Priorities for Fuels Treatment

Fig. 1 - Priorities for fuels treatment

The map for fuels treatment priorities (Figure 1a) took into account most of the same factors as used to produce the map for fire danger and its components (Figure 2), but with weighting of criteria and subcriteria by a fire ecologist and also considering the influence of wildland-urban interface (Figure 1b). Ideally, when developing operational decision models for management, derivation of weights would be performed by a panel of managers and scientists. Indeed, we emphasize the importance of such collaborative development in our conclusions. Here, for illustration purposes, and considering a simple decision model in which three of the four decision criteria are more technical in nature, development of weights by a fire ecologist seemed appropriate.

Fig. 2 - Composite of all partial
product evaluations

Fig. 3 - Detailed views of
example subregions

The majority of subwatersheds with a priority rating of high or very high occurred in the southern two-thirds of the map zone (Figure 1a). The map of treatment priorities (Figure 1a) was strongly conditioned by the presence of wildland-urban interface in a subwatershed because of the emphasis placed on this criterion in the decision model. Normalized weights on primary criteria, derived from the pair-wise comparison process, were: wildland-urban interface, 0.50; fire behavior, 0.27; fire hazard, 0.15; and ignition risk, 0.08. A more detailed view of a small region in Figure 1 (Figure 3) shows the correspondence between wildland-urban interface and decision scores for fuels treatment for subwatersheds. Notice that all subwatersheds with wildland-urban interface ≥ 16.64 percent (Figure 3b) were classified as very high priority (Figure 3a).

Fig. 4 - Contributions of primary
decision criteria

Model output from the Priority Analyst (Figure 4) shows how the four primary decision criteria contribute to the overall decision score for a sampling of 10 subwatersheds. The three highest ranked subwatersheds (Figure 4) are also labeled in Figure 3b. Notice that the three highest ranked cases could be distinguished from the next seven cases by the level of influence of the wildland-urban interface. Furthermore, although the relative contribution of fire behavior was fairly consistent across the top 10 cases, the contributions of fire hazard and ignition risk were relatively low among the top three.