Research Database
Displaying 61 - 80 of 169
Ability of seedlings to survive heat and drought portends future demographic challenges for five southwestern US conifers
Year: 2023
Climate change and disturbance are altering forests and the rates and locations of tree regeneration. In semi-arid forests of the southwestern USA, limitations imposed by hot and dry conditions are likely to influence seedling survival. We examined how the survival of 1-year seedlings of five southwestern US conifer species whose southwestern distributions range from warmer and drier woodlands and forests (Pinus edulis Engelm., Pinus ponderosa Douglas ex C. Lawson) to cooler and wetter subalpine forests (Pseudotsuga menziesii (Mirb.) Franco, Abies concolor…
Publication Type: Journal Article
Prescribed Burns as a Tool to Mitigate Future Wildfire Smoke Exposure: Lessons for States and Rural Environmental Justice Communities
Year: 2023
Smoke from wildfires presents one of the greatest threats to air quality, public health, and ecosystems in the United States, especially in the West. Here we quantify the efficacy of prescribed burning as an intervention for mitigating smoke exposure downwind of wildfires across the West during the 2018 and 2020 fire seasons. Using the adjoint of the GEOS-Chem chemical transport model, we calculate the sensitivities of population-weighted smoke concentrations in receptor regions, including states and rural environmental justice communities, to fire emissions upwind of the receptors. We find…
Publication Type: Journal Article
Mechanical thinning restores ecological functions in a seasonally dry ponderosa pine forest in the inland Pacific Northwest, USA
Year: 2023
An increasingly important goal of federal land managers in seasonally dry forests of the western US is restoring forest resilience. In this study, we quantified the degree to which a thinning treatment in a dry forest of eastern Oregon restored aspects of forest resilience by focusing on key functional attributes of our study system. First, we measured several physiological responses of overstory trees that are associated with resilience, including radial growth, resin production, abundance of non-structural carbohydrates (NSC), and leaf area. Second, we investigated understory vegetation…
Publication Type: Journal Article
Social Vulnerability in USCommunities Affected by WildfireSmoke, 2011 to 2021
Year: 2023
Objectives. To describe demographic and social characteristics of US communities exposed to wildfire smoke.
Methods. Using satellite-collected data on wildfire smoke with the locations of population centers in the coterminous United States, we identified communities potentially exposed to light-, medium-, and heavy-density smoke plumes for each day from 2011 to 2021. We linked days of exposure to smoke in each category of smoke plume density with 2010 US Census data and community characteristics from the Centers for Disease Control and Prevention’s Social Vulnerability Index to describe…
Publication Type: Journal Article
Consistent spatial scaling of high-severity wildfire can inform expected future patterns of burn severity
Year: 2023
Increasing wildfire activity in forests worldwide has driven urgency in understanding current and future fire regimes. Spatial patterns of area burned at high severity strongly shape forest resilience and constitute a key dimension of fire regimes, yet remain difficult to predict. To characterize the range of burn severity patterns expected within contemporary fire regimes, we quantified scaling relationships relating fire size to patterns of burn severity. Using 1615 fires occurring across the Northwest United States between 1985 and 2020, we evaluated scaling relationships within fire…
Publication Type: Journal Article
Fire-regime variability and ecosystem resilience over four millennia in a Rocky Mountain subalpine watershed
Year: 2023
- Wildfires strongly influence forest ecosystem processes, including carbon and nutrient cycling, and vegetation dynamics. As fire activity increases under changing climate conditions, the ecological and biogeochemical resilience of many forest ecosystems remains unknown.
