Figueroa-Rangel, B.L., Willis, K.J. and Olvera-Vargas, M. 2010. Cloud forest dynamics in the Mexican neotropics during the last 1300 years. Global Change Biology 16: 1689-1704.
Working in the Sierra de Manantlan Biosphere Reserve (SMBR) in west-central Mexico, the authors constructed a 1300-year history of the reserve's cloud forest vegetation via analyses of fossil pollen, microfossil charcoal and organic and inorganic sediment data obtained from a 96-cm core of black organic material retrieved from a small forest hollow located at approximately 19°35'32"N, 104°16'56"W. Prior studies had revealed, in the words of Figueroa-Rangel et al., that "during intervals of aridity, cloud forest taxa tend to become reduced," but that "during intervals of increased humidity, the cloud forest thrives." Based on these facts, they determined from their data that there was a major dry period that lasted from approximately AD 800 to 1200 in the SMBR; and numerous earlier studies conducted in and about the region had demonstrated that this dry interval was the major manifestation of the Medieval Warm Period in that part of the world.