Full Citation: Iniguez, Jose M.; Swetnam, Thomas W.; Baisan, Christopher H. 2016. Fire history and moisture influences on historical forest age structure in the sky islands of southern Arizona, USA. Journal of Biogeography 43(1):85-95.
External Identifier(s): 10.1111/jbi.12626 Digital Object Identifier
Location: Rincon Peak, Saguaro National Park, Arizona, U.S.; Rose Canyon, Santa Catalina Ranger District, Arizona, U.S.
Ecosystem types: Sky islands; gradient
Southwest FireCLIME Keywords: None
FRAMES Keywords: Arizona, moisture, Pinus ponderosa, ponderosa pine, tree establishment, age structure, fire frequency, wildfires, age classes, regeneration, fire management, forest management

Fire history and moisture influences on historical forest age structure in the sky islands of southern Arizona, USA

Jose M. Iniguez, Thomas W. Swetnam, Christopher H. Baisan


Summary - what did the authors do and why?

The authors examined synchrony of stand age and structure between geographically separated sites, or sky islands, to determine the influence of moisture and/or drought variability versus fire frequency on historic stand development.


Publication findings:

The authors found that fire frequency appeared to be the primary influence on tree age structure in the sky island communities. Fire free periods were related to age peaks. The authors suggest that climate did not limit tree establishment and regeneration, however, climate did influence fire frequency and thus indirectly influenced age structure pattern in these stands. Within the study sites, age peaks occurred synchronously in the early 19th century, coinciding with a period of increased moisture within the ENSO cycle that reduced fire activity.

Climate and Fire Linkages

The authors suggest that climate did not limit tree establishment and regeneration, however, climate did influence fire frequency and thus indirectly influenced age structure pattern in these stands. Within the study sites, age peaks occurred synchronously in the early 19th century, coinciding with a period of increased moisture within the ENSO cycle that reduced fire activity.

Fire and Ecosystem Effects Linkages

The authors found that fire frequency appeared to be the primary influence on tree age structure in the sky island communities. Fire free periods were related to age peaks. The authors suggest that climate did not limit tree establishment and regeneration, however, climate did influence fire frequency and thus indirectly influenced age structure pattern in these stands. Within the study sites, age peaks occurred synchronously in the early 19th century, coinciding with a period of increased moisture within the ENSO cycle that reduced fire activity.