"codex" wrote in message
news:Rcxpd.7969$K36.4493@trndny03...
Thanks, but there's some problems with that technique. First, I don't
have
a tool that would remove a hollow core from these trees (The largest are
3.5-4.0 ft. in diameter). Second, its intrusive and I'd rather not bore
into the tree. Finally, I'd like to survey a hundred trees or so which
would make it impractical.

The "growth factor" method involves a quick and easy measurement with a
tape, and an estimate is all I need, not spot on accuracy.

Thanks again.




Maybe one could do a high-frequency echo (like done on pregnant women) and
then count the rings revealed.
Then calculate an algorithm based on a sample of trees, and then apply this
to the remainder.

The following:
http://www.botanik.uni-bonn.de/conif...ics/oldest.htm

gives usual methods including the simple one (with picture) I suggested
before.

If you go the Google thing and type in "tree age" in the 'exact phrase' box,
a whole lot of links come up.
Good luck.