Research Database
Displaying 81 - 100 of 231
An aridity threshold model of fire sizes and annual area burned in extensively forested ecoregions of the western USA
Year: 2023
Wildfire occurrence varies among regions and through time due to the long-term impacts of climate on fuel structure and short-term impacts on fuel flammability. Identifying the climatic conditions that trigger extensive fire years at regional scales can enable development of area burned models that are both spatially and temporally robust, which is crucial for understanding the impacts of past and future climate change. We identified region-specific thresholds in fire-season aridity that distinguish years with limited, moderate, and extensive area burned for 11 extensively forested ecoregions…
Publication Type: Journal Article
Incorporating pyrodiversity into wildlife habitat assessments for rapid post-fire management: A woodpecker case study
Year: 2023
Spatial and temporal variation in fire characteristics—termed pyrodiversity—areincreasingly recognized as important factors that structure wildlife communitiesin fire-prone ecosystems, yet there have been few attempts to incorporatepyrodiversity or post-fire habitat dynamics into predictive models of animaldistributionsandabundancetosupportpost-firemanagement.Weusetheblack-backed woodpecker—a species associated with burned forests—as a case study todemonstrate a pathway for incorporating pyrodiversity into wildlife habitatassessments for adaptive management. Employing monitoring data (2009–…
Publication Type: Journal Article
The persistence of smoke VOCs indoors: Partitioning, surface cleaning, and air cleaning in a smoke-contaminated house
Year: 2023
Wildfires are increasing in frequency, raising concerns that smoke can permeate indoor environments and expose people to chemical air contaminants. To study smoke transformations in indoor environments and evaluate mitigation strategies, we added smoke to a test house. Many volatile organic compounds (VOCs) persisted days following the smoke injection, providing a longer-term exposure pathway for humans. Two time scales control smoke VOC partitioning: a faster one (1.0 to 5.2 hours) that describes the time to reach equilibrium between adsorption and desorption processes and a slower one (4.8…
Publication Type: Journal Article
Avoided wildfire impact modeling with counterfactual probabilistic analysis
Year: 2023
Assessing the effectiveness and measuring the performance of fuel treatments and other wildfire risk mitigation efforts are challenging endeavors. Perhaps the most complicated is quantifying avoided impacts. In this study, we show how probabilistic counterfactual analysis can help with performance evaluation. We borrow insights from the disaster risk mitigation and climate event attribution literature to illustrate a counterfactual framework and provide examples using ensemble wildfire simulations. Specifically, we reanalyze previously published fire simulation data from fire-prone landscapes…
Publication Type: Journal Article
Long-term mortality burden trends attributed to black carbon and PM2·5 from wildfire emissions across the continental USA from 2000 to 2020: a deep learning modelling study
Year: 2023
Background
Long-term improvements in air quality and public health in the continental USA were disrupted over the past decade by increased fire emissions that potentially offset the decrease in anthropogenic emissions. This study aims to estimate trends in black carbon and PM2·5 concentrations and their attributable mortality burden across the USA.
Methods
In this study, we derived daily concentrations of PM2·5 and its highly toxic black carbon component at a 1-km resolution in the USA from 2000 to 2020 via deep learning that integrated big data from satellites, models, and surface…
Publication Type: Journal Article
Evaluating the potential role of federal air quality standards in constraining applications of prescribed fire in the western United States
Year: 2023
Prescribed fire is a useful tool for building resilient landscapes in fire-prone areas across the globe. In the western U.S., prescribed fire is employed by federal, state, and Tribal land managers and planned during particular meteorological and air quality conditions to manage air quality impacts. As agencies prepare to plan and permit more prescribed fire, an ongoing question will be whether existing air quality conditions constrain the potential for more prescribed fire. We performed a set of spatial and statistical analyses to evaluate how prescribed burns are potentially constrained by…
Publication Type: Journal Article
Exploring and Testing Wildfire Risk Decision-Making in the Face of Deep Uncertainty
Year: 2023
We integrated a mechanistic wildfire simulation system with an agent-based landscape change model to investigate the feedbacks among climate change, population growth, development, landowner decision-making, vegetative succession, and wildfire. Our goal was to develop an adaptable simulation platform for anticipating risk-mitigation tradeoffs in a fire-prone wildland–urban interface (WUI) facing conditions outside the bounds of experience. We describe how five social and ecological system (SES) submodels interact over time and space to generate highly variable alternative futures even within…
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
Metal toxin threat in wildland fires determined by geology and fire severity
Year: 2023
Accentuated by climate change, catastrophic wildfires are a growing, distributed global public health risk from inhalation of smoke and dust. Underrecognized, however, are the health threats arising from fire-altered toxic metals natural to soils and plants. Here, we demonstrate that high temperatures during California wildfires catalyzed widespread transformation of chromium to its carcinogenic form in soil and ash, as hexavalent chromium, particularly in areas with metal-rich geologies (e.g., serpentinite). In wildfire ash, we observed dangerous levels (327-13,100 µg kg−1) of reactive…
Publication Type: Journal Article
Performance of Fire Danger Indices and Their Utility in Predicting Future Wildfire Danger Over the Conterminous United States
Year: 2023
Predicting current and future wildfire frequency and size is central to wildfire control and management. Multiple fire danger indices (FDIs) that incorporate weather and fuel conditions have been developed and utilized to support wildfire predictions and risk assessment. However, the scale-dependent performance of individual FDIs remains poorly understood, which leads to large uncertainty in the estimated fire sizes under climate change. Here, we calculate four commonly used FDIs over the conterminous United States using high-resolution (4 km) climate and fuel data sets for the 1984–2019…
Publication Type: Journal Article
Comparing particulate morphology generated from human-made cellulosic fuels to natural vegetative fuels
Year: 2022
