via; http://dispossessed.wordpress.com/2007/10/20/dendrochronology/

“The science that analyzes temporal and spatial consistencies of various processes using tree rings. The tree rings are dated to their exact year of formation. This data can be used across several disciplines: anthropology, geology, climatology, and ecology. […] The primary data bank is located at The International Tree-Ring Data Bank and is maintained by the NOAA Paleoclimatology Program and World Data Center for Paleoclimatology.”

• http://www.ncdc.noaa.gov/paleo/treering.html

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There’s lots of good news here:

• the datasets are generally “big lists of (small positive) integers” (plus a hash of metadata), which Lisp can slice through like a hot knife through butter
• the state-of-the-art algorithms aren’t that complex (or, alternatively, there’s lots of exploration left to be done!)
• there’s a ton of free data to play with, as you’ve found
• there’s even some free software to be found, though sometimes you have to type it in and port it from ALGOL or a very early FORTRAN and then fix the bugs
• a lot of the algorithms are more or less just “try to do by computer what your eye can do”, so you can make pretty graphics and test your heuristic by just looking at it