Research Database
Displaying 181 - 200 of 379
Severe fire has impacted populations of the California spotted owl more than fuels management or drought-related tree mortality
Year: 2025
Reducing fuel densities is the primary tool available to improve forest resilience to intensifying disturbance, but implementation is constrained by concern of effects to mature-forest associated species, such as spotted owls (Strix occidentalis). While the negative effects of severe fire on spotted owls are well studied, the influence of drought and fuels management on populations is uncertain, impeding fuels management. We integrated a novel dataset of California disturbance history with passive acoustic monitoring to compare the effects of severe fire, drought, and fuels…
Publication Type: Journal Article
Perspectives: The pace and scale challenge: Leveraging wildfire footprints to increase forest resilience to future high-severity fire
Year: 2025
In historically frequent fire forests, wildfires are burning larger areas and driving forest loss across western North America, yet they also produce extensive low- to moderate-severity effects that can be leveraged to harden landscapes against future high-severity fire. Here, we operationalize prior conceptual calls by presenting a framework that identifies opportunities to leverage recent wildfire footprints via three management pathways to increasing resistance to high-severity fire: create (use burned edges as containment lines to treat adjacent unburned forest), enhance…
Publication Type: Journal Article
Forest floor properties in pine forests of the southeastern and western United States
Year: 2025
BackgroundWildland fuels are fundamental variables in modeled predictions of fire behavior and effects. In forest ecosystems, accumulated forest floor layers, including recently fallen litter and highly decomposed organic material (i.e., duff), often constitute most surface fuel—biomass and stored carbon. Associated error in estimated litter and duff biomass can thus propagate to major sources of uncertainty in predicted fire effects, including tree mortality and smoke production. Distributions of forest floor biomass are difficult to measure, and estimates of litter and duff…
Publication Type: Journal Article
Fire refugia in forest ecosystems of the Pacific Northwest, USA: Science and applications for conservation, adaptation, and stewardship
Year: 2025
Concepts and models of fire refugia are increasingly important components of forest management and adaptation discussions in the context of wildland fire, forest and habitat conservation, and global change. Recent stand-replacing fires in mature and old-growth forests of the Pacific Northwest (PNW) region of the western United States have increased land manager and scientific interest in fire refugia that can provide important ecosystem services. Here we provide an overview of fire refugia concepts and products being actively developed and applied in forests of the PNW (Washington, Oregon,…
Publication Type: Journal Article
Wildfire recovery in Pacific Northwest Latine communities: how community capitals shape disaster resilience
Year: 2025
Wildfires are increasingly affecting people’s lives in the Pacific Northwest. Latine populations, in particular, often face unique challenges in their recovery process. This study examines individual Latine wildfire recovery experiences to understand the strengths and barriers in the community’s post-fire recovery process in two wildfire-affected areas in Oregon and Washington. Perceptions of recovery of Latine community members and community-based organizations that serve these populations were collected through focus groups, semi-structured interviews, and participant observation at…
Publication Type: Journal Article
A post-fire reforestation assessment and prioritization tool for the Western United States
Year: 2025
BackgroundIncreasing wildfire area burned has left millions of hectares in the western United States (US) in need of reforestation. Recent federal legislation allows for increased investments in tree planting to address the backlog of planting needs in previously burned areas. To support post-fire planning and assessment, we developed Regenmapper, a web-based decision support system (DSS) that provides spatial information on natural regeneration potential within post-fire environments. The program is freely available from a web browser (…
Publication Type: Journal Article
The Diffusion of Risk Management Assistance for Wildland Fire Management in the United States
Year: 2025
The wildland fire management system is increasingly complex and uncertain, which challenges suppression actions and increases stress on an already strained system. Researchers and managers have called for the use of strategic, risk-informed decision making and decision support tools (DSTs) in wildfire management to manage complexity and mitigate uncertainty. This paper evaluated the use of an emerging wildfire DST, the Risk Management Assistance (RMA) dashboard, during the 2021 and 2022 wildfire seasons. We used a mixed-method approach, consisting of an online survey and in-depth interviews…
