worker safety due to impaired cognitive function.AimsWe investigated the associations between sleep, shift characteristics, and cognitive function in wildland firefighters.MethodsWe conducted a within-subject observational study with 25 wildland firefighters from the British Columbia Wildfire Service, Canada. Data were collected remotely during the 2021 and 2022 fire seasons. Wrist-worn actigraphy and the psychomotor vigilance task served…
Publication Type: Journal Article
Collapse and restoration of mature forest habitat in California
Year: 2025
Mature and old-growth forests provide critically important ecosystems services and wildlife habitats, but they are being lost at a rapid rate to uncharacteristic mega-disturbances. We developed a simulation system to project time-to-extinction for mature and old-growth forest habitat in the Sierra Nevada, California, USA. The simulation parameters were derived from a 1985–2022 empirical time-series of habitat for the southern Sierra Nevada fisher (Pekania pennanti), an endangered native mammal and old-forest obligate that has seen a 50 % decline in its habitat over the past…
Publication Type: Journal Article
Intensifying Fire Season Aridity Portends Ongoing Expansion of Severe Wildfire in Western US Forests
Year: 2025
Area burned by wildfire has increased in western US forests and elsewhere over recent decades coincident with warmer and drier fire seasons. However, high–severity fire—fire that kills all or most trees—is arguably a more important metric of fire activity given its destabilizing influence on forest ecosystems and direct and indirect impacts to human communities. Here, we quantified area burned and area burned severely in western US forests from 1985 to 2022 and evaluated trends through time. We also assessed key relationships between area burned, extent and proportion burned severely…
Publication Type: Journal Article
A fire deficit persists across diverse North American forests despite recent increases in area burned
Year: 2025
Rapid increases in wildfire area burned across North American forests pose novel challenges for managers and society. Increasing area burned raises questions about whether, and to what degree, contemporary fire regimes (1984–2022) are still departed from historical fire regimes (pre-1880). We use the North American tree-ring fire-scar network (NAFSN), a multi-century record comprising >1800 fire-scar sites spanning diverse forest types, and contemporary fire perimeters to ask whether there is a contemporary fire surplus or fire deficit, and whether recent fire years are unprecedented…
Publication Type: Journal Article
Leveraging wildfire to augment forest management and amplify forest resilience
Year: 2025
Successive catastrophic wildfire seasons in western North America have escalated the urgency around reducing fire risk to communities and ecosystems. In historically frequent-fire forests, fuel buildup as a result of fire exclusion is contributing to increased fire severity. The probability of high-severity fire can be reduced by active forest management that reduces fuels, prompting federal and state agencies to commit significant resources to increase the pace and scale of fuel reduction treatments. However, lower severity areas of wildfires also have the potential to act as “treatments,”…
Publication Type: Journal Article
Bucking the suppression status quo: incentives to shift the wildfire management paradigm around natural ignitions
Year: 2025
Background: Wildfire policy has evolved rapidly over the past three decades, necessitating repeated shifts in management and communication strategies for US land management agencies. One growing focus considers the use of “other than full suppression” (OTFS) strategies, where managers use natural ignitions to achieve management objectives when conditions allow. While policy and guidance give managers operational flexibility, various sociopolitical, operational, and organizational factors contribute to risk aversion that inhibits OTFS use. This research investigates if…
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
Evidence for strong bottom-up controls on fire severity during extreme events
Year: 2025
BackgroundRecord fire years in recent decades have challenged post-fire forest recovery in the western United States and beyond. To improve management responses, it is critical that we understand the conditions under which management can mitigate severe wildfire impacts, and when it cannot. Here, we evaluated the influence of top-down and bottom-up fire severity forcings on 17 wildfires occurring during two consecutive record-setting years in the eastern Cascade Mountains of Washington State. Despite much of the area having been burned after an extended period of fire…
