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About Us: Dynamic Vegetation Models—MC1

The transient model, MC1 was originally conceived under Phase I of the VEMAP (Vegetation/Ecosystem Modeling and Analysis Project) as the integration of the MAPSS biogeography model and the CENTURY biogeochemistry model into a new dynamic vegetation model. Significant changes resulted from this model integration, however, such as new biogeography rules, changes in the parameterization of CENTURY, use of the simplified CENTURY hydrology (as opposed to the MAPSS hydrology) and a new dynamic fire module developed to simulate the occurrence and impacts of fire events that are relatively infrequent but extreme.

MC1 consists of three linked modules simulating
biogeography, biogeochemistry, and fire disturbance.

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 belowground 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 aboveground 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 fireline intensity) and vegetation structure. Fire effects feed back to the biogeochemistry module to adjust levels of various carbon and nutrient pools.

Publications

Lenihan, J.M.; Daly, C.; Bachelet, D.; Neilson, R.P. 1998. Simulating broad-scale fire severity in a dynamic global vegetation model. Northwest Science. 72: 91-103. (Abstract)

Daly, C.; Bachelet, D.; Lenihan, J.M.; Neilson, R.P.; Parton, W.J.; Ojima, D. 2000. Dynamic simulation of tree-grass interactions for global change studies. Ecological Applications. 10(2): 449-469. (Abstract)

Bachelet, D.; Lenihan, J.M.; Daly, C.; Neilson, R.P. 2000. Interactions betwen fire, grazing and climate change at Wind Cave National Park, SD. Ecological Modelling 134: 229-244. (Abstract)

These new dynamic vegetation models will be useful for exploring management options at all scales from landscape to regional, national, and global.

Maps

Percentage Change Vegetation Carbon 2090-2099

US Forest Service - Pacific Northwest Research Station, Mapped Atmosphere-Plant-Soil System Study
Last Modified: Monday, 17 March 2008 at 13:06:48 EDT