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Tom Swetnam

@firescar.bsky.social

3.7K followers 1.3K following 72 posts

Tree-ring scientist, forest ecologist, forest fires, climate and human interactions. Regents Professor Emeritus Univ AZ; home in New Mexico.

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Tom Swetnam @firescar.bsky.social · Dec 11

My forthcoming book on natural and cultural history in my home landscape is now available for pre-order on the University of New Mexico Press website. To be published April 2025. Description, table of contents, and blurbs are also here.
www.unmpress.com/978082636775...

The Jemez Mountains

The Jemez Mountains are a quintessential New Mexico landscape. For centuries, Pueblo, Spanish, and Anglo cultures have mixed and melded here. Many ancient vi...

www.unmpress.com

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Botanical Society of America @botsocamerica.bsky.social · 13d

🔥🌱 From the #AJB Special Issue: “Understanding novel #ﬁre regimes using plant trait‐based approaches" 🌱🔥

#Sequoia and Sequoiadendron: Two paleoendemic megatrees with markedly different adaptive responses to recent high-severity fires

By Jon Keeley & @jgpausas.bsky.social

doi.org/10.1002/ajb2...

Although most trees in western USA conifer forests are killed by high intensity crown fires, most California coast redwoods survive by resprouting (photo by Jon Keeley, 2 years after the CZU Fire in Big Basin State Park).

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Dr. Crystal A. Kolden @pyrogeog.bsky.social · 6d

Published today: our new paper showing a 44-year trend of increasing global wildfire disasters (fatalities and economic losses) due to climate change-induced extreme weather. www.science.org/doi/10.1126/...

Climate-linked escalation of societally disastrous wildfires

Climate change and land mismanagement are creating increasingly fire-prone built and natural environments. However, despite worsening fire seasons, evidence is lacking globally for trends in socially ...

www.science.org

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Mike Dettinger @mdettinger.bsky.social · 19d

National Academies of Science panel finds that: The EPA was right in 2009 (when it found that climate change driven by society’s emissions of greenhouse gases are endangering human health & lives), and that everything we've learned since has only made it more right.

arstechnica.com/science/2025...

Despite congressional threat, National Academies releases new climate report

Things have changed since 2009: We’re more certain about the problems.

arstechnica.com

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Mike Dettinger @mdettinger.bsky.social · 19d

New Science Advances paper on the feedback loop between loss of snow feeding more wildfire, and wildfire resulting in earlier snowmelt. As to latter, in snow obs, under average conditions, snow melts earlier during 1st-yr postfire in 99%(!) of western snow zones.

www.science.org/doi/10.1126/...

Impact of current and warmer climate conditions on snow cover loss in burned forests

Wildfires are causing earlier snowmelt across the western US, and this effect would be exacerbated with projected warmer winters.

www.science.org

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Kevin Anchukaitis @thirstygecko.bsky.social · 22d

Changing Climate, Changing Fire: Understanding Ecosystem-Specific Fire–Climate Dynamics in Arizona and New Mexico journals.ametsoc.org/view/journal...

journals.ametsoc.org

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Daniel Malmer @malmer.com · 25d

This is an archived government report that found that “Since 1990, far-right extremists have committed far more ideologically motivated homicides than far-left or radical Islamist extremists.”

It existed yesterday and is gone today.

What NIJ Research Tells Us About Domestic Terrorism

Militant, nationalistic, white supremacist violent extremism has increased in the United States. In fact, the number of far-right attacks continues to outpace all other types of terrorism and domestic...

web.archive.org

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Matthew Hurteau @mhurteau.bsky.social · Sep 8

The Garnet Fire has burned through a place I have worked since 2002. A place I hold dear. We knew this wasn't a matter of if, but when. Unfortunately the leadership on the Sierra National Forest didn't have the same urgency that we did. My eulogy for Teakettle.
www.hurteaulab.org/blog/a-eulog...

A Eulogy for Teakettle

Justice William O. Douglas, in his dissenting opinion of the Supreme Court’s decision in Sierra Club v. Morton, said “Contemporary public concern for protecting nature’s ecological equilibrium...

www.hurteaulab.org

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Tom Swetnam @firescar.bsky.social · Sep 7

Our op-ed in the Santa Fe New Mexican today highlights the potential losses from closure of the nine US Forest Service Regional Offices, namely local leadership knowledge and capacity, experienced people, and priceless documentary records: www.santafenewmexican.com/opinion/my_v...

The legacy lost when Forest Service offices shut down

After 117 years of operation, the U.S. Forest Service’s Southwest Regional Office in Albuquerque is closing by order of the secretary of agriculture. Since 1908, this office has directed the

www.santafenewmexican.com

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GrumpyUncleSean🔥 @grumpyunclesean.bsky.social · Sep 4

According to supplemental figure 4 of this paper (www.nature.com/articles/s41...), here's the 1748 pattern (top-right panel). 🔥🧪🌍

Figure S4. Percent of sites recording fire that burned in 1652 (a), 1748 (b), 1800 (c), 1855 (d), 2011 (e), and 2021 (f). These correspond to the years in which the highest average percent of sites burned within
hexels in the historical (1600-1880; a-d) and contemporary (1984-2022; e-f) time periods (refer to Fig. 2b). Historically, fires in particularly active fire years were generally widespread across the study area. In 2011, however, fire was more localized and concentrated in the south-central United States (e), and in 2021,
most fire occurred in the Pacific Northwest, with a few additional hexels recording fire elsewhere (f). Overall, fire in particularly active historical fire years was spatially more widespread and ubiquitous
compared to contemporary active fire years

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Tom Swetnam @firescar.bsky.social · Sep 5

Well, this is a stimulating review! Some nice kudos, and a few critiques that are partly accurate, I’d say. I especially like the comparison with “psychedelic wanderings” of hippies! And I agree, it is a “modest intervention” in scholarly history of the Southwest.

Daniella M. @farsouthhistory.bsky.social · Sep 4

Check out Zachary Crouch's review of @firescar.bsky.social's "The Jemez Mountains: A Cultural and Natural History," published in 2025 by @unmpress.bsky.social; review now available @hnetreviews.bsky.social #envhist #envhum
www.h-net.org/reviews/show...

www.h-net.org

Reposted by Tom Swetnam

GrumpyUncleSean🔥 @grumpyunclesean.bsky.social · Sep 4

One more thing:
The fire severity data used to conduct this study can be downloaded here. This is a gridded dataset of satellite-derived fire severity and pre-fire NDVI for all fires in the western US that burned from 1985 to 2022.
🔥🌍🧪 #OpenScience

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Andrew Dessler @andrewdessler.com · Sep 2

On The Climate Brink, I write about the DOE report and our response.

The merchants of doubt are back

But this time, it's the U.S. government pushing doubt

www.theclimatebrink.com

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Proceedings of the National Academy of Sciences @pnas.org · Aug 18

Tree-ring fire records from 649 pine trees in central and eastern Arizona show that fires occurred more often in the territory of the Western Apache, or Ndee, than in other regions between 1600–1870, suggesting a culturally controlled fire regime. In PNAS: www.pnas.org/doi/10.1073/...

A 1940 Western Apache (Ndee) farm site with two wickiups in a ponderosa pine forest.
CREDIT: Lee Russell/Library of Congress

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University of New Mexico Press @unmpress.bsky.social · Aug 13

New Mexico Magazine recommends THE JEMEZ MOUNTAINS by @firescar.bsky.social!

What to Read: The Jemez Mountains by Thomas W. Swetnam

Thomas Swetnam's new book explores the Jemez Mountains through memory, science, and story.

www.newmexicomagazine.org

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Steve Pyne @sjpyne.bsky.social · Aug 10

Thread. Yet another avatar for Dragon Bravo - burning an isolated mesa in the Canyon, this time The Dragon itself (one of the Canyon's most apt placenames).

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Mother Jones @motherjones.com · Aug 6

The massive Grand Canyon fire is burning out of control

The Trump administration's US Forest Service staffing cuts may have hampered the agency's ability to respond.

www.motherjones.com

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David Sacerdote @davidsacerdote.bsky.social · Aug 6

A open-access paper on how wildfire season starts earlier in California thanks to the higher temperatures that fossil fuel burning have caused, and I wasn't able to find one of the authors on here. Kind of the first in a while.

www.science.org/doi/10.1126/...

Anthropogenic warming drives earlier wildfire season onset in California

Anthropogenic warming accelerates wildfire season onset in California.

www.science.org

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𝙲𝚑𝚊𝚛𝚕𝚎𝚜 𝙲. 𝙼𝚊𝚗𝚗 @charlescmann.bsky.social · Aug 5

Fine work that both extends our knowledge of the past and has implications for today. Ndee (Western Apache) land management did a remarkable job controlling forest fires, even in drought-heavy eras like ours. It defies belief to think today's fire-torn SW has nothing to learn from those guys.

Tree rings reveal persistent Western Apache (Ndee) fire stewardship and niche construction in the American Southwest | PNAS

Identifying the influence of low-density Indigenous populations in paleofire records has been methodologically challenging. In the Southwest United...

www.pnas.org

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Christopher Roos @pyroos.bsky.social · Aug 5

1/New Open Access paper in PNAS with an outstanding team of collaborators:
Tree rings reveal persistent Western Apache (Ndee) fire stewardship and niche construction in the American Southwest.
www.pnas.org/doi/10.1073/...

PNAS

Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans...

www.pnas.org

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Tom Swetnam @firescar.bsky.social · Aug 4

Interesting paper. Odd though that they don’t cite the ur-paper on tree “Longevity Under Adversity” Schulman’s classic on aridity and ancient trees in Science https://www.jstor.org/stable/1682970

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Margaret Evans @mekevans.bsky.social · Jul 31

New paper out on the dangers of using patterns across spatial climate gradients to predict what will happen with changing climate. That includes species distribution modeling. Space-for-time substitution can be misleading in sign, not just the magnitude of effects.
www.nature.com/articles/s41...

Reconsidering space-for-time substitution in climate change ecology - Nature Climate Change

Ecologists often leverage patterns observed across spatial climate gradients to predict the impacts of climate change (space-for-time substitution). We highlight evidence that this can be misleading n...

www.nature.com

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Zack Labe @zacklabe.com · Jul 26

Every time I open LinkedIn, someone from a science agency shares an unplanned (forced) early retirement or RIF. Lately it’s NASA & EPA. In spring, NOAA. I think people have no idea how deep this loss really is. I don’t know what rebuilding federal science looks like, but it won’t be simple or quick.

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Tom Swetnam @firescar.bsky.social · Jul 21

Generally it was large sheep herds and other livestock that first caused the cessation of spreading fires in SW forests. We see this in some places with early Spanish livestock grazing, and some areas later after the railroads came. FS had a few rangers putting out fires in the Gila by 1908-10.

Tom Swetnam @firescar.bsky.social · Jul 21

I don't know enough to comment about the Laguna Fire yet, except that it seemed to be low severity in many places. Here is an article from a few years ago. mostly about the problem of high severity fires in NM, but also the need for managed fire: searchlightnm.org/the-age-of-c...

The age of consequence: Wildfires in New Mexico | Searchlight New Mexico

Drought and climate change will spark catastrophic fires unless forests are better managed — starting now.

searchlightnm.org

Tom Swetnam @firescar.bsky.social · Jul 20

References and further reading about Gila fire history and ecology studies: 18/18

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