Dendrochronology (or tree-ring dating) is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed in order to analyze atmospheric conditions during different periods in history.Dendrochronology is useful for determining the timing of events and rates of change in the environment (most prominently climate) and also in works of art and architecture, such as old panel paintings on wood, buildings, etc.
For example, if the cultural contents of the lower deposit are Mauryan in character, appropriately this deposit may be assigned a date between 400-200 B. Similarly, if the cultural equipment of the upper deposit are of the Sunga period, this deposit has to placed between 200-73 B. Quite often, the archaeologist decided the change of stratum on the basis of the feed of the deposit.
Growth rings are the result of new growth in the vascular cambium, a lateral meristem, and are synonymous with secondary growth.
Visible rings result from the change in growth speed through the seasons of the year, thus one ring usually marks the passage of one year in the life of the tree.
In 1859, the German-American Jacob Kuechler (1823–1893) used crossdating to examine oaks (Quercus stellata) in order to study the record of climate in western Texas.
During the first half of the 20th century, the astronomer A. Douglass founded the Laboratory of Tree-Ring Research at the University of Arizona.