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Correlation between harvest results 1683-1780 and tree ring

Posted: 10 Aug 2011, 17:17
by taxelson
Occasionally I found a list of "judgments" according the harvest results in Sweden for each year between 1683 and 1780. I transformed it into numbers, and found it matching some tree ring data very well! See

Re: Correlation between harvest results 1683-1780 and tree r

Posted: 11 Jan 2012, 10:23
by ale
Very interesting!

Many years ago I read something (a book? A paper? It was at university…) in which a series of detailed historic annual annotations about the harvest of grapes – I think I remember it was in France - were used in order to reconstruct climate… when grapes was collected sooner or later than usual, the author speculated about climate of this given summer. Regrettably I don’t remember the bibliographic reference (neither I’m sure about contents…) but I’m quite convinced that the author didn’t imply dendrochronology. Later, I always thought that it would have been intriguing some experiment with annual tree ring growth and this kind of annotation data.


Re: Correlation between harvest results 1683-1780 and tree r

Posted: 13 Jan 2012, 23:22
by ale
What an in-cre-di-ble coincidence!

Few days later than Taxelson brought to my memory this case, and while I was searching for bibliography about a totally different argument, I found something strictly related to it, if not the original paper I was thinking about…

J. Roger Bray 1982, Alpine glacial advance in relation to a proxy summer temperature index based mainly on wine harvest dates, A.D. 1453–1973, in “Boreas”, Volume 11, Issue 1, pp. 1–10.

There is an abstract on “Wiley online library” ( ... x/abstract):

“A highly significant correlation was calculated between French wine harvest dates and central England summer temperature from 1659 to 1879 which harvest dates might be used to approximate western European summer temperatures for the pre-instrumental period. A proxy summer temperature index was thereby constructed which combined French and German wine harvest and central England temperature data. This index was significantly correlated with a tree-ring density prealpine Swiss summer temperature index from 1484 to 1973 and also with Northern Hemisphere annual temperatures from 1579 to 1973 (…)”

Though the author is probably the same one with a 0,80 P2Yrs CorrC (I don’t think many people dedicate themselves to this specific argument, and furthermore I recall something about relationship with glacial advance…), I would not assure that this is the paper I referred to, since I think I remember it was not in English. I would say that it was in French or Italian: in this latter case that would be probably a translated edition of a book. Anyway, it seems that I was wrong about application of dendrochronology, since it appears that he uses indices derived from tree ring density too.