Two respected dendrochronologists wrote in criticizing my recent post averaging new white spruce chronology contributions to the ITRDB data bank. [Update: see post here with further thoughts on the location of this site. Next post in category] Rob Wilson wrote, using an uncharacteristic Gavin-esque sigh, as follows:
Location, location, location!
ecology, ecology, ecology!
you are confusing the issue again.
Your little “spiel” above is meaningless without some site information.
Where are the spruce sites located (?Map)?
How close are these sites to the high elevation or high latitude tree-line?
For what purposes were these sites originally sampled?
For readers of this blog, PLEASE understand that one cannot randomly sample trees from any location and expect there to be a valid climate signal (temperature or precipitation).
In fairness, Rob, I don’t think that there are any readers of this blog that expect that one can randomly sample trees from any location and expect there to be a valid climate signal. I’d say that the concern of this blog is more whether it is valid to choose sites ex post and expect there to be a valid climate signal.
As Rob points out in 3 and 28, Steve’s analysis is flawed! You can easily search out for yourself where the Meko sites are located using Google Earth. They are a long way from latitudinal tree line or the mountains!
Both are concerned that “misinformation” not be spread through inappropriate selection of sites. Rob says:
Criticism is fine, but misinformation is counter productive.
I endorse this comment and I do not wish to contribute to any spread of misinformation. I am happy to correct or amend any incorrect statements. As Mike Pisaric suggested, I located the Melo sites on Google Earth, as shown below together with the Gaspé site, used in Jacoby and d’Arrigo 1989, 1992 (their northern treeline reconstruction used in many multiproxy studies); MBH98 as Ross and I discussed and, as far as I can decode in the absence of a listing of sites, even in D’Arrigo et al 2006.
Figure 1 showing Meko location and Gaspé location
Now here is a closer view of the Gaspé peninsula. I’ve used the coordinates for the Gaspé site (to the nearest minute) from ITRDB series cana036 (St Anne River). The site itself looks like it is in a river valley, which I dare say will prove to be the St Anne River. As far as I can tell, this site is nowhere near latitudinal or altitudinal treeline. I’ve endeavoured to obtain a more precise location for this site, so that I could commission re-sampling, but Jacoby said that the sampling was done before GPS and he was unable to provide directions to the site.
I’m grateful that both Rob Wilson and Mike Pisaric are taking such keen interest in rooting out inappropriately selected sites from multi-site averages. I’m sure that Mike Pisaric will agree that the use of the St Anne series as a temperature proxy, given its distance from latitudinal and altitudinal tree line, makes it “flawed!” and will communicate this opinion to all of the authors of Mann etal 1998 and D’Arrigo et al 2006 with the same alacrity with which he reproached my use of the Meko sites.
Likewise, I’m sure that Rob Wilson will write to the authors of D’Arrigo et al 2006 advising them that their ” little ‘spiel’ is meaningless without some site information” and ask “where are the sites located (?Map)?” (and, Rob, a big red dot in Alaska for multiple sites doesn’t count as a location map). If Rob gets that information, maybe he can pass it along to me.
Figure 2. Gaspé peninsula