Fire Ecology & Effects

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Proportion of forest area burned at high-severity increases with increasing forest cover and connectivity in western US

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High-severity burn area increased with increasing fuel availability and connectivity and decreased with increasing heterogeneity. In 2020, multiple large high-severity burn areas occurred in forests with high fuel availability, which only had small high-severity burn areas prior to 2020.

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Contemporary wildfires are more severe compared to the historical reference period in dry conifer forests in the West

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Study results indicate, that as a proportion of area burned, contemporary fires experienced 2.9 to 13.6 times more stand-replacing fire (depending on the ecoregion) compared to the pre-colonization period. Non-wilderness areas exhibit somewhat higher prevalence of stand-replacing fire, relative to the historical fire regime, than wilderness areas (where logging is prohibited). The relatively small difference between non-wilderness and wilderness suggests that fuel accumulation resulting from fire exclusion has played a larger role than historical logging activities on the prevalence of contemporary stand-replacing fire. Prescribed fires do not exhibit a higher prevalence of stand-replacing fire compared to the historical fire regime.

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Facing Fire: Aesthetics, Environment, and Policy in the West

Facing Fire: Aesthetics, Environment, and Policy in the West

The panel discussion was livestreamed and recorded by Utah Public Radio. View the recording here.

A cross-disciplinary panel with artists, policy makers, and a fire fighter to explore how we experience, perceive, respond, and research fire in the West. Following the discussion we will have a reception in the museum to see the new Facing Fire exhibition. Moderated by Brian Steed, PhD., Executive Director, Janet Quinney Lawson Institute for Land, Water, and Air.

Panelists:
Jamie Barnes, Director of Utah Division of Forestry, Fire, and State Lands
Noah Berger, Wildlife Photographer in Facing Fire
Samantha Fields, Painter in Facing Fire
Eric LaMalfa, PhD., Ecologist
Wade Snyder, Deputy State Fire Management Officer and Former Alta Hotshot

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Trends, impacts, and cost of catastrophic and frequent wildfires in the sagebrush biome

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More frequent, larger, and severe wildfires necessitate greater resources for fire-prevention, fire-suppression, and postfire restoration activities, while decreasing critical ecosystem services, economic and recreational opportunities, and cultural traditions. Increased flexibility and better prioritization of management activities based on ecological needs, including commitment to long-term prefire and postfire management, are needed to achieve notable reductions in uncharacteristic wildfire activity and associated negative impacts. Collaboration and partnerships across jurisdictional boundaries, agencies, and disciplines can improve consistency in sagebrush-management approaches and thereby contribute to this effort. Here, we provide a synthesis on sagebrush wildfire trends and the impacts of uncharacteristic fire regimes on sagebrush plant communities, dependent wildlife species, fire-suppression costs, and ecosystem services. We also provide an overview of wildland fire coordination efforts among federal, state, and tribal entities.

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The REBURN model: Simulating system-level forest succession and wildfire dynamics

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Here, we present a detailed characterization of REBURN — a geospatial modeling framework designed to simulate reburn dynamics over large areas and long time frames. We interpret fire-vegetation dynamics for a large testbed landscape in eastern Washington State, USA. The landscape is comprised of common temperate forest and nonforest vegetation types distributed along broad topo-edaphic gradients. Each pixel in a vegetation type is represented by a pathway group (PWG), which assigns a specific state-transition model (STM) based on that pixel’s biophysical setting. STMs represent daily simulated and annually summarized vegetation and fuel succession, and wildfire effects on forest and nonforest succession. Wildfire dynamics are driven by annual ignitions, fire weather and topographic conditions, and annual vegetation and fuel successional states of burned and unburned pixels.

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Habitat-relationships reveal potential negative effects of conifer removal on a non-target species

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Our results indicate pinyon jay populations are declining within Bird Conservation Region 16. Jay density was positively associated with sagebrush cover, Palmer Drought Severity Index, and pinyon-juniper cover. Conversely, jay populations were negatively associated with Normalized Difference Vegetation Index (NDVI). We found higher pinyon jay densities within locations possessing both sagebrush and pinyon-juniper cover; conditions characteristic of phase I and II conifer encroachment which are preferentially targeted for conifer removal to restore sagebrush communities. Conifer removal, if conducted at locations with high pinyon jay densities, is therefore likely to negatively affect jay abundance.

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A review of methods used to link remotely sensed data with the Composite Burn Index

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Study findings largely reflect methods applied in North America – particularly in the western USA – due to the high number of studies in that region. We find the use of different methods across studies introduces variations
that make it difficult to compare outcomes. Additionally, the existing suite of comparative studies focuses on one or few of many possible sources of uncertainty. Thus, compounding error and propagation throughout the many decisions made during analysis is not well understood. Finally, we suggest a broad set of methodological information and key rationales for decision-making that could facilitate future reviews.

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Evaluating fireline effectiveness across large wildfire events in north-central Washington State

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Our study found that fire perimeter source and fireline buffer width had the largest impact on quantified fireline effectiveness metrics. Misclassification of firelines produced dramatic erroneous results which artificially increased the effectiveness and decreased suppression effort. High-severity fires were shown to be less effective across all fireline types and required higher suppression than most low- and moderate-severity fires.

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High-severity burned area and proportion exceed historic conditions in Sierra Nevada, CA, and adjacent ranges

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Although fire is a fundamental ecological process in western North American forests, climate warming and accumulating forest fuels due to fire suppression have led to wildfires that burn at high severity across larger fractions of their footprint than were historically typical. These trends have spiked upwards in recent years and are particularly pronounced in the Sierra Nevada–Southern Cascades ecoregion of California, USA, and neighboring states. We assessed annual area burned (AAB) and percentage of area burned at high and low-to-moderate severity for seven major forest types in this region from 1984 to 2020. We compared values for this period against estimates for the pre-Euro-American settlement (EAS) period prior to 1850 and against a previous study of trends from 1984 to 2009.

Fire smoke in western mtns.

The western fire problem – A story map of five regions with different fire challenges

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But over the past few decades, wildfires have worsened by almost every metric. It’s impossible to ignore this new consequence of environmental change. Fires are getting larger, more severe, more destructive and dangerous, and eliminating entire patches of forests, grasslands, and shrublands.

The combination of changing climate, extreme weather, land use, aggressive fire suppression policies, and wildland urban interface expansion have contributed to altered fire behavior regimes. And all of these past and current factors are converging in a big way in the western U.S. Today’s megafires pose an increasing threat to human health, infrastructure, natural resources, and ecosystem resilience.

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