>"you can start with a freshly-cut tree or core sample and work backwards to date an older sample. This is highly accurate and does not depend on records of whe

>"you can start with a freshly-cut tree or core sample and work backwards to date an older sample. This is highly accurate and does not depend on records of when a tree was cut down." Assuming that the matching of rings is done perfectly (from my looking it up this is not trivial, where is the best place to find the raw data for one of the reference sequences btw?), I don't see how you could trust this without matching some rings to wood from known artifacts to "check it". I mean can't you get a decade-long drought and so miss 10 years? And here is a source reporting that missing rings become more frequent as you look back further (it grows to 6% missing at 150 years): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4885872/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4885872/ Of course that all depends on the species, etc so maybe it can be avoiding by only selecting the "right" samples. Can you share a good source where I can see how one of the reference sequences has been arrived at from scratch?