l-bow

I've have been arguing with a creationist about tree rings. Does the below make any sense? In previous posts, he (sds) has been arguing that a single ring is good enough for a match, if you use intra-annular rings. But now he turns around and says a single ring isn't good enough. I get the feeling that this guy is actually a troll, trying to piss me off, by doing this.

> sds,
>
> You have written in previous posts that even a single ring could be
> statistically significant. Well, if that's the case, then would not
> considering wore than one ring make it even more significant?

Seems to me the more rings the better.

> And if
> the tree rings (imporatant-plural ) didn't match then wouldn't this
> mean the positive result from using one tree ring be invalidated?

Certainly could be that way. It would depend on how poorly the adjacent
rings matched and how closely the one "good" ring matched. It would require
the adjacent rings not be "messed up" and unusable for some reason. It's
hard for me to imagine a situation where what you are suggesting would not
be correct. It's hard for me to imagine a single ring being unique enough
and matching well enough to ever carry much weight. But it is possible, in
principle, for it to do so.

> If
> you ask why, here's why: If the trees experienced the same
> environmental conditions for one year, then they should have also
> experienced the same environmental conditions over several. Therefore,
> the results have to be valid for both the single tree ring and
> multiple tree rings cases in order for there to be a match.

Is this really that meaningful? Maybe I'm not following you. Couldn't we say
the same thing about 2 or 5 or 12 rings? IOW, if we accept a 5 ring match,
how do we ignore the fact that rings adjacent to that 5 ring set *don't*
match (if they don't)? Same for 12 or 20, ISTM. I understand your point (I
think), but I don't see why it's any more applicable to a small number of
rings (even a single one) than it is to a large number. In general, the more
rings in the matched pattern, the more likely the trees grew those rings in
the same local environment. If the pattern has 3 rings, then it wouldn't
take as much of a mismatch in the adjacent rings to "override" the match as
it would if the pattern had 15 rings. Maybe that's what you are saying? I
agree with that too. Seems to me the statistical significance of a match is
based on three things - the uniqueness of the pattern, the closeness of the
match, and the number of rings in the pattern. So, within some reasonable
limits, it is possible for a very unique 10 ring pattern which matches very
well to be more reliable than a not-as-unique 15 ring pattern which matches
not quite as well - but I think it would be unusual to find such a thing
for real.

Do we disagree on something here? Surely we do. I don't know how to respond
otherwise

[ October 14, 2002: Message edited by: l-bow ]

[ October 14, 2002: Message edited by: l-bow ]</p>

Tom Sawyer

I don't know anything about tree rings myself, but this guy says he does. Check it out and maybe it will be helpful to you:

<a href="http://web.utk.edu/~grissino/" target="_blank">Tree Rings</a>

Dr.GH

I would need more from the tread to understand what you are discussing. A very good pair of dendro sites are linked below:

<a href="http://www.sonic.net/bristlecone/dendro.html" target="_blank">http://www.sonic.net/bristlecone/dendro.html</a>

<a href="http://web.utk.edu/~grissino/" target="_blank">The ULTIMATE tree-ring pages!</a>

Jesus Tap-Dancin' Christ

Creationist argument? Make sense? Surely you jest.