MIRROR POSTING: YAD06 – the Most Influential Tree in the World

Climate Audit is getting hit with traffic again, so this is a mirror post for interested parties. – Anthony

YAD06 – the Most Influential Tree in the World

by Steve McIntyre on September 30th, 2009

Obviously there’s been a lot of discussion in the last few days about the difference between the CRU 12 and the Schweingruber 34. In making such comparisons, it’s always a good idea to look at the data in detail – something that obviously should have been done by Briffa and the Team before the widespread use of the Yamal proxy in so many reconstructions, rather than this late date, over 9 years since its original use in Briffa 2000.

In a previous thread, I showed a plot of the actual ring widths of the 10 CRU trees ending in 1990. Today I’m going to show a similar plot of the “dimensionless index” for the same 10 trees. It is the “dimensionless index” that is averaged to make the “chronology”.

Recall that in RCS, a “standard” is established for the decline in ring width with age – the decline is assumed to be a negative exponential curve plus a constant (“generalized negative exponential”) and the index is the observed ring width divided by the “age standard” ring width for the age of the given tree in that year.

For comparison, I’m going to do a similar plot for 18 Schweingruber trees (17 sampled in 1990 plus one). The plots are shown on a uniform vertical scale (0,9) and a uniform horizontal scale (1850,2000). I’ve marked 1990 with a vertical red line and a horizontal line at 1 (the overall mean ratio.)

First, here is the plot for the 18 Schweingruber trees. Probably your first reaction is: why did he choose such a squished vertical scale for this graphic – we can’t see this as clearly as we’d like. Your second reaction is probably – well, if there’s a stick in there, it would take something like Mannian principal components to dig it out.


Figure 1. 18 Schweingruber russ035w trees, 17 ending in 1990. Age-adjusted index.

Next here is the corresponding plot for the CRU 10. Without doing any sort of fancy statistical test, one can readily see a difference. None of the YAD** trees on the right are especially old – the graph shows their full history – all start after AD1800. However, instead of the standard negative exponential declining growth, these particular trees started off very slowly, like old trees, and then got a burst of virility when they got to be 100 years old. Benjamin Button trees so to speak. Because of the one size fits all RCS standardization, this post-100 growth pulse is divided by a small standard denominator – YAD06 reaches 8 sigma and is the most influential tree in the world. YAD06 does not always drink beer, but when it does, it drinks Dos Equis. Stay thirsty, my friends.


Figure 2. 10 CRU trees ending in 1990. Age-adjusted index.

(Yellow Highlight by Watts)

UPDATE: Oct 1. Tom P in a comment below asserts:

These plots explain why it would be extremely difficult to extract a centennial signal from the live cores of Schweingruber series. Most are under 100 years old! The Schweingruber series is therefore of very limited utility for a valid comparison with the much longer-lived trees of the CRU archive. Your earlier sensitivity test is comparing a signal to noise.

I agree 100% that it “would be extremely difficult to extract a centennial signal” when “most [of the cores] are under 100 years!”. However, I disagree that the trees in the CRU archive are “much longer-lived”, other than the trees selected for the modern comparison. The following graphic shows the average of tree by year in the CRU archive, the average age in the “Schweingruber variation” in which russ035w is used instead of the CRU12 to represent living cores. Prior to around 1800, the average age of the tree in a given year was around the 100-year mark that Tom complains about. There is a profound inhomogeneity in the age composition of the living trees in the CRU archive relative to the subfossil archive, which is much reduced in the Schweingruber Variation. Does the age inhomogeneity in the CRU version “matter”? It’s the sort of thing that should have been reported and discussed in a site report, prior to using this chronology in multiproxy studies.


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October 1, 2009 10:45 am

So the entire hoax of AGW was built on a single tree ring?
And we are a Senate vote away from taxing ourselves into oblivion based on this hoax?
This really should end the practice of bending over backwards to be civil to [snip] team.

October 1, 2009 10:55 am

Hockey sticks and Magic wands are made from trees…

October 1, 2009 11:13 am

Maybe that tree is where Roy Hobbs’ “Wonderboy” came from. 😉

Henry chance
October 1, 2009 11:20 am

[snip] It seems a good experiment would toss out a single extreme sample whether it was high or low. Having said that. An extreme sample carries much more weight if there are 10 other trees sampled than if there are 100 other trees samp[led. I will assume if it is all about one tree that explains why he wanted to use a small sample size. It sure didn’t take very many Mann hours to fork over a sample of 10 tree records. Why stall for 3 years?

October 1, 2009 11:32 am

OHhhhhhhh all is clear now! Was good enough in the 1600’s but we’ll totally toss the same ages later. WHY?

