By Michael Jacobs
Arizona Daily Wildcat
October 14, 1997

Tree ring scientist flies to windy city

Leigh-Anne Brown Arizona Daily Wildcat Dendrochronology Research Associate Richard Warren examines some tree core samples at the tree-ring research lab.

The strokes of an archaeologist's brush can open a picture window on past societies.

So says renowned UA tree ring lab scientist Stephen Nash, who has often drudged through an abyss of archaeological evidence trying to precisely date ancient ruins.

"Tree ring analysis didn't revolutionize archaeology," he said. "It revolutionized the pre-history," which is archaeological interpretation.

However, for the next two years and perhaps beyond that, Nash will not don a "Property of Arizona" T-shirt. The UA couldn't offer him a position, so he took one as an archivist at the University of Chicago Field Museum.

Rex Adams, a tree ring lab research specialist, said he was sorry to see Nash leave.

"As a student, Dr. Nash was an important part of the lab," Adams said. "We hate to lose anybody, but there were no openings in the lab."

"The turnover of staff is slow due to tenure and the desire for professionals to work in a place as nice as this lab," he added.

The UA tree ring lab has reached it's maximum of seven faculty members, Adams said. He said the lab is the only laboratory in North America that performs tree ring dating.

Many tree ring related courses are offered by the Anthropology Department, however, the department does not extend grants to researchers in the field.

Nash, a postdoctoral student who has worked UA tree ring lab projects since 1991, has many achievements over the last eight years. He has:

• experience in 16 professional archaeological digs
• received five research grants
• been granted five different scholarships
• written eight different publications
• taught four different UA courses
• participated in 14 different professional activities
• membership in four professional associations
• been awarded the A.E. Douglass Award from the laboratory of tree ring research at the UA

"If archaeologists are so interested in chronological dating, then we have to have the most reliable technology," Nash said. "Tree ring dating is accurate, concise and reliable."

He said that tree ring dating compressed the time scale and was able to pinpoint ecological variables in the past. Therefore, it changed the ideas of rates of culture changes and socioeconomic implications throughout history.

Techniques of dendrochronology, the science of tree ring dating, categorize annual growth of tree layers within a certain year and use the properties of tree rings to uncover the history of the tree's environment.

"Water is the limiting factor in southwestern specimens," Nash said. "Alternating bonds of wide rings, characterized by a lot of water, and narrow rings, characterized by a small amount of water, are cross-dated," Nash said. "Cross-dating assigns calendar dates to rings by matching growth patterns to living specimens."