The main functions of the Biogeography module are to:
(1) predict the composition of deciduous/evergreen tree and C3/C4 grass lifeform mixtures;
(2) classify the predicted biomass from the biogeochemistry module into different vegetation classes.
The Biogeochemistry module simulates monthly carbon and nutrient dynamics for a given ecosystem. Above- and below-ground processes are modeled in detail, and include plant production, soil organic matter decomposition, and water and nutrient cycling. Parameterization of this module is based on the lifeform composition of the ecosystems, which is updated annually by the biogeography module.
The Fire module simulates the occurrence, behavior and effects of severe fire. Allometric equations, keyed to the lifeform composition supplied by the biogeography module, are used to convert above-ground biomass to fuel classes. Fire effects (i.e., plant mortality and live and dead biomass consumption) are estimated as a function of simulated fire behavior (i.e., fire spread and fire line intensity) and vegetation structure. Fire effects feed back to the biogeochemistry module to adjust levels of various carbon and nutrient pools. (U.S. Fire Risk Forecasts updated monthly-lower left corner on web page)
