4.3 Dendrochronology

DendrochronologyA dating method that analyses the growth rings of trees to determine exact calendar years, often used for wooden artefacts or structures. is a potent archaeological method in our toolkit, and makes use of the growth patterns of trees to effectively count years and establish an absolute chronologyA timeline that assigns specific calendar dates to archaeological events or materials, often established through scientific dating methods like dendrochronology or radiocarbon dating..

How it Works

At its core, this method involves counting tree rings. These rings are the result of yearly growth in trees, as the plant expands gradually outward year on year by creating new bark. In temperate regions, where seasons have a noticeable and profound effect on tree growth, these rings serve as obvious lines between years. These rings can, quite simply, be counted. If a living tree were chopped down today and we counted the number of rings in a cross section of the trunk, we would know the age of the tree to within a handful of years. If we then counted back from this year we could establish the calendar year that the tree started growing. This works archaeologically as well, and if the cross section of a tree were found on site we could count back its age in the distant past. At first this may not appear to be that useful, but the number of trees in the world and degree of preservation we have found tree rings in has allowed us to construct reference chronologies dating back hundreds and thousands of years.