EMILIO SEGRE VISUAL ARCHIVES, BRITTLE BOOKS COLLECTION / AMERICAN INSTITUTE OF PHYSICS / SCIENCE PHOTO LIBRARY EMILIO SEGRE VISUAL ARCHIVES, BRITTLE BOOKS COLLECTION / AMERICAN INSTITUTE OF PHYSICS / SCIENCE PHOTO LIBRARY
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Andrew Ellicott Douglass (1867-1962), US astronomer. Douglass pioneered the science of dendrochronology. This involved the study of tree rings to provide information on the dating of archaeological ruins and past changes in the Earth's climate. Douglass's work revealed a correlation between tree rings and the sunspot cycle. He succeeded in establishing a chronology based on tree rings dating back to AD 700. Some of these discoveries were made on expeditions funded by the National Geographic Society. Douglass worked at the University of Arizona, where he established the Laboratory of Tree-Ring Research (LTRR) in 1937.
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