Research Database
Displaying 1 - 20 of 233
Wildfires drive multi-year water quality degradation over the western United States
Year: 2025
Wildfires can dramatically alter water quality, resulting in severe implications for human and freshwater systems. However, regional-scale assessments of these impacts are often limited by data scarcity. Here, we unify observations from 1984–2021 in 245 burned watersheds across the western United States, comparing post-fire signals to baseline levels from 293 unburned basins. Organic carbon and phosphorus exhibit significantly elevated levels (p ≤ 0.05) in the first 1–5 years post-fire, while nitrogen and sediment show significant increases up to 8 years post-fire. During peak post-…
Publication Type: Journal Article
Wildfire disturbance and ecological cascades: Teasing apart the direct and indirect effects of fire on tick populations
Year: 2025
- Wildfires are a significant ecological force in the western United States, reshaping landscapes and ecological communities. However, assessing wildfires' full impact is challenging due to the complexity of fire severity and its varied effects on ecological dynamics. Understanding species-specific responses to disturbances within their environmental context is essential for predicting cascading ecological impacts. Arthropods, including ticks, are particularly sensitive to both abiotic and biotic changes, making them especially vulnerable to the impacts of wildfire.
- In this…
Publication Type: Journal Article
Rapid Declines in Southern Sierra Nevada Fisher Habitat Driven by Drought and Wildfire
Year: 2025
Aim: Forest disturbances are a natural ecological process, but climate and land-use change are altering disturbance regimes at an unprecedented rate, posing significant threats to biological communities and the species of concern. Our aim was to develop an automated habitat monitoring system for the Southern Sierra Nevada Distinct Population Segment of fisher (Pekania pennanti) in California, USA, to investigate long-term habitat trends and the effects of a recent megadrought and numerous megafires on fisher habitat.Location: Southern Sierra Nevada, California, USA.Methods: We used…
Publication Type: Journal Article
Extreme Weather Magnifies the Effects of Forest Structure on Wildfire, Driving Increased Severity in Industrial Forests
Year: 2025
Despite widespread concern over increases in wildfire severity, the mechanisms underlying this trend remain unclear, hampering our ability to mitigate the severity of future fires. There is substantial uncertainty regarding the relative roles of extreme weather conditions, which are exacerbated by climate change, and forest management, in particular differences between private industrial timber companies and public land agencies. To investigate the effects of extreme weather and forest management on fire severity, we used light detection and ranging (LiDAR) data to characterize pre-fire…
Publication Type: Journal Article
Carbon costs of different pathways for reducing fire hazard in the Sierra Nevada
Year: 2025
Restoring a low-intensity, frequent-fire regime in fire-prone forests offers a promising natural climate solution. Management interventions that include prescribed fire and/or mechanical treatments have effectively reduced fire hazards in the Western United States, yet concerns remain regarding their impact on forest carbon storage. This study used results from a long-term, replicated field experiment to assess the impacts of a restored disturbance regime on carbon dynamics in a Sierra Nevada, mixed conifer forest. The carbon consequences of the treatments were compared to a dynamic baseline…
Publication Type: Journal Article
Pre-fire structure drives variability in post-fire aboveground carbon and fuel profiles in wet temperate forests
Year: 2025
Biological legacies (i.e., materials that persist following disturbance; “legacies”) shape ecosystem functioning and feedbacks to future disturbances, yet how legacies are driven by pre-disturbance ecosystem state and disturbance severity is poorly understood—especially in ecosystems influenced by infrequent and severe disturbances. Focusing on wet temperate forests as an archetype of these ecosystems, we characterized live and dead aboveground biomass 2–5 years post-fire in western Washington and northwestern Oregon, USA, to ask: How do pre-fire stand age (i.e., pre-disturbance ecosystem…
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
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
Quantifying Western US tree carbon stocks and sequestration from fires
Year: 2025
Background: Forest ecosystems function as the largest terrestrial carbon sink globally. In the Western US, fires play a crucial role in modifying forest carbon storage, sequestration capacity, and the transfer of carbon from live to dead carbon pools. We utilized remeasurements of more than 700,000 trees from 24,000 locations from the US Department of Agriculture Forest Service’s Forest Inventory and Analysis program (FIA) and incorporated supplementary information on wildfires from the Monitoring Trends in Burn Severity dataset. These datasets allowed us to develop models that examined the…
Publication Type: Journal Article
Implications of recent wildfires for forest management on federal lands in the Pacific Northwest, USA
Year: 2025
Adoption of the Northwest Forest Plan (NWFP) in 1994 marked a pivotal moment in federal forest management in the Pacific Northwest, shifting focus away from intensive timber harvest toward an ecosystem management approach that emphasized late successional and old forest habitat with the creation of a reserve network across moist and dry forest zones. Thirty years after implementation, concerns over accelerating wildfire threats have prompted efforts to adapt the Plan to a warming climate, yet the actual effects of recent fires on NWFP forests are not well understood. In this study, we…
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
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
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
Decreasing landscape carbon storage in western US forests with 2 °C of warming
Year: 2025
Changing climate is altering the amount of carbon that can be sustained in forest ecosystems. Increasing heat and drought is already causing increased mortality and decreased regeneration in some locations. These changes have implications for landscape carbon storage with ongoing climate change. We used a climate analogs approach to project aboveground forest carbon density under +2 °C warming above pre-industrial climate for western US forests. We calculated analogs for current climate and under +2 °C warming and associated carbon density for each time period. We found that in most…
Publication Type: Journal Article
Following megafires fishes thrive and amphibians persist even in severely burned watersheds
Year: 2025
Wildfires are increasing in severity, frequency and size, potentially threatening freshwater species that adapted under different disturbance regimes. However, few wildfire studies have comprehensively evaluated freshwater populations and assemblages following wildfire over broad spatial scales while accounting for post-fire salvage practices in the watershed. We reveal that stream vertebrate assemblages across thirty 4th order streams, spanning a range of both watershed fire severity and post-fire forest management extent, were minimally influenced by immediate effects of fire alone (…
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
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
Going slow to go fast: landscape designs to achieve multiple benefits
Year: 2025
Introduction: Growing concerns about fire across the western United States, and commensurate emphasis on treating expansive areas over the next 2 decades, have created a need to develop tools for managers to assess management benefits and impacts across spatial scales. We modeled outcomes associated with two common forest management objectives: fire risk reduction (fire), and enhancing multiple resource benefits (ecosystem resilience).Method: We evaluated the compatibility of these two objectives across ca. 1-million ha in the central Sierra Nevada,…
Publication Type: Journal Article
Near real-time indicators of burn severity in the western U.S. from active fire tracking
Year: 2025
BackgroundTimely information on wildfire burn severity is critical to assess and mitigate potential post-fire impacts on soils, vegetation, and hillslope stability. Tracking individual fire spread and intensity using satellite active fire data provides a pathway to near real-time (NRT) information. Here, we generated a large database (n = 2177) of wildfire events in the western United States (U.S.) between 2012 and 2021 using active fire detections from the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on the Suomi National Polar-orbiting Partnership (SNPP) satellite and…
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