Research Database
Displaying 1 - 20 of 135
A Negative Fire–Vegetation Feedback Substantially Limits Reburn Extent Across the North American Boreal Biome
Year: 2025
The North American boreal biome (NAB) is warming at 2–4 times the mean global rate, contributing to increasing wildfire activity. The degree to which this trend alters biome-level feedbacks to global climate depends on how strongly bottom-up feedbacks between fire and vegetation dampen the effects of climate drivers. As young vegetation recovering from fire covers a growing portion of the landscape, it could resist reburning, buffering against further increases in fire. Resistance to reburning could be particularly strong in the NAB, where slow post-fire fuel accumulation is sometimes…
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
Power and planning: a critical discourse analysis of tribal and non-tribal Oregon wildfire protection plans
Year: 2025
BackgroundSince the late 1800s, the US government has largely removed Indigenous fire stewardship practices from the landscape by implementing a top-down fire suppression system that criminalized traditional fire practices and denaturalized the role of fire in forested environments. A century of routine fire suppression produced dense, homogenous forests capable of sustaining high-intensity wildfire that exceeds the suppression capabilities of land management organizations in many regions, spurring federal leaders to modify management approaches. As part of this change,…
Publication Type: Journal Article
Anthropogenic warming drives earlier wildfire season onset in California
Year: 2025
Annual wildfire area in California has rapidly grown in recent decades, with increasingly negative impacts on people. The fire season is also lengthening, with an earlier onset. This trend has been hypothesized to be driven by anthropogenic warming, but it has yet to be quantitatively attributed to climate drivers. Using a comprehensive fire occurrence dataset, we analyze fire season onset and climate controls on its variability and change during 1992–2020 in 13 California ecoregions. Northern California ecoregions show stronger trends toward earlier onset compared to more arid southern…
Publication Type: Journal Article
Governance of Indigenous data in open earth systems science
Year: 2025
In the age of big data and open science, what processes are needed to follow open science protocols while upholding Indigenous Peoples’ rights? The Earth Data Relations Working Group (EDRWG), convened to address this question and envision a research landscape that acknowledges the legacy of extractive practices and embraces new norms across Earth science institutions and open science research. Using the National Ecological Observatory Network (NEON) as an example, the EDRWG recommends actions, applicable across all phases of the data lifecycle, that recognize the sovereign rights of…
Publication Type: Journal Article
Increasing Hydroclimatic Whiplash Can Amplify Wildfire Risk in a Warming Climate
Year: 2025
On January 7 and 8, 2025, a series of wind-driven wildfires occurred in Los Angeles County in Southern California. Two of these fires ignited in dense woody chaparral shrubland and immediately burned into adjacent populated areas–the Palisades Fire on the coastal slopes of the Santa Monica Mountains and the Eaton fire in the foothills of the San Gabriel Mountains. Both fires ultimately eclipsed the traditionally-defined “wildland-urban interface” boundaries by burning structure-to-structure as an urban conflagration. The scope of the devastation is staggering; at the time of writing, the…
Publication Type: Report
A tale of two fire systems: indigenous fire stewardship in British Columbia and California
Year: 2025
BackgroundAn increasing wildfire problem in western North America has created a policy space for Indigenous fire stewardship (IFS) to mitigate wildfire. We compare how British Columbia and California have supported IFS—two jurisdictions with distinct ecosystems but similar histories of colonialism and its socio-ecological consequences. We examine how IFS is incorporated into each jurisdiction’s institutional framework, and the barriers to, and opportunities for implementation.ResultsEach jurisdiction’s approach to recognizing IFS is shaped by different…
Publication Type: Journal Article
Trees in Fire-Maintained Forests Have Similar Growth Responses to Drought, but Greater Stomatal Conductance Than Trees in Fire-Excluded Forests
Year: 2025
In the western US, increased tree density in dry conifer forests from fire exclusion has caused tree growth declines, which is being compounded by hotter multi-year droughts. The reintroduction of frequent, low-severity wildfire reduces forest density by removing fire-intolerant trees, which can reduce competition for water and improve tree growth response to drought. We assessed how lower forest density following frequent, low-severity wildfire affected tree stomatal conductance and growth response to drought by coring and measuring competition surrounding ponderosa pines (Pinus…
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
Evaluating a simulation-based wildfire burn probability map for the conterminous US
Year: 2025