Fire Effects and Fire Ecology, Fire History, Fuels and Fuel Treatments, Restoration and Hazardous Fuel Reduction
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
Big trees burning: Divergent wildfire effects on large trees in open- vs. closed-canopy forests
Year: 2025
Wildfire activity has accelerated with climate change, sparking concerns about uncharacteristic impacts on mature and old-growth forests containing large trees. Recent assessments have documented fire-induced losses of large-tree habitats in the US Pacific Northwest, but key uncertainties remain regarding contemporary versus historical fire effects in different forest composition types, specific impacts on large trees within closed versus open canopies, and the role of fuel reduction treatments. Focusing on the 2021 Schneider Springs Fire, which encompassed 43,000 ha in the eastern Cascade…
Publication Type: Journal Article
Impact of wildfire smoke, heat stress and sleep deprivation on the brain health of wildland firefighters
Year: 2025
Wildland firefighters (WLFFs) face significant brain health risks due to prolonged exposure to smoke, extreme heat, dehydration, physical exertion and irregular sleep patterns. Here, the literature is presented as a narrative review on studies that inform our knowledge on WLFF brain health. The neurotoxic components of wildfire smoke, such as particulate matter, carbon monoxide and polycyclic aromatic hydrocarbons, can disrupt brain function by inducing oxidative stress, neuroinflammation and hypoxia, which can contribute to cognitive decline and increase the risk of neurodegenerative…
Publication Type: Journal Article
The 2023 wildfires in British Columbia, Canada: impacts, drivers, and transformations to coexist with wildfire
Year: 2025
In 2023, all regions of British Columbia (BC) experienced record-breaking fire weather and wildfires, with extreme behavior and social-ecological effects. In total, 2245 wildfires burned 2840 545 hectares. Contemporary wildfires are the culmination of a century of altered human–forest–wildfire relationships, exacerbated by climate change. Transformative change is urgently needed for the ecosystems and communities to be resilient to wildfire. We present six interrelated strategies needed to amplify the pace and scale of change in response to recent wildfire extremes: (1) Immediately diversify…
Publication Type: Journal Article
Finding floral and faunal species richness optima among active fire regimes
Year: 2025
Changing fire regimes have important implications for biodiversity and challenge traditional conservation approaches that rely on historical conditions as proxies for ecological integrity. This historical-centric approach becomes increasingly tenuous under climate change, necessitating direct tests of environmental impacts on biodiversity. At the same time, widespread departures from historical fire regimes have limited the ability to sample diverse fire histories. We examined 2 areas in California's Sierra Nevada (USA) with active fire regimes to study the responses of bird, plant, and bat…
Publication Type: Journal Article
A Quantitative Analysis of Firefighter Availability and Prescribed Burning in the Okanogan–Wenatchee National Forest
Year: 2025
Wildfire activity in the western United States has been on the rise since the mid-1980s, with longer, higher-risk fire seasons projected for the future. Prescribed burning mitigates the risk of extreme wildfire events, but such treatments are currently underutilized. Fire managers have cited lack of firefighter availability as a key barrier to prescribed burning. We use both principal component analysis (PCA) and logistic regression modeling methodologies to investigate whether or not (and if yes, under what conditions) personnel shortages on a given day are associated with lower odds of a…
Publication Type: Journal Article
Comparing modeled soil temperature and moisture dynamics during prescribed fires, slash-pile burns and wildfires
Year: 2025
Background: Wildfires, prescribed fires and slash-pile burns are disturbances that occur in many terrestrial ecosystems. Such fires produce variable surface heat fluxes causing a spectrum of effects on soil, such as seed mortality, nutrient loss, changes in microbial activity and water repellency. Accurately modeling soil heating is vital to predicting these second-order fire effects. The process-based Massman HMV (Heat–Moisture–Vapor) model incorporates soil water evaporation, heat transport and water vapor movement, and captures the observed rapid evaporation of soil moisture. Aims:…
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