Research Database
Displaying 41 - 60 of 353
Smoldering of Wood: Effects of Wind and Fuel Geometry
Year: 2024
Large and downed woody fuels remaining behind a wildfire’s flame front tend to burn in a smoldering regime, producing large quantities of toxic gases and particulate emissions, which deteriorates air quality and compromises human health. Smoldering burning rates are affected by fuel type and size, the amount of oxygen reaching the surface, and heat losses to the surroundings. An external wind has the dual effects of bringing fresh oxidizer to the fuel surface and porous interior, while at the same time enhancing convective cooling. In this work, a series of experiments were conducted on…
Publication Type: Journal Article
Patterns, drivers, and implications of postfire delayed tree mortality in temperate conifer forests of the western United States
Year: 2024
Conifer forest resilience may be threatened by increasing wildfire activity and compound disturbances in western North America. Fire refugia enhance forest resilience, yet may decline over time due to delayed mortality—a process that remains poorly understood at landscape and regional scales. To address this uncertainty, we used high-resolution satellite imagery (5-m pixel) to map and quantify delayed mortality of conifer tree cover between 1 and 5 years postfire, across 30 large wildfires that burned within three montane ecoregions in the western United States. We used statistical models to…
Publication Type: Journal Article
Five social and ethical considerations for using wildfire visualizations as a communication tool
Year: 2024
BackgroundIncreased use of visualizations as wildfire communication tools with public and professional audiences—particularly 3D videos and virtual or augmented reality—invites discussion of their ethical use in varied social and temporal contexts. Existing studies focus on the use of such visualizations prior to fire events and commonly use hypothetical scenarios intended to motivate proactive mitigation or explore decision-making, overlooking the insights that those who have already experienced fire events can provide to improve user engagement and understanding of wildfire…
Publication Type: Journal Article
Moderating effects of past wildfire on reburn severity depend on climate and initial severity in Western US forests
Year: 2024
Rising global fire activity is increasing the prevalence of repeated short-interval burning (reburning) in forests worldwide. In forests that historically experienced frequent-fire regimes, high-severity fire exacerbates the severity of subsequent fires by increasing prevalence of shrubs and/or by creating drier understory conditions. Low- to moderate-severity fire, in contrast, can moderate future fire behavior by reducing fuel loads. The extent to which previous fires moderate future fire severity will powerfully affect fire-prone forest ecosystem trajectories over the next century. Further…
Publication Type: Journal Article
A Characterization of Fire-Management Research: A Bibliometric Review of Global Networks and Themes
Year: 2024
Although humans have interacted with wildfires for millennia, a science-based approach to fire management has evolved in recent decades. This paper reviews the development of fire-management research, focusing on publications that use this term in their title, abstract, or keywords identified on the Scopus platform. This resulted in the identification of 5624 documents published between 1973 and 2021. Publication rates have particularly increased since 2010. The paper details the characteristics of this body of the literature, including the main authors, institutions, and countries.…
Publication Type: Journal Article
When do contemporary wildfires restore forest structures in the Sierra Nevada?
