Research Database
Displaying 1 - 20 of 190
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
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
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
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
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
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
Extreme Fire Spread Events Burn More Severely and Homogenize Postfire Landscapes in the Southwestern United States
Year: 2025
Extreme fire spread events rapidly burn large areas with disproportionate impacts on people and ecosystems. Such events are associated with warmer and drier fire seasons and are expected to increase in the future. Our understanding of the landscape outcomes of extreme events is limited, particularly regarding whether they burn more severely or produce spatial patterns less conducive to ecosystem recovery. To assess relationships between fire spread rates and landscape burn severity patterns, we used satellite fire detections to create day‐of‐burning maps for 623 fires comprising 4267 single‐…
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
Short-term impacts of operational fuel treatments on modelled fire behaviour and effects in seasonally dry forests of British Columbia, Canada
Year: 2025
Background: In response to increasing risk of extreme wildfire across western North America, forest managers are proactively implementing fuel treatments.Aims: We assessed the efficacy of alternative combinations of thinning, pruning and residue fuel management to mitigate potential fire behaviour and effects in seasonally dry forests of interior British Columbia, Canada.Methods: Across five community forests, we measured stand attributes before and after fuel treatments in 2021 and 2022, then modelled fire behaviour and effects using the…
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
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
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
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
Drivers and Impacts of the Record-Breaking 2023 Wildfire Season in Canada
Year: 2024
The 2023 wildfire season in Canada was unprecedented in its scale and intensity, spanning from mid-April to late October and across much of the forested regions of Canada. Here, we summarize the main causes and impacts of this exceptional season. The record-breaking total area burned (~15 Mha)can be attributed to several environmental factors that converged early in the season: early snowmelt, multi annual drought conditions in western Canada, and the rapid transition to drought in eastern Canada. Anthropogenic climate change enabled sustained extreme fire weather conditions, as the meanMay–…
Publication Type: Journal Article
Stream chemical response is mediated by hydrologic connectivity and fire severity in a Pacific Northwest forest
Year: 2024
Large-scale wildfires are becoming increasingly common in the wet forests of the Pacific Northwest (USA), with predicted increases in fire prevalence under future climate scenarios. Wildfires can alter streamflow response to precipitation and mobilize water quality constituents, which pose a risk to aquatic ecosystems and downstream drinking water treatment. Research often focuses on the impacts of high-severity wildfires, with stream biogeochemical responses to low- and mixed-severity fires often understudied, particularly during seasonal shifts in hydrologic connectivity between hillslopes…
Publication Type: Journal Article
Review of fuel treatment effects on fuels, fire behavior and ecological resilience in sagebrush (Artemisia spp.) ecosystems in the Western U.S.
Year: 2024
BackgroundSagebrush ecosystems are experiencing increases in wildfire extent and severity. Most research on vegetation treatments that reduce fuels and fire risk has been short term (2–3 years) and focused on ecological responses. We review causes of altered fire regimes and summarize literature on the longer-term effects of treatments that modify (1) shrub fuels, (2) pinyon and juniper canopy fuels, and (3) fine herbaceous fuels. We describe treatment effects on fuels, fire behavior, ecological resilience, and resistance to invasive annual grasses.ResultsOur review revealed tradeoffs in…
Publication Type: Journal Article
Few large or many small fires: Using spatial scaling of severe fire to quantify effects of fire-size distribution shifts
Year: 2024
As wildfire activity increases and fire-size distributions potentially shift in many forested regions worldwide, anticipating the spatial patterns of burn severity expected with future fire activity is critical for ecological understanding and informing management and policy. Because spatial patterns of burn severity are influenced by a complex mixture of drivers, they remain difficult to predict for any given burned landscape. At broader extents, however, spatial scaling relationships relating high-severity patch size and shape to overall fire size, when combined with scenarios regarding…
Publication Type: Journal Article
Molecular shifts in dissolved organic matter along a burn severity continuum for common land cover types in the Pacific Northwest, USA
Year: 2024
Increasing wildfire severity is of growing concern in the western United States, with consequences for the production, composition, and mobilization of dissolved organic matter (DOM) from terrestrial to aquatic systems. Our current understanding of wildfire impacted DOM (often termed pyrogenic DOM) composition is largely built from temperature-based studies that can be difficult to extrapolate to field conditions, which are often defined by ‘burn severity’, or the post-wildfire impact observed at a site. Thus, burn severity can encapsulate a broader range of fire and environmental conditions…
Publication Type: Journal Article
Hydrometeorology-wildfire relationship analysis based on a wildfire bivariate probabilistic framework in different ecoregions of the continental United States
Year: 2024
Wildfires are a natural part of the ecosystem in the U.S.. It is vital to classify wildfires using a comprehensive approach that simultaneously considers wildfire activity (the number of wildfires) and burned area. On this basis, the influence of hydrometeorological variables on wildfires can be further analyzed. Therefore, this study first classified wildfire types using a wildfire bivariate probability framework. Then, by considering six hydrometeorological variables, the dominant hydrometeorological variables for different wildfire types in 17 ecoregions of the United States were…
Publication Type: Journal Article
Fire severity drives understory community dynamics and the recovery of culturally significant plants
Year: 2024
Anthropogenic influences are altering fire regimes worldwide, resulting in an increase in the size and severity of wildfires. Simultaneously, throughout western North America, there is increasing recognition of the important role of Indigenous fire stewardship in shaping historical fire regimes and fire-adapted ecosystems. However, there is limited understanding of how ecosystems are affected by or recover from contemporary “megafires,” particularly in terms of understory plant communities that are critical to both biodiversity and Indigenous cultures. To address this gap, our collaborative…
Publication Type: Journal Article