In 2010, construction crews found the hull of a very old ship, buried at the site of the World Trade Center towers. Using dendrochronology, scientists now know how old the ship is and what city it was made in.
Meg Gannon at LiveScience has a good, well-detailed story on how the scientists were able to learn about the ship by studying the tree rings visible in the timbers used to build it. Fair warning, the LiveScience website is just a mess of ads and rollover popups. Gannon's article is worth reading, despite all that.
"What makes the tree-ring patterns in a certain region look very similar, in general, is climate," said the leader of the new study, Dario Martin-Benito, who is now a postdoctoral fellow at the Swiss Federal Institute of Technology (ETH) in Zurich. Regional ring patterns arise from local rain levels and temperatures, with wetter periods producing thicker rings and drier periods producing smaller rings, he said.
…The ship's signature pattern most closely matched with the rings found in old living trees and historic wood samples from the Philadelphia area, including a sample taken during an earlier study from Independence Hall, which was built between 1732 and 1756.