A fire history of the high Chisos, Big Bend National Park, Texas [Forest Area]

Fire history was studied in cypress forests and pinyon-juniper savannas. Fire dates were determined by tree ring counts from scars on Pinus cembroides. At least 10 fires occurred in the vicinity of Boot Canyon and at least eight on the Rim between 1770 and 1940. Episodic ground fires seem an important mortality factor of established pinyon and cypress saplings, but as trees grow to larger sizes, fire mortality is reduced. Longer fire intervals probably are filters that permit trees to survive into larger, fire-impervious sizes. Surface fires about every 50 years are one way to maintain the vegetation in some semblance of a natural, fire-regulated condition.