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Capabilities

Characteristics

FETM is dynamic: This means that the model tracks changes in vegetation composition (as well as other fire effects) over time.  The starting condition in any year is linked to the ending condition in the previous year, in a chain that extends back to the starting point of the simulation.  The predicted changes in landscape composition are used to calculate smoke-constituent emissions from prescribed fire and wildland fire events, to estimate costs and benefits (net value change, in fire planning parlance) associated with wildland fire and fuel treatment, to track the number of treated acres annually, among other factors.

FETM is non-spatial: This means that while the model can predict the overall outcome of a treatment (for example, prescribed fire) within the Analysis Area, it cannot predict the geographic location of the impacts.  For example, within a particular stand type (Immature Ponderosa pine, for example), FETM predicts the number of acres in that stand type that will be affected by wildland fire, but cannot predict where (geographically speaking) within Analysis Area that those effects will occur or if they will be contiguous or dispersed.

This approach is appropriate for strategic planning models such as FETM.  Spatial models (SIMPPLLE, for example), which are more tactical by design, may be used to predict the effects of treatments in specific locations.  But because of the large number of iterations that would be required, spatial models may not be able to provide a broader perspective on the optimal levels of fuel treatment to reduce wildland fire acres burned across the entire landscape.

FETM is stochastic:   Ecosystem disturbance processes, including wildland fire, occur randomly in time and space and are highly variable in their effects on the landscape.  A stochastic modeling approach (that is, one that employs one or more random variables) is appropriate.  FETM includes two random variables: wildland fire frequency by fire weather class, and wildland fire size for the fires that fall outside the range of recent historic data for the Analysis Area.

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