October 1, 2009 11:36 am

How were weights assigned? Why aren’t they each given equal weight?

October 1, 2009 11:37 am

“Unwilling to wait for Congress to act, the Obama administration announced on Wednesday that it was moving forward on new rules to regulate greenhouse gas emissions from hundreds of power plants and large industrial facilities.
… under the rule proposed Wednesday, the E.P.A. would assume authority for the greenhouse gas emissions of 14,000 coal-burning power plants, refineries and big industrial complexes…” New York Times
Those words “AUTHORITY for greenhouse gas emissions” are very bothering. “OK lads, this plant has put out enough CO2 for the day. Turn it way down.” Or limit the rate of CO2 emissions, which will limit the amount of power output. Shades of the former USSR.

Mike G
October 1, 2009 11:52 am

I find it truly depressing to see scientists carrying on like witch doctors of old staring at chicken bones to try to discern the future. Trees are not much of an improvement on chicken bones
This tree ring data tells nothing. It is a multi-parameter amalgam and the temperature influence may be parabolic!
On second thoughts the chicken bones are a better idea – find some fossilised chickens and correlate bone size with temperature – yout could call this the the Kentucky proxy
I need a drink

October 1, 2009 11:55 am

Is there an image of YAD061 tree ring cut?
I am thinking there is a fattening on one side, or a low branch that is sliced obliquely, making for one heck of a fat tree ring lobe in a segment.
You could also have 2 trees that grew together (they do that).
Something is funny with this tree.

p.g.sharrow "PG"
October 1, 2009 11:57 am

It really is too bad modern sciencetists are so narrowly educated and desperate to make a reputation.
When we were in early grammar school science we were told that tree rings represented warm and cold weather years, later years we were taught that the rings thickness represented wet and dry years. In high school ag. and forestry classes we were taught they were caused by competition for sunlight and nutrients.
In business the creation of spread sheets can give a very good idea of time and material costs if all of the information is properly accounted for. The cherry picking of data and hidden formulas is a sign of lazy work or a conman or both.
Unfortunately many reviewers are too lazy to do the work or have their own agenda that fits in, one hand washing the other.
Luckily, on this site, even the “unlettered” sciencetists are willing to dig into the details.

October 1, 2009 12:09 pm

Years of fewer jobs, high prices and pain, and a billion barrels of jet
fuel and caviar consumed on Agenda 21 Junkets,
One Tree !!!!!
Im rad faced angry, and histerically laughing at the same time.

Bill P
October 1, 2009 1:02 pm

In his rebuttal, Briffa says that Mr. McIntyre replaced his own chronologies with chronolgies of lesser “weight”.
As an ignorant high school teacher I tried to avoid this concept, which just confused the heck out of everybody. A test was worth a hundred points, which was obviously worth a lot more than daily assignments of 10 to 20. Still, the number stood for itself. There were not multipliers.
But do dendros routinely “weight” underrepresented cores in their series? Is there direct evidence that Briffa did something unethical in so doing?
WRT the seemingly suspicious or “ironic” under-representation of modern period, and the consequent need for “weighting”: Pictures of the Yamal area kindly provided by one of the readers here show a land virtually deforested. At least one of the implications of this is that the place was aggressively deforested by people over the centuries, which might make live tree cores and even 20th century cores harder to come by than sub-fossil tree cores.

He (Mr. McIntyre) offers no justification for excluding the original data; and in one version of the chronology where he retains them, he appears to give them inappropriate low weights.”

Perhaps if anyone should be tried in the crucible of peer review, and crucified for their misrepresentation of the facts, it need not be he who calls for “more weight” (?)

October 1, 2009 1:17 pm

Oh boy! Talk about not being able to see the wood for tree 😉

Peter Plail
October 1, 2009 1:23 pm

Guess which tree the bear used to c**p under.
They live 30 to 40 years and Boris the Siberian bear got a liking for this particular tree in about 1960 and used it for the rest of its life.

Peter Plail
October 1, 2009 2:18 pm

I’ve just seen a post on another thread that the Russkis let off an A-bomb close by in 1961. Maybe Boris the bear just died under that tree.

October 1, 2009 2:51 pm


October 1, 2009 2:55 pm

All this proves, is that when a tree gets tall enough to get its head above the tree-canopy, it grows quicker. Axiomatic, one would have thought. And this has been interpreted as Global Warming????
Oh, dear. Its back to the Dark Ages of science.

October 1, 2009 3:56 pm

Clearly these trees are growing in response to increases in available light. And that could be completely in contradiction to climate. Cold (dry) weather could kill off a few forest giants and the young trees in its shade immediately will take off and grow quickly as they begin receiving more light.