Background: Wildfire simulation models are used to derive maps of burn probability (BP) based on fuels, weather, topography and ignition locations, and BP maps are key components of wildfire risk assessments.Aims: Few studies have compared BP maps with real-world fires to evaluate their suitability for near-future risk assessment. Here, we evaluated a BP map for the conterminous US based on the large fire simulation model FSim.Methods: We compared BP with observed wildfires from 2016 to 2022 across 128 regions representing similar fire regimes (‘pyromes’). We…
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
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
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
State of Wildfires 2024–2025
Year: 2025
Climate change is increasing the frequency and intensity of extreme wildfires globally, yet our understanding of these high-impact events remains uneven and shaped by media attention and regional research biases. The State of Wildfires project systematically tracks global and regional fire activity of each annual fire season, analyses the causes of prominent extreme wildfire events, and projects the likelihood of similar events occurring in future climate scenarios. This, its second annual report, covers the March 2024 to February 2025 fire season. During the 2024–2025 fire season, fire-…
Publication Type: Journal Article
Integrated fire management as an adaptation and mitigation strategy to altered fire regimes
Year: 2025
Altered fire regimes are a global challenge, increasingly exacerbated by climate change, which modifies fire weather and prolongs fire seasons. These changing conditions heighten the vulnerability of ecosystems and human populations to the impacts of wildfires on the environment, society, and the economy. The rapid pace of these changes exposes significant gaps in knowledge, tools, technology, and governance structures needed to adopt informed, holistic approaches to fire management that address both current and future challenges. Integrated Fire Management is an approach that combines fire…
Publication Type: Journal Article
A fire-use decision model to improve the United States’ wildfire management and support climate change adaptation
Year: 2024
The US faces multiple challenges in facilitating the safe, effective, and proactive use of fire as a landscape management tool. This intentional fire use exposes deeply ingrained communication challenges and distinct but overlapping strategies of prescribed fire, cultural burning, and managed wildfire. We argue for a new conceptual model that is organized around ecological conditions, capacity to act, and motivation to use fire and can integrate and expand intentional fire use as a tool. This result emerges from more considered collaboration and communication of values and needs to address…
Publication Type: Journal Article
Fire history in northern Sierra Nevada mixed conifer forests across a distinct gradient in productivity
Year: 2024
BackgroundUnderstanding the role of fire in forested landscapes is fundamental to fire reintroduction efforts, yet few studies have examined how fire dynamics vary in response to interactions between local conditions, such as soil productivity, and more broadscale changes in climate. In this study, we examined historical fire frequency, seasonality, and spatial patterning in mixed conifer forests across a distinct gradient of soil productivity in the northern Sierra Nevada. We cross-dated 46 different wood samples containing 377 fire scars from 6 paired sites, located on and off of…
Publication Type: Journal Article
Pre-contact Indigenous fire stewardship: a research framework and application to a Pacific Northwest temperate rainforest
Year: 2024
Fire is a key disturbance process that shapes the structure and function of montane temperate rainforest in the Pacific Northwest (PNW). Recent research is revealing more frequent historical fire activity in the western central Cascades than expected by conventional theory. Indigenous peoples have lived in the PNW for millennia. However, Indigenous people's roles in shaping vegetation mosaics in montane temperate forests of the PNW has been overlooked, despite archaeological evidence of long-term, continuous human use of these landscapes. In this paper, we present a generalizable research…
Publication Type: Journal Article
Tribal stewardship for resilient forest socio-ecosystems
Year: 2024
The Yurok Tribe, along with other tribal communities in northwest California, non-profit organizations, universities, and governmental agencies are working to restore forests and woodlands to be more resilient to wildfires, drought, pests and diseases. Our current work within ancestral Yurok territory is designing and evaluating effects of forest treatments including fuels reduction, tree harvesting, and intentional burning based upon indigenous knowledge and associated traditional stewardship practices. Central to these evaluations are the potential availability, quantity, and quality of…
Publication Type: Journal Article
Boundary spanners catalyze cultural and prescribed fire in western Canada
Year: 2024
Western Canada is increasingly experiencing impactful and complex wildfire seasons. In response, there are urgent calls to implement prescribed and cultural fire as a key solution to this complex challenge. Unfortunately, there has been limited investment in individuals and organizations that can navigate this complexity and work to implement collaborative solutions across physical, cognitive, and social boundaries. In the wildfire context, these boundaries manifest as jurisdictional silos, a lack of respect for certain forms of knowledge, and a disconnect between knowledge and practice. Here…
Publication Type: Journal Article