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How trusted is dendrology?

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I'm a novice to all of this, but can dendrology be a game changer when it comes to authenticating an old instrument that is disputed? For example, there is a Rugeri where back in the 1930's it was authenticated a original Rugeri circa 1690. Then in 1990's it was authenticated as "Follower of Rugeri"and that it was circa 1760. There has been some talk the willingness for someone to put their name/reputation behind an instrument, but if a dendrology report is done then I would assume then it would give way more confidence to authenticate the instrument?

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It can (contrary to the usual model) prove a negative : that an instrument was not made by the maker whose label in in it. I.e., a top made of wood dating to 1870 at the latest could not have been made by a maker who died in 1770.

It just cannot prove a positive : that an instrument with a Giovanni Pastavino label was made by him.

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From what I have been told here dendro only works on tops, so if the top has been replaced then all bets are off, right? Don't know that it happens alot, but it is perhaps one more limitation. It would be nice to be able to date all parts through something like C14 testing (fyi, I really don't know anything about that either) to see if all the parts are at least x years old. 

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Dendrochronology is a tool that helps experts determine age. As has already been suggested, it can show how new a piece of spruce is. Finding out that the piece is very old doesn’t necessarily mean that the age of the wood and the instrument are the same, as many makers used and still use old wood. 

The way I see it, it’s a marker for identification, much like other elements like varnish, purfling, and edge work. I wouldn’t expect to nail down an attribution with it alone, but it can help rule out some possibilities. 

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12 minutes ago, Brad Dorsey said:

What you are talking about is dendrochronology (tree ring dating), not dendrology (the study of woody plants).

Darn, you beat me to it.  :P

1 hour ago, glebert said:

From what I have been told here dendro only works on tops, so if the top has been replaced then all bets are off, right? Don't know that it happens alot, but it is perhaps one more limitation. It would be nice to be able to date all parts through something like C14 testing (fyi, I really don't know anything about that either) to see if all the parts are at least x years old. 

C14 won't help you here.  The usual cut-off for radiocarbon dating is 500 years B.P.  Violins are too recent to get a usably precise date from.  :)

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Most experts seem to start their assessment of a violin with a 'dendro'. For one it gives a sort of good starting point knowing after which year the violin must have been made. And for another thing it is wise not to get trapped in 'wrong dating'. (Would be too embarrassing) 

However as The Violin Beautiful already said, it doesn't make a good expert, because you need to know much more to pin an instrument correctly down to one maker.

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As was mentioned, repairs on the top might compromise the dendrochronology.  I assume the person doing the dendro would look for evidence of repairs.

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On 6/6/2019 at 10:26 AM, Andreas Preuss said:

Most experts seem to start their assessment of a violin with a 'dendro'. For one it gives a sort of good starting point knowing after which year the violin must have been made. And for another thing it is wise not to get trapped in 'wrong dating'. (Would be too embarrassing) 

Actually, in my experience, I have often found it more effective to develop an opinion concerning the origin/maker of the instrument first, and use the results of dendrochronology as support for that opinion (if they do). The data bases for spruce seem vast enough now to usually be able to date the wood, and often help to determine if there are similarities to other related instruments or geographic regions.  In most cases that I've experienced, the opinions developed have been supported, but a recent experience a colleague and I had determined the wood was much younger than we expected... but honestly we had it tested because something didn't "feel" quite right.  The top was made 130 years too late (thank you Peter!).  Quite a convincing copy... :) Our first impressions, concerns and the results of the test provided us with a limited pool of makers who were likely to pull something like that off.

In other words, I don't think embarrassment is much of a concern as long as one plans to use dendro when it's wise to, no matter what the order of things.

 

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Dendrochronology has had a lot of bad press since the late 1990s which really emanates from the trust that was placed on Prof. Peter Klein's report on the Messiah, how it was used and the fact that it was ultimately discredited. Thereafter as the discipline evolved various people got on board the bandwagon with rather dubious and scientifically unrigorous methods. They have largely moved on, but not without causing lasting damage. More recently, just sheer nincompoopery, such as a recent privately published book on the Messiah that simply uses out of date sources and betrays a thorough lack of understanding in the science, but contributes to the heresay that it it is open to be questioned when this could not be further from the truth. 

I write that to give a taste of why this question is often asked about dendrochronology. However, perhaps the most important thing about the Topham & McCormick method that was developed in the late 1990s is that every single result is logged on a database, and every new result is crossmatched with the whole database. It actually goes as far as to say that the "date" importance is almost secondary in some cases to the understanding of what instruments your example cross matches - or fails to cross match. For example, a while ago I submitted a potentially Florentine instrument for examination, and it came up with hundreds of French cross matches and not a single Italian one. It provided information that confirmed a direction of research that ultimately yielded results. In consequence, using a dendrochonologist such as John Topham or Peter Ratcliff has the advantage of this process of cross matching against vast databases.. 

Dates can indeed be helpful too, and for a layman can provide absolute proof. I recently had a correspondent who claimed to have a del Gesu which I disputed, and ultimately I recommended a dendro on the basis that it would settle the matter scientifically, rather than prevaricating about stylistic points on poor photographs which would only embitter him further. 

Furthermore, dendrochronologists using the computer method are able to rate cross matches statistically - ultimately there can be random shadow results that look good but are not. Neither Topham nor Ratcliff will publish a result unless it has a statistical value of T=8, which is very high, and if no result meets that bar, they will report no result even if there may arguably be trace readings that inevitably are of ahem.. "interest". 

Lastly, nothing is ever simple. Often instruments won't render a result for one reason or another. Often also a result may be completely nebulous, especially if the purpose of the dendro is to authenticate an instrument that is a mystery to the experts in the first place. So it works exceptionally well on the instruments it is good for, but the absence of a result has to be regarded neutrally and not as a black mark against the instrument. It is never the be all and end all, except when eliminating possibilities by virtue of a strong later date. 

Peter Ratcliff's video here is excellent. Well recommended. 
 

 

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Wow... thanks for all the interesting feedback and discussion! I see there is much varied opinion about this subject and all of this is very interesting indeed. And thanks for correcting the difference between "dendrology" vs "dendrochronology" :)

So, back to my original thread ... let's say if I had dendrochronology and it comes back saying that the wood matches that of other Rugeri cellos they have on file. So then at that point would an appraiser have more confidence to certify the cello as a Rugeri? I know this probably is a very open ended question with lots of varying opinion again.:wacko: Would the certificate be written in a such a way to say they based their determination off dendrochronology? I'm just curious because this all seems very fascinating! ;)

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14 hours ago, Jwillis said:

Any idea if it works on heavily repaired tops ie many repaired cracks etc? 

I think if they are well closed and no material was removed then there is no problem. Even if some material was removed each ring is measured separately so I believe few missing points won't change the dendro result of whole top dramatically. And they can be approximated by looking at less damaged areas of those rings.

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