The felling of the oak trees used to build the Karschau ship took place in or around the AD 1140s. The tree-ring curves from the oak planks from the Karschau Ship match best with site-means from Odense, a medieval town on the island of Funen, Denmark. New research being carried out by the author is allowing the determination of the provenance of ancient oak to a more local level. Through this dendrochronological research, it is now possible to differentiate between small regions of timber sources for shipbuilding, allowing a more nuanced interpretation. © 2006 The Author