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.