Summary

The simple effects model shown here demonstrates how an important driver of forest outcomes—namely fire behavior—can be modeled in terms of conditional probability. This process transparently shows how assumptions of expected results may or may not matter. By varying vegetation and fuel inputs with proposed fuel treatment options, management outcomes can be considered within this same framework. Moreover, the uncertainties associated with the effects of different fire behaviors can be addressed with an expanded belief network.

The range of fire behavior that occurs during a single scenario in our model shows that the project area has a mixed severity fire regime. This is consistent with retrospective analyses of past fires (Odion and others 2004, Taylor and Skinner 2003). Large fires burn under a range of fire weather and wind scenarios, and this leads to further variation in fire behavior. Due to the combined influence of these spatial and temporal patterns, the fire regimes of the Klamath Mountains are truly complex. This complexity is likely to have contributed to the high biodiversity that characterizes the Klamaths, but it makes multi-resource management decisions more challenging.

In order to be meaningful, comparative risk assessments must be capable of accommodating this ecological complexity. The CRAFT process allows managers to incorporate diverse objectives and sophisticated effects modeling to deal with these complexities and their associated uncertainties.