Fuels & Fuel Treatments
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Increased understanding of how mechanical thinning, prescribed burning, and wildfire affect subsequent wildfire severity is urgently needed as people and forests face a growing wildfire crisis. In response, we reviewed scientific literature for the US West and completed a meta-analysis that answered three questions: (1) How much do treatments reduce wildfire severity within treated areas? (2) How do the effects vary with treatment type, treatment age, and forest type? (3) How does fire weather moderate the effects of treatments? We found overwhelming evidence that mechanical thinning with prescribed burning, mechanical thinning with pile burning, and prescribed burning only are effective at reducing subsequent wildfire severity, resulting in reductions in severity between 62% and 72% relative to untreated areas. In comparison, thinning only was less effective – underscoring the importance of treating surface fuels when mitigating wildfire severity is the management goal. The efficacy of these treatments did not vary among forest types assessed in this study and was high across a range of fire weather conditions. Prior wildfire had more complex impacts on subsequent wildfire severity, which varied with forest type and initial wildfire severity. Across treatment types, we found that effectiveness of treatments declined over time, with the mean reduction in wildfire severity decreasing more than twofold when wildfire occurred greater than 10 years after initial treatment. Our meta-analysis provides up-to-date information on the extent to which active forest management reduces wildfire severity and facilitates better outcomes for people and forests during future wildfire events.
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Predicted fire-moderation benefits over the first 4 years of fuel break implementation were modest and variable, but, generally, increases in exotic annual grasses and their associated fire risks were not observed. Nonetheless, ancillary evidence from shrublands would suggest that treatment-induced shifts from shrub to herbaceous fuel dominance are expected to improve conditions for active fire suppression in ways not readily represented in available fire models.
The SageSTEP research team invites you to join us for a tour of the Onaqui research site near Tooele, Utah on May 21, 2024. We will tour the SageSTEP (https://sagestep.org/) shrubland network, SageSTEP woodland network and NEON sites (https://www.neonscience.org/field-sites/onaq), hear results from the past 15 years of data collection, and discuss management needs and research priorities for the next decade. We are particularly interested in hearing management perspectives on areas of greatest future need. 2024 field tour flyer
Logistics
Tooele is less than an hour from SLC. Lodging options include the Holiday Inn and Best Western. We recommend SUV/Trucks, particularly if there is rain prior to the tour.
Meet at 8am on Tuesday, May 21 at the Holiday Inn in Tooele (Address: 1531 N Main St, Tooele, UT 84074) to carpool/caravan to the Onaqui site. We plan to return to Tooele by 5pm. Please bring adequate food/water and be prepared to be outside all day.
There will be a no-host dinner on Monday, May 20 at 6 pm for any who can join.
Please RSVP to Lisa Ellsworth at: lisa.ellsworth@oregonstate.edu
Burn Plan Event information and registration.
Event flyer to forward to others.
Join us in the field to discuss prescription burn planning, treatments, monitoring, and results with Duncan Leao, Steve Howell, and Ali Paulson, USFS. This is an informal discussion open to all.
Webinar recording.
Sam “Jake” Price and Matt Germino, USGS Forest & Rangeland Ecosystem Science Center, present findings from their recent publication on the Soda Fire fuel breaks and how they might help to break the annual grass-fire cycle. Q&A to follow the presentation.
Webinar recording.
In this LANDFIRE Office Hour, USFS Research Ecologists, Jen Costanza and Matt Reeves walk viewers through the USDA Forest Service’s Resource Planning Act (2020) Assessment, with a focus on how LANDFIRE data supports understanding of recent and future drought exposure for rangeland vegetation types across the western U.S. The also discuss emerging technologies for evaluating vegetative drought response and fuels management reliant on several forms of LANDFIRE data.
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This review revealed tradeoffs in woody fuel treatments between reducing canopy fuels vs. increasing understory herbaceous vegetation (fuels) and fire behavior. In pinyon-juniper expansion areas, all treatments decreased crown fire risk. Prescribed fire and cut and broadcast burn treatments reduced woody fuels long-term but had higher risk of invasion. Mechanical treatments left understory vegetation intact and increased native perennial plants. However, cut and leave treatments increased downed woody fuel and high-intensity wildfire risk, while cut and pile burn and mastication caused localized disturbances and annual grass invasion. Ecological outcomes depended on ecological resilience; sites with warm and dry conditions or depleted perennial native herbaceous species experienced lower recovery and resistance to invasive annual grasses. In invasive annual grass dominated areas, high-intensity targeted grazing reduced fine fuels but required retreatment or seeding; in intact ecosystems with relatively low shrub cover, dormant season targeted grazing reduced fine fuel and thus fire spread. Preemergent herbicides reduced annual grasses with differing effects in warm and dry vs. cool and moist environments.
Webinar recording.
Fire and land manager-focused panel discussion hosted by the USDA Forest Service Rocky Mountain Research Station
Webinar recording.
Sean Parks, USFS RMRS.
View article.
Wildfire frequency varied significantly across the sagebrush region, and our statistical model represented much of that variation. Biomass of annual and perennial grasses and forbs, which we used as proxies for fine fuels, influenced wildfire probability. Wildfire probability was highest in areas with high annual forb and grass biomass, which is consistent with the well-documented phenomenon of increased wildfire following annual grass invasion. The effects of annuals on wildfire probability were strongest in places with dry summers. Wildfire probability varied with the biomass of perennial grasses and forbs and was highest at intermediate biomass levels. Climate, which varies substantially across the sagebrush region, was also predictive of wildfire probability, and predictions were highest in areas with a low proportion of precipitation received in summer, intermediate precipitation, and high temperature.