Dating oak tree
Nowadays, the internationally agreed upon calendar calibration curves reach as far back as about 48000 BC (Reimer et.
al., INTCAL13 and Marine13 radiocarbon age calibration curves 0 – 50000 yrs cal BP, Radiocarbon 55(4), 2013).
It should be noted that a BP notation is also used in other dating techniques but is defined differently, as in the case of thermoluminescence dating wherein BP is defined as AD 1980.
These changes were brought about by several factors including, but not limited to, fluctuations in the earth’s geomagnetic moment, fossil fuel burning, and nuclear testing.
The most popular and often used method for calibration is by dendrochronology.
Libraries of tree rings of different calendar ages are now available to provide records extending back over the last 11,000 years.
The trees often used as references are the bristlecone pine (Pinus aristata) found in the USA and waterlogged Oak (Quercus sp.) in Ireland and Germany.