The hard part in the mountains is that it may be less clear what is the windward side of a tree

In addition to wind & sun exposure, I wonder about snow albedo and abrasion (loose pumice soils in summer and/or ice crystals in winter). Any thoughts there? Also: is the “strippiest” side of the tree not obvious from external inspection? And if so, does this vary among trees within a locale?

The hard part in the mountains is that it may be less clear what is the windward side of a tree. You may have to further analyze neighboring slopes, nearby tree cover, etc.

extreme snow could led to strip formation by breaking off branches

Dessication, winter or summer, could lead to partial cambium dieback. Is stripping more common on the windward, southern-exposed side?

I will bet you that stripping is synchronized among stems, does not occur randomly through time.

That was our impression tho it would take more info to establish this. The “loudest” event in the Almagre chronology was the extreme low growth in the 1840s and impressionistically some strip bark pulses seem to originate around that period, Pete thought that extreme snow could led to strip formation by breaking off branches – he noticed some wounds in progress as some branches were tearing bark off as they fell down. Ironically, the growth pulse would be a reaction to the 1840s. Recall that Mann’s bizarre “CO2″ adjustment was mainly to late 19th century growth. On this scenario, the extreme 1840s caused a non-random time distribution of strip barking.

Is it an intrinsic property of tree ring cores, that as they approach the outer bark, the rings are fatter and are then interpreted as higher temps in the present?

No. Typically, it’s the opposite. (Hence the common use of the negative exponential detrending spline.) However, in the special case of stripbark bcps, well, read my previous comment. Whether you get a fattened outer set of rings depends on (1) when you sample relative to the time of stripping and (2) whether or not you get your corer into the fattest part of the growth rebound. Recall not all cross-sections have the same degree of rebound.

Graybill said that he preferentially selected strip bark trees. In a small sample, such as Graybill, having even a few extra strip bark cores in their excursion phase, could cause a HS shape all by itself.

I will bet you that stripping is synchronized among stems, does not occur randomly through time.

http://lvo.wr.usgs.gov/CO2.html

Here is a map of the CO2 emission sites around Mammoth.

http://lvo.wr.usgs.gov/images/treekilb.jpg

Watch where you go snow mobiling around there!

#25. As I’ve said on many occasions, the “spectacular growth” in Graybill’s chronologies was not replicated by Ababneh and may well be an artifact. So it’s completely premature to think of theories until the chronology can be replicated.

You’re undoubtedly right that the Sheep Mtn. HS is just a stripbark growth surge effect, as evidenced by Ababneh’s suppressed replication effort.

However, the burden of proof is on Mann et al to demonstrate that all their ceterises were really paribus, including local CO2 and volcanic ash fertilization, if potentially relevant. Halpern (aka “Eli”) therefore is to be thanked for calling attention to yet another crack in the stick.