What is tree ring dating
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.
Carbon-14 is a naturally occurring isotope of the element carbon.
Radiocarbon measurements are based on the assumption that atmospheric carbon-14 concentration has remained constant as it was in 1950 and that the half-life of carbon-14 is 5568 years.
Calibration of radiocarbon results is needed to account for changes in the atmospheric concentration of carbon-14 over time.
Dendrochronology is a science of precise dating, by the accurate counting of annual tree growth-rings, which allows dating wooden items to the year.
The American botanist, Douglas, established the first tree-ring chronology in 1929 with a pine chronology for the south-west of America extending back to 701 AD.
In most tree species in the British Isles a single tree-ring is produced each year and the tree-ring’s width varies in response to environmental factors, particularly rainfall and temperature.