dendrochronology

—dendrochronological /den'droh kron'l oj"i keuhl/, adj. —dendrochronologically, adv. —dendrochronologist, n.

/den'droh kreuh nol"euh jee/, n.

the science dealing with the study of the annual rings of trees in determining the dates and chronological order of past events.

[1925-30; DENDRO- + CHRONOLOGY]

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Method of scientific dating based on the analysis of tree rings.

Because the width of annular rings varies with climatic conditions, laboratory analysis of timber core samples allows scientists to reconstruct the conditions that existed when a tree's rings developed. By taking thousands of samples from different sites and different strata within a particular region, researchers can build a comprehensive historical sequence that becomes a part of the scientific record. Such master chronologies are used by archaeologists, climatologists, and others.

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▪ paleontology

also called  tree-ring dating 

      the scientific discipline concerned with dating and interpreting past events, particularly paleoclimates and climatic trends, based on the analysis of tree rings. Samples are obtained by means of an increment borer, a simple metal tube of small diameter that can be driven into a tree to get a core extending from bark to centre. This core is split in the laboratory, the rings are counted and measured, and the sequence of rings is correlated with sequences from other cores.

      Dendrochronology is based on the fact that many species of trees produce growth rings during annual growing seasons. The width of the ring (i.e., the amount of growth) for each year is determined by various internal and external factors, but it tends to vary mainly in proportion to either the amount of available precipitation or the prevailing temperatures. The ring measurements taken from trees with overlapping ages can extend knowledge of climates back thousands of years. The bristlecone pines (bristlecone pine) of California have proven to be particularly suitable for such chronologies, since some individual trees are more than 4,000 years old.

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