Often the borer does not reach the center of the trunk, so the total number of years must be extrapolated from the radius of the trunk.The radius (r) can be determined from the circumference of the trunk (C=2πr), or from special tape measures that give the diameter directly. Wolffia using a increment borer to age-date an old sierra juniper (Juniperus occidentalis var.australis) on a steep 9,000 foot ridge of Pine Mountain in the San Gabriel Range of southern California.Tree-ring dating provides scientists with three types of information: temporal, environmental, and behavioral.

In a dry year, trees will produce a narrow growth ring.

Together older trees and younger trees are used to create long, chronological, growth sequences that can help us date artifacts and archaeological sites that are hundreds, even, thousands of years old.

The sequence is created by overlaping the tree rings so a long series of rings can be seen.

Dendrochronology, or Tree-ring dating, has emerged in the last decade as one of the most important dating tools for medieval carpentry and timberwork in general.

Briefly stated, dendrochronology creates a statistically-based calendar from the meticulous measurement of the variation in width and character of annual tree rings.