Publication Type: Journal Article
Large projected increases in area burned and wildfire frequency by 2050 in Utah, USA
Year: 2025
Changes in wildfire regimes may disrupt ecosystem processes as wildfires burn larger areas or burn more frequently than the recent natural range of variability. The climatic drivers of wildfire behavior may change in strength, but these effects are not likely to be uniform across space and different vegetation types. Increased understanding of how weather and climate influence patterns of burn area and frequency across vegetation types may assist in better predicting and managing future wildfire regimes. We examined a dataset of all 1469 wildfires ≥40 ha from 1984 - 2021 in Utah, USA, and…
Publication Type: Journal Article
Awareness and Social Interactions Influence Natural Resource Professionals’ Recommendations for Prescribed Fire Use
Year: 2025
Restoring fire in fire-adapted ecosystems is necessary to curtail woody plant expansion, enhance biodiversity, and reduce wildfire risks, yet prescribed fire is promoted less by federal agencies than other grassland conservation practices. The U.S. Department of Agriculture…
Fire and Rangelands, Prescribed Burning, Public Perceptions of Fire and Smoke, Restoration and Hazardous Fuel Reduction
Publication Type: Journal Article
The hidden variable: Impacts of human decision-making on prescribed fire outcomes
Year: 2025
This study investigates the key drivers influencing prescribed fire effects across 16 sites in northern and central California, with particular emphasis on how operational decisions by fire practitioners shape burn outcomes. Data from the California Prescribed Fire Monitoring Program revealed that prescribed fires reduced total fuel loads by an average of 60 %, with greater consumption of postfrontal smoldering fuels (coarse fuels, 65 %) compared to frontline spreading fuels (fine fuels, 49.0 %).Crown scorch height showed a strong relationship to crown base height (R2 =…
Fire Effects and Fire Ecology, Fuels and Fuel Treatments, Prescribed Burning, Restoration and Hazardous Fuel Reduction
Publication Type: Journal Article
Rising rates of wildfire building destruction in the conterminous United States
Year: 2025
Many regions of the world have seen an increase in highly destructive wildfires, driven by well-documented increases in burned area and growth of housing in the wildland–urban interface (WUI), which exposes more homes to fire. However, it is unclear whether wildfires are also becoming more destructive due to changes in wildfire behavior or in the development patterns of exposed communities. Here, we assessed trends in wildfire building exposure and destruction rates in the conterminous United States from 2002 to 2022. We mapped destroyed and surviving buildings within 100 m of all wildfires…
Publication Type: Journal Article
Yosemite’s Merced Grove of giant sequoias: critical restoration continues despite legal challenges
Year: 2025
BackgroundGiant sequoias are the most massive individual trees on earth, and among the longest-lived. They also have a limited distribution, covering ~10,000 ha across ~70 distinct groves. Severe wildfires in 2020 and 2021 impacted 82% of the range, killing roughly 13-19% of the entire population of these irreplaceable trees. Within the giant sequoia range, the Merced Grove is one of the most at risk of burning at high severity. Located in Yosemite National Park, it has no recorded wildfire history and has received minimal restoration treatment, most of which occurred…
Public Perceptions of Fire and Smoke, Restoration and Hazardous Fuel Reduction, Social and Community Impacts of Fire
Publication Type: Journal Article
Emissions from burned structures in wildfires as significant yet unaccounted sources of US air pollution
Year: 2025
Structure fires in the wildland–urban interface (WUI) are becoming more frequent and destructive, yet their emissions of air pollutants remain poorly quantified and are not included in national inventories. Here we present a conterminous-scale inventory of WUI-related structure fire emissions in the United States from 2000 to 2020. A small number of highly destructive events dominate structure fire emissions—the 20 most destructive fires account for 68% of total carbon monoxide emissions. Structure fire emissions are more spatially concentrated than vegetation fire emissions, and in several…
Publication Type: Journal Article
The Marshall Fire: Scientific and policy needs for water system disaster response
Year: 2023
