One of the great things about WUWT is that people from all walks of life frequent here. We have PhD’s right down to Average Joe that read and post comments here. Everyone has something to contribute.
A general truism that I’ve noticed through life is that the people that actually work “hands on” with the things they study often know far more about them than the people that study them from afar. As in the case of the surface stations project, top scientists missed the fact that many of the climate monitoring stations are poorly sited because they never bothered to visit them to check the measurement environment. Yet the people in the field knew. Some scientists simply accepted the data the stations produced at face value and study its patterns, coaxing out details statistically. Such is the case with Briffa and Yamal tree rings apparently, since the tree ring data was gathered by others, field researchers Hantemirov and Shiyatov.
American Indians have been said to be far more in tune with the patterns of the earth than modern man. They had to be, survival depended on it. They weren’t insulated by technology as we are. Likewise somebody who works in the forest whose daily livelihood is connected to trees might know a bit more about their growth than somebody sitting behind a desk.
WUWT commenter “Caleb”, who has worked with trees for 50 years, wrote this extraordinary essay on Briffa’s lone tree core known as YAD061, which has a pronounced 8 sigma effect on the set of 10 tree cores Briffa used in his study. Caleb’s essay is in comments here, which I’m elevating to a full post. While we may never know the true growth driver for YAD06, this is one possible explanation.
Guest comment by Caleb Shaw:
I’ve worked outside since I was a small boy in the 1950’s, and have cut down hundreds of trees. I always check out the rings, for every tree has its own story.
I’ve seen some rather neat tricks pulled off by trees, especially concerning how far they can reach with their roots to find fertilizer or moisture. For example, sugar maple roots will reach, in some cases, well over a hundred feet, and grow a swift net of roots in the peat moss surrounding a lady’s azalea’s root ball, so that the azalea withers, for the maple steals all its water.
I’ve also seen tired old maples perk right up, when a pile of manure is heaped out in a pasture a hundred feet away, and later have seen the tree’s rings, when it was cut down, show its growth surged while that manure was available.
After fifty years you learn a thing or two, even if you don’t take any science classes or major in climatology, and I’ve had a hunch many of the tree-ring theories were bunkum, right from the start.
The bristlecone records seemed a lousy proxy, because at the altitude where they grow it is below freezing nearly every night, and daytime temperatures are only above freezing for something like 10% of the year. They live on the borderline of existence, for trees, because trees go dormant when water freezes. (As soon as it drops below freezing the sap stops dripping into the sugar maple buckets.) Therefore the bristlecone pines were dormant 90% of all days and 99% of all nights, in a sense failing to collect temperature data all that time, yet they were supposedly a very important proxy for the entire planet. To that I just muttered “bunkum.”
But there were other trees in other places. I was skeptical about the data, but until I saw so much was based on a single tree, YAD061, I couldn’t be sure I could just say “bunkum.”
YAD061 looks very much like a tree that grew up in the shade of its elders, and therefore grew slowly, until age or ice-storms or insects removed the elders and the shade. Then, with sunshine and the rotting remains of its elders to feed it, the tree could take off.
I have seen growth patterns much like YAD061 in the rings of many stumps in New Hampshire, and not once have I thought it showed a sign of global warming, or of increased levels of CO2 in the air. Rather the cause is far more simple: A childhood in the under-story, followed by a tree’s “day in the sun.”
Dr. Briffa should spend less time gazing at computer screens, and actually get out and associate with trees more. At the very least, it might be good for his health.
Caleb might not make it to the Nobel Prize, but
The Word of the Year is: “bunkum”
You should give it a special place on WWUT. And again I ask: Who were the peers who reviewed Briffa’s paper?
Pompous Git (18:04:58) :
Henry chance (15:09:07) :
“Common sense. did Briffa even visit the area?
Many people admire charles darwin,. I don’t. He had a theology degree and was carefull note taker. No one discredits his education because they like him.”
