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Joukowsky Institute for Archaeology



Joukowsky Institute for Archaeology & the Ancient World
Brown University
Box 1837 / 60 George Street
Providence, RI 02912
Telephone: (401) 863-3188
Fax: (401) 863-9423
[email protected]


Through tree-ring analysis, dendrochronology establishes the specific chronology of archeological ruins. In many trees, growth rings are created annually as a result of seasonal climate fluctuations. Large, thin-walled light colored cells are produced in the spring, and over the course of the year cells grow progressively smaller and darker. This seasonal lightening and then darkening of cellular growth results in discernable rings. The relative size of the rings is determined by two main factors: trees experience more dramatic growth, and thus larger rings, earlier in life. Climate conditions are the other determining factor of ring size. Larger ring growth indicates weather conditions favorable to growth, such as plentiful rain. Conversely, smaller rings may be the result of drought.

Because trees will exhibit similar growth patterns as they experience similar climatic episodes, dendrochronology can be used to establish a historical timeline of tree growth. This is done by comparing the growth patterns of many trees from differing periods, generating a cross-dated chronology. Once such a chronology has been established, newly discovered timber can be compared to the chronology of growth, providing an accurate date of when the timber was felled.

The image below is an example of the dendrochronological timeline used to date construction timbers from an excavation at Assiros in Greece. Dendrochronology was used to provide the “first direct near-absolute dates for the start of the Early Iron Age in Macedonia and of the Protogeometric period in Southern Greece” (Newton, M., Wardle, K.A., Kuniholm, P.I.).

Uploaded Image Image Source: Newton, M., Wardle, K.A., Kuniholm, P.I. “Dendrochronology and Radiocarbon Determinations From Assiros and the Beginning of the Greek Iron Age”, 2005.


“Dating In Exposed and Surface Contexts”, ed.: Beck, Charlotte. University of New Mexico Press: Albuquerque, NM, 1994.

Michels, Joseph. “Dating Methods in Archaeology”. Seminar Press, New York: NY, 1973.

Newton, M., Wardle, K.A., Kuniholm, P.I. “Dendrochronology and Radiocarbon Determinations From Assiros and the Beginning of the Greek Iron Age”, 2005.

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Posted at Dec 17/2007 09:05AM:
RG: Who knew that something we learned in preschool or elementary school would turn out to be so important in the real world? Usually when you think of tools of chronological analysis, you think of things like carbon dating and obsidian hydration-- things that are not very accessible to most of us. This is a really interesting process and one that is easy for a layperson to understand.

Posted at Dec 18/2007 10:09PM:
KYL: Wow!!! This is pretty cool. I always wondered, watching CSI, how they date the buildings and wooden structures. This is what makes archaeology science, I guess...