The Fire and Fuels Extension (FFE) to the Forest Vegetation Simulator (FVS) simulates fuel dynamics and potential fire behavior over time, in the context of stand development and management. Existing models of fire behavior and fire effects were added to FVS to form this extension. New submodels representing snag and fuel dynamics were created to complete the linkages. This report contains four chapters. Chapter 1 states the purpose and chronicles some applications of the model. Chapter 2 details the model's content, documents links to the supporting science, and provides annotated examples of the outputs. Chapter 3 is a user's guide that presents options and examples of command usage. Chapter 4 describes how the model was customized for use in different regions. Fuel managers and silviculturists charged with managing fire-prone forests can use the FFEFVS and this document to better understand and display the consequences of alternative management actions.

FFE-FVS is a model linking stand development, fuel dynamics, fire behavior and fire effects. It allows comparison of mid- to long-term effects of management alternatives including harvest, mechanical fuel treatment, prescribed fire, salvage, and no action. Geographical variants use locally calibrated growth algorithms, decay parameters, fire effects relationships, and fuel modeling logic.

The Forest Vegetation Simulator (FVS) is a stand-based, individual tree growth and yield model designed and maintained by the USDA Forest Service. It is used by land managers on public and private ownerships to simulate and compare the effects of silvicultural treatments on forest stand dynamics including tree growth, mortality, and regeneration. The Fire and Fuels Extension (FFE) of FVS is designed to simulate changes in fuel loading through time and can incorporate user-specified fuel treatments into projections. We tested whether the default model fuel loading values from two FVS variants (Central States and Southern variants) were representative of field-based fuel loads using FIA data collected in the Ozark Highland region. We also compared fuel loads projected by FVS-FFE to empirical data collected from a 14-year study examining the impact of harvesting and burning on fuel loading in the Missouri Ozarks. Preliminary findings indicate that default values for both variants were not representative of light fuels (litter, 1, and 10 hour fuels), while larger fuel classes were represented better by the Central States variant than the Southern variant. Choice of variant did not significantly change projected fuel loading for all fuel classes at the end of the 14-year simulation. Results suggest that choice of variant has little impact on short-term projections and that using observed fuel values rather than defaults can improve projection accuracy in the short-term.