Impact of fire on Arizona Pine populations in Rhyolite Canyon, Chiricahua National Monument

Barton, Andrew

For several reasons, Rhyolite Canyon provides a unique opportunity to investigate the impact of fire on the dynamics of tree populations in Madrean ecosystems. In most areas of the southwest where fire occurs frequently, intervals between fires are so small (5-10 years) and the accuracy of dating trees so inexact (e.g., + 2-5 years) that attributing age structure or growth patterns from tree-rings to past fires is problematical. The 50-year hiatus in upper Rhyolite is ample for detecting correspondence between fire and tree population histories. Furthermore, the adjacent lower Rhyolite area, where fires continued to burn during the 50-year period, can be used as a "control" area. Because the two areas on each side of Sarah Deming Canyon are nearly identical in physiography, differences between their tree population structures may be attributed to differences in disturbance history rather than climate. Hargrove and Pickering (1992) argued that, because true landscape level experiments are often not possible, such "quasi-experiments" can be productive, even if they fall short of being statistically replicated field experiments.