What is Dendrochronology?
Dendrochronology is an exact method of dating wood.
Tree growth only occurs in the outer layer between the bark and the actual trunk.
In temperated zones of the world, trees only grow
during the warm period of the year. During the summer the growth is relatively fast resulting in a
light wood. In the autumn the growth is slower and gives a dark wood. If the weather is warm with
a lot of rain we get a wide ring of new wood that year. If the weather is cold or there is no rain for
a long period the ring width of that year will be very narrow. This creates a
pattern of individual tree rings of varying width depending on the current local climate, i.e.
depending on the variations in precipitation and temperature.
The weather variation over a number of years gives a ring width growth pattern which is characteristic for
those years. We could say that it looks like an individual fingerprint of that period.
By measuring tree growth over a long period, a reference curve can be constructed showing mean
values of the differences in annual growth. The curve is constructed from tree samples of varying age
where the period of growth for any sample overlaps the periods of growth for some other samples.
Usage. Today, dendrochronology is used around the world for identifying variations in local and world climate.
It is also used for dating historical buildings and archeological findings of wood.