Fuels & Fuel Treatments
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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.
Webinar recording.
Webinar sessions will be half presentation and half question and answer. All presenters are scientists at the Rocky Mountain Research Station.
Fuel and restoration treatments seeking to mitigate the likelihood of uncharacteristic high-severity wildfires in forests with historically frequent, low-severity fire regimes are increasingly common, but long-term treatment effects on fuels, aboveground carbon, plant community structure, ecosystem resilience, and other ecosystem attributes are understudied. We present 20-year responses to thinning and prescribed burning treatments commonly used in dry, low-elevation forests of the western United States from a long-term study site in the Northern Rockies that is part of the National Fire and Fire Surrogate Study. We provide a comprehensive synthesis of short-term (<4 years) and mid-term (<14 years) results from previous findings. We then place these results in the context of a mountain pine beetle (MPB; Dendroctonus ponderosae) outbreak that impacted the site 5–10 years post-treatment and describe 20-year responses to assess the longevity of restoration and fuel reduction treatments in light of the MPB outbreak. Thinning treatments had persistently lower forest density and higher tree growth, but effects were more pronounced when thinning was combined with prescribed fire. The thinning +prescribed fire treatment had the additional benefit of maintaining the highest proportion of ponderosa pine (Pinus ponderosa) for overstory and regeneration. No differences in understory native plant cover and richness or exotic species cover remained after 20 years, but exotic species richness, while low relative to native species, was still higher in the thinning+prescribed fire treatment than the control
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Fuel-treatments targeting shrubs and fire-prone exotic annual grasses (EAGs) are increasingly used to mitigate increased wildfire risks in arid and semiarid environments, and understanding their response to natural factors is needed for effective landscape management. Using field-data collected over four years from fuel-break treatments in semiarid sagebrush-steppe, we asked 1) how the outcomes of EAG and sagebrush fuel treatments varied with site biophysical properties, climate, and weather, and 2) how predictions of fire behavior using the Fuel Characteristic Classification System fire model related to land-management objectives of maintaining fire behavior expected of low-load, dry-climate grasslands. Generalized linear mixed effect modeling with build-up model selection was used to determine best-fit models, and marginal effects plots to assess responses for each fuel type. EAG cover decreased as antecedent-fall precipitation increased and increased as antecedent-spring temperatures and surface soil clay contents increased. Herbicides targeting EAGs were less effective where pre-treatment EAG cover was >40 % and antecedent spring temperatures were >9.5 °C. Sagebrush cover was inversely related to soil clay content, especially where clay contents were >17 %. Predicted fire behavior exceeded management objectives under 1) average fire weather conditions when EAG or sagebrush cover was >50 % or >26 %, respectively, or 2) extreme fire weather conditions when EAG or sagebrush cover was >10 % or >8 %, respectively. Consideration of the strong effects of natural variability in site properties and antecedent weather can help in justifying, planning and implementing fuel-treatments.
You’re invited to join this USGS-led workshop developing Ecological Site Group State and Transition Models with a focus on Fire and Fuels across the upper Colorado Plateau. There is no registration or attendance fee. Please fill out this form to be included in future emails with details and pre-workshop materials.
Dates and Locations
Salt Lake City, UT – Feb 20 (12:30pm – 5:30pm) & 21 (8:30am – 12pm)
Wallace F. Bennett Federal Building, 125 State St. SLC, UT
Denver CO – Feb 22 (12:30pm – 5:30pm) & 23 (8:30am – 12pm)
Federal Center in Lakewood, CO
We will be covering an update from the previous year’s workshop on fire and fuels mapping across the Upper Colorado Plateau in Utah and Colorado using Ecological Site Groups. This will include updated field data collection, updated mapping efforts of current ecological states based on statistical clustering and identification of state transitions. Participants of this year’s workshop will be asked to help us identify potential options for desired conditions for the state and transition models based on the population of ecological states. We need your feedback on our results This will include hindcasting our state maps from 1984 to 2022 and analyzing state-change temporally and spatially with respect to land-use, fire, and climate. If you’d like a refresher on Ecological Site Groups and our developing of ESG State and Transition Models here is a short YouTube video from Anna Knight highlighting the overall process. Previous workshop attendance is NOT required.
More information, contact: Tara Bishop (tbishop@uvu.edu) or Mike Duniway (mduniway@usgs.gov)
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This study found three primary themes across relevant legislative proposals: (1) reforms to simplify permitting and regulatory approval processes (primarily in Australia); (2) efforts to mitigate the risk of legal liability for escaped burns (primarily in California); and (3) recent recognition of and support for cultural burns (primarily in California).
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Potential Operational Delineations (PODs) a strategic collaborative spatial wildfire planning framework and decision support tool for wildfire response and mitigation. Background, primer, and use of sections included.
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This study found that Potential Wildfire Operational Delineations (PODs) were helpful for validating fuels treatment plans and supporting communication among agency staff, and with private landowners and collaborators. Challenges included lack of technical knowledge and skills, unclear leadership direction, potential misalignment with other forest management goals and community and agency buy-in to using PODs.
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Reducing PODs (potential operational delineations) to a network of suppression-focused fuel breaks may dilute the intent and diminish the richness of the framework. Using PODs and fuel breaks to perpetuate fire exclusion is not likely to be effective and may set us up for failure. In many forest types, we may need to rethink design of fuel breaks along POD boundaries to support expansion of proactive use of fire.
Save the date flyer.
In-person attendance is full, but stay tuned for some post-event resources and recordings.