Dendrochronological Responses to a Tornado

Tree-ring responses to a historic tornado (Sheppard et al. 2005) are documented here. Little research has been published showing tree-ring responses to tornadoes, that is, long-term growth changes due to short-term, intense winds. The tornado of interest occurred at Sunset Crater Volcano National Monument, northern Arizona (Fig. 1a, b), at about 2:30 PM on 24 October 1992 (Arizona Daily Sun Newspaper, 25 October 1992; Crisp 1996). The tornado first touched ground south of Sunset Crater and then moved generally north-northwest toward O’Leary Peak (Fig. 1c) before dissipating. Many trees were uprooted and killed by the intense winds of the tornado, while other trees growing within the swaths were damaged by the tornado but survived the event and continue living today. This tornado is historically well-documented (Arizona Storms Database 2004) and thus can serve as a test case for calibrating ring-growth changes in trees that were buffeted – but not killed – by high winds. Such a calibration could serve to identify tornadoes of the past within tree-ring records.