Priceless Climategate email 682: Tom Wigley tells Michael Mann that his son did a tree ring science fair project (using trees behind NCAR) that invalidated the centerpiece of Mann’s work
'A few years back, my son Eirik did a tree ring science fair project using trees behind NCAR. He found that widths correlated with both temp and precip. However, temp and precip also correlate. There is much other evidence that it is precip that is the driver, and that the temp/width correlation arises via the temp/precip correlation'