Dating the age of an oak tree Adultchatroullet
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.
This remarkable tree was approximately 1400 years old, and grew on this rugged mountain ridge during the time of Mohammed.
The increment borer removes a small cylinder or core of wood from the tree trunk.
Instead, estimates are made based on the tree's size and presumed growth rate.
The second table includes trees with these estimated ages.
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.
Ages for clonal colonies, often based on current growth rates, are estimates.
Several genetically identical males that have reproduced vegetatively.
The core is sanded and treated with a wood oil to make the rings more distinct.
Since the rings are so close together, they must be counted under a dissecting microscope.
The radius (r) can be determined from the circumference of the trunk (C=2πr), or from special tape measures that give the diameter directly.