Research Database
Displaying 1 - 20 of 224
Long-term influence of prescribed burning on subsequent wildfire in an old-growth coast redwood forest
Year: 2025
Background: Prescribed burning is an effective tool for reducing fuels in many forest types, yet there have been few opportunities to study forest resilience to wildfire in areas previously treated. In 2020, a large-scale high-intensity wildfire burned through an old-growth coast redwood (Sequoia sempervirens) forest with a mixed land management history, providing a rare opportunity to compare early post-wildfire data between areas with and without previous application of prescribed burning. The purpose of this study was to analyze the differences between these two treatments in…
Publication Type: Journal Article
Reliability of satellite-based vegetation maps for planning wildfire-fuel treatments in shrub steppe: Inferences from two contrasting national parks
Year: 2025
Protecting habitat threatened by increasing wildfire size and frequency requires identifying the spatial intersection of wildfire behavior and ecological conditions that favor positive management outcomes. In the perennial sagebrush steppe of Western North America, invasions by fire-prone annual grasses are a key concern, and management of them requires reliable maps of vegetation cover, fuels, and wildfire behavior. We compared commonly used, publicly available vegetation cover and fuels maps, specifically the Rangeland Analysis Platform (RAP) and LANDFIRE, with field-based assessments at…
Publication Type: Journal Article
Wildfires drive multi-year water quality degradation over the western United States
Year: 2025
Wildfires can dramatically alter water quality, resulting in severe implications for human and freshwater systems. However, regional-scale assessments of these impacts are often limited by data scarcity. Here, we unify observations from 1984–2021 in 245 burned watersheds across the western United States, comparing post-fire signals to baseline levels from 293 unburned basins. Organic carbon and phosphorus exhibit significantly elevated levels (p ≤ 0.05) in the first 1–5 years post-fire, while nitrogen and sediment show significant increases up to 8 years post-fire. During peak post-…
Publication Type: Journal Article
Short-term impacts of operational fuel treatments on modelled fire behaviour and effects in seasonally dry forests of British Columbia, Canada
Year: 2025
Background: In response to increasing risk of extreme wildfire across western North America, forest managers are proactively implementing fuel treatments.Aims: We assessed the efficacy of alternative combinations of thinning, pruning and residue fuel management to mitigate potential fire behaviour and effects in seasonally dry forests of interior British Columbia, Canada.Methods: Across five community forests, we measured stand attributes before and after fuel treatments in 2021 and 2022, then modelled fire behaviour and effects using the…
Publication Type: Journal Article
Post-fire delayed tree mortality in mesic coniferous forests reduces fire refugia and seed sources
Year: 2025
Context: Ecological functions provided by fire refugia are critical for supporting conifer forest resiliency under increased fire activity across the western United States. The spatial distribution and persistence of fire refugia over time are uncertain as fire-injured trees continue to die over subsequent years post-fire.Objectives: We examined how post-fire delayed tree mortality affects the spatial distribution and attributes of fire refugia at patch and landscape scales following high-severity wildfires.Methods: To explore changes in fire…
Publication Type: Journal Article
Experimental study on the evolution of canyon fire spread behavior under different terrains and the critical conditions for eruptive fire
Year: 2025
BackgroundThe spread of canyon fire often involves sudden acceleration, which is related to eruptive fire.AimsThe purpose of the study is to explore the pattern of fire line evolution and rate of spread (ROS) with topographic conditions in canyon fire, and to clarify the critical conditions for and mechanism of eruptive fire.MethodsA systematic experimental study on canyon fire was conducted by igniting dead pine needles with a point ignition.Key resultsFour different types of fire line contours were identified under…
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
Small-scale fire refugia increase soil bacterial and fungal richness and increase community cohesion nine years after fire
Year: 2025
Small-scale variation in wildfire behavior may cause large differences in belowground bacterial and fungal communities with consequences for belowground microbial diversity, community assembly, and function. Here we combine pre-fire, active-fire, and post-wildfire measurements in a mixed-conifer forest to identify how fine-scale wildfire behavior, unburned refugia, and aboveground forest structure are associated with belowground bacterial and fungal communities nine years after wildfire. We used fine-scale mapping of small (0.9–172.6 m2) refugia to sample soil-associated burned and…
Publication Type: Journal Article
Review of thermal behaviour of firebrands and their role in fuel bed and structure ignition
Year: 2025
Firebrands or embers are a crucial phenomenon in wildfire behaviour. Firebrands – small, burning or smouldering pieces of wood or other flammable materials – can be carried by wind considerable distances, leading to ignition of new fires ahead of the main fire front. This process, called spotting, significantly contributes to the rapid spread of fires, particularly in wildland–urban interface (WUI) areas. Spot fires pose a severe threat to people and properties. Better understanding the thermal behaviour of firebrands and their ability to ignite various natural fuel beds and structural…
Publication Type: Journal Article
Mapping Delayed Canopy Loss and Durable Fire Refugia for the 2020 Wildfires in Washington State Using Multiple Sensors
Year: 2025
Fire refugia are unburned and low severity patches within wildfires that contribute heterogeneity that is important to retaining biodiversity and regenerating forest following fire. With increasingly intense and frequent wildfires in the Pacific Northwest, fire refugia are important for re-establishing populations sensitive to fire and maintaining resilience to future disturbances. Mapping fire refugia and delayed canopy loss is useful for understanding patterns in their distribution. The increasing abundance of satellite data and advanced analysis platforms offer the potential to map fire…
Publication Type: Journal Article
