Overview

We utilized aerial detection survey maps (2000-2006), our custom fuel models, historic weather data and data from the LANDFIRE project to create FARSITE/FlamMap landscapes. These landscapes were used to model and compare fire growth and intensity in a lodgepole pine forests prior to and during a current mountain pine beetle epidemic on the Sawtooth National Forest, ID. Historic weather data input consisted of 30 randomly selected three-day weather windows within the peak fire season (August and September). All fire growth simulations used the same FARSITE options as well as the same ignition locations. FARSITE simulations were also run in a 20-year post-outbreak, lodgepole pine forest on the Ashley National Forest, UT. The historic weather data input used for these simulations consisted of 30 randomly selected five-day weather windows within the peak fire season (August and September). These simulations were calibrated with actual fire events that occurred in the bark beetle-affected areas on the Sawtooth National Forest in 2006 as well as on the Ashley National Forest in 2005. Model outputs were exported into ArcMAP to display the results.

Figures 1 and 2 show the FARSITE projections of endemic and current epidemic mountain pine beetle conditions, respectively. The different colors represent the probability of fires growing from the ignition point to a given boundary over the randomly selected, three-day weather window. The acres in the output legend display the cumulative acre sizes that include all of the polygons with higher probabilities. For example, the less than 5% acre value is the size of the entire polygon including all of the smaller polygons within it. Interpretation of these FARSITE model simulations should consider the weather windows used and the limitations inherent in conventional surface and crown fire spread and initiation models (i.e. live canopy fuel moisture).

Figure 1. FARSITE projection of endemic conditions on the Sawtooth National Forest
Figure 2. FARSITE projection of epidemic conditions on the Sawtooth National Forest