If It Doesn’t Survive Here, It Could Be Gone Forever

Samples that have been touched by forest fires are archived in distinctive red boxes.
January 24, 2011

When you walk into the Laboratory of Tree-Ring Research deep beneath the UA football stadium, the first thing you sense – aside from the comfortable smell of aged, dry wood – is that you are journeying into some fantastic world of discovery.

And that is exactly where you have arrived. You’re literally surrounded the world’s richest collection of tree-ring specimens, as you walk among shelves and boxes that house over 2 million samples tracking the past 8,000 years of Earth and human history.

Pearce Paul Creasman understands the one-of-a-kind nature of this resource, as he has been recently hired as the lab’s curator.  "We hold the world's largest collection of tree rings and it's an irreplaceable, one-of-a-kind resource of environmental and cultural history."  

“Having the collection here in Tucson, in a safe, consistently dry climate, is key to its success,” he says. If there is an ideal geographic location for such an endeavor, this is it.

A 29-year old archaeologist, Creasman did most of his research in Cairo studying boat hulls. While to most of us a sunken ship represents a single archaeological artifact, to Creasman, each boat – and each timber used to build it – can tell thousands of stories about the past. 

He now dedicates a large amount of his time to setting up the systems for organizing the lab’s specimens and turning raw data into useful, accessible information for scholars around the globe.

The tree-ring lab got its start in 1937, but surprisingly, the study of trees was not the original motivation. The man who got the work off the ground was actually looking skyward.

UA astronomer A. E. Douglass was studying the sun. He tried, with little success, to correlate the cycles of sunspots and solar variations to the patterns of tree rings. So was born the field of dendochronology or tree-ring dating, a scientific method of dating based on the analysis of tree ring patterns.

Since its founding, the UA Laboratory of Tree-Ring Research has been collecting samples from around the world. Each sample can tell myriad stories and answer any number of questions:  When and how long did this tree live? What was the climate like during its lifespan in the geographic area that it grew? What was the composition of the soil?

Using an almost 9,000 yearlong tree-ring record from California, the lab provided the first complete calibration, or independent check, of the radiocarbon timescale used in many fields such as archaeology and geology.

The history preserved and studied through dendochronology serves as a resource, providing invaluable data for archeologists, climatologists, entomologists, and any number of other disciplines – even public health. According to Creasman, the lab is always operating at maximum capacity, fielding inquiries from around the world.

As for Creasman, he has his work cut out for him. "Curating this collection is an archaeological excavation. You have to map everything where it is, and then you have to ask the right questions," he says as he walks among the shelves of wooden discs, stacked from floor to ceiling spanning countless low-light halls and rooms beneath the stadium.  

“There will never be another opportunity to get this data,” he says as the lab’s door locks shut behind him. “If it doesn’t survive here, it will be gone forever.”

To learn more about the lab, visit http://www.ltrr.arizona.edu