An introduction to tree ring dating
The Nottingham Laboratory undertakes work not only for major conservation authorities such as English Heritage and The National Trust, but also for archaeological units, local authorities, architects, developers and builders, estate managers, local history and heritage groups as well as many private individuals.
Enquiries are strongly encouraged and are welcomed with enthusiasm and interest.
Tree-ring dating relies on obtaining the growth pattern of trees from sample timbers of unknown date by measuring the width of the annual growth-rings.
This is done to a tolerance of 1/100 of a millimetre.
The growth patterns of these samples of unknown date are then compared with a series of reference patterns or chronologies, the date of each ring of which is known.
The greater the number of samples in a site chronology the greater is the climatic signal of the group and the weaker is the non-climatic input of any one individual.When samples from the same phase do cross-match with each other they are combined at their matching positions to form what is known as a "site chronology".As with any set of data, this has the effect of reducing the anomalies of any one individual (brought about in the case of tree-rings by some non-climatic influence) and enhances the overall climatic signal.The pattern of a short period of growth, 20, 30 or even 40 consecutive years, might conceivably be repeated two or even three times in the last one thousand years.A short pattern might also be repeated at different time periods in different parts of the country because of differences in regional micro-climates.