The most popular and often used method for calibration is by dendrochronology.
The science of dendrochronology is based on the phenomenon that trees usually grow by the addition of rings, hence the name tree-ring dating.
In principle, the age of a certain carbonaceous sample can be easily determined by comparing its radiocarbon content to that of a tree ring with a known calendar age.
If a sample has the same proportion of radiocarbon as that of the tree ring, it is safe to conclude that they are of the same age.
In practice, tree-ring calibration is not as straightforward due to many factors, the most significant of which is that individual measurements made on the tree rings and the sample have limited precision so a range of possible calendar years is obtained.
And indeed, results of calibration are often given as an age range rather than an absolute value.
At present, tree rings are still used to calibrate radiocarbon determinations.
Libraries of tree rings of different calendar ages are now available to provide records extending back over the last 11,000 years.Dendrochronological findings played an important role in the early days of radiocarbon dating.Tree rings provided truly known-age material needed to check the accuracy of the carbon-14 dating method.At first glance, it appears easy to date tree rings by just counting them, but reality is often more complicated than that.Calibration is not only done before an analysis but also on analytical results as in the case of radiocarbon dating—an analytical method that identifies the age of a material that once formed part of the biosphere by determining its carbon-14 content and tracing its age by its radioactive decay.The trees often used as references are the bristlecone pine (Pinus aristata) found in the USA and waterlogged Oak (Quercus sp.) in Ireland and Germany.Tags: Adult Dating, affair dating, sex dating