Research Database
Displaying 1 - 9 of 9
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
Contextualizing recent increases in Canadian boreal wildfire activity: decadal burn rates still within historical variability of the two past centuries
Year: 2025
With approximately 15 million hectares burned, the 2023 wildfire season in Canada was exceptional. However, it remains unclear whether such recent increases in burned areas exceed the range of variability observed over past centuries. The objective of this study was to leverage available dendrochronological reconstructions of decadal burn rates to contextualize their recent increase within their historical variability over the past two centuries. We compared decadal burn rate reconstructions based on dendrochronological data (1800s–2023) for five large eastern and western Canadian boreal…
Publication Type: Journal Article
Resource objective wildfires shifted forest structure and fuels toward pre-fire-exclusion conditions in a remote Arizona wilderness
Year: 2025
BackgroundLarge, severe fires are increasing throughout frequent-fire forests of the western United States due to warming climatic conditions, as well as legacies of early twentieth century land-use practices and anthropogenic fire exclusion. Resource objective (RO) wildfires—where naturally ignited wildfires are allowed to burn to accomplish management objectives—are increasingly accepted due to relatively low cost and flexibility on lands where mechanical treatments are not allowed (e.g., designated wilderness) or economically feasible. We previously implemented a field…
Publication Type: Journal Article
Spatiotemporal Synchrony of Climate and Fire Occurrence Across North American Forests (1750–1880)
Year: 2025
Aim: Increasing aridity has driven widespread synchronous fire occurrence in recent decades across North America. The lack of historical (pre-1880) fire records limits our ability to understand long-term continental fire-climate dynamics. The goal of this study is to use tree-ring reconstructions to determine the relationships between spatiotemporal patterns in historical climate and widespread fire occurrence in North American forests, and whether they are stable through time. This information will address a major knowledge gap required to inform projections of future fire.Location: North…
Publication Type: Journal Article
Motivating parents to protect their children from wildfire smoke: the impact of air quality index infographics
Year: 2025
Background. Wildfire smoke events are increasing in frequency and intensity due to climate change. Children are especially vulnerable to health effects even at moderate smoke levels. However, it is unclear how parents respond to Air Quality Indices (AQIs) frequently used by agencies to communicate air pollution health risks. Methods. In an experiment (3 × 2 × 2 factorial design), 2,100 parents were randomly assigned to view one of twelve adapted AQI infographics that varied by visual (table, line, gauge), index type (AQI [0-500], AQHI [1-11+]), and risk…
Publication Type: Journal Article
Long-range PM2.5 pollution and health impacts from the 2023 Canadian wildfires
Year: 2025
Smoke from extreme wildfires in Canada adversely affected air quality in many regions in 20231,2. Here we use satellite observations, machine learning and a chemical transport model to quantify global and regional PM2.5 (particulate matter less than 2.5 μm in diameter) exposure and human health impacts related to the 2023 Canadian wildfires. We find that the fires increased annual PM2.5 exposure worldwide by 0.17 μg m–3 (95% confidence interval, 0.…
Publication Type: Journal Article
Wildland Fire–Related Smoke PM2.5 and Cardiovascular Disease Emergency Department Visits in the Western United States
Year: 2025
BackgroundThe impact of short‐term exposure to fine particulate matter with a diameter ≤2.5 μm (PM2.5) due to wildland fire smoke on the risk of cardiovascular disease (CVD) remains unclear. We investigated the association between short‐term exposure to wildfire smoke PM2.5 and emergency department visits for acute CVD in the western United States from 2007 to 2018.MethodsWe analyzed 49 759 958 emergency department visits for primary or secondary diagnoses of atrial fibrillation (AF), acute myocardial infarction, heart failure, stroke, and total CVD across 5…
Publication Type: Journal Article
Wildfire-specific fine particulate matter and preterm birth: a US ECHO Cohort analysis
Year: 2025
BackgroundExposure to PM2·5 from wildfire smoke during pregnancy has been implicated as a risk factor for preterm birth. We investigated this association in the prospective nationwide US Environmental Influences on Child Health Outcomes (ECHO) Cohort, focusing on prenatal wildfire PM2·5 exposure intensity, duration, and timing.MethodsIn this cohort analysis, we included live singleton births recorded in the ECHO Cohort with available data on gestational age at birth and birthweight and dates of conception between Jan 1, 2006, and March 20, 2020. Census tract-level estimates of daily mean…
Publication Type: Journal Article
Wildfire smoke exposure and mortality burden in the USA under climate change
Year: 2025
Wildfire activity has increased in the USA and is projected to accelerate under future climate change1,2,3. However, our understanding of the impacts of climate change on wildfire activity, smoke and health outcomes remains highly uncertain because of the difficulty of modelling the causal chain from climate to wildfire to air pollution and health. Here we quantify the…
Publication Type: Journal Article