Dendrochronology is the method of dating based on the analysis of grow rings which can be seen on a cross section cut perpendicularly through the trunk of a tree. Well established and correlated chronologies extend back more than 8,500 years (Southwest US) and 10,000 years (South Germany), in several types of wood, to the exact calendar year.

Recently I’ve noticed that, at least in some incidents, the time could be determined up to hours and minutes, not just calendar year. Take a look on the photo: it’s 11:15, don’t you see it?