Do tree rings show the age of the tree in years, or does it show the different periods of wet and dry times. So if a tree has 50rings in it does it mean that it is 50 yrs old or it has gone through different times of wet and dry periods.?
Hi Gemmy, this is an interesting subject, the rings found in the cross section of a tree are annual secondary growth rings, so each ring represents one year's growth. The science is called 'Dendrochronology' and is a very useful tool for dating almost anything that is or is made of wood. Each year has a different growth cycle, warm and wet years cause greater growth and so wider rings, so hot dry years produce very narrow rings, so by using a sequence of over-lapping records, archaeologists can date buildings by their beams, looking for a match in the records. If I remember correctly, we have a record of over 5000 years at this point, and dendrochronology can be used to calibrate short range radio-metric dating systems.