Dendrochronology (Gk.: dendro = tree, chronos = time, logos = knowledge) is a very precise dating technique, accurate to within a year. By comparing the sequence of annual growth rings of an individual tree with established chronologies (the master chronology) wood samples can be ordered chronologically, or crossdated. It's application is widely used in archaeology, dating of historic buildings, and even dating of works of art.
Along with climatic and environmental research, dendrochronology can also make a valuable contribution to environmental science: particularly studies of river, lake, coastline and volcanic activities. Dating aside, studies such as these when combined with the data stored from tree rings can allow us to monitor and interpret different types of influences on the environment.
Trees which grow in the same location or under identical climatic conditions, whether this be semiarid or temperate or boreal zones, will display a similar annual ring-growth pattern. The individual growth pattern - the variation from broad to narrow annual rings in a single tree - can be visually compared with other patterns, and subsequently crossdated. After measuring the width of each tree-ring the data is translated into graph form to make visual comparison easier. Statistical calculations, with the help of specific correlation software, assist this process. With the help of mean calculations for the annual ring width patterns, it is possible to establish long chronological series, which then become the basis for comparing and dating further wood samples.
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