Dendrochronology dating method
Fully anchored chronologies that extend back more than 10,000 years exist for river oak trees from South Germany (from the Main and Rhine rivers).
Timber core samples measure the width of annual growth rings.
Visible rings result from the change in growth speed through the seasons of the year, thus, one ring usually marks the passage of one year in the life of the tree.
The wood could have been reused from an older structure, may have been felled and left for many years before use, or could have been used to replace a damaged piece of wood.Likewise, in areas where trees grew in marginal conditions such as aridity or semi-aridity, the techniques of dendrochronology are more consistent than in humid areas.These tools have been important in archaeological dating of timbers of the cliff dwellings of Native Americans in the arid Southwest.Growth rings, also referred to as tree rings or annual rings, can be seen in a horizontal cross section cut through the trunk of a tree.Growth rings are the result of new growth in the vascular cambium, a lateral meristem, and are synonymous with secondary growth.