Harold Blue Tooth
October 1, 2009 5:57 pm

“Climate Audit is getting hit with traffic again, so this is a mirror post for interested parties.”
The victory is tasting sweet to many people.

October 1, 2009 6:48 pm

Steve McIntyre is smart not to assess intention in reference to the way Briffa used his data, insisting that malfeasance on Briffa’s part is not his belief but that stubborness on Briffa’s end and other factors may more accurate in accounting for the perception. He goes with what he knows and from his own experience.
However, I do question how a person (forget him being a scientist) can stand by and just let one’s work be used by the AGW alarmists and not reconsider one’s methodology and work. Where is the line when a character attribute, what Steve McIntyre calls Briffa’s “stubborness” (see (http://www.climateaudit.org/?p=7257) ) is inadequate to explain, not the initial findings, but the sustaining of those findings when it is obvious that there are legitimate alternative ways to slice and dice the available data. And then, why hide your data from skilled professional inquirers? Briffa brought it upon himself the easy to reach perception and conclusion that he actively (now, this would be malfeasance) sought out or kept in those data elements which too conveniently support AGW hysteria. In any case, it stinks. The AGW mindset has already done so much damage to science and to public discourse and anyone who contributes to this either intentionally or unitentionally, should ask some hard questions in the mirror.

C Colenaty
October 1, 2009 7:36 pm

I think that within statistical terminology YAD06 would be called an outlier, and any scientist who based conclusions on it would be valled a damn lier.

October 1, 2009 8:08 pm

C Colenaty (19:36:05) :
I think that within statistical terminology YAD06 would be called an outlier, and any scientist who based conclusions on it would be valled a damn lier.
If you were a statistician then you should not cherry pick data – YAD06 is just one record – it may be the only VALID one. According to McIntyre you cannot chose which data to include.
As an engineer, I would bin YAD06 in the same way as I would bin any that did not correspond with the valid temperature of the Yamal area. Apparently this is not statisically valid and will lead to bias (in my view bias to valid).

Keith Minto
October 2, 2009 12:29 am

“However, instead of the standard negative exponential declining growth, these particular trees started off very slowly, like old trees, and then got a burst of virility when they got to be 100 years old. Benjamin Button trees so to speak. ”
Nice irony there……To me this is most telling area of all, tree rings do get smaller with age. Every one in Fig 2. shows an increase in ring width with age. It is as if tree ring volume was being measured !

October 2, 2009 4:52 am

I agree they should only compare similar aged trees (just to have a chance) and using younger trees in the early centuries and only older ones later is highly questionable. Even if you try to make correction factors based on the ages used, you couldn’t possibly do that without first comparing real thermometers vs. tree growth for 1000’s of trees over 100’s of years under 100’s of conditions and establishing a relationship with correction factors for age and other factors, of high enough statistical quality to give you confidence your tree is actually a thermometer. Especially for discerning a signal so small!
I just don’t believe it’s been done and think it’s possible that it can’t be done even if you had the time. It is, however, very easy to say it’s been done if you don’t show it and if nobody calls you on it…

October 2, 2009 6:50 am

Given all of this, I keep thinking about a Monty Python edisode:
Voice Over (and CAPTION:)
‘NO. 1’
Photo of a larch tree.
Voice Over The larch. The larch.

October 2, 2009 2:38 pm

Could the Tunguska event have knocked down the elders? Many of the trees seem to spurt after 1908?
…just a thought. It might explain why trees in this area were affected and not others. Trees on the side of a river would b emore susceptable to a shock wave having roots that sit in less solid ground.

October 2, 2009 7:37 pm

Another perspective:
Dendrochronology is an excellent dating technique for archeological and anthropological projects. Matched rings from a known area can tell when logs were felled for a shelter, boat, crib, crypt, etc.
However, the size of rings in a single tree, a grove, or forest may be affected by temperature, sunlight, water, nutrients, and/or ambient CO2. These and other factors are variable from year-to-year. I have stumbled across studies where the broader rings in the same isolated grove are seen as evidence in Study A of increased rainfall, and in Study B of increased temperature.
Dendrochronology has a solid foundation. Dendrothermometry and dendrohydrometry are highly questionable. Looking back a hundred years, who has the ability to track windfalls, lightning strikes, beaver dams, dead carcasses within the drip line, or migrating herds leaving more or less fertilizer? There are far too many variables for the certainty that is asserted in these learned and subtle reports. I take them all with a grain (or more) of salt.

November 15, 2009 6:50 pm

Hey everyone just wanna say hello and introduce myself!

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