Research and Publications
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Forest treatments such as prescribed burns, mastication, and thinning are widely implemented across the western USA to reduce fuels and enhance wildfire resilience. These practices also influence snow accumulation and melt, which, in turn, affect snow storage and duration. Since many regions depend on seasonal snow for water resources, it is essential that forest management practices preserve or even enhance snow storage as a buffer against the impacts of climate change. To test the hypothesis that thinning and canopy gap creation can maximize snow storage, particularly on north-facing slopes, experimental forest treatments representing a range of thinning intensities were implemented on Cle Elum Ridge in the headwaters of the Yakima River Basin, Washington, USA. Ground-based snow observations, combined with pre-treatment (2021) and post-treatment (2023) snow-on lidar, show that canopy thinning increased snow depth and storage by 30% on north-facing slopes and by 16% on south-facing slopes. Snow depth was positively related to canopy openness, as measured by sky view fraction and canopy edge metrics, with stronger effects on north-facing slopes. In contrast, there was no clear relationship between snow depth and degree of thinning as measured by forest basal area, a common forestry metric used to plan treatment prescriptions. Using canopy edge metrics and sky view fraction relationships, we estimated the hydrologic benefit of thinning during 2023 at 12.3 acre-feet of water storage per 100 acres of north-facing forest and 5.1 acre-feet on south-facing slopes. These findings highlight the potential to incorporate hydrologic resilience as a co-benefit when planning fuel reduction strategies.
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When the Black Fire ignited in southwestern New Mexico in 2022, it had all the ingredients for disaster: record-high winds, extremely low humidity, and over 131,000 hectares (323,708 acres) of forest fuels to feed on. But something unexpected happened. Instead of becoming another catastrophic megafire, it burned mostly at low to moderate severity. The secret? The landscape had already experienced dozens of previous fires, both planned and natural, that helped tame the beast.
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To restore ecosystem health and reduce the negative impacts of wildfire, scientists and land managers argue that more prescribed fire is needed on the land. However, a lack of effectively trained personnel in the role of “burn boss” is a barrier to increasing safe and effective prescribed burning. Burn bosses are responsible for planning and implementing prescribed burns. There are two key contributors to the shortage of these positions: the first is retirement without replacing personnel, and the second is insufficient training mechanisms necessary to increase the number of personnel capable of responding to the challenges of conducting prescribed burns. This research brief summarizes a case study on the redesign of federal prescribed fire training, utilizing up-to-date understanding of adult learning to enhance training effectiveness.
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Networks of linear fuel treatments (Fuel Break Networks) are widely implemented in California, USA, fuel types to improve firefighter safety and facilitate fire containment. Despite frequent construction, landscape scale evaluations of their effectiveness with fire modeling remain limited in this region. This study presents a framework to assess how fuel break configuration, arrangement, and firefighter tactics influence fire control opportunities using a customized spatial metric for Uncontrollable Wildfire Risk (UWR). UWR combines outputs from fire modeling software widely available to fire and land management practitioners with suppression difficulty weights derived from previous literature. Fire spread simulations were conducted across four case study fuel break configurations in Southern California: Single Segment, Branching Network, Enclosed Network, and Multiple Segment Network. Three leverage scenarios (unstaffed, firebreak, and firing operations) were applied to each landscape. Linear mixed effects models and spatial analysis quantified the effects of distance from treatment, wind alignment, topography, treatment width, length, sinuosity, and proximity to other treatments on UWR. Results showed that increased leverage intensity consistently reduced UWR, while treatment geometry and spatial arrangement influenced risk reduction in some models. Notably, in some instances unstaffed fuel breaks increased burned area due to changes in fuel characteristics and subsequent fire behavior. This research highlights the importance of selecting appropriate outcomes for wildfire modeling evaluations of fuel break placement and operational utilization.
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While firebreaks remain an important tool in wildfire management, their reliability is constrained under extreme fire conditions. Future research should prioritize the development of spatially explicit, predictive models that integrate fire weather, fuel continuity, topography, and suppression efforts; the expansion of standardized, georeferenced databases on firebreak breaches; and assessments of ecological and social trade-offs. Advances in remote sensing and high-resolution fire monitoring offer opportunities to better evaluate performance and anticipate breaches. Integrating firebreaks into broader, adaptive wildfire management strategies—including fuel reduction, land-use planning, and community preparedness—will be critical to enhancing landscape resilience and maximizing the protective benefits of these structures.
