A History of Archaeological Tree-Ring Datin: 1914-1945

Dendrochronology, the science of assigning precise and accurate calendar dates to annual growth rings in trees, was the first independent dating technique available to prehistorians. Archaeological tree-ring dating came of age at a time when North American archaeologists concerned themselves primarily with time-space systematics, yet had no absolute and independent dating techniques available to guide their analyses. The history of archaeological tree-ring dating from 1914 through the end of World War II is often reduced to discussions of the discovery of specimen HH-39 on June 22, 1929 and considerations of the National Geographic Society Beam Expeditions of 1923, 1928, and 1929. The development and integration of archaeological tree-ring dating is in fact much more complex than these simplistic histories indicate. The “bridging of the gap,” as symbolized by the discovery of HH-39, represents merely the culmination of an intense 15-year long research effort that included at least seven “beam expeditions” and a great deal of laboratory and brilliant archaeological research. By 1931, four Southwestern archaeological research institutions had hired dendrochronologists to conduct archaeological tree-ring dating in support of their various research interests. By 1936, dendrochronology was being applied in support archaeological research in the Mississippi Valley and Alaska. By 1942 however, Southwestern archaeological tree-ring dating once again became the exclusive domain of the Laboratory of Tree-Ring Research at the University of Arizona, and by 1950 efforts to extend tree-ring dating to other parts of North America as well. A controlled analysis and comparison of tree-ring sample collection activity, correspondence, unpublished research records, and the publication record relevant to North American archaeological tree-ring dating from 1914 to 1945 provides a chronicle of important events in the development of archaeological dendrochronology, provides an understanding of the processes through which tree-ring dating became incorporated in increasingly sophisticated archaeological analyses and interpretations of Southwestern and indeed North American prehistory, serves as a case study for a proposed unilineal model of the development and incorporation of analytical techniques in archaeology, and lays the foundation for a body of theory regarding the development of ancillary chronometric and archaeometric techniques and their application to archaeological problems.