Historical stand-replacing fire in upper montane forests of the Madrean Sky Islands and Mogollon Plateau, southwestern USA
The authors reconstructed fire dates and stand-replacing fire patch sizes using four dendrological approaches to document the historical role of high severity and/or stand-replacing fire in upper elevation mixed-conifer, aspen, and spruce-fir forests.
The authors found evidence of large patches (>100 acres) of stand-replacing fire in upper elevation mixed-conifer forests prior to European settlement in the region via aspen and conifer recruitment pulses, corresponding fire scar and mortality dates, and lack of surviving trees prior to large fire dates. This suggests that recent large patches of high severity fire are within the historical range of variability for upper elevation forests. However, in aspen stands, fire suppression over the past 130 years has likely affected the age and stand structure of these stands. Aspen stands shifted from frequently burned stands with dense and multi-aged cohorts of trees toward a monoculture of open, same-aged trees.