Dendrochronology
Dendrocronología
- Date
- 1929 · confidence high
- Place
- Tucson, Arizona, United States
- Credited to
- Andrew Ellicott Douglass
- Field
- Knowledge & symbols
What it is
A method of dating wood by counting and comparing tree growth rings, whose width varies with each year's climate. Douglass developed it in Arizona from 1901 and in 1929 linked a sequence of timber from Native American ruins with the series from living trees, with dates to the exact year.
Douglass studied solar cycles in rings, and the 1929 link (beam HH-39 from Show Low) closed a gap of centuries. European series (oaks) reach about 12,000 years.
What it led to
- absolute dates for ruins of the American Southwest and historic buildings
- calibration of radiocarbon dating
- reconstruction of past climate from tree rings