Climate & Fire & Adaptation
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In this study, we combine climate projections with information on prescribed burning windows for ecoregions across the contiguous United States (CONUS) to compute the number of days when meteorological conditions allow for the safe and effective application of prescribed fire under present-day (2006–2015) and future climate (2051–2060) conditions. The resulting projections, which cover 57% of all vegetated area across the CONUS, indicate fewer days with conditions suitable for prescribed burning across ecoregions of the eastern United States due to rising maximum daily temperatures, but opportunities increase in the northern and northwestern United States, driven primarily by rising minimum temperatures and declining wind speeds.
Workshop information and registration.
The Bureau of Land Management and U.S. Forest Service will host a public workshop to present information and gather feedback on a range of topics regarding the science and management of pinyon and juniper woodlands, particularly mature and old-growth forests.
The workshop will occur May 8, 1-5 p.m. and May 9, 9 a.m.-5 p.m., 2024, at the Nugget Casino Resort, 1100 Nugget Ave., Sparks, NV, 89431. This event is part of BLM’s ongoing public comment period on pinyon and juniper woodlands, during which interested parties may also submit comments regarding management and conservation of pinyon and juniper ecosystems. Please see more information on how to comment below.
Workshop information and registration
Topics for the workshop will include classifying the various pinyon and juniper systems and understanding their geographic and population dynamics, methods for assessing woodland conditions, values associated with old-growth pinyon and juniper woodlands, management objectives and effectiveness, and opportunities for increasing climate resilience. Participants will have opportunities to engage and interact on a range of topics.
To attend the event, individuals are required to reserve a spot. This is a two-day workshop, but you must register for both days to attend. To attend on May 8, please register through the eventbrite portal for day one. To attend on May 9, please register through the eventbrite portal for day two.
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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.
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Increases in fire activity and changes in fire regimes have been documented in recent decades across the western United States. Climate change is expected to continue to exacerbate impacts to forested ecosystems by increasing the frequency, size, and severity of wildfires across the western United States (US). Warming temperatures and shifting precipitation patterns are altering western landscapes and making them more susceptible to high-severity fire. Increases in large patches of high-severity fire can result in significant impacts to landscape processes and ecosystem function and changes to vegetation structure and composition. In this synthesis, we examine the predicted climatic influence on fire regimes and discuss the impacts on fire severity, vegetation dynamics, and the interactions between fire, vegetation, and climate. We describe predicted changes, impacts, and risks related to fire with climate change and discuss how management options may mitigate some impacts of predicted fire severity, and moderate some impacts to forests, carbon, and vegetation changes post fire.
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This study uses tree cores gathered at three 4-hectare plots to make inferences about temporal aspects of tree recruitment in pine-dominated ecosystems of the California Sierra Nevada and the Sierra San Petro Martir in northwestern Mexico.
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This report highlights recent science on primary threats to persistent woodlands, identifies the role of changing climate, and highlights new efforts and approaches to develop management strategies focusing on building pinyon-juniper woodland health and climate resilience.
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In the face of this national challenge, Congress took bipartisan action to establish the Wildland Fire Mitigation and Management Commission through the 2021 Infrastructure Investment and Jobs Act. The legislation charged the 50-member Commission with the ambitious task of creating policy recommendations to address nearly every facet of the wildfire crisis, including mitigation, management, and postfire rehabilitation and recovery. Recognizing the urgency of the crisis, the Commission was given just a single year to conduct a sweeping review of the wildfire system and produce a comprehensive set of policy priorities.
Webinar registration.
Presenters: John Kim, USDA Forest Service
Alex Dye, Oregon State University
Description: Fire is an integral part of the disturbance regime of the Pacific Northwest’s moist temperate forests, but future fire patterns for this region remain uncertain. Using Energy Release Component (ERC) from 12 global climate models (GCM), we simulated thousands of plausible fire seasons with the fire spread model FSim for mid-21st century (2035-2064) for 5 northwestern pyromes. Projected changes to burn probability, fire size, and number of fires varied among pyromes and GCMs. The largest increases in burn probability and fire size occur in the cooler and wetter northern parts of the region (North Cascades, Olympics & Puget Lowlands) and Oregon West Cascades, with more moderate changes projected for the Washington West Cascades and Oregon Coast Range. We provide new insights into changing fire regimes characterized by the possibility of shifts towards more frequent large fires (especially > 40,000 ha), and shifts in seasonality, including more fires burning at the beginning of fall when extreme synoptic weather events have the potential to increase fire spread and fire’s impact on communities. Our work highlights the potential geographic variability in climate change effects in the Northwest, pointing to a rapid acceleration of fire in the coming decades for which current wildfire risk reduction strategies based on recent historical data, and not climate change or rare events, may be insufficient.
Risk assessments that account for climate change and rare events can help prepare expectations for how future changes to fire regimes will impact communities, and we explore these impacts using two different methods for the present and future time periods. We used building location data to evaluate community wildfire exposure and identify plausible disasters that are not based on mean-based statistical approaches. Nearly half of communities are vulnerable to a future disaster, and the magnitude of plausible disasters exceeds any recent historical events. Ignitions on private land are most likely to result in very high community exposure. We also conducted a screening of wildfire evacuation vulnerability for 696 Oregon and Washington rural towns. By combining the road and fire metrics, we score and rank all towns by their overall evacuation vulnerability. Many of the most vulnerable towns are located in remote, forested, mountainous terrain, where topographic relief constrains the available road network and high fuel loads increase wildfire hazard. Work is underway to characterize how the vulnerabilities shift by mid-century.
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From 1992–2020, 50% of recreation-caused ignitions in these three states occurred on lands managed by the U.S. Forest Service. The mean annual number of recreation-caused ignitions on national forests in the three states during this period was relatively stable, about 500, whereas recreation-caused ignitions within other jurisdictions decreased by 40%. Improved understanding of the impact of human and climatic factors on recreation-caused ignitions could provide valuable insights for shaping policy and management decisions. We found that mean annual densities of recreation-caused ignitions on national forests were 7 times greater within 1 km of designated campgrounds than >1 km from campgrounds, although 80% of recreation-caused ignitions occured >1 km from designated campgrounds. Ignition density in campgrounds increased non-linearly with overnight visitor density; a doubling of visitor density was associated with a ∼40% increase in ignitions. Large (≥4 ha) recreation-caused wildfires, especially those ignited in designated campgrounds, tended to occur concurrent with drought and 1–2 years after anomalously wet conditions. These results suggest that accounting for drought in implementation of fire restrictions, and targeting wildfire-prevention awareness to recreational users outside designated campgrounds, might reduce the likelihood of recreation-caused ignitions.
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The results project increases in the number of simultaneous 1000+ acre (4+ km2) fires in every part of the Western USA at multiple return periods. These increases are more pronounced at higher levels of simultaneity, especially in the Northern Rockies region, which shows dramatic increases in the recurrence of high return levels.