Year: 2024
Background: Following a century of fire suppression in western North America, managers use forest restoration treatments to reduce fuel loads and reintroduce key processes like fire. However, annual area burned by wildfire frequently outpaces the application of restoration treatments. As this trend continues under climate change, it is essential that we understand the effects of contemporary wildfires on forest ecosystems and the extent to which post-fire structures are meeting common forest restoration objectives. In this study, we used airborne lidar to evaluate fire effects across yellow…
Publication Type: Journal Article
Landsat assessment of variable spectral recovery linked to post-fire forest structure in dry sub-boreal forests
Year: 2024
Forest disturbances such as wildfires can dramatically alter forest structure and composition, increasing the likelihood of ecosystem changes. Up-to-date and accurate measures of post-disturbance forest recovery in managed forests are critical, particularly for silvicultural planning. Measuring the live and dead vegetation post-fire is challenging because areas impacted by wildfire may be remote, difficult to access, and/or dangerous to survey. The difficulties of post-fire monitoring are compounded by the global increase in the frequency and severity of disturbances, as expansion of…
Publication Type: Journal Article
An optimization model to prioritize fuel treatments within a landscape fuel break network
Year: 2024
We present a mixed integer programming model for prioritizing fuel treatments within a landscape fuel break network to maximize protection against wildfires, measured by the total fire size reduction or the sum of Wildland Urban Interface areas avoided from burning. This model uses a large dataset of simulated wildfires in a large landscape to inform fuel break treatment decisions. Its mathematical formulation is concise and computationally efficient, allowing for customization and expansion to address more complex and challenging fuel break management problems in diverse landscapes. We…
Publication Type: Journal Article
Forest fire management, funding dynamics, and research in the burning frontier: A comprehensive review
Year: 2024
We indexed 8,970 scientific publications on forest fires in order to bridge the gap between research and policy discussions on forest fires. Journal articles and conference papers dominated the literature, with an emphasis on environmental science, agricultural and biological sciences, earth and planetary sciences, engineering, and computer science. Research in the field of fire has historically focused on terms such as "Forest Fire”, “Wildfire", and “Deforestation", but recent trends have highlighted terms such as "MODIS," "Artificial Intelligence," "Algorithm," "Satellite Data," and "…
Publication Type: Journal Article
A fast spectral recovery does not necessarily indicate post-fire forest recovery
Year: 2024
BackgroundClimate change has increased wildfire activity in the western USA and limited the capacity for forests to recover post-fire, especially in areas burned at high severity. Land managers urgently need a better understanding of the spatiotemporal variability in natural post-fire forest recovery to plan and implement active recovery projects. In burned areas, post-fire “spectral recovery”, determined by examining the trajectory of multispectral indices (e.g., normalized burn ratio) over time, generally corresponds with recovery of multiple post-fire vegetation types, including trees and…
Publication Type: Journal Article
Using focus groups for knowledge sharing: Tracking emerging pandemic impacts on USFS wildland fire operations
Year: 2024
In early 2020 the US Forest Service (USFS) recognized the need to gather real-time information from its wildland fire management personnel about their challenges and adaptations during the unfolding COVID-19 pandemic. The USFS conducted 194 virtual focus groups to address these concerns, over 32 weeks from March 2020 to October 2020. This management effort provided an opportunity for an innovative practice-based research study. Here, we outline a novel methodological approach (weekly, iterative focus groups, with two-way communication between USFS staff and leadership), which culminated in a…
Publication Type: Journal Article
Fuel constraints, not fire weather conditions, limit fire behavior in reburned boreal forests
Year: 2024
Fire frequency in boreal forests has increased via longer burning seasons, drier conditions, and higher temperatures. However, fires have historically self-regulated via fuel limitations, mediating the effects of changes in climate and fire weather. Early post-fire boreal forests (10–15 years postfire) are often dominated by mixed conifer-broadleaf or broadleaf regeneration, considered less flammable due to the higher foliar moisture of broadleaf trees and shrubs compared to their more intact conifer counterparts. However, the strength of self-regulation in the context of changing fire…
Publication Type: Journal Article
Tribal stewardship for resilient forest socio-ecosystems
Year: 2024
The Yurok Tribe, along with other tribal communities in northwest California, non-profit organizations, universities, and governmental agencies are working to restore forests and woodlands to be more resilient to wildfires, drought, pests and diseases. Our current work within ancestral Yurok territory is designing and evaluating effects of forest treatments including fuels reduction, tree harvesting, and intentional burning based upon indigenous knowledge and associated traditional stewardship practices. Central to these evaluations are the potential availability, quantity, and quality of…
Publication Type: Journal Article
Factors influencing wildfire management decisions after the 2009 US federal policy update
Year: 2024
Background
The decision making process undertaken during wildfire responses is complex and prone to uncertainty. In the US, decisions federal land managers make are influenced by numerous and often competing factors.
