The LANDFIRE (LF) 2001 historical Percent of Replacement Severity Fires (PRS) product quantifies the percent of all fires that were of low severity. Replacement severity fires cause greater than 75% average replacement of dominant overstory aboveground biomass within a typical fire perimeter. This product is derived from the vegetation and disturbance dynamics model Vegetation Dynamics Development Tool (VDDT) and is intended to describe one component of fire regime characteristics in the context of the broader historical time period represented by the LF Biophysical Settings (BPS) product. The PRS product is created by linking the BPS Group attribute with the Refresh Model Tracker (RMT) data. Historical percents of mixed severity fires were classified into 20 categories using 5% increments. Additional data layer values were included to represent Water (111), Snow / Ice (112), Barren (131), and Sparsely Vegetated (132). Vegetated areas that never burned during the simulations were included in the category "Indeterminate Fire Regime Characteristics" (133); these vegetation types either had no defined fire behavior or had extremely low probabilities of fire ignition.