Goodness gracious, Friends, do I love the science of tree-ring dating!
My dissertation research, which I published in 1997 as Time, Trees, and Prehistory, explored the 15-year-long effort, from 1914 to 1929, in which Andrew Ellicott Douglass, an astronomer at the University of Arizona (UA) here in Tucson, along with his rag-tag team of associated archaeologists, developed and first applied tree-ring dating at archaeological sites in the American Southwest.
Since 1929, tree-ring dating has been used to date thousands of archaeological sites in the American Southwest, the American Southeast, the greater Mediterranean region, northern Europe, and a host of other places around the world. It has been used to date famous musical instruments, oak panel paintings, and even shipwrecks in Europe. It has been used to reconstruct precipitation, temperature, and a host of other climatic phenomena around the world. It has been used to reconstruct wildfire histories around the world, as well.
The Laboratory of Tree-Ring Research (LTRR) at UA is the world’s best tree-ring laboratory and home to an astonishing array of scholars who pursue entrepreneurial research. Although I don’t have much time to be physically present at LTRR, where I am a research associate, I do try to keep up with what my colleagues are doing, particularly on the archaeological side of things.
Earlier this week I was thrilled to see that Nick Kessler and colleagues just published some amazing new research—they dated a marker post from the Mitchell Mound in the ancient urban center of Cahokia, just outside of modern-day St. Louis, Missouri.
Kessler and his team used a combination of methods from tree-ring dating, radiocarbon dating, and isotopic analysis to determine that people harvested a massive bald cypress tree sometime between 1122 and 1126 CE from a forest at least 100 miles distant from Cahokia. That beam was probably floated along a river or two and then ultimately carried to its final location at Mitchell Mound, where it was erected and used for about two human generations.
Making all of this even more impressive, Kessler’s analysis suggests that the beam was about 18 meters (60 feet) long and weighed more than four metric tons when it was originally being moved. (For a summary overview of Kessler’s research, go here; for the full scholarly paper, go here.)
Archaeologists and Indigenous descendant communities have long known that Cahokia was a major urban center in the 11th and 12th centuries (1000s through 1100s) of the Common Era calendar. Population estimates indicate that Cahokia probably had more residents at that time than either London or what is now Mexico City!
Archaeological evidence suggests that its inhabitants had trade relationships with people all over North America and into Mesoamerica. Ecological evidence suggests that folks living in the area took advantage of a wide array of plant and animal species to gather and hunt and were productive farmers, as well.
I love it when tree-ring dating allow us specific insights into human behavior, and by extension what it meant to be alive at a point in history. Certainly, not all people who lived in and around Cahokia at that time knew or even cared about the effort to erect that marker post, but a lot probably did—it was a massive, coordinated undertaking that required a lot of support. I can only imagine the celebrations at the end of that project!
Thanks, and congratulations, Nick and colleagues, for a really cool analysis!
Until next time,
Steve Nash
President & CEO, Archaeology Southwest
Banner image: Lake Turkana, Kenya, by AdamPG, CC BY-SA 3.0, via Wikimedia Commons
Human Ancestors Created Tools Continuously for 300,000 Years
So when did our human ancestors start making tools? Well, the earliest artifacts that we know of date back more than 3 million years, but early finds had been scattered and inconsistent until new findings from modern-day Kenya. Researchers had studied a site there for 15 years and uncovered more than a thousand artifacts—tools made and used by early humans continuously for 300,000 years. Ailsa Chang interview with David Braun on All Things Considered (NPR) | Listen now »
Read the scholarly article in Nature Communications 16 (2025). Download now (open access) »
Archaeology in Action: Inspiring the Next Generation Through LEGO
This year, the FIRST LEGO League introduced the UNEARTHED theme, challenging students to find solutions to real-world problems in archaeology. At Save History, we were eager to support several schools in exploring current issues in archaeology, including Skyline Gila River School here in Arizona and schools as far-flung as Illinois, Iowa, New York, Oklahoma, Oregon, Wisconsin, and Washington. SaveHistory.org | Read more »
Commentary: As Copper Is Declared Critical, What Are Implications for Oak Flat and Other Heritage Places? For Resource Governance in the US?
