Lab News

Dr. Ron Towner Leads Tree-Ring Workshop for Crow Canyon Staff

by Jamie Merewether, Collections Manager
February 27, 2007

In January 2007, Dr. Ron Towner of the Laboratory of Tree-Ring Research (University of Arizona, Tucson) conducted a two-day workshop for research and education staff members on the Crow Canyon campus. The workshop was designed to teach staff who work in the field and lab how to assess whether a tree-ring sample has the potential to yield a date.

Crow Canyon received funding for the workshop from a grant awarded by the Canyonlands Natural History Association’s “Discovery Pool.” The Discovery Pool is a new program that promotes science and research at many Southwestern national parks and monuments, including those managed by our partners at the Southeast Utah Group of the National Park Service.

Dr. Towner began the workshop with a general introduction to tree-ring dating. After presenting a brief history of tree-ring dating in the Southwest, he discussed factors relevant to the dating process, including the mechanism by which trees grow, the conditions that affect growth, and the species of tree. He showed staff how to identify tree species when looking at a cross section of a wood sample, which—because some species are better for dating than others—should help staff make better assessments.

Dr. Towner also described how the Tree-Ring Lab examines a wood sample, collects specific data, and compares the results with the Lab’s master chronology for the Southwest. He explained how to interpret the analysis results, especially the codes describing sample condition, and he illustrated how each condition appears on a sample. Importantly, staff learned which characteristics to look for when trying to determine if a sample has good dating potential.

The introductory session provided the background for the second part of the workshop, during which the participating research and education staff members examined all 274 samples collected from Goodman Point Pueblo during Crow Canyon’s first two field seasons (2005–2006). As each sample was examined under a microscope, the tree species and ring-width variation were recorded.

After staff completed their evaluations, the samples were boxed and loaded into Dr. Towner’s truck to be taken to the Tree-Ring Lab. When Crow Canyon receives the results of the Lab’s analysis, perhaps as early as May 2007, the research staff will compare those results to the observations recorded during the workshop.

As a result of the knowledge gained from this experience, Crow Canyon staff will be able to assess the quality of tree-ring samples collected in all future excavations before the samples are sent to the Tree-Ring Lab. This should help the Lab analyze the samples—and provide Crow Canyon researchers with critical dating information—quicker than ever before.

Thank you, Canyonlands Natural History Association, for providing the funding for the workshop, and thank you, Dr. Towner, for sharing your wealth of information!