Synthesis / Tech Report
This paper provides a synthesis of the key laboratory- and field-based observational studies focused on wildland fire and atmospheric turbulence connections that have been conducted from the early 1900s through 2021. Included in the synthesis are reports of anecdotal turbulence observations, direct measurements of ambient and fire-induced turbulent flow in laboratory and wildland environments, and remote sensing measurements of fire-induced turbulent plume dynamics. Although considerable progress has been made in advancing our understanding of the connections between atmospheric turbulence and wildland fire behavior and smoke dispersion, gaps in that understanding still exist and are discussed to conclude the synthesis.
Based on the existing literature, significant policy, regulatory, physical, and social barriers impede the use of managed wildfire. For fire managers, use of this strategy requires a complex decision-making process that includes consideration of institutional influences, operational considerations, fire outcomes, fire environment, perceived risk, and sociopolitical context. Some new treatment and response planning tools, such as Potential Operational Delineations (PODs), may facilitate greater use by easing some of these barriers and concerns. The scale of the wildfire challenge across the country suggests that, in the future, managed wildfire will play an essential role in managing fuels, reducing burn severity, enhancing suppression effectiveness, fostering forest resilience, and improving human’s ability to coexist with fire.
This study focused on alternative perspectives of successful fuel break use and the impact of fuel break configurations and management actions on fire risk across a given landscape. This was accomplished using a variety of methods. We used a survey of wildland fire management personnel to gather information on perceptions of fuel break effectiveness, data on fuel break use, and locations of the fuel breaks in question. Input was sought from
managers for fuel breaks throughout California. Managers who were responsible for a specific fuel break or were familiar with suppression operations on a fuel break were eligible to take this survey.
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The National Cohesive Wildland Fire Management Strategy has been officially updated.
New critical emphasis areas include:
-Workforce capacity, health, and wellbeing
-Diversity, equity, inclusion, and environmental justice
The Nature Conservancy and the Aspen Institute have spent the last year responding to this opportunity by hosting a series of workshops that sought input from all levels of government, Tribal Nations, the private sector, fire-prone communities, philanthropists, academics and other stakeholders, culminating in a Roadmap for Wildfire Resilience. The Roadmap concentrates on the two pillars of the 2014 National Cohesive Wildland Fire Management Strategy—resilient landscapes and fire-adapted communities—that require an investment commensurate with the third pillar—safe and effective wildfire response—to alter the current wildfire trajectory. This Roadmap weaves together lessons from decades of policy and practice with forward-thinking approaches that incorporate new technology and knowledge.
Using soil moisture information to better understand and predict wildfire danger: A review of recent developments and outstanding questions
This review summarises a growing body of evidence indicating that greater use of in situ, remotely sensed, and modelled soil moisture information in fire danger rating systems could lead to better estimates of dynamic live and dead herbaceous fuel loads, more accurate live and dead fuel moisture predictions, earlier warning of wildfire danger, and better forecasts of wildfire occurrence and size. Potential uses of soil moisture information in existing wildfire danger rating systems include (1) as a supplement or replacement for drought indices, (2) for live and (3) dead fuel moisture modelling, (4) for estimating herbaceous fuel curing, and (5) for estimating fuel loads. We identify key remaining research questions and note the logistical challenge of convincing wildfire professionals of the importance of soil moisture compared with more familiar wildfire danger metrics. While obstacles remain, the path forward is clear. Soil moisture information can and should be used to improve fire danger rating systems and contribute to more effective fire management for the protection of communities and ecosystems worldwide.
Fuel treatment effectiveness at the landscape scale: A review of simulation studies comparing treatment scenarios
Qualifying studies focused primarily but not exclusively on forested landscapes of the western USA and ranged in size from 200 to 3,400,000 ha. Most studies showed that scenarios with fuel reduction treatments had lower levels of wildfire compared to untreated scenarios. Damaging wildfire types decreased while beneficial wildfire increased as a result of treatments in most cases where these were differentiated. Wildfire outcomes were influenced by five dimensions of treatment design (extent, placement, size, prescription, and timing) and other factors beyond the treatments (weather, climate, fire/fuel attributes, and other management inputs). Studies testing factorial combinations showed that the relative importance of these factors varied across landscapes and contexts.
This report examines the needs for native plant restoration and other activities, provides recommendations for improving the reliability, predictability, and performance of the native seed supply, and presents an ambitious agenda for action. An Assessment of Native Seed Needs and the Capacity for Their Supply considers the various challenges facing our natural landscapes and calls for a coordinated public-private effort to scale-up and secure a cost-effective national native seed supply.
We systematically selected and reviewed 20 thinning studies to analyze key variables affecting machine productivity and harvesting costs. The average cost of forest thinning was lowest for a mechanized whole-tree thinning operation at $21.34/ton or $2,075/ha. Feller-bunchers and skidders showed the highest productivity in felling and extraction machines, respectively.
Here, we synthesized literature and conducted a survey of forest and fire managers to assess current understanding of how fire interacts with aspen stands, as well as to examine possible factors that influence fire occurrence, behavior, and severity in aspen communities. We found evidence that the presence of aspen reduces fire occurrence, fire behavior, and fire severity, but this effect is dependent on many factors, including the percentage of aspen vs conifers in the overstory, load and type of understory fuels, weather, and season. We did not find any quantitative management guidelines on how to create, maintain, or use aspen stands to reduce fire risk. The large gap between “common knowledge” and empirical evidence regarding aspen’s ability to inhibit fire requires further research.