The 2021 Marshall Fire was the costliest fire in Colorado's history and destroyed more than 1,000 homes and businesses. The disaster displaced over 40,000 people and damaged six public drinking water systems. A case study was developed to better understand decisions, resources, expertise, and response limitations during and after the wildfire. The fire caused all water systems to lose power. Power loss was sometimes coupled with structure destruction, distribution depressurization, and the failure of backup power systems. These consequences jeopardized fire-fighting support and allowed for…
Publication Type: Journal Article
Different approaches make comparing studies of burn severity challenging: a review of methods used to link remotely sensed data with the Composite Burn Index
Year: 2023
The Composite Burn Index (CBI) is commonly linked to remotely sensed data to understand spatial and temporal patterns of burn severity. However, a comprehensive understanding of the tradeoffs between different methods used to model CBI with remotely sensed data is lacking. To help understand the current state of the science, provide a blueprint towards conducting broad- scale meta-analyses, and identify key decision points and potential rationale, we conducted a review of studies that linked remotely sensed data to continuous estimates of burn severity measured with the CBI and related…
Publication Type: Journal Article
Conifer encroachment increases foliar moisture content in a northwestern California oak woodland
Year: 2023
Foliar moisture content influences crown fire ignition and behaviour. Some spatial variation in foliar moisture is attributable to differences in stand conditions but evidence describing this role is lacking or contradicting. Aims. To examine the role of stand conditions on tree physiology and foliar moisture content in Oregon white oak (Quercus garryana) and Douglas-fir (Pseudotsuga menziesii). Methods. We monitored foliar moisture content in both species, and tree physiology (stomatal conductance and leaf water potential) in oak, across three stand conditions, including intact stands (…
Publication Type: Journal Article
Examining the influence of mid-tropospheric conditions and surface wind changes on extremely large fires and fire growth days
Year: 2023
Background: Previous work by the author and others has examined weather associated with growth of exceptionally large fires (‘Fires of Unusual Size’, or FOUS), looking at three of four factors associated with critical fire weather patterns: antecedent drying, high wind and low humidity. However, the authors did not examine atmospheric stability, the fourth factor. Aims: This study examined the relationships of mid-tropospheric stability and dryness used in the Haines Index, and changes in surface wind speed or direction, to growth of FOUS. Methods. Weather measures were paired with daily…
Publication Type: Journal Article
Environmental justice analysis of wildfire-related PM2.5 exposure using low-cost sensors in California
Year: 2023
Highlights • Wildfire may exacerbate health disparities & environmental justice concerns. • Low-cost PM2.5 sensors improve wildfire impact assessment. • Increases in PM2.5 correlate with wildfire activity (within 30 km). • Indoor increases in PM2.5 concentrations mimic outdoor PM2.5 increase patterns. The increasing number and severity of wildfires is negatively impacting air quality for millions of California residents each year. Community exposure to PM2.5 in two main population centers (San Francisco Bay area and Los Angeles County area) was assessed using the low-cost PurpleAir sensor…
Publication Type: Journal Article
High-severity burned area and proportion exceed historic conditions in Sierra Nevada, California, and adjacent ranges
Year: 2023
Although fire is a fundamental ecological process in western North American forests, climate warming and accumulating forest fuels due to fire suppression have led to wildfires that burn at high severity across larger fractions of their footprint than were historically typical. These trends have spiked upwards in recent years and are particularly pronounced in the Sierra Nevada–Southern Cascades ecoregion of California, USA, and neighboring states. We assessed annual area burned (AAB) and percentage of area burned at high and low-to-moderate severity for seven major forest types in this…
Publication Type: Journal Article
High-severity fire drives persistent floristic homogenization in human-altered forests
Year: 2023
Ecological disturbance regimes across the globe are being altered via direct and indirect human influences. Biodiversity loss at multiple scales can be a direct outcome of these shifts. Fire, especially in dry forests, is an ecological disturbance that is experiencing dramatic changes due to climate change, fire suppression, increased human population in fire-prone areas, and alterations to vegetation composition and structure. Dry western conifer forests that historically experienced frequent, low-severity fires are now increasingly burning at high severity. Relatively little work has been…
Publication Type: Journal Article