Fire History
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Human-dominated pyromes (85% mean anthropogenic ignitions), with moderate fire size, area burned, and intensity, covered 59% of CONUS, primarily in the East and East Central. Physically dominated pyromes (47% mean anthropogenic ignitions) characterized by relatively large (average 439 mean annual ha per 50 km pixel) and intense (average 75 mean annual megawatts/pixel) fires occurred in 14% of CONUS, primarily in the West and West Central. The percent of anthropogenic ignitions increased over time in all pyromes (0.5–1.7% annually). Higher fire frequency was related to smaller events and lower FRP, and these relationships were moderated by vegetation, climate, and ignition type. Notably, a spatial mismatch between our derived modern pyromes and both ecoregions and historical fire regimes suggests other major drivers for modern U.S. fire patterns than vegetation-based classification systems. This effort to delineate modern U.S. pyromes based on fire observations provides a national-scale framework of contemporary fire regions and may help elucidate patterns of change in an uncertain future.
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The Wildland Fire Trends Tool (WFTT) is a data visualization and analysis tool that calculates and displays wildfire trends and patterns for the western U.S. based on user-defined regions of interest, time periods, and ecosystem types. Users can use the tool to easily generate a variety of maps, graphs, and tabular data products that are informative for all levels of expertise. The WFTT provides information that can be used for a wide range of purposes, from helping to set agency fire management objectives to providing useful information to scientists, interested public, and the media.
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Monitoring Trends in Burn Severity (MTBS) includes all fires 1000 acres or greater in the west and 500 acres or greater in the east. The extent of coverage includes the continental U.S., Alaska, Hawai’i and Puerto Rico. MTBS data are freely available to the public.
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The average annual acreage burned by wildfires in the United States has increased over the past 30 years, affecting both federal and nonfederal lands. In this report, the Congressional Budget Office analyzes trends in wildfire activity; considers the effects of wildfires on the federal budget, the environment, people’s health, and the economy; and reviews forest-management practices meant to reduce the likelihood and seriousness of fire-related disasters.
Webinar recording.
Description: A recent collaboration by ~90 tree-ring and fire-scar scientists has resulted in the publication of the newly compiled North American Tree-Ring Fire-Scar Network* (NAFSN), which contains 2,562 sites, > 37,000 fire-scarred trees, and covers large parts of North America. In this publication, authors investigate the NAFSN in terms of geography, sample depth, vegetation, topography, climate, and human land use.
In this webinar presenters will present major findings from the publication, demonstrate data accessibility, highlight management applications, and discuss future steps planned for the NAFSN.
Presenter: Ellis Margolis, Research Ecologist, USGS Fort Collins Science Center and Dr. Christopher Guiterman, Cooperative Institute for Research in Environmental Sciences (CIRES) University of Colorado at Boulder, and NOAA’s National Centers for Environmental Information (NCEI)
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Description: In the southwestern US humans and ecosystems share a history of fire. Here, contemporary ecological patterns and processes that are thought to be natural may be highly influenced by past human land use legacies, at millennial time scales. The Jemez Mountains of central New Mexico provide a landscape laboratory rich in archaeological, ethnographic, and ecological data sets, within which to study the reciprocal, long-term interactions of humans and fire. Evidence from tree-rings, fire scars, and charcoal sediments suggests that prior to the 20th century, southwestern pine forests sustained frequent, low-severity surface fires. During a period of dense occupation in the 13th and 14th centuries, land and resource use may have significantly influenced forest structure, fuel properties, ignitions, and landscape fire dynamics. We developed complex spatial models, informed by rich archaeological, ethnographic, and dendroarchaeological data sets, to examine how plausible scenarios of human activities influenced forests and fire regimes ca. 1200-1900 CE. We found that prehistoric populations influenced forest and fire patterns at broad spatial scales, with feedbacks that maintained ecological resilience. Our results highlight the complexity and extent of long-term human-environment interactions and can be used as a comparative framework within which to evaluate the significance of contemporary and predicted anthropogenic impacts on landscapes and ecosystems.
Presenter: Rachel Loehman is a landscape and fire ecologist with the US Geological Survey. Her research focuses on the role of natural and anthropogenic disturbances in shaping ecological patterns and processes. Her current research projects include developing strategies for enhancing ecosystem and forest resilience to changing climate and disturbance regimes (western U.S.) and monitoring and modeling fire impacts to archaeological resources (southwestern U.S.).
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This study shows that extreme fire events such as seen in 2020 are not unknown historically, and what stands out as distinctly new is the increased number of large fires (defined here as > 10,000 ha) in the last couple years, most prominently in 2020. Nevertheless, there have been other periods with even greater numbers of large fires, e.g., 1929 had the second greatest number of large fires. In fact, the 1920’s decade stands out as one with many large fires.
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Conflagrations like the 1871 Peshtigo have reemerged as important threats across North America and around the world. Understanding the factors and the phenomena that produced the fire environment of that day is possible because of weather observations collected and recorded at the time and studies of extreme fire behavior that continue to this day. Recounting it should be a cautionary tale for our lives as we continue to live them.
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Our data revealed that ventenata frequency and cover increased on all plots. However, there was not significantly higher abundance in burned plots in any of the sampling years. In addition, ventenata abundance did not increase more in burned plots over time. Our findings suggest that, unlike cheatgrass, fire may not be a driving factor in the spread and increase of ventenata across the PNB Prairie. This finding has important implications for the management and control of ventenata, as well as the conservation of the PNB Prairie.
Webinar recording.
Dendrochronology: The trees that surround us have a story to tell, yet so many of us have no idea what that story is. What is dendrochronology? How old is the oldest recorded tree? Can trees get scars? Where are some of the oldest forests located? These are just some of the questions we aim to answer with our guest Dr. Justin DeRose, Assistant Professor of Silviculture and Applied Forest Ecology at Utah State University.