David Stahle has published (yet another) important article on dendrochronology and archaeology. This one describes a new dendrochronological sequence he and his colleagues have developed for central Mexico. It is derived from the Montezuma baldcypress, and it extends back 1,238 years, back to the Late Classic period. The paleoclimatic reconstruction created from the sequence indicates a series of major droughts corresponding to significant historical changes. The Terminal Classic Maya drought is evident and can now be dated between A.D. 897 and A.D. 922. (That's one major advantage of dendrochronology over other paleoclimate proxy methods: dendrochronology can provide dates precise to the year. Methods such as paleolimnology rarely, if ever, provide such precise dating.) Another major drought occurred between 1149 and 1167, close to the end of the Toltec reign (if that's what the Toltecs did). Another drought, from 1378 to 1404, was the most extreme in the dendrochronological sequence, but its historical correlates are not obvious. Finally, a major drought occurred around the time of the Spanish conquest, from 1514 to 1539. This may have found an echo in the 1535-1536 drought in Yucatan that drove the Xiu to try to cross the province of Sotuta, which led to their massacre by Nachi Cocom, which helped motivate the Xiu alliance with the Spanish.
All in all, an important article. Here's the reference: