Archaeologists sometimes study the ring patterns in beams or other pieces of wood from archaeological sites to help date the sites; they may also study the ring patterns to infer the local climatic history.
Extended tree ring chronology is not an independent confirmation/calibration of carbon dating earlier than historically validated dates, as has been claimed. Well, this site provides over 30 years of information. Would you support our efforts to keep this information coming for 30 more years?) of the White Mountains of Eastern California, were dated in 1957 by counting tree rings at 4,723 years old.This would mean they pre-dated the Flood which occurred around 4,350 years ago, taking a straightforward approach to Biblical chronology.From recording tree-ring patterns in several geographic areas, scientists have found that all the region’s trees have the same pattern. He reasoned if he could trace patterns far enough back in time, he could outline a history of regional climate and see if sun spots could be related.Douglass used a bridging method to create his chronology.This, in turn, let him determine the year each tree started growing.
The calculation was straightforward: count the dark rings inward and subtract that number from the year the tree was cut.
There are many points in a given sequence where a sequence from a new piece of wood matches well (note that even two trees growing next to each other will not have recognized that ring pattern matches are not unique.
The best match (using statistical tests) is often rejected in favour of a less exact match because the best match is deemed to be ‘incorrect’ (particularly if it is too far away from the carbon-14 ‘age’).
The extended tree ring chronologies are far from absolute, in spite of the popular hype.
To illustrate this we only have to consider the publication and subsequent withdrawal of two European tree-ring chronologies.
Recent research on seasonal effects on tree rings in other trees in the same genus, the plantation pine , has revealed that up to five rings per year can be produced and extra rings are often indistinguishable, even under the microscope, from annual rings.