Posts on pyrogeography
I recently had the pleasure of visiting Utah State University, where I gave two talks as part of the Ecology Center Seminar series. You can catch both talks below as well as a short radio interview that I did for the local NPR station.
Check out the NPR interview here.
Fire is an important part of maintaining some ecosystems but it can also be a catalyst for change. An illustration of this are the small but persistent shrub patches that dot pine forests across the Southwest US. These shrub patches were created by high-severity fires that killed the canopy, thus allowing resprouting species, such as Gambel oak to establish. But just how long these shrub patches can persist has not been clear.
Chris Guiterman and I used tree-rings and soil charcoal to identify the timing of high-severity fires that established three of the largest shrub patches in the Jemez Mountains of northern New Mexico. You can read more about it here.
The Southwest Fire Science Consortium webinar that I co-lead with Chris Toya and John Galvan from the Pueblo of Jemez Natural Resources Department is now available to stream on Youtube. Here I lay out the science and traditions behind centuries of sustainable Jemez (Hemish) fire management before Spanish colonialism. Chris and John put this in a cultural and contemporary context.
Come see me at the March 4 SW Fire Science Consortium webinar (noon MST). With colleagues from Jemez Pueblo, I will be talking about lessons for coexistence with wildfire from Native American fire management at an ancient wildland-urban interface.
As residential development continues into flammable landscapes, wildfires increasingly threaten homes, lives, and livelihoods in the so-called ‘wildland-urban interface’ or WUI. Although this problem seems distinctly modern, Native American communities have lived in WUI contexts for centuries. When carefully considered, the past offers valuable lessons for coexisting with wildfire, climate change, and related challenges. Here we show that ancestors of Native Americans from Jemez Pueblo used ecologically savvy intensive burning and wood collection to make their ancient WUI resistant to climate variability and extreme fire behavior. Learning from the past offers modern WUI communities more options for addressing contemporary fire challenges. Public-private-tribal partnerships for wood and fire management can offer paths forward to restore fire-resilient WUI communities.
I recently published an interdisciplinary paper in Proceedings of the National Academy of Sciences that documents centuries of sustainable wood and fire use by Hemish people (Ancestral Pueblo) in the Jemez Mountains of northern New Mexico. You can find the article here or on my publications page.
Roos, Christopher I., Thomas W. Swetnam, T.J. Ferguson, Matthew J. Liebmann, Rachel A. Loehman, John R. Welch, Ellis Q. Margolis, Christopher H. Guiterman, William C. Hockaday, Michael J. Aiuvalasit, Jenna Battillo, Joshua Farella, and Christopher A. Kiahtipes (2021). Native American Fire Management at an Ancient Wildland-Urban Interface in the Southwest United States. Proceedings of the National Academy of Sciences 118(4): e2018733118.
Many tree-ring and charcoal studies indicate that the period of fire suppression (the last 120+ years) is unique for its paucity of fire over multi-century to multi-millennial timescales in dry forests across the Western US. Nevertheless, there are still some scholars and environmentalists who suggest that fire behaviors (for example, fire intensity, or temperature for a given area) and impacts (for example, fire severity, or the degree of above ground biomass consumption or mortality) in modern fires that follow that fire free period are within the historical range of variability for the West. Tree ring and charcoal methods are generally unable to get at fire intensities of the past to evaluate the uniqueness of fire intensities from fire suppression and fuel accumulation today.
With colleagues at Utah State University, the University of Arizona, the US Geological Survey, Southern Methodist University, and Harvard University, I have just published an innovative application of archaeological luminescence dating to assess the consequences of fire suppression and fuel accumulation on fire intensity relative to a millennium or more of frequent surface fires. By using the heat sensitive luminescence signal from archaeological ceramics exposed to historical surface fires (documented in tree-ring records) and those exposed to a 2012 prescribed burn under mild weather conditions, we were able to isolate the impact of fire suppression-generated fuel buildup on fire intensity. All ceramics burned in the 2012 fire with modern fuels had their luminescence signal reset, indicating that they were heated high enough and long enough to free electrons from crystaline traps and reset the luminescence clock. In contrast, none of the ceramics exposed to at least 14 historically documented surface fires had any evidence of resetting, indicating that fire intensities (and duration) in modern fuels had no precedent since at least before the site was established roughly 900 years ago.
Add climate change to the scenario and the combustible situation with modern fuels requires urgent action.
Roos, Christopher I., Tammy M. Rittenour, Thomas W. Swetnam, Rachel A. Loehman, Kacy L. Hollenback, Matthew J. Liebmann, and Dana Drake Rosenstein
2020 Fire Suppression Impacts on Fuels and Fire Intensity in the Western US: Insights from Archaeological Luminescence Dating in Northern New Mexico. Fire 3:32.
Around the globe, anthropogenic burning regimes often involve burning very small patches at relatively high frequencies. This creates a fine-grained mosaic of post-fire succession communities that benefits many species and often promotes biodiversity. This anthropogenic pyrodiversity is often difficult to identify in the historical ecology of environments that already experience frequent fires. Is this a weakness of paleofire methods? Is it an inherent problem in identifying fire regime differences that are relatively low-contrast?
In a recent paper with Grant Williamson and David Bowman in the journal Fire, I explore these issues with a simple cellular model of varying fire regimes and simulated fire-scar tree-ring records. Although anthropogenic pyrodiversity is not necessarily invisible in paleofire records, it is much easier to identify when paleofire and cultural information are integrated.
Roos, Christopher I., Grant W. Williamson, and David M.J.S. Bowman (2019) Is Anthropogenic Pyrodiversity Invisible in Paleofire Records? Fire, 2, 42.
Tribal communities and their traditional wisdom play an important role in fire management of our forests and rangelands today and into the future.
In the wake of the devastating 2018 fire season in California, I penned a guest column for the Albuquerque Journal on the lessons from the past to coexist with wildfire today. Ancestors of Native American residents of Jemez Pueblo lived sustainably in fire-prone Southwestern Ponderosa Pine forests for centuries. I have been fortunate to work with tribal members from Jemez Pueblo in an interdisciplinary research project to document fire and human history in their ancestral landscape.
We tend to treat our contemporary fire problems as uniquely modern ones. This overlooks the thousands of years of experience that indigenous communities have with fire on their lands. We have a lot to learn from the past. We should look to interdisciplinary environmental archaeology and the traditional ecological knowledge still held in these native communities today to help us make better decisions as our forests and communities are transformed by fire risk on a warming planet.
This is a Throwback Thursday post to share the video of a public talk I gave as part of the Archaeology Southwest Archaeology Cafe series in Tucson in 2016. Here I talk about my work in Arizona documenting the benefits of indigenous burning on the long-term resilience of Southwestern forests.