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.

LANDFIRE's (LF) Biophysical Settings (BPS) product (https://www.landfire.gov/bps.php) 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 and both serve as key inputs to the LANDSUM landscape succession model (Keane et al. 2006). The actual time period for this data set is determined by historical context provided by the fire regime, vegetation system dynamics modeling, and the recent field and geospatial inputs used to create it. Weather data from the Daily Surface Weather and Climatological Summaries database [(DAYMET) https://daymet.ornl.gov/) were compiled from 1980 to 1997. LF uses BPS to depict reference conditions of vegetation systems across landscapes and should not be regarded as a representation of existing vegetation. LF Remap BPS is unchanged from LF Nationals BPS except for updates made to water, barren and snow classes (additions or removal), so that not vegetated cover types within the spatial BPS product matches LF existing vegetation and fuel products.

LANDFIRE's (LF) Biophysical Settings (BPS) product (https://www.landfire.gov/bps.php) 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 and both serve as key inputs to the LANDSUM landscape succession model (Keane et al. 2006). The actual time period for this data set is determined by historical context provided by the fire regime, vegetation system dynamics modeling, and the recent field and geospatial inputs used to create it. Weather data from the Daily Surface Weather and Climatological Summaries database [(DAYMET) https://daymet.ornl.gov/) were compiled from 1980 to 1997. LF uses BPS to depict reference conditions of vegetation systems across landscapes and should not be regarded as a representation of existing vegetation. LF Remap BPS is unchanged from LF Nationals BPS except for updates made to water, barren and snow classes (additions or removal), so that not vegetated cover types within the spatial BPS product matches LF existing vegetation and fuel products.

LANDFIRE's (LF) 2001 Biophysical Settings (BPS) product 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 (Comer et al 2003). 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 LANDFIRE Annual Disturbance products for 1999-2007 are included within the LF 2001 version and are developed through a multistep process. Inputs to this process include (but are not limited to): Landsat imagery derived Normalized Burn Ratio (NBR) data (in CONUS only), polygon data developed by local agencies, fire data obtained from Monitoring Trends in Burn Severity (MTBS), Burned Area Reflectance Classification (BARC), and Rapid Assessment of Vegetation Condition after Wildfire (RAVG) fire mapping efforts, and Protected Area Database (PAD) data. Event polygon data are provided to LANDFIRE by various local, regional, and national agencies and organizations. Disturbance type and year information is included as attributes for each polygon and transferred to the disturbance grids. Severity is determined by using dNBR (difference Normalized Burn Ratio) data classified into high, medium, and low severity levels based on a statistical comparison with the MTBS, BARC, and RAVG fire severity. Vegetation Tracker (VCT, Huang, et. al. 2010) algorithms are used to identify disturbances outside of LF 2001 Events. VCT data are developed for each year identifying disturbed areas and severity. Since disturbance type (i.e. causality) is not determined in the VCT process, a spatial analysis was done comparing the VCT output to buffered (1 kilometer) LF 2001 Events and PAD GAP land use characteristics. While not providing a precise type of disturbance, this analysis provides information useful for narrowing down the types of disturbance that could or could not typically occur. Each zone has ten disturbance grids, one for each year 1999 to 2007. Each grid is attributed with year, disturbance type (if known, otherwise a description of possible types), severity, and the data sources used to create the data.

LANDFIRE's (LF) Biophysical Settings (BPS) product (https://www.landfire.gov/bps.php) 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 and both serve as key inputs to the LANDSUM landscape succession model (Keane et al. 2006). The actual time period for this data set is determined by historical context provided by the fire regime, vegetation system dynamics modeling, and the recent field and geospatial inputs used to create it. Weather data from the Daily Surface Weather and Climatological Summaries database [(DAYMET) https://daymet.ornl.gov/) were compiled from 1980 to 1997. LF uses BPS to depict reference conditions of vegetation systems across landscapes and should not be regarded as a representation of existing vegetation. LF Remap BPS is unchanged from LF Nationals BPS except for updates made to water, barren and snow classes (additions or removal), so that not vegetated cover types within the spatial BPS product matches LF existing vegetation and fuel products.

LANDFIRE's (LF) Biophysical Settings (BPS) product (https://www.landfire.gov/bps.php) 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 and both serve as key inputs to the LANDSUM landscape succession model (Keane et al. 2006). The actual time period for this data set is determined by historical context provided by the fire regime, vegetation system dynamics modeling, and the recent field and geospatial inputs used to create it. Weather data from the Daily Surface Weather and Climatological Summaries database [(DAYMET) https://daymet.ornl.gov/) were compiled from 1980 to 1997. LF uses BPS to depict reference conditions of vegetation systems across landscapes and should not be regarded as a representation of existing vegetation. LF Remap BPS is unchanged from LF Nationals BPS except for updates made to water, barren and snow classes (additions or removal), so that not vegetated cover types within the spatial BPS product matches LF existing vegetation and fuel products.

The LANDFIRE Annual Disturbance products for 1999-2007 are included within the LF 2001 version and are developed through a multistep process. Inputs to this process include (but are not limited to): Landsat imagery derived Normalized Burn Ratio (NBR) data (in CONUS only), polygon data developed by local agencies, fire data obtained from Monitoring Trends in Burn Severity (MTBS), Burned Area Reflectance Classification (BARC), and Rapid Assessment of Vegetation Condition after Wildfire (RAVG) fire mapping efforts, and Protected Area Database (PAD) data. Event polygon data are provided to LANDFIRE by various local, regional, and national agencies and organizations. Disturbance type and year information is included as attributes for each polygon and transferred to the disturbance grids. Severity is determined by using dNBR (difference Normalized Burn Ratio) data classified into high, medium, and low severity levels based on a statistical comparison with the MTBS, BARC, and RAVG fire severity. Vegetation Tracker (VCT, Huang, et. al. 2010) algorithms are used to identify disturbances outside of LF 2001 Events. VCT data are developed for each year identifying disturbed areas and severity. Since disturbance type (i.e. causality) is not determined in the VCT process, a spatial analysis was done comparing the VCT output to buffered (1 kilometer) LF 2001 Events and PAD GAP land use characteristics. While not providing a precise type of disturbance, this analysis provides information useful for narrowing down the types of disturbance that could or could not typically occur. Each zone has ten disturbance grids, one for each year 1999 to 2007. Each grid is attributed with year, disturbance type (if known, otherwise a description of possible types), severity, and the data sources used to create the data.

The LANDFIRE Annual Disturbance products for 1999-2007 are included within the LF 2001 version and are developed through a multistep process. Inputs to this process include (but are not limited to): Landsat imagery derived Normalized Burn Ratio (NBR) data (in CONUS only), polygon data developed by local agencies, fire data obtained from Monitoring Trends in Burn Severity (MTBS), Burned Area Reflectance Classification (BARC), and Rapid Assessment of Vegetation Condition after Wildfire (RAVