In Memoriam: Marvin A. Stokes, Professor Emeritus of Dendrochronology

Stokes loved teaching and inspired many students to study environmental and cultural history by using tree rings.
April 15, 2010
Memorial Service for Marvin Stokes
6-9 p.m. Saturday, June 5
San Pedro Chapel, 5230 E. Fort Lowell Road
Marvin Stokes, in the field holding a
tree-ring core and a long metal rod called an extractor.
Marvin Stokes, in the field holding a tree-ring core and a long metal rod called an extractor.
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Marvin A. Stokes, a University of Arizona professor who studied tree rings in ancient Navajo sites and in Spanish Colonial mission churches, died April 7. He was 82.

Stokes' tree-ring dating of wooden beams from ancient Navajo dwellings and other structures was used by the U.S. Indian Claims Commission in the 1960s to settle reparation claims by the Navajo Nation. Stokes' research was key in supporting the Navajo Nation's claim that its people had been living in the American Southwest for centuries.

A memorial service will be held 6-9 p.m. June 5 at the San Pedro Chapel, 5230 E. Fort Lowell Road.

"Marv loved field work and the joy of finding old trees, sampling them and crossdating their tree rings. But more than that, he loved teaching and sharing these pleasures of discovery with others. What a great gift that was to so many of us," said Thomas W. Swetnam, professor and director of the UA's Laboratory of Tree-Ring Research.

"Marv was a gentle man, in the literal sense... and he had a wry wit," he said.

Stokes was Swetnam's first advisor and mentor when he arrived at the UA as a graduate student in 1980. Stokes and the late Jack Dieterich were using tree rings to study forest fire history, and Stokes hired Swetnam to assist with that research.

Swetnam is now one of the world's experts in using tree rings to reconstruct regional histories of forest fire.

A native of Aberdeen, S.D., Stokes served in the U.S. Army Air Corps from 1945-48 conducting geodetic surveys in Greenland and elsewhere. He was a park ranger at Mesa Verde National Park in 1953. He earned a bachelor's degree in anthropology in 1952 from the University of Colorado Denver and a master's degree in botany from the University of Arizona in 1965. He joined the UA's Laboratory of Tree-Ring Research in 1953 as a laboratory assistant. He was appointed assistant professor in 1967, associate professor in 1972, professor in 1977, and professor emeritus upon his retirement in 1989.

Following the Navajo Land Claim work, Stokes led expeditions to Northern Mexico to sample tree rings in ancient trees and roof beams of old mission churches, including ones established by Father Eusebio Kino. In addition to helping confirm the age of the missions, the tree-ring chronologies were used to establish the climate and fire history of the region. Stokes' wide-ranging field studies plus the work of other researchers contributed to a continental-scale network of tree-ring width chronologies from drought-sensitive trees.

In addition, tree-ring data that Stokes and his colleagues collected in the Four Corners region were the basis for the first statistically calibrated reconstructions of the Colorado River's flows and the region's drought history extending back before 1600.

Stokes co-wrote one of the most frequently cited books in the use of tree rings for the study of environmental and cultural history – the field known as dendrochronology. Originally published in 1968, the University of Arizona Press re-issued the book, "An Introduction to Tree-Ring Dating," in 1996.

Stokes is remembered with affection and gratitude by a generation of dendrochronology students.

Edward R. Cook, who earned his master's and doctorate from the UA and is now director of the Tree-Ring Laboratory at Columbia University's Lamont-Doherty Earth Observatory, wrote in an e-mail, "Marv was the one who introduced me to tree-ring analysis in the Fall 1969 semester with his 'Introduction to Dendrochronology' class, and I am forever grateful."

Cook added, "It truly did change my life for the good. He was a wonderful and very generous man and an excellent teacher. ...My proudest moment was in working on some very difficult samples with lots of missing rings. When I correctly completed the dating on my own, Marv said to me, ‘Well, I guess you are a dendrochronologist now.' It couldn't get any better than that. I still consider it one of the highlights of my life."

David W. Stahle, distinguished professor and director of the Tree-Ring Laboratory at the University of Arkansas in Fayetteville, was an undergraduate at the UA when he met Stokes.

Stahle wrote in an e-mail, "Marv was far more than just a mentor to me. He saw something in an enthusiastic but very immature undergraduate student – me – and helped him grow up and pursue a meaningful career. He hired me as an assistant in the Modern Studies section, and then as his student assistant on the Mexican Tree-Ring Project.

"What an adventure and privilege it was to tour the remote forests of the Sierra Madre, to study the authentic Jesuit and Franciscan era missionary churches of northern Mexico and to build tree-ring chronologies where they had not existed before. Around the campfire we often spoke about the goal of extending the tree-ring record into central Mexico to document climate changes during the development of Mesoamerican civilization."

Stahle added, "I called Marv a few weeks ago to tell him that Jose Villanueva (a UA alumnus who is now a prominent dendrochronologist in Mexico) and I have finally achieved that goal with the development of the long Montezuma baldcypress tree-ring chronology in Queretaro dating from AD 771-2008. ...One of the legacies of Marvin Stokes has been my career and the continuing development of dendrochronology in Mexico. He was a generous and trusting person and one I've tried to emulate."

Stokes is survived by Tally Stokes, his wife of 32 years, his former wife, Ruth Stokes, his children Christine Stokes and Kathleen Little and four grandchildren.