David Stahle Embedded within this period of drought is a well above average growth ring in the year 1576
1576. The precise date of the second Cocolitztli epidemic
When Stahle looks in detail at the 1540’s he spots a similar sequence of rings.
First a series of very thin rings – indicating severe drought. Then in 1545 a thick ring – indicating high rainfall. 1545 is also the year of the first Cocolitztli epidemic when as many as 15 million Aztecs died…