In this political climate, the designation of copper as a “critical mineral” assumes a significance that far exceeds its technical rationale. … In practice, these designations can recast tribal consultation, water protection, and sacred site preservation as potential impediments to U.S. strategic interests. …
What does it mean for a place to carry deep cultural meaning while also containing resources the modern world depends on? Len Necefer’s All at Once Newsletter (opens at Substack) | Read more »
The Fight to Protect Chaco Continues
Earlier this month, the administration announced that the Bureau of Land Management will seek to reduce protections for Chaco Canyon, an area many Indigenous tribes hold sacred. Those protections included a 20-year moratorium on new oil and gas leasing on around 336,400 acres of public land within a 10-mile radius of the park, designed to protect cultural sites, wildlife and the environment from consequences of drilling. Now, the administration wants to allow drilling. …
It’s clear Trump wants to move fast, since the administration only is allowing a 14-day comment period — when it starts and ends is still unclear. But the comment period apparently will take place during a time most Pueblo people, for example, are busy with the winter ceremonial season. Opposition will be fierce, but the government is making it as difficult as possible for individuals, governments and tribal nations to speak up. That’s on purpose. Santa Fe New Mexican editorial board | Read more »
Commentary: The Damage to National Parks Is Just Beginning
National Park staff are returning to work today following the longest government shutdown in American history. One in which national parks were kept open, despite furloughs that impacted 60 percent or more of the staff who remain, following the administration’s attempts to gut the department. What will they find? Wes Siler’s Newsletter (opens at Substack) | Read more »
The Impacts of Federal Grant Cancellations on US Museums
In the years since the pandemic, American museums have been working hard to restore their attendance and financial health. But a new survey of museum directors reveals that the glimmer of progress is reversing, in part due to targeted executive orders and federal cutbacks for the arts. …
[T]he report paints the clearest picture yet of the widespread impact of grant cancellations from federal organizations, including the Institute of Museum and Library Services (I.M.L.S.), the National Endowment for the Humanities (N.E.H.), and the National Endowment for the Arts (N.E.A.). …
Around half of the 511 directors who responded to the survey lead art and history museums; the rest oversee science museums, children’s museums, and other kinds of museums. Julia Halperin for the New York Times | Read more »
Inside Today’s NEH: Acting Chair Handpicks Recipients
Since its creation in 1965, the National Endowment for the Humanities has distributed more than $6.5 billion to support more than 70,000 projects, from landmark works like Ken Burns’s documentary “The Civil War” to small local efforts in every corner of the country. …
Many of its nearly 50 grant programs have been paused or ended, according to an examination of its website. About two thirds of the staff has been laid off and, last month, most members of the scholarly council that must review a majority of grants were abruptly fired by the White House.
Still, the money has been flowing out the door. Jennifer Schuessler for the New York Times | Read more »
Publication Announcement: Repatriation after the 2023 NAGPRA Rule
Emily R. Holtzman, “ ‘My Museum’s Reluctant Undertakers’: Repatriation After the 2023 NAGPRA Rule,” Columbia Journal of Law and Social Problems 59:1, 2025. Download now (open access) »
REMINDER: Nov. 20 Online Event: An Expedition Torn Asunder: O’odham Responses to the Coronado Expedition
With Deni Seymour. Dr. Seymour’s research on the 1539–1542 Coronado expedition in southeastern Arizona has revealed how O’odham resistance helped bring an end to this episode of Spanish colonial exploration. Third Thursday Food for Thought series (Old Pueblo Archaeology Center) | Learn more and register (free) »
REMINDER: Nov. 21 Online and In-Person Event (Phoenix AZ): Updates on Research of the Leupp Isolation Center
With Davina Two Bears. Dr. Two Bears will give an update on the Leupp Isolation Center Community Accountable Archaeological Project. Old Leupp is a site of entwined histories of both the Navajo people and Japanese Americans. Our community accountable archaeological project seeks to understand and share these histories of assimilation in federal Indian boarding schools and Japanese American incarceration on Indigenous lands by the US government in the early 20th century. Available in-person and online. Deer Valley Petroglyph Preserve (Arizona State University) | Learn more »
Davina Two Bears is a member of Archaeology Southwest’s Board of Directors.
December In-Person Lectures (Santa Fe NM)
Dec. 1, Tierra Adentro Charter School Performance, Raíces (Roots): Flamenco’s Passion, Rhythm & Tradition (held at Santa Fe Women’s Club, 1616 Old Pecos Trail); Dec. 8, Thatcher Seltzer-Rogers, Ascendancy of Casas Grandes, Chihuahua, Mexico; Dec. 15, Sarah Oas, Foodways and Archaeology: What Histories of Flavor and Cuisine Tell us about the Past. 6:00 p.m., Hotel Santa Fe. $20 at the door or $55 for the series of 3 programs. Southwest Seminars | Learn more »
Dec. 2 Online and In-Person (Tucson AZ) Event: Path of Light: Retracing the Expeditions of Charles L. Bernheimer
With Morgan Sjogren. In 1929, explorer Charles L. Bernheimer dreamed up a National Park proposal that may have prevented Glen Canyon Dam and protected the surrounding landscape. Inspired by a decade of expeditions in the Four Corners region, Bernheimer wanted to “do more than be a sightseeing tourist.” To contextualize past and present efforts to protect Glen Canyon, author Morgan Sjogren retraced Bernheimer’s more than 300-day-long Glen Canyon expedition, guided by historic journals and photographs. Archaeology Café (Archaeology Southwest) | Register to attend in person (free) » | Register to attend online (free) »
Dec. 4 Online Event: Sonic Landscapes: Sounds of Labor in Lowell
With Sarah Buchmeier. Buchmeier’s project, The Measure of Work: Sounds of Labor in Lowell, uses sound and music to rethink dominant narratives of the American Industrial Revolution. It asks audiences to consider how, over more than two centuries, industrialization has transformed Lowell’s sonic landscapes— and what that can reveal about work, labor, and sense of place. Living Landscape Observer | Learn more and register (free) »
Dec. 5 Online Event: Macaws for Metal?
With Michael Mathiowetz. After AD 900, scarlet macaws from tropical Mesoamerica became significant in ritualism of Mogollon and Puebloan societies in the US Southwest and Mexican Northwest. A cross-continental “Aztatlán-Huasteca Network” may have connected Aztatlán societies in west Mexico to the Gulf Coast during the Postclassic period, thereby facilitating the eastward transmission of metals and metallurgy to the Huasteca with scarlet macaws moving along the Gulf Coast westward to Aztatlán societies and northward to the SW/NW. Mathiowetz will explore the evidence and logistics of these ritual economies in northern Mesoamerica. Pre-Columbian Society of Washington DC | Learn more and register (free) »
Dec. 13 In-Person Workshop (Tucson AZ): Arrowhead-making and Flintknapping
With Sam Greenleaf. Participants will learn how to make arrowheads, spear points, and other flaked stone artifacts from obsidian and other stone like ancient peoples did. The class is designed to foster understanding of how early peoples made essential tools, not to make artwork for sale. Reservation and $45 payment (which includes all materials and equipment) required by 5:00 p.m. December 11. Old Pueblo Archaeology Center | Learn more »
Save the Date: Jan. 17 In-Person Event (Nogales AZ): Honoring Sheriff Estrada
Join us to honor (retired) Sheriff Tony Estrada at our Annual Meeting. Come out to lovely Hacienda Monarca (formerly Ralph Wingfield Ranch) for a delicious lunch and be regaled with intriguing tales by this intrepid lawman. Stroll the historic grounds, see the John Wayne room, view the Corona Murals the famous bullfighter painted on the hacienda walls. Watch pimeriaaltamuseum.org for details and to purchase your ticket. (Available December 1.) Pimeria Alta Historical Society and Museum | Learn more »
Video Channel Roundup
In case you missed any presentations this past month! A simple click on any of the links to the YouTube channels of our Partners and Friends should catch you up. (And please do let us know if your channel isn’t in this list but should be.)
Albuquerque Archaeological Society
American Rock Art Research Association
Amerind Foundation
Archaeology Southwest
Arizona Archaeological and Historical Society
Arizona State Museum
Aztlander
Bears Ears Partnership
Cotsen Institute of Archaeology at UCLA
Crow Canyon Archaeological Center
Grand Canyon Trust
Grand Staircase Escalante Partners
Mesa Prieta Petroglyphs Project
Mission Garden (Friends of Tucson’s Birthplace)
Museum of Indian Arts and Cultures
Museum of Northern Arizona
Old Pueblo Archaeology Center
Pacific Coast Archaeological Society
San Diego Archaeological Center
School for Advanced Research
SHUMLA Archaeological Center
Southwest Seminars
The Archaeological Conservancy
Verde Valley Archaeology Center
Remember to send us notice of upcoming events and webinars, tours and workshops, and anything else you’d like to share with the Friends. Thanks!
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