I have a feeling we are talking past each other with views based on assumptions not expressed.
Let's take it down a notch and see?
Dendrochronology is based on the concept of counting annual rings of growth in many 'signature' tree species, from European oak to California bristlecone pine. This is based on the assumption that one ring, composed of fast summer growth and slow winter growth, is easily discernable and that it represents an actual year of growth.
The first step in establishing such a system is to verify that the data is accurate, that the rings are in fact annual, and that there are not significant factors that can cause false data. Some of these factors are discussed on the tree ring website cited, and this is usually checked by using many more than one sample. Tree rings can be counted from cores from many trees, for instance. Climate changes cause differences in the growth rates and thus in the size of the annual rings, and these can be used to check from one sample to another to see if there is a consistent pattern of growth. This climate data can also be used to extend the chronology from living trees to recently dead samples and eventually even to fossil trees, but there needs to be sufficient numbers of samples with plenty of overlap so that pieces can be aligned and the data repeated. Think of the climate pattern as the fingerprint of the tree rings. This is one level of calibration. Sources and frequencies of errors give you the accuracy of the system in (+/-)%.
The second step is correlations with other tree ring systems to see if the data matches on climate: some years are better for growing than others, and the patterns of growth show variations in climate in the size of the tree rings. Other checks are marker events, like the "year without a summer" or wood buried by Pompeii or in Egyptian tombs of known dates, that show up at the correct place for annual growth rings to match the historical records. Climate is global, and the data shows similar trends around the world, from oaks in Europe to pines in California. This is another level of calibration.
When a piece of wood is dated using Dendrochronology the ‘fingerprint’ of the climate pattern is compared to the master file to find the best match, and the accuracy depends on the tree species and the size of the sample (how many rings to match).
There is more information in a series of slides at:
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Essentially calibration comes down to verifying that the rings accurately represent annual growth.
we are limited in our ability to understand
by our ability to understand
Rebel
AAmerican
.Zen
[Deist
{{{Buddha walks off laughing with joy}}}