Dan,

Although I am indeed the lazy type, I do understand how the sequence of rings
allows one to establish when the tree grew (I suppose it's like bar code; but
even if it's not, I understand it).

What I was asking is how anybody can tell when the tree was cut unless you
have an identifiable last ring below the bark. Let's say the rectangular
timber we're looking at includes the center of the tree and the first 65
growth rings, and that we know from the sequence of rings that we're looking
at a tree that sprouted in 1750, and we can see until 1815.  But how does one
know that there weren't another 30 (or 70) rings beyond the edges of the
timber you're looking at?

Shall I try it again, louder?

Ralph