- To investigate the resilience of forest ecosystems to changing climate and wildfire activity over decades to millennia, we developed a 4800-year high-resolution lake-sediment record from Silver Lake, Montana, USA (47.360° N, 115.566° W). Charcoal particles, pollen grains, element concentrations and stable…
Publication Type: Journal Article
A comparison of smoke modelling tools used to mitigate air quality impacts from prescribed burning
Year: 2023
Background. Prescribed fire is a land management tool used extensively across the United States. Owing to health and safety risks, smoke emitted by burns requires appropriate manage- ment. Smoke modelling tools are often used to mitigate air pollution impacts. However, direct comparisons of tools’ predictions are lacking. Aims. We compared three tools commonly used to plan prescribed burning projects: the Simple Smoke Screening Tool, VSmoke and HYSPLIT. Methods. We used each tool to model smoke dispersion from prescribed burns conducted by the North Carolina Division of Parks and Recreation…
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
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
Cognition of feedback loops in a fire-prone social-ecological system
Year: 2022
Increasing wildfire severity highlights the need for large-scale shifts in management of fire-prone landscapes. While prior research has focused on cognitive biases, social norms, and institutional disincentives that limit reform, such factors are best understood as components of feedback loops that operate within complex adaptive systems. We evaluated the prominence and function of feedback loops embedded in cognitive maps—beliefs about patterns of causal relationships that drive system dynamics—elicited from a diverse cross-section of stakeholders in a fire-prone region in the U.S. West. We…
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
Oregon Wildfire Smoke Communications and Impacts: An Evaluation of the 2020 Wildfire Season
Year: 2022
Oregon Health Authority and the University of Oregon partnered to conduct a survey-based evaluation of wildfire smoke communications and impacts experienced by Oregon residents during the 2020 wildfire season. The purpose of this survey was to (1) understand how Oregonians respond to wildfire smoke and (2) provide an open-source evaluation tool and data to support wildfire smoke communication practitioners in Oregon.
Publication Type: Journal Article
Reimagine fire science for the anthropocene
Year: 2022
Fire is an integral component of ecosystems globally and a tool that humans have harnessed for millennia. Altered fire regimes are a fundamental cause and consequence of global change, impacting people and the biophysical systems on which they depend. As part of the newly emerging Anthropocene, marked by human-caused climate change and radical changes to ecosystems, fire danger is increasing, and fires are having increasingly devastating impacts on human health, infrastructure, and ecosystem services. Increasing fire danger is a vexing problem that requires deep transdisciplinary, trans-…
Publication Type: Journal Article
Increasing co-occurrence of fine particulate matter and ground-level ozone extremes in the western United States
Year: 2022
Wildfires and meteorological conditions influence the co-occurrence of multiple harmful air pollutants including fine particulate matter (PM2.5) and ground-level ozone. We examine the spatiotemporal characteristics of PM2.5/ ozone co-occurrences and associated population exposure in the western United States (US). The frequency, spatial extent, and temporal persistence of extreme PM2.5/ozone co-occurrences have increased significantly between 2001 and 2020, increasing annual population exposure to multiple harmful air pollutants by ~25 million person-days/year. Using a clustering methodology…
Publication Type: Journal Article
Wildfire, Smoke Exposure, Human Health, and Environmental Justice Need to be Integrated into Forest Restoration and Management
Year: 2022
Purpose of Review: Increasing wildfire size and severity across the western United States has created an environmental and social crisis that must be approached from a transdisciplinary perspective. Climate change and more than a century of fire exclusion and wildfire suppression have led to contemporary wildfires with more severe environmental impacts and human smoke exposure. Wildfires increase smoke exposure for broad swaths of the US population, though outdoor workers and socially disadvantaged groups with limited adaptive capacity can be disproportionally exposed. Exposure to wildfire…
Publication Type: Journal Article
Cultivating Collaborative Resilience to Social and Ecological Change: An Assessment of Adaptive Capacity, Actions, and Barriers Among Collaborative Forest Restoration Groups in the United States
Year: 2022
Collaboration is increasingly emphasized as a tool to realize national-level policy goals in public lands management. Yet, collaborative governance regimes (CGRs) are nested within traditional bureaucracies and are affected by internal and external disruptions. The extent to which CGRs adapt and remain resilient to these disruptions remains under-explored. Here, we distill insights from an assessment of the Collaborative Forest Landscape Restoration Program (CFLRP) projects and other CGRs. We asked (1) how do CGRs adapt to disruptions? and (2) what barriers constrained CGR resilience? Our…
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
Wildfire and climate change adaptation of western North American forests: a case for intentional management
Year: 2021
We review science-based adaptation strategies for western North American (wNA) forests that include restoring active fire regimes and fostering resilient structure and composition of forested landscapes. As part of the review, we address common questions associated with climate adaptation and realignment treatments that run counter to a broad consensus in the literature. These include the following: (1) Are the effects of fire exclusion overstated? If so, are treatments unwarranted and even counterproductive? (2) Is forest thinning alone sufficient to mitigate wildfire hazard? (3) Can forest…
Publication Type: Journal Article