These represent growth patterns that reflect the conditions of the season or the year (4) and it is these rings on which the entire study of dendrochronology is based.
They come in all shapes and sizes from the smallest saplings up to the colossal redwoods of North America - it could be said that we take them for granted, yet they are vital to teaching us about many aspects of our past. Before then, tree ancestors may have looked slightly tree-like but they were not trees in any proper sense.
The dawn of the age of true trees came with the evolution of wood in the late Devonian period.
This says nothing about either when the particular tree was felled, nor about the date it was used (8).
In past times, good quality timber may have been reused (10) and for the archaeologist, it is important to check other records against the new data.
In each growth season, trees create a new ring that reflects the weather conditions of that growth season.