LANDFIRE's (LF) 2023 Update Biophysical Settings (BPS) product for Alaska represents the vegetation system that may have been dominant on the landscape prior to Euro-American settlement. BPS is based on both the current biophysical environment and an approximation of the historical disturbance regime. Map units are based on NatureServe's Ecological Systems classification and represent the natural plant communities that may have been present during the reference period. Each BPS map unit is matched with a model of vegetation succession which is used to estimate reference fire frequency and severity. LANDFIRE uses BPS to depict reference conditions of vegetation systems across landscapes and should not be regarded as a representation of existing vegetation. The LF 2023 BPS product uses the revised Ecological Systems classification for AK and was created by reviewing and modifying the LF 2016 Remap Existing Vegetation Type (EVT) data and adapting it to represent BPS concepts. This includes splitting and lumping EVTs to ensure they are compatible with the recent classification changes in BPS.