Treeringlore

Treeringlore is a lore which works to give the year of a beam of wood by meting its rings.

Every tree grows during the spring and summer, and stops growing during fall and winter. These two spells of time can be seen in the rings of a tree: a thick ring for a time of growth, and a thin ring for a time of no growth. But not all years are alike in weather, and some are wetter or dryer, some brighter or darker, and some hotter or cooler. These things all shape how much a tree can or cannot grow, thus making each ring unalike in thickness.

It is this unalikeness which, when streched over many years, give a plot of ring thicknesses that can only be for those years. By starting with wood of a known year, other wood can be matched to it and thus to a year.