Fire has been an important evolutionary influence in forests, affecting species composition, structure, and functional aspects of forest biology. Restoration of wildland forests of the future will depend in part on restoring fire to an appropriate role in forest ecosystems. This may include the "range of natural variability" or other concepts associated with fire as a disturbance factor. Yet fire on the forested landscape has not been a constant in either space or time. Its frequency, intensity, seasonality, extent, and other characters - collectively know as a fire regime-varied considerably across western forest landscapes. A series of techniques can be used to understand this history, and accurate interpretation depends on using the best fire history technique for a given fire regime. The following synopsis of these techniques is based on a more detailed explanation provided in Agee (1993).