Tree ring dating techniques
Andrew Ellicott Douglass, an astronomer at the University of Arizona in Tucson, is considered the father of tree-ring dating.
He introduced the American public to the technique in a December 1929 article in entitled “Talkative Tree-Rings and the Tales They Tell.” In that article, Douglass published construction dates for six cliff dwellings at Mesa Verde National Park (MVNP) in southwestern Colorado, including Balcony House, Cliff Palace, Oak Tree House, Spring House, Spruce Tree House, and Square Tower House.
australis) on a steep 9,000 foot ridge of Pine Mountain in the San Gabriel Range of southern California.
A small core of the wood is removed and the rings are painstakingly counted.
From the Falls Creek rock shelters outside Durango, it dates to 272 BC.Tree-ring dating provides scientists with three types of information: temporal, environmental, and behavioral.The temporal aspect of tree-ring dating has the longest history and is the most commonly known—tree rings can be used to date archaeological sites, such as the Cliff Dwellings found at Mesa Verde National Park (MVNP) or historic cabins.Although the exact dates Douglass published have long since been refined, his general dating has not changed: the vast majority of cliff dwellings were built and occupied in the mid-1200s.
These dates came as a shock to many archaeologists who, on the basis of little more than educated guesswork, thought that the cliff dwellings were much older.Second, sample sizes must be large in order to understand tree-growth variability in a given region.