Background: In wildland–urban interface (WUI) fires, particulates from the combustion of both natural vegetative fuels and engineered cellulosic fuels may have deleterious effects on the environment. Aims: The research was conducted to investigate the morphology of the particulate samples generated from the combustion of oriented strand board (OSB). Findings were compared to the particulate samples collected from the combustion of noble-fir branches. Methods: The exposure conditions were varied to induce either smouldering combustion or flaming combustion of the specimens. Particulate samples…
Publication Type: Journal Article
Comparing particulate morphology generated from human- made cellulosic fuels to natural vegetative fuels
Year: 2022
Background: In wildland–urban interface (WUI) fires, particulates from the combustion of both natural vegetative fuels and engineered cellulosic fuels may have deleterious effects on the environment. Aims: The research was conducted to investigate the morphology of the particulate samples generated from the combustion of oriented strand board (OSB). Findings were compared to the particulate samples collected from the combustion of noble-fir branches. Methods: The exposure conditions were varied to induce either smouldering combustion or flaming combustion of the specimens. Particulate samples…
Publication Type: Journal Article
Comparing smoke emissions and impacts under alternative forest management regimes
Year: 2022
Smoke from wildfires has become a growing public health issue around the world but especially in western North America and California. At the same time, managers and scientists recommend thinning and intentional use of wildland fires to restore forest health and reduce smoke from poorly controlled wildfires. Because of the changing climate and management paradigms, the evaluation of smoke impacts needs to shift evaluations from the scale of individual fire events to long-term fire regimes and regional impacts under different management strategies. To confront this challenge, we integrated…
Publication Type: Journal Article
Lifestyle and environmental factors may induce airway and systemic inflammation in firefighters
Year: 2022
Health status depends on multiple genetic and non-genetic factors. Nonheritable factors (such as lifestyle and environmental factors) have stronger impact on immune responses than genetic factors. Firefighters work is associated with exposure to air pollution and heat stress, as well as: extreme physical effort, mental stress, or a changed circadian rhythm, among others. All these factors can contribute to both, short-term and long-term impairment of the physical and mental health of firefighters. Increased levels of some inflammatory markers, such as pro-inflammatory cytokines or C-reactive…
Publication Type: Journal Article
Multi-Objective Scheduling of Fuel Treatments to Implement a Linear Fuel Break Network
Year: 2022
We developed and applied a spatial optimization algorithm to prioritize forest and fuel management treatments within a proposed linear fuel break network on a 0.5 million ha Western US national forest. The large fuel break network, combined with the logistics of conducting forest and fuel management, requires that treatments be partitioned into a sequence of discrete projects, individually implemented over the next 10–20 years. The original plan for the network did not consider how linear segments would be packaged into projects and how projects would be prioritized for treatments over time,…
Publication Type: Journal Article
Strategies to reduce wildfire smoke in frequently impacted communities in south-western Oregon
Year: 2022
Background: Efforts to mitigate the adverse effects of wildfire smoke have focused on modifying human behaviour to minimise individual exposure, largely accomplished by providing smoke forecasts, monitoring, and consistent public messaging. Aims: To identify a strategy to reduce the amount of wildfire smoke in frequently impacted communities. Methods: We identify frequent air pathways that transport smoke into five communities in south-western Oregon. We present a case study comparing the potential change in the 24-h average PM2.5 concentration between fuels burned during a wildfire which are…
Publication Type: Journal Article
Evaluating Satellite Fire Detection Products and an Ensemble Approach for Estimating Burned Area in the United States
Year: 2022
Fire location and burning area are essential parameters for estimating fire emissions. However, ground-based fire data (such as fire perimeters from incident reports) are often not available with the timeliness required for real-time forecasting. Fire detection products derived from satellite instruments such as the GOES-16 Advanced Baseline Imager or MODIS, on the other hand, are available in near real-time. Using a ground fire dataset of 2699 fires during 2017–2019, we fit a series of linear models that use multiple satellite fire detection products (HMS aggregate fire product, GOES-16,…
Publication Type: Journal Article
Designing forest restoration projects to optimize the application of broadcast burning
Year: 2022
Active forest restoration programs on western US national forests face multiple challenges to meet their broad ecological goals while designing projects that generate sufficient revenue to build and maintain private forest management capacity needed to expand the scale and scope of treatments. We explored ways to design projects where admixing of treatments along gradients of dry and moist mixed conifer forest types could maximize financial viability while including substantial area where broadcast burning could be applied in conjunction with other treatments. In general, we found that…
Publication Type: Journal Article
More smoke today for less smoke tomorrow? We need to better understand the public health benefits and costs of prescribed fire
Year: 2022
Rapidly scaling up the use of prescribed fire is being promoted as an important pathway for reducing the growing damages of wildfire events in the United States, including limiting the health impacts from smoke emissions. However, we do not currently have the science needed to understand how the health impacts associated with prescribed fire smoke in the present compare to wildfire smoke exposure in the future. In particular, we lack an understanding of how the potential long-term public health benefits of prescribed fire on future wildfire smoke and health impacts compare to prescribed fire’…
Publication Type: Journal Article
Sand and fire: applying the sandpile model of self-organised criticality to wildfire mitigation
Year: 2022
Background: Prescribed burns have been increasingly utilised in forest management in the past few decades. However, their effectiveness in reducing the risk of destructive wildfires has been debated. The sandpile model of self-organised criticality, first proposed to model natural hazards, has been recently applied to wildfire research for describing a negative linear relationship between the logarithm of fire size, in area burned, and the logarithm of fire incidence number of that size. Aims: We demonstrate the applicability of the sandpile model to an understanding of wildfire incidence and…
Publication Type: Journal Article