Darwin put his evolutionary theorising aside for many years and spent 8 years analysing many thousands of barnacle species. This work alone was sufficient to establish his reputation as a formidable scientist, not just in his day. His dogged persistence in this enterprise has inspired many a budding scientist, not just crusty old historians of science.
BTW, many, if not most field biologists prior to the 20th C were clergymen. Do you reject Bayesian statistics because Rev Thomas Bayes had a theology degree, rather than one in mathematics? Sheesh…”
In Darwin’s time it was compulsory for anyone teaching or researching in Oxford or Cambridge to take holy orders. This is largely what gave rise to the phenomenon of the “Church of England Atheist,” which went beyond just the sciences (the Rev Charles Lutwidge Dodgson, aka Lewis Carroll, is another example. What do we make of his “believing six impossible things before breakfast” in the Looking Glass? Dodgson was a significant mathematician, working in mathematical logic).
When Darwin took his degree in 1831, Cambridge did not offer a degree in natural sciences. This was instituted in 1851. By taking a theology degree, at the time, he was keeping his options open.
During the time when the Church of England had real wealth, not just property (real estate) which it can’t afford to sustain, many clergymen with time on their hands were pioneering observers in all areas of ‘natural philosophy.’ We owe much of our further knowledge to their practical observations (like those of Caleb).
Troubled Childhoods:
I have looked at the raw RW archive for Yamal and the YAD group in particular, to see what, if anything, is unusual about them.
I presume that the data are ring widths and if you sum them you get a radius.
If so, there may be something unusal about the YAD group.
I have calculated a radius for age for the last (most recent) 33 (all I’ve had time for) of the Yamal trees.
At the start of the 20th Century the three oldest trees of the group YAD061, 041, & 121 (ages 97,97, & 95) were, by this measure, small for ther age, 061 particularly so at about 55% of the average. By 1995, two of these three were above average and the other (121) just a little below, 061 turned out to have the largest radius along its core of the three.
Of the other two, YAD071 had a terrible time for its first 70-80 years and then perked up but is still below the average that I have calculated.
YAD081, the youngest, ( only 25 in 1900), got off to a rocket start and was by 1995 the tallest of the entire group. At the age 0f 97, the same as YAD061 in 1900, YAD081 was about 70% taller than the average for its age.
Now, I do not know anyting much about trees but perhaps, trees that have had a trouble childhood are prone to massive growtrh spurts in later years. I think this is what Caleb has told us. Well four of the YAD five were seem to have had a hard time for at least their first 70 years.
Alex
There is the “First Fallacy of Acadaemia”, which goes
In acadaemia getting 95% results in an “A”
Takes a fair bit of re-adjusting in real life to realize that there
Getting 95% can result in a real cock-up
Prof. Briffa is not an idiot. Anyone who has planted anything knows that the local environment affects growth. Briffa is one of the top dendrochronologists in the world. To suggest he isn’t fully aware of the most basic environmental factors that affect the growth of trees is ridiculous.
Briffa knows exactly what he has done. There is absolutely no possibility that he has made a simple mistake. This data has appeared in prestigious peer-reviewed publications for 10 years. Not only does Briffa know exactly what he has done, all his co-authors and reviewers know too.
Thanks to the tenacity of Steve McIntyre, what a large number of well respected scientists have known for many years, is now made public.
Seriously, it is inconceivable that a large number of scientists were unaware of the paucity of the data. That is precisely why the journals other than Phil. Trans. Roy. Soc. refused to enforce their own data availability policies.
R
What a strange world we live in.
We have McIntyre and acolytes saying in one breath –
1. It is not valid to sort samples before you analyse them. Briffa should have used all samples from the area, and then come to a conclusion.
2. Then they say The 10/12 Briffa trees should not have been included as we have these 34 schweingruber(?) trees, and look no 20thC warming.
3. Someone then says that the Briffa trees should have been included
4. McIntyre adds them and finds a smaller hockey stick.
5. McIntyre analyses the Briffa trees and find a golden hockey stick tree which provides most of the late 20thC warming.
6. McIntyre then says this result is 8 sigma outside the normal and should not be included.
How do you reconcile statement 1 with statement 6??????
In my view if you are not allowed to sort for correlation between ring width and temperature over the period where we have instrumental records. Then you are not allowed to sort at all.
Consider this scenario
At a junk sale you purchase a number of instruments various environmental parameters over time. None are very accurate, and you have no idea which parameter they are measuring. You want to record temperature, so you set them up in the same location. Some years later you can afford a calibrated temperature recorder which you also set up in the same location.
Some of these instruments will have recorded sunlight, precipitation, soil nutrient levels, fungal spore levels, ambient temperature, and temperature of the soil 1 metre down.
If you want to know what the temperature was when you set up the first instruments do you
a. normalise all readings of all instruments then average them.
b. average them all without normalising
c. compare the outputs from all instruments with the calibrated temperature recorder and throw out all that show no correlation. normalise the results remaining and then average them
d. as c. but additionally throw out units deviating by significant amounts from the average.
Which of a. b. c. is going to give you best historic temperatures?
Personally as an engineer not a statistician I would go with d. or if insufficient instruments to find the outliers c.
I realise that this is going to bias the results to giving the same result as the calibrated instrument, but may I suggest this is exactly what you want.
It seems a statistician would go for 1 as this would not bias the result to valid temperatures. I just cannot understand this.
jeez (14:17:50) : “This is your field of expertise not mine, but wouldn’t a simple tree line reconstruction of temperatures be complicated by forest succession and species changes?”
Not a problem, the only succession here is from Tundra (treeless) to Tiaga (trees)
As for tree species it would be the pioneer species- in this case Siberian Larch (Larix sibirica) growing in monoculture. This species has a number of adaptations to allow it to survive under these extreme conditions.
(Mazepa and Devi (2007) Development of Multistemmed Life Forms of Siberian Larch Asan Indicator of Climate Change in the Timberline Ecotoneof the Polar Urals. Russian Journal of EcologyVol. 38, No. 6, pp. 440–443. Original Russian Text © V.S. Mazepa, N.M. Devi, 2007, published in Ekologiya, 2007, Vol. 38, No. 6, pp. 471–475.)
JT “Yes … But … I would expect there will be a lag in that the tree line will recede with declining temperatures but the temperatures will decline first and the tree line will follow, and when temperatures increase it will be a while before the trees can expand their range into the newly warmed territory. What the lag will be I don’t know but (waving hands)”
It can happen remarkably quickly- Esper and Schweingruber report “larger-scale patterns of treeline changes related to decadal-scale temperature variations”.
Esper and Schweingruber (2004). Large-scale treeline changes recorded in Siberia. Geophysical Research Letters 31.
You have said it all pretty much. Theory is great, the proof is in the physical observation based on reality, if they match up, the theory could be right, if they don’t the theory could be wrong. Simple really. One dosen’t need a PhD to work that one out!
Don Keiller (04:38:11)
The paper in full:
http://www.wsl.ch/staff/jan.esper/publications/GRL_2004.pdf
It is obvious that YAD061’s growth rate was caused by a change in its micro-environment. Briffa had to have known this.
Divergence pitfalls in tree-ring research
http://www.wsl.ch/staff/jan.esper/publications/Esper_2009_CC_PIT.pdf
The IPCC on a heterogeneous Medieval Warm Period
http://www.wsl.ch/staff/jan.esper/publications/Esper_2009_CC_IPCC.pdf
What are the Sources of Uncertainty in the Tree-Ring Data: How can They be
Quantified and Represented?
White paper on tree rings submitted by Keith Briffa and Ed Cook
http://freespace.virgin.net/rob.dendro/Tree-Ring/Trieste_tree_rings2008.pdf
Data Base/Archiving Needs
The ITRDB is a great resource. It needs to be continually improved to allow easy storage
of other than “usual” tree-ring width data. Improved meta data should be sought for all
submissions, including tree dimensions and architecture and information on context of
measurements (routinely including estimates of missing rings to pith). When standardised
indices are archived, precise details of standardisation options should always accompany
them. This should include detailed output from the programs used for standardization,
such as the ARSTAN program. Only in this way can others replicate how standardized
tree-ring chronologies were developed.
However, it is not just the measurement data that should be highlighted in this discussion.
As an example the following is a quote from Jonathan Palmer:
Major crisis looming here are the physical samples. We are loosing the trees. Steady
can tell you about his efforts in SE-Asia. In NZ, we have 40,000 year old ancient kauri
being mined. I reckon it will be exhausted within 10 years. The holocene sites in 5 years.
Saw-millers are already starting to buy farms so that they can secure some future supply.
We have set-up an archive at a local museum for biscuits of kauri for future research
programs. In other words I have adopted a fire-fighting approach – save as many
samples as I can and hope there might be funding to work on them later. Steady has
funded me over the last 5 years to collect silver pine (Halocarpus biformis) from the West
Cost. We have multi-millennial chronos thanks to that investment – but some sources
have been completely destroyed by the land being converted to dairy pastures. The other
area is now a kiwi habitat sanctuary so the permit process for further sampling has
become much harder. So, data archiving is vital, but I’m first trying to save samples!
Many dendro people, in different parts of the world, could tell similar stories. PAGES
highlighted this problem once, but little came of it. The sources of old tree-ring material
are disappearing around the world and as old dendrochronologists whither away, their
sample collections often disappear with them!
*****************************
Tim Groves (23:09:45) :
It seems to me that using tree-rings to try to ascertain paleoclimatic conditions is as much an art as a science. The only way to approach a useful degree of accuracy is to have a sufficiently large sample size. A single tree sample is likely to provide about as much information as an exit poll carried out on a single voter.
*****************************
Before we accept any more tree ring temperature studies, shouldn’t we study the technique on all the various trees in various climes in order to demonstrate the technique works at all? If the response of tree growth to temperature is parabolic, then one can filter out a set of trees to “prove” a wide variety of hypotheses. In fact, that appears to be what is happening. Sample size might well be the least of problems.
Bill,
Any thoughts on the relevance of sample size?
Sorry for the repetition, but it should have been posted on this thread;
There is a paper awaiting publication in the highly influential UK ‘Beano’ (widely circulated among the next generation of environmentalists ) It has been peer-group reviewed by their resident subject-matter experts Biffo-The-Bear, and that world-famous ursine coprologist, Winnie-the-Pooh.
The paper puts forward the scientific reason for the inclusion of outliers in the analysis of tree-ring data, in order to descry past climatic conditions.
The hypothesis is based on the postulate that bears*** is deposited in woodlands. As it is rich in nutrients, it ought to give any nearby tree a growth boost for a season or so.
So, records of tree-ring thickness variations may contain information on the fluctuations in the bear population, and so could act as proxy for past climatic conditions.
Now as Bears are creatures of habit, they tend to ‘go’ in the same places. So there will be a need to pick tree cores that have anomalous growth-spurts …. aka ‘outliers’ …..
http://www.daysgonebyshop.co.uk/883_1970-the-beano-biffo-the-bear-canvas-print.html
Caleb:
“Rather the cause is far more simple: A childhood in the under-story, followed by a tree’s “day in the sun.”
I have just read a definition of Occam’s razor on WikiPedia. It includes the following:
…To quote Isaac Newton, “we are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances. Therefore, to the same natural effects we must, so far as possible, assign the same causes.”
To summarize the common understanding of the principle, “of several acceptable explanations [for a phenomenon], the most accurate and well-ordered theory of explanation is preferable, provided that it does not contradict the observed facts.”
And an interesting parallel. R. J. Mitchell the aircraft designer once said to a test pilot; “If you read a document that you don’t understand then it’s no good” (or words to that affect).
When the Mann controversy was raging over at CA the statement that struck me the most was the assumption that ring width increases linearly with temperature. It seemed bizarre that after ten thousand years of agriculture there was anything to assume, it had to be known. So I asked the arborists who come to take care of my huge maple trees. They explained that every leaf on a tree has its own tiny root and that the growth of a tree can be asymmetrical because one side of the tree gets more nutrients than the rest from the network of roots. This shows up as asymmetric tree rings and the asymmetry can vary from year to year because the distribution of nutrients can change.
I haven’t had time to read the entire thread but I would like to point out that dendro studies are not or should not be done on trees of the same age.
Core samples should be taken from one area and the trees should be at different stages of maturity. There are probably many ways to date the samples but in essence the rings are matched date for date to see if they all display the same signal.
If the study is not done this way then you are only studying the life cycle of a particular species.
Recent growth presents the problem of not undergoing the same compaction as the older deeper rings have endured as the tree matures.
I always suspected that die-hard CAGW’ers were barking up the wrong tree.
From the book “Rocket Men” by Craig Nelson, Chapter 11 “The Fluid Front”, page 147 hard cover version (about the early days of NASA):
” “We were going to launch a pig and we put him in the (Mercury) cradle and started monitoring him, and the pig died,” aerospace technician Alan Kehlet remembered of those very early days. “One of our secretaries was a farm girl, and she said, “If you’d asked me before you had the pig in there, I would have told you that you never put a pig on his back, that the belly fat on there will suffocate the pig.” And that’s exactly what happened. So we went from pigs to monkeys.” “
I agree with what Shamus said in a previous Gore/Mann/Briffa ‘bad science’ post, “I blame CAGW on these tree fellas.”
supercritical (06:12:42) :
Bill,
Any thoughts on the relevance of sample size?
If you do not select for correlation with known tempreatures or do not choose known temperature responders then
small sample – you can prove any temperature profile
large sample – you end up with a horizontal flat line
If you select on correlation with temperature then the more the better.
But you need to read what they have to do to retreive sensible data – eg trees grow a different rates during their life cycle so you need to adjust ring width according to age. etc. Check out this Briffa paper:
A Closer Look at Regional Curve Standardization of Tree-Ring Records: Justification of the Need, a Warning of Some Pitfalls, and Suggested Improvements in Its Application (2008) (draft paper)
http://www.cru.uea.ac.uk/cru/people/briffa/Briffa_HB_2008.pdf
Nothing seems to give a useful proxy to temperature. Some of the better ones are grape harvest and budbust dates. But these only go back to about 1300s.
http://img101.imageshack.us/img101/6204/grapeharvestcetlongqc0.jpg
http://img101.imageshack.us/img101/9180/grapeharvestnantescetmf2.jpg
Note that grape harvest has not been converted to temp. so high temp = early harvest!
one of those plots should have been this:
http://img101.imageshack.us/img101/9180/grapeharvestnantescetmf2.jpg
Pompous Git (19:25:46) :
Bill Tuttle (15:03:27) :
…Wrong, sorry! Increased atmospheric CO2 enables the leaf stomata (breathing pores) to become smaller. This reduces the amount of H2O transpired during photosynthesis. The plant thus needs less water for a given unit of growth. Every agronomist knows that the major crop limiting factor is water.
Oh, good Lowered — now we’ll have to consider pore core bores, too! But how does that affect my statement that an increase in atmospheric CO2 doesn’t *directly* affect the tree’s growth?
Chris Schoneveld (00:45:09) :
Tuttle (15:03:27) :
…Bill, you are very wrong: http://www.youtube.com/watch?v=P0cqsdIsFBU
And rye grass isn’t a tree, Chris. To grass, *everything* is a nutrient.
Except in my lawn.
I’m not a botanist, but I *did* stay at a Holiday Inn Express one time…