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Many non-native invasive grass species increase wildfire activity and regenerate more quickly than native species. This invasive grass-fire cycle has severe negative consequences for ecosystems, creating a need to understand how different invasive grass species alter fuel characteristics and fire behavior, as well as effective treatments to control their abundance. To address these needs and increase fire and natural resource management preparedness, we performed a review and meta-analysis of recent (1985 – 2023) scientific literature. We focused on the Intermountain West, USA, where six dominant invasive grass species have already transformed ecosystems, including winter annuals – cheatgrass, medusahead, red brome, and Mediterranean grass; and summer perennials – buffelgrass and Lehmann’s lovegrass. Of the 204 selected articles, B. tectorum was the most well-studied species, treatment effectiveness was the most common study type, and more studies addressed fuel accumulation than fire characteristics. While initial reductions in B. tectorum following wildfire were followed by large increases, P. ciliare initially increased and then steadily declined, and other invasive grass species had no significant post-fire changes over time. Chemical treatments were more effective than other treatments for B. tectorum , P. ciliare , and Schismus spp. , though T. caput-medusae had a larger reduction with chemical treatments compared to the other species. In many cases, treatment effectiveness was enhanced when treatment types were combined or repeat treatments were conducted. Both B. tectorum and T. caput-medusae increased to pre-treatment conditions within 3 and 5 years, respectively, though there were no detectable trends for other species. Our results provide comprehensive comparisons of the effect of invasive grass species on fuel and fire characteristics, and much needed insight on effective strategies for reducing their impact to ecosystems.
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The impacts of climate shifts on ecosystems dominated by long-lived perennials are likely most pronounced during community reassembly after disturbances such as fire and confounded by interactions between disturbances and plant community composition. A 30-year-experimental hydroclimate manipulation of multiple sagebrush steppe communities was completely consumed by a 2019 wildfire, providing an opportunity to evaluate effects of precipitation deficit on ecosystem recovery. Ambient precipitation was doubled for 23 years via irrigation in winter or summer in grassland or shrub–steppe communities until 2016. Plots that had received irrigation thus experienced drought for three years preceding and continuing after the fire. These landscapes are vulnerable to invasion by exotic annuals such as Bromus tectorum L. (cheatgrass) that promote wildfire occurrence, which favors even greater invasion levels. Thus, we asked whether patterns of invasion after the compound disturbance of drought and fire related to the long-term pre-fire climate and plant community structure. Established theory led to the prediction that plant communities developed under wetter climates would have greater resistance to invasion. The most resistant plots were the most arid (that is, never irrigated control plots with no drought) which had the least pre-fire canopy cover of shrubs and nitrogen-fixing forbs and greater proportional cover of perennial bunchgrasses. Plots that developed under winter irrigation had greater cover of shrubs and N-fixing forbs, corresponding to pulses of plant available soil nitrogen that were 8.2-fold greater than pre-fire levels, compared to a 0.20-fold post-fire reduction in soil nitrogen observed in the ambient plots. Nitrogen pulses and invasion were most evident in the inter-canopy bare-soil patches (‘interspaces’) and were least evident where perennial grasses were most abundant. Long-term hydroclimate altered pre-fire plant community composition in ways that affected post-fire resistance to invasion such that the combined effects of fire and water deficit led to greater than expected invasion in wetter regions that are conventionally considered resistant to invasion and resilient to wildfire.
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We developed a non-parametric index of fire regime departure that quantifies distributional changes to fire regime attributes between time periods using the Earth Mover’s Distance. We used this departure metric to compare fire frequency and burn severity between historical (~1600–1880) and contemporary (1985–2021) time periods in western US forests. In addition, we compared the proposed metrics with a standard suite of measures of central tendency. Departure metrics based on measures of central tendency reported lower relative departures within frequent fire forests and higher relative departures within infrequent fire forests than the EMD-based method. We found that 89% of western US forests are experiencing less frequent and more severe wildfires than historical baselines. Large departures are associated with increased human land-use intensity, and landscapes prioritized by the Wildfire Crisis Mitigation plan are on average, more departed than non-priority landscapes.
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Wildland firefighters were aware of commonly identified hazards of their work, including smoke exposure, heat, and “human factors” such as fatigue and diet. Firefighters experience additional hazards that are rarely discussed. Routine but generally unacknowledged hazards include non-vegetation smoke, dust, chemicals in gear and equipment, and fuels and exhaust. Incident- and location-specific hazards include food and water quality concerns, hazards in government housing, and military, radiation, industrial, and mining hazards. Addressing these hazards is challenging because of both practical and cultural barriers.
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Study highlights the mental health risks of conducting wildfire research, in which both direct and secondary traumatic experiences can often be compounded by feelings of climate anxiety and ecological grief. We then reflect on our own experiences conducting interdisciplinary and community-engaged research in western North America during and after recent wildfire seasons, including the challenges of recognizing and addressing the psychological impacts of this work. Finally, we synthesize actionable recommendations, and share practical frameworks and tools, for individual researchers, supervisors, and institutions to support researcher mental health and wellbeing in wildfire-related research.