NEW CLIMATE SENSITIVE TREE-RING CHRONOLOGIES FOR NORTHERN MEXICO AND THE POTENTIAL FOR LONG-TERM FIRE FREQUENCY STUDIES

VILLANUEVA-DIAZ, J. (1), CERANO-PAREDES, J., STAHLE, D.W., THERRELL, M.D., CLEAVELAND, M.K. AND CERANO-PARADES, J.

(1) INIFAP CENID RASPA, Km 6.5 Margen Derecha del Canal Sacramento, Gomez Palacio, Durango, Mex. 35140.

On the last five years over 25 climate sensitive tree-ring chronologies mostly from Douglas-fir have been developed along the Western and Eastern Sierras Madre. Annual tree growth on this region is highly related to the cool season precipitation which in turn is affected by ENSO and winter storms or “Nortes” coming from higher latitudes. Winter-spring precipitation reconstructions have been produced for northwestern Chihuahua and Durango and southern Nuevo Leon Coahuila. The seasonal winter-spring precipitation reconstructions extended 530 years (1472 – 2002) for Chihuahua, 228 year (1765 – 1993) for Durango, 602 years (1400 – 2002) for Nuevo Leon, 342 years (1659 – 2001) for Coahuila, and 515 years (1478- 1995) for Tamaulipas. High frequency events were specific for each reconstruction, but dominant low frequency events were observed in most of the reconstructions; specific cases are the droughts of the 1810s, 1860s, 1870s, and 1950s. However, the ENSO influence on Winter-Spring precipitation varied with time. The relationship between the presence of fires and climate was evident in 1998, when over 10,000 wildfires burned around a million hectares of forest land in Mexico. Long-term fire studies of mixed conifer forest in northern Mexico indicate frequencies of 4 to 6 years which may be related to warm phase of ENSO.

Figure 1. Network of climate sensitive tree-ring chronologies distributed along the Western and Eastern Sierras Madre in Mexico. Fire is dominant component of forest ecosystems on these mountain ranges.