Assessing mitigation of wildfire severity by fuel treatments - an example from the Coastal Plain of Mississippi

Abstract

Fuel treatments such as prescribed fire are a controversial tenet of wildfire management. Despite a well-established theoretical basis for their use, scant empirical evidence currently exists on fuel treatment effectiveness for mitigating the behaviour and effects of extreme wildfire events. We report the results of a fire severity evaluation of an escaped prescribed fire that burned into an area previously treated with repeated prescribed fires. We observed significantly lower scorch heights, crown damage, and ground char in the treated area. We attribute the moderated fire severity in the treated area to a significantly altered fuel profile created by the repeated prescribed fires. Though our results represent just one treatment area in a single wildfire, they add to a depauperate database and bring us a step closer to defining the conditions under which fuel treatments are an effective pre-suppression strategy.

Effects of Wildland-Urban Interface Fuel Treatments on Potential Fire Behavior and Ecosystem Services in the Central Sierra Nevada Mountains of California

“…They are also likely to impact both wildfire occurrence and property losses due to wildfire, through both their effects on the number of structures proximate to wildfire risks, and fire suppression strategies and effectiveness (Ibid. large part, the focus has turned to improving wildland fuels management (Stephens and Ruth, 2005), despite the fact that researchers have yet to empirically demonstrate the effectiveness of specific fuel treatments in modifying severe wildfire behavior (Carey and Schumann, 2003;GAO, 2007;Martinson and Omi, 2008). Wildland fuels management has traditionally been the responsibility of government, while residential fuels have been the domain of homeowners or local community organizations (Mell et al, 2010).…”

“…As of 2008, 23 studies based on this type of situation had been published; all of them relied on post facto analysis (Martinson and Omi, 2008). Unfortunately, only five of these studies included both a statistical test and adequate control to discern a fuel treatment effect in an actual wildfire (Ibid.).…”

“…Although much anecdotal evidence exists showing the efficacy of fuel treatments in mitigating severe fire behavior under moderate fire weather conditions, Martinson and Omi (2008) describe fuel treatment effectiveness as being a controversial subject, noting that "despite a well-established theoretical basis for their use, scant empirical evidence currently exists on fuel treatment effectiveness for mitigating the behavior and effects of extreme wildfire events." In northern California mixed-conifer forests, fuel treatments have been observed to fail (i.e., have no effect on wildfire severity or effects) under extreme weather conditions that included high winds, high temperatures, and low relative humidity (R. Tompkins, Plumas National Forest, personal communication).…”

“…The previously mentioned nationwide Fire and Fire Surrogate Study (FFS) uses this methodology with real-world fuel treatments under experimental conditions (Weatherspoon and McIver, 2000). However, because the assumptions used in modeling have not been validated, particularly under extreme fire weather conditions, the results of modeling experiments are best viewed as "hypotheses awaiting an empirical test" (Martinson and Omi, 2008).…”

“…Although fuel treatments tested under experimental burning conditions appear to be effective at reducing fire intensity (Graham et al, 2004;Stephens et al, 2009a), empirical evidence for their efficacy in uncontrolled wildfire situations, particularly under extreme fire weather conditions, is restricted to a handful of examples (Martinson and Omi, 2008;Figure 1.4). Furthermore, fire management is not the only consideration that forest managers must take into account during land use planning efforts.…”