Research Brief

In recent years, smoke from wildland fire has increased in duration and frequency and is a recognized public health risk. This has driven a corresponding need for more information on these topics and an increase in systematic reviews seeking to better understand the state of science and identify ongoing knowledge gaps. The goal of this document is to summarize recent review articles that synthesize the state of wildland fire smoke communication research. We provide a summary of primary themes and then list key findings by article. Please note that each review article encompasses multiple studies, and here we focus on the themes shared across the articles. The review articles and the studies they cover offer abundant additional information, nuance, and detail for those seeking a deeper understanding of the available research.

On 7 September 2020, strong winds in western Oregon ignited and spread many small fires, leading to multiple simultaneous megafires (fires > 404 km2) that burned across multiple land ownerships. These fires burned at differing severities, resulting in a range of post-fire riparian and freshwater conditions and an opportunity to evaluate aquatic and riparian responses to fire across ownerships that vary in elevation, forest stand age, and forest-management strategies. To better understand these dynamics, the authors in this study measured riparian overstory survival, LW, and coarse wood (wood in riparian areas), as well as in-stream physical, chemical, and biological variables to fire severity and pre-fire stand age in 24 streams in western Oregon from 8-11 months following multiple fires, including the Riverside, Beachie, and Holiday Farm Fires.

Biological disturbance agents (BDAs) can affect forest composition and structure in multiple ways, including by changing fuels in ways that affect fire risk and behavior. While some research has shown that BDAs can increase the likelihood and severity of wildfires, other research has shown the opposite. These opposing findings have led to confusion around the influence of BDAs on fuels and fire behavior, and uncertainty about the best ways to manage for their impacts in western fire-adapted forests. To better understand the complex relationships at play in how BDAs impact fuels and fire, authors of this article identified the major BDA groups in western coniferous U.S. forests and reviewed existing literature on these groups to conceptualize how BDA-affected fuels will influence fire risk and outcomes. The resulting conceptual framework provides a generalized approach for characterizing BDA outcomes on fuels over time and space, including expected impacts on fuels heterogeneity throughout a BDA groups’ life history. These expected fuels outcomes in turn help develop hypotheses for BDA effects on fire risk and severity.

The wildfires that ignited September 7-9, 2020 (collectively named the “Labor Day Fires”) on the west side of the Oregon Cascades (Westside) were a devastating reminder that these communities and forests are at risk from wildfires. The fires collectively burned more than 2.2 million acres, caused fatalities and billions of dollars in damage, placed more than 10% of the state’s residents under evacuation advisories, and created hazardous air quality conditions across the northwestern US. The fires left researchers, practitioners, and local residents questioning how to better expect and prepare for similar events in the future. The three articles summarized in this brief focused on the challenges of understanding and communicating about wildfire surprises and risk in Westside systems, and how to better predict where similar events might happen in the future. A fourth article summarizes the key meteorological drivers behind the Labor Day fires.

The Palouse Prairie is a highly endangered ecosystem found along the Idaho–Washington border. The Palouse Prairie intermixes with the imperiled ponderosa pine savanna along this border, making the ecotone between these communities particularly diverse and ecologically important. Unfortunately, like many grassland and savanna communities across North America and the world, this rich prairie–pine ecotone is now highly fragmented and degraded.

For this study, researchers conducted 54 key informant interviews across the 11 western states to investigate policy-relatedbarriers to prescribed fire on federal lands. In particular, they examined how laws, policies, and policy implementationaffect prescribed fire application, and identified common challenges to and opportunities for increasing application.

In this study, researchers examined print media coverage, data of burned homes, and demographic data of towns impacted by two major wildfires in Washington State. The Carlton Complex burned over 250,000 acres and hundreds of homes in the Methow Valley in 2014, becoming the largest wildfire in Washington’s history. In 2015, the fires that made up the Okanogan Complex burned over 300,000 acres in the same part of northcentral Washington, destroying hundreds more structures and resulting in three firefighter fatalities. Researchers investigated the topics that were prominent and that were ignored in the media coverage of these two wildfires. In particular, they examined media coverage related to wildfire risk and firefighter safety, and compared the locations focused on in the media coverage of the fires in relation to the locations with the greatest damage from the fires.

In this study, the authors characterized historical fire return intervals, seasonality, and relationships with local and regional factors for 13 sites representative of southwestern Oregon dry forests on ridges and midslopes in the Rogue Basin of the Klamath Ecoregion. They used dendrochronology (cross-dated fire-scars from trees) to develop fire histories. Then using a systematic literature review, the authors were able to link local fire histories to a regional dataset and evaluate the data relative to more intensively studied conifer/hardwood forest types in California.

In this study, researchers measured vegetation structure and fuel moisture (pre-burn), weather conditions, belowground heat dosages, and peak temperatures (during the burn), and burn severities and unburned refugia (post-burn) for paired morning and afternoon prescribed burns at each of ten prairie sites throughout the south Puget Sound in 2014.