The chronometric, or time measurement, application of dendrochronology has the longest history and is the most commonly known to nonspecialists. Tree-ring dating is routinely used to date artifacts, features, sites, and, by extension, abstract archaeological entities including periods, stages, phases, and styles. Tree-ring dates have also been used to confirm and provide absolute dates for chronological sequences provided by relative dating techniques including ser-iation and stratigraphic analysis. Tree rings are used to calibrate radiocarbon dates and to confirm the veracity of dates provided by other chronometric techniques, including archaeomagnetic, obsidian hydration, luminescence, and historic dates (see Electron Spin Resonance Dating; Obsidian Hydration Dating). As but one example of many, when treering dates were first used to calibrate the radiocarbon curve in Europe in the 1960s, archaeologists’ understanding of European prehistory was turned on its head. Although megalithic sites in western Europe were once assumed to postdate the pyramids of classical Egypt, and monumental architecture was assumed to have diffused from Egypt to the West, tree-ring calibration of the radiocarbon date curve demonstrated that western European megaliths actually predated the pyramids, and the supposed diffusion of technology could not possibly have happened.
The environmental application of modern dendrochronology enjoys the most worldwide application, as tree-ring chronologies can be used to mathematically reconstruct many environmental variables, including precipitation, temperature, stream flow, drought severity, fire frequency and intensity, insect infestation, atmospheric circulation patterns, and other parameters. These kinds of analyses have proved useful for archaeologists when compared to excavation data to determine potential cause-and-effect relationships between paleoenvironmental conditions and the human occupation of a given area.
The behavioral application of dendrochronology has a shorter and more restricted pedigree, but the analysis of tree-ring dates within their archaeological contexts allows archaeologists to make inferences regarding wood-use practices, trade, and other economic variables and relationships. As but one example, dendrochronological study of wood use at Walpi Pueblo, on the Hopi Mesas in Arizona, yields precise chronometric data on three different wood-use regimes at the site: (1) prehistoric use of stone axes by Native Americans to cut down living trees; (2) early historic use of metal axes by Hispanic populations to cut down and use both living and dead trees; and (3) the use of milled lumber by Anglos and others with the arrival of the railroad in the 1880s.
World History
