Abstract - The buildup and continuity of fuels on National Forest Lands in southwest Utah pose a serious fire risk to surrounding subdivisions on private lands within the Duck Creek, UT., wildland urban interface area. A high intensity wildfire could cause significant damage to these properties and the natural resources in the Duck Creek area in southwest Utah. As fuel loads have increased, the residential population of the private subdivisions has also increased. Increased recreational use is also occurring, increasing the risk that a human-caused fire may occur.

The Forest Vegetation Simulator (FVS) with the Fuels and Fire Effects Extension (FFE) (Reinhardt and Ryan 1998) and the Utah variant was used to characterize fuel dynamics, potential fire behavior and fire effects over time in the context of stand development and management within the 30,000 acre Duck Creek watershed. FFE links changes in forest vegetation due to growth, natural or fire-caused mortality, and management activities to changes in expected fire severity and behavior. (Beukema and others 2000). FVS-FFE and the Utah variant was used to evaluate proposed forest management activities by Dixie National Forest fire/fuels personnel and to determine effects on stand dynamics, fuel hazard and fire effects. Simulated fuel treatments included prescribed fire, thinning, pruning, mechanical treatments and no treatment. Wildland fires were also modeled. Model outputs included predicted fuel loadings over time, predicted fire behavior, fuel consumption, smoke production, tree mortality and measures of fire hazard including potential flame length, canopy base height and canopy bulk density, torching and crowning indices and predicted stand mortality over various simulation periods. The Stand Visualization system (SVS) (McGaughey 1997) was used to render drawings of how the stand might look on the ground before, during and after various planned treatments.

The Duck Creek Fuel Management Demonstration Area served as a site that allowed research personnel to demonstrate the utility of using FVS-FFE and its Utah variant for Dixie National Forest personnel. It allowed forest personnel to examine, on a stand level, proposed treatments both within forested areas of the Dixie National Forest and in particular in forested areas adjacent to rapidly expanding Wildland Urban Interface areas within the Forest. The flexibility of the FFE model enabled forest managers to investigate various silvicultural and prescribed fire treatments under varying environmental and site conditions. Our conclusion is that the FVS-FFE model provided an effective and powerful tool for resource managers to use to assess conditions, characterize fuel dynamics, analyze potential fire behavior and effects, and to assess consequences of proposed treatments.