Complexities in post-wildfire governance: lessons from Colorado’s 2020 wildfires
Year: 2025
Background: The increasing size and severity of western U.S. wildfires in recent years has generated greater attention towards post-wildfire response and recovery. Post-fire governance requires coordinating response and recovery capacities across jurisdictions, landscapes, and time scales. The presence of wildfire on federal public lands necessitates federal agency involvement in both suppression and recovery efforts, and program coordination with lower levels of government and non-governmental organizations. Using semi-structured interviews, we investigated experiences of leaders across the…
Publication Type: Journal Article
Planted seedling regeneration using gap-based silviculture without herbicide in a wildfire-impacted forest of the Sierra Nevada
Year: 2025
Gap-based silviculture, which we define as the creation and maintenance of multi-aged stands through the periodic harvesting of discrete canopy gaps, provides a potential mechanism for converting previously high-graded stands into more heterogeneous, multi-aged structures. An advantage of small canopy gaps, relative to even-aged regeneration methods, is their potential to suppress shrub competition while allowing seedling growth without the use of herbicides or other means of managing shrub competition. While this idea has been proposed in principle, it has not been tested. The objective of…
Publication Type: Journal Article
Extreme Weather Magnifies the Effects of Forest Structure on Wildfire, Driving Increased Severity in Industrial Forests
Year: 2025
Despite widespread concern over increases in wildfire severity, the mechanisms underlying this trend remain unclear, hampering our ability to mitigate the severity of future fires. There is substantial uncertainty regarding the relative roles of extreme weather conditions, which are exacerbated by climate change, and forest management, in particular differences between private industrial timber companies and public land agencies. To investigate the effects of extreme weather and forest management on fire severity, we used light detection and ranging (LiDAR) data to characterize pre-fire…
Publication Type: Journal Article
Fire gives avian populations a rapid and enduring boost in protected forests of California
Year: 2025
BackgroundFire can impact ecosystems and species over both short and long timeframes, resulting in pervasive impacts on the structure of avian communities. While recent research has highlighted the strong impact of fire on bird communities in the short term, there remains a need for understanding long-term population processes following fire, particularly in forested landscapes that are burning more frequently than in the past century. We analyzed avian response to fire using point-count data from 1999–2019 within national parks of the Sierra Nevada Inventory & Monitoring Network,…
Publication Type: Journal Article
Temporal and spatial pattern analysis of escaped prescribed fires in California from 1991 to 2020
Year: 2025
Background: Prescribed fires play a critical role in reducing the intensity and severity of future wildfires by systematically and widely consuming accumulated vegetation fuel. While the current probability of prescribed fire escape in the United States stands very low, their consequential impact, particularly the large wildfires they cause, raises substantial concerns. The most direct way of understanding this trade-off between wildfire risk reduction and prescribed fire escapes is to explore patterns in the historical prescribed fire records. This study investigates the spatiotemporal…
Publication Type: Journal Article
Multifactor Change in Western U.S. Nighttime Fire Weather
Year: 2025
Reports from western U.S. firefighters that nighttime fire activity has been increasing during the spans of many of their careers have recently been confirmed by satellite measurements over the 2003–20 period. The hypothesis that increasing nighttime fire activity has been caused by increased nighttime vapor pressure deficit (VPD) is consistent with recent documentation of positive, 40-yr trends in nighttime VPD over the western United States. However, other meteorological conditions such as near-surface wind speed and planetary boundary layer depth also impact fire behavior and exhibit…
Publication Type: Journal Article
Mobile radar provides insights into hydrologic responses in burn areas
Year: 2025
Background. Wildfires often occur in mountainous terrain, regions that pose substantial challenges to operational meteorological and hydrologic observing networks. Aims. A mobile, postfire hydrometeorological observatory comprising remote-sensing and in situ instrumentation was developed and deployed in a burnt area to provide unique insights into rainfall-induced post-fire hazards. Methods. Mobile radar-based rainfall estimates were produced throughout the burn area at 75-m resolution and compared with rain gauge accumulations and basin response variables. Key results. The mobile radar was…
Publication Type: Journal Article
Long-term soil nutrient and understory plant responses to post-fire rehabilitation in a lodgepole pine forest
Year: 2025
Wildfires and other disturbances play a fundamental role in regenerating lodgepole pine forests. Though severe, stand-replacing fires are typical of this ecosystem, they can have dramatic impacts on soil properties and biogeochemical processes that influence the rate and composition of vegetation recovery. Organic soil amendments are often applied to manage post-fire erosion, but they can also improve soil moisture and nutrient retention and potentially alter the trajectory of post-fire revegetation. We compared change in soil nutrients, microbial communities, and understory plant cover and…
Publication Type: Journal Article
Effects of long-term ecological research and cognitive biases on the evaluation of scientific information by public land managers in Oregon and Washington, USA
Year: 2025
Natural resource managers (managers) value and use scientific information to inform their decision-making process in a variety of ways. The scientific information managers use depends on a variety of factors, including the source of the information and ease of access. Barriers, such as paywalls, insufficient capacity, and information overload play an important role in determining what scientific information managers have access and attend to. Additionally, characteristics of managers themselves also influence what scientific information they prioritize and implement. Specific factors likely…
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