Research Database
Displaying 1 - 16 of 16
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
Evidence for strong bottom-up controls on fire severity during extreme events
Year: 2025
BackgroundRecord fire years in recent decades have challenged post-fire forest recovery in the western United States and beyond. To improve management responses, it is critical that we understand the conditions under which management can mitigate severe wildfire impacts, and when it cannot. Here, we evaluated the influence of top-down and bottom-up fire severity forcings on 17 wildfires occurring during two consecutive record-setting years in the eastern Cascade Mountains of Washington State. Despite much of the area having been burned after an extended period of fire…
Fire Effects and Fire Ecology, Fire History, Fuels and Fuel Treatments, Restoration and Hazardous Fuel Reduction
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
Comparing modeled soil temperature and moisture dynamics during prescribed fires, slash-pile burns and wildfires
Year: 2025
Background: Wildfires, prescribed fires and slash-pile burns are disturbances that occur in many terrestrial ecosystems. Such fires produce variable surface heat fluxes causing a spectrum of effects on soil, such as seed mortality, nutrient loss, changes in microbial activity and water repellency. Accurately modeling soil heating is vital to predicting these second-order fire effects. The process-based Massman HMV (Heat–Moisture–Vapor) model incorporates soil water evaporation, heat transport and water vapor movement, and captures the observed rapid evaporation of soil moisture. Aims:…
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
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
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
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
Increasing trends in high-severity fire in the southwestern USA from 1984 to 2015
Year: 2019
In the last three decades, over 4.1 million hectares have burned in Arizona and New Mexico and the largest fires in documented history have occurred in the past two decades. Changes in burn severity over time, however, have not been well documented in forest and woodland ecosystems in the southwestern US. Using remotely sensed burn severity data from 1621 fires (>404 ha), we assessed trends from 1984 to 2015 in Arizona and New Mexico in (1) number of fires and total area burned in all vegetation types; (2) area burned, area of high-severity, and percent of high-severity fire in all forest…
Publication Type: Journal Article
Predicting increasing high severity area burned for three forested regions in the western United States using extreme value theory
Year: 2019
More than 70 years of fire suppression by federal land management agencies has interrupted fire regimes in much of the western United States. The result of missed fire cycles is a buildup of both surface and canopy fuels in many forest ecosystems, increasing the risk of severe fire. The frequency and size of fires has increased in recent decades, as has the area burned with high severity in some ecosystems. A number of studies have examined controls on high severity fire occurrence, but none have yet determined what controls the extent of high severity fire. We developed statistical models…
Publication Type: Journal Article
A multi-century history of fire regimes along a transect of mixed-conifer forests in central Oregon, U.S.A
Year: 2019
Dry mixed-conifer forests are widespread in the interior Pacific Northwest, but their historical fire regimes are poorly characterized, in particular the relative mix of low- and high-severity fire. We reconstructed a multi-century history of fire from tree rings in dry mixed-conifer forests in central Oregon. These forests are dominated by ponderosa pine (Pinus ponderosa Lawson & C. Lawson), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and grand fir (Abies grandis (Douglas ex D. Don) Lindl.). Across four, 30-plot grids of ~800 ha covering a mosaic of dry mixed-conifer forest types…
Publication Type: Journal Article
Historical patterns of fire severity and forest structure and composition in a landscape structured by frequent large fires: Pumice Plateau ecoregion, Oregon, USA
Year: 2019
Context Lack of quantitative observations of extent, frequency, and severity of large historical fires constrains awareness of departure of contemporary conditions from those that demonstrated resistance and resilience to frequent fire and recurring drought. Objectives Compare historical and contemporary fire and forest conditions for a dry forest landscape with few barriers to fire spread. Methods Quantify differences in (1) historical (1700–1918) and contemporary (1985–2015) fire extent, fire rotation, and stand-replacing fire and (2) historical (1914–1924) and contemporary (2012) forest…
Publication Type: Journal Article
Short- and long-term effects of ponderosa pine fuel treatments intersected by the Egley Fire Complex, Oregon, USA
Year: 2019
Background Fuel treatments are widely used to alter fuels in forested ecosystems to mitigate wildfire behavior and effects. However, few studies have examined long-term ecological effects of interacting fuel treatments (commercial harvests, pre-commercial thinnings, pile and burning, and prescribed fire) and wildfire. Using annually fitted Landsat satellite-derived Normalized Burn Ratio (NBR) curves and paired pre-fire treated and untreated field sites, we tested changes in the differenced NBR (dNBR) and years since treatment as predictors of biophysical attributes one and nine years after…
Publication Type: Journal Article
Contributions of fire refugia to resilient ponderosa pine and dry mixed-conifer forest landscapes
Year: 2019
Altered fire regimes can drive major and enduring compositional shifts or losses of forest ecosystems. In western North America, ponderosa pine and dry mixed‐conifer forest types appear increasingly vulnerable to uncharacteristically extensive, high‐severity wildfire. However, unburned or only lightly impacted forest stands that persist within burn mosaics—termed fire refugia—may serve as tree seed sources and promote landscape recovery. We sampled tree regeneration along gradients of fire refugia proximity and density at 686 sites within the perimeters of 12 large wildfires that occurred…
Publication Type: Journal Article
Examining post-fire vegetation recovery with Landsat time series analysis in three western North American forest types
Year: 2019
Background: Few studies have examined post-fire vegetation recovery in temperate forest ecosystems with Landsat time series analysis. We analyzed time series of Normalized Burn Ratio (NBR) derived from LandTrendr spectral-temporal segmentation fitting to examine post-fire NBR recovery for several wildfires that occurred in three different coniferous forest types in western North America during the years 2000 to 2007. We summarized NBR recovery trends, and investigated the influence of burn severity, post-fire climate, and topography on post-fire vegetation recovery via random forest (RF)…
Publication Type: Journal Article
Wild bee diversity increases with local fire severity in a fire‐prone landscape
Year: 2019
As wildfire activity increases in many regions of the world, it is imperative that we understand how key components of fire‐prone ecosystems respond to spatial variation in fire characteristics. Pollinators provide a foundation for ecological communities by assisting in the reproduction of native plants, yet our understanding of how pollinators such as wild bees respond to variation in fire severity is limited, particularly for forest ecosystems. Here, we took advantage of a natural experiment created by a large‐scale, mixed‐severity wildfire to provide the first assessment of how wild bee…
Publication Type: Journal Article