A coarse scale assessment and mapping effort was initiated as two associated projects. The first project, called Fire Regimes for Fuels Management and Fire Use, began in 1997 through an agreement with USDA Forest Service, Fire and Aviation Management, State and Private Forestry. This project involved mapping and characterization of historic natural fire regimes and current vegetation conditions, and development of an index of departure for use in national-level fire management planning. Development of the initial map of Historical Natural Fire Regimes for the conterminous United States was done under this agreement. Under the fire regime project, the concept of risk was defined as the 'risk of losing key components that define a system' or specifically, losses attributed to the occurrence or introduction of fire,either wildland or prescribed fire. Within that framework, we classify current conditions as a function of departure from historical natural conditions. The second project, now called Ecosystems at Risk, was undertaken to add a fire-related component to the USDA Forest Service's Forests at Risk project. The Joint Fire Sciences Program (JFSP) subsequently funded completion of these two efforts for interagency use in 1998, with specifications for development of several additional spatial data layers.

These data integrate biophysical information and pre-existing remotely sensed products. We have incorporated disturbance and successional processes, including development of stylized successional pathways for unique combinations of historical fire regime and potential natural vegetation. We organized and facilitated seven regional panels of expert ecologists, silviculturists, and fire managers to review and refine the spatial data layers, develop the pathway diagrams, and assign fire management condition classes. These data are intended for national, programmatic and strategic planning, and will be used by federal land managers, states, and other non-governmental organizations in fire and fuel management planning, assessments of ecosystem health, and risk assessments.