Dendro dating wood
See the cal BP discussion for additional information about radiocarbon calibration.
Tree-ring dating works because a tree grows larger--not just height but gains girth--in measurable rings each year in its lifetime.
Because of that precision, dendrochronology is used to calibrate radiocarbon dating, by giving science a measure of the atmospheric conditions which are known to cause radiocarbon dates to vary.
Radiocarbon dates which have been corrected--or rather, calibrated--by comparison to dendrochronological records are designated by abbreviations such as cal BP, or calibrated years before the present.
Tying tree ring fragments in the tools to established chronologies, Bill and Daly (2012) discovered that all three of the mounds were opened and the grave goods damaged during the 10th century, likely as part of Harald Bluetooth's campaign to convert Scandinavians to Christianity.
As archaeological dating techniques go, dendrochronology is extremely precise: if the growth rings in a wooden object are preserved and can be tied into an existing chronology, researchers can determine the precise calendar year--and often season--the tree was cut down to make it.
For further information, please find below a leaflet and two example reports for down load.
One on sampling of live trees on the Ancient Oak at Lullingstone Park and one on dating a timber-frame building at The Rock Inn, Chiddingstone.
Lübeck's medieval history includes several events that are pertinent to the study of tree rings and forests, including laws passed in the late 12th and early 13th century establishing some basic sustainability rules, two devastating fires in 12, and a population crash between about 13 resulting from the Black Death.
It had long been known that three 9th century Viking period boat-grave mounds near Oslo, Norway (Gokstad, Oseberg and Tune) had been broken into at some point in antiquity.