Dendrochronology-based fire history of Jeffrey pine-mixed conifer forests in the Sierra San Pedro Martir, Mexico
The authors used dendrochronological techniques to describe the historical fire regime of a Jeffrey pine-mixed conifer forest that experienced little fire suppression or logging (but did experience some livestock grazing impacts) in northern Mexico.
The authors found that fire was frequent with median intervals of less than 15 years in the Jeffrey pine-mixed conifer forests. However, a period of reduced fire occurrence from the 1790s to 1830s coincided with a similar fire-free period across the Southwest and southern South America. The authors and others found a reduction in the amplitude of ENSO during this time that likely contributed to this reduction in fire occurrence. However, an increase in livestock grazing intensity and a reduction of fire use by native peoples occurred at the same time and likely also had strong influences on the fire regime during this period.
Climate and Fire Linkages
The authors found that fire was frequent with median intervals of less than 15 years in the Jeffrey pine-mixed conifer forests. However, a period of reduced fire occurrence from the 1790s to 1830s coincided with a similar fire-free period across the Southwest and southern South America. The authors and others found a reduction in the amplitude of ENSO during this time that likely contributed to this reduction in fire occurrence. However, an increase in livestock grazing intensity and a reduction of fire use by native peoples occurred at the same time and likely also had strong influences on the fire regime during this period.