- The mechanistic links between fire-caused injuries and post-fire tree mortality are poorly understood. Current hypotheses differentiate effects of fire on tree carbon balance and hydraulic function, yet critical uncertainties remain about the relative importance of each and how they interact.
- We utilize two prescribed burns with Douglas-fir and ponderosa pine to examine: the relative evidence for fire-caused changes in hydraulic function and carbon dynamics, and how such impacts relate to fire injuries; which impacts most likely lead to post-fire mortality; and how these…
Research Database
Displaying 1 - 20 of 252
Fire directly affects tree carbon balance and indirectly affects hydraulic function: consequences for post-fire mortality in two conifers
Year: 2025
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
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
Long-term influence of prescribed burning on subsequent wildfire in an old-growth coast redwood forest
Year: 2025
Background: Prescribed burning is an effective tool for reducing fuels in many forest types, yet there have been few opportunities to study forest resilience to wildfire in areas previously treated. In 2020, a large-scale high-intensity wildfire burned through an old-growth coast redwood (Sequoia sempervirens) forest with a mixed land management history, providing a rare opportunity to compare early post-wildfire data between areas with and without previous application of prescribed burning. The purpose of this study was to analyze the differences between these two treatments in…
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
Post-fire delayed tree mortality in mesic coniferous forests reduces fire refugia and seed sources
Year: 2025
Context: Ecological functions provided by fire refugia are critical for supporting conifer forest resiliency under increased fire activity across the western United States. The spatial distribution and persistence of fire refugia over time are uncertain as fire-injured trees continue to die over subsequent years post-fire.Objectives: We examined how post-fire delayed tree mortality affects the spatial distribution and attributes of fire refugia at patch and landscape scales following high-severity wildfires.Methods: To explore changes in fire…
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
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
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
Mapping Delayed Canopy Loss and Durable Fire Refugia for the 2020 Wildfires in Washington State Using Multiple Sensors
Year: 2025
Fire refugia are unburned and low severity patches within wildfires that contribute heterogeneity that is important to retaining biodiversity and regenerating forest following fire. With increasingly intense and frequent wildfires in the Pacific Northwest, fire refugia are important for re-establishing populations sensitive to fire and maintaining resilience to future disturbances. Mapping fire refugia and delayed canopy loss is useful for understanding patterns in their distribution. The increasing abundance of satellite data and advanced analysis platforms offer the potential to map fire…
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
Decreasing frequency of low and moderate fire weather days may be contributing to large wildfire occurrence in the northern Sierra Nevada
Year: 2025
Previous analyses identified large-scale climatic patterns contributing to greater fuel aridity as drivers of recent dramatic increases in wildfire activity throughout California. This study revisits an approach to investigate more local fire weather patterns in the northern Sierra Nevada; a region within California that has experienced exceptionally high wildfire activity recently. The annual percentages of fire season days above 90th and 95th percentile Energy Release Component (ERC) values were very low prior to 1994 (Fig. 3). Since 1994, years with noticeable percentages of exceedances (…
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
Planted seedling regeneration using gap-based silviculture without herbicide in a wildfire-impacted forest of the Sierra Nevada
Year: 2025
Gap-based silviculture, which we define as the creation and maintenance of multi-aged stands through the periodic harvesting of discrete canopy gaps, provides a potential mechanism for converting previously high-graded stands into more heterogeneous, multi-aged structures. An advantage of small canopy gaps, relative to even-aged regeneration methods, is their potential to suppress shrub competition while allowing seedling growth without the use of herbicides or other means of managing shrub competition. While this idea has been proposed in principle, it has not been tested. The objective of…
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
COVID‐19 Fueled an Elevated Number of Human‐Caused Ignitions in the Western United States During the 2020 Wildfire Season
Year: 2025
The area burned in the western United States during the 2020 fire season was the greatest in the modern era. Here we show that the number of human-caused fires in 2020 also was elevated, nearly 20% higher than the 1992–2019 average. Although anomalously dry conditions enabled ignitions to spread and contributed to record area burned, these conditions alone do not explain the surge in the number of human-caused ignitions. We argue that behavioral shifts aimed at curtailing the spread of COVID-19 altered human-environment interactions to favor increased ignitions. For example, the number of…
Publication Type: Journal Article
Small-scale fire refugia increase soil bacterial and fungal richness and increase community cohesion nine years after fire
Year: 2025
Small-scale variation in wildfire behavior may cause large differences in belowground bacterial and fungal communities with consequences for belowground microbial diversity, community assembly, and function. Here we combine pre-fire, active-fire, and post-wildfire measurements in a mixed-conifer forest to identify how fine-scale wildfire behavior, unburned refugia, and aboveground forest structure are associated with belowground bacterial and fungal communities nine years after wildfire. We used fine-scale mapping of small (0.9–172.6 m2) refugia to sample soil-associated burned and…
Publication Type: Journal Article
Mobile radar provides insights into hydrologic responses in burn areas
Year: 2025
Background. Wildfires often occur in mountainous terrain, regions that pose substantial challenges to operational meteorological and hydrologic observing networks. Aims. A mobile, postfire hydrometeorological observatory comprising remote-sensing and in situ instrumentation was developed and deployed in a burnt area to provide unique insights into rainfall-induced post-fire hazards. Methods. Mobile radar-based rainfall estimates were produced throughout the burn area at 75-m resolution and compared with rain gauge accumulations and basin response variables. Key results. The mobile radar was…
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
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