Aims
To assess and validate the presence of decision factors relevant to the wildfire decision making context that were previously known and to identify those that have emerged since the US federal wildfire policy was updated in 2009.
Methods
Interviews were conducted across the US while wildfires were actively burning to elucidate time-of-fire decision factors. Data…
Publication Type: Journal Article
Retention of highly qualified wildland firefighters in the Western United States
Year: 2024
Federal agencies responsible for wildland fire management face increasing needs for personnel as fire seasons lengthen and fire size continues to grow, yet federal agencies have struggled to recruit and retain firefighting personnel. While many have speculated that long seasons, challenging working conditions, and low wages contribute to recruitment and retention challenges, there has been…
Publication Type: Journal Article
Nonstructural carbohydrates explain post-fire tree mortality and recovery patterns
Year: 2024
Trees use nonstructural carbohydrates (NSCs) to support many functions, including recovery from disturbances. However, NSC’s importance for recovery following fire and whether NSC depletion contributes to post-fire delayed mortality are largely unknown. We investigated how fire affects NSCs based on fire-caused injury from a prescribed fire in a young Pinus ponderosa (Lawson & C. Lawson) stand. We assessed crown injury (needle scorch and bud kill) and measured NSCs of needles and inner bark (i.e., secondary phloem) of branches and main stems of trees subject to fire and at an…
Publication Type: Journal Article
Matching the scales of planning and environmental risk: an evaluation of Community Wildfire Protection Plans in the western US
Year: 2024
Theory predicts that effective environmental governance requires that the scales of management account for the scales of environmental processes. A good example is community wildfire protection planning. Plan boundaries that are too narrowly defined may miss sources of wildfire risk originating at larger geographic scales whereas boundaries that are too broadly defined dilute resources. Although the concept of scale (mis)matches is widely discussed in literature on risk mitigation as well as environmental governance more generally, rarely has the concept been rigorously quantified. We…
Publication Type: Journal Article
Prefire Drought Intensity Drives Postfire Recovery and Mortality in Pinus monticola and Pseudotsuga menziesii Saplings
Year: 2024
Increasing frequency of droughts and wildfire are sparking concerns that these compounded disturbance events are pushing forested ecosystems beyond recovery. An improved understanding of how compounded events affect tree physiology and mortality is needed given the reliance of fire management planning on accurate estimates of postfire tree mortality. In this study, we use a toxicological dose-response approach to quantify the impact of variable-intensity drought and fire on the physiology and mortality of Pinus monticola and Pseudotsuga menziesii saplings. We show that the…
Publication Type: Journal Article
Review of fuel treatment effects on fuels, fire behavior and ecological resilience in sagebrush (Artemisia spp.) ecosystems in the Western U.S.
Year: 2024
BackgroundSagebrush ecosystems are experiencing increases in wildfire extent and severity. Most research on vegetation treatments that reduce fuels and fire risk has been short term (2–3 years) and focused on ecological responses. We review causes of altered fire regimes and summarize literature on the longer-term effects of treatments that modify (1) shrub fuels, (2) pinyon and juniper canopy fuels, and (3) fine herbaceous fuels. We describe treatment effects on fuels, fire behavior, ecological resilience, and resistance to invasive annual grasses.ResultsOur review revealed tradeoffs in…
Publication Type: Journal Article
A Review of the Occurrence and Causes for Wildfires and Their Impacts on the Geoenvironment
Year: 2024
Wildfires have short- and long-term impacts on the geoenvironment, including the changes to biogeochemical and mechanical properties of soils, landfill stability, surface- and groundwater, air pollution, and vegetation. Climate change has increased the extent and severity of wildfires across the world. Simultaneously, anthropogenic activities—through the expansion of urban areas into wildlands, abandonment of rural practices, and accidental or intentional fire-inception activities—are also responsible for a majority of fires. This paper provides an overall review and critical appraisal of…
Climate Change and Fire, Fire Effects and Fire Ecology, Smoke and Air Quality, Soils and Woody Debris
Publication Type: Journal Article