text: In Mr. Wigleys view at the time, ice cores were unreliable and correlate very poorly with temperature. He said the link between ice core and temperature variation was close to zero and tree rings were less than 50% reliable. The main external candidate is solar, and more work is required to improve the paleo solar forcing record. Another U.S. scientist, Gary Funkhauser of the Laboratory of Tree-Ring Research at the University of Arizona, was also cool to the idea of tree rings as indicators of past temperatures. He wrote in September, 1996, that he tried every trick out of my sleeve to get meaningful climate records out of certain tree ring records collected by Russian scientist Stephan Shiyatov.