Research Database
Displaying 1 - 20 of 409
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
Trailing edge contractions common in interior western US trees under varying disturbances
Year: 2025
As climate warms, trees are expected to track their ideal climate, referred to as ‘range shifts’; however, lags in tree range shifts are currently common. Disturbance events that kill trees may help catalyse tree migrations by removing biotic competition, but can also limit regeneration by eliminating seed sources, and it is unknown whether disturbance will facilitate or inhibit tree migrations in the face of climate change. Here we use national forest inventory data to show that seedlings of 15 dominant tree species in the interior western United States occupy historically cooler areas than…
Publication Type: Journal Article
Burning from the ground up: the structure and impact of Prescribed Burn Associations in the United States
Year: 2025
Background: To combat losses and threats from fire exclusion and extreme wildfire events, communities in the United States are increasingly self-organizing through locally led Prescribed Burn Associations (PBAs) to plan and implement prescribed burns on private lands.Aim: Our study aimed to document the expansion of PBAs and provide insight into their structure, function, and impacts.Methods: Leaders from 135 known PBAs across the United States were invited to participate in an online survey.Key results: Survey results demonstrate a widespread emergence of PBAs in the United States,…
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
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
Rising from the ashes: treatments stabilize carbon storage in California’s frequent-fire forests
Year: 2025
The stability of seasonally dry Western mixed-conifer forests is threatened by the history of fire suppression, logging, and now increasing climate-driven aridity. Durable aboveground carbon storage in living trees–a key ecosystem service of these fire-adapted forests–is at risk due to the disruption of natural fire cycles. Restoring the relationship between fire and forest structure is essential for long-term resilience. Fuel and density reduction treatments can help reestablish this balance by reducing fire severity and enhancing forest function.We evaluated the effectiveness of 216…
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
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
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
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
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
The national Fire and Fire Surrogate study: Effects of fuel treatments in the Western and Eastern United States after 20 years
Year: 2025
The national Fire and Fire Surrogate (FFS) study was initiated more than two decades ago with the goal of evaluating the ecological impacts of mechanical treatments and prescribed fire in different ecosystems across the United States. Since then, 4 of the original 12 sites remain active in managing and monitoring the original FFS study which provides a unique opportunity to look at the long-term effects of these treatments in different regions. These sites include California (Blodgett Forest Research Station), Montana (Lubrecht Experimental Forest), North Carolina (Green River Game Land), and…
Publication Type: Journal Article
When the wilderness burns: an analysis of current fire management and the case for prescribed fire in designated wilderness in the United States
Year: 2025
BackgroundUnited States wilderness areas face increasing challenges from altered fire regimes and climate change, and land managers face ever more complex decisions about fire use. While federal policies permit various fire management strategies in wilderness, including prescribed fire, managers predominantly rely on suppression despite broad support to restore and sustain fire's natural role in these landscapes. Consequently, wilderness fire regimes continue to diverge from historical norms. To better understand wilderness fire management, we used surveys and interviews with…
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
Assessing costs and constraints of forest residue disposal by pile burning
Year: 2025
Pile burning of thinned residues is a critical tool to dispose of fuels and to reduce wildfire risk in overstocked, fire-prone forests globally. However, cost estimates of pile burning are limited. In the Western United States, where fuel reduction and pile burning are key strategies to mitigate risk of severe wildfire, previous reports estimate that the average cost of pile burning after machine treatment is $543 ac−1 ($1,343 ha−1). There is, however, limited information on the costs of hand thinning and pile burning. In response, this study quantified the costs of cutting and yarding,…
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
Ecological scenarios: Embracing ecological uncertainty in an era of global change
Year: 2025
Scenarios, or plausible characterizations of the future, can help natural resource stewards plan and act under uncertainty. Current methods for developing scenarios for climate change adaptation planning are often focused on exploring uncertainties in future climate, but new approaches are needed to better represent uncertainties in ecological responses. Scenarios that characterize how ecological changes may unfold in response to climate and describe divergent and surprising ecological outcomes can help natural resource stewards recognize signs of nascent ecological transformation and…
Publication Type: Journal Article
Causal analysis of fire regime drivers in California
Year: 2025
BackgroundUnderstanding the relative contribution of climate and human factors to wildfires is critical for managing risk across California’s diverse ecosystems, in the United States (US).AimsWe propose a model that distinguishes between proximate and ultimate drivers of fire regimes and apply it to a century of fire and climate data to assess regional variation in causal mechanisms.MethodsWe analyzed fire statistics (1910–2021) alongside climate and weather data, stratifying the state by 10 ecoregions.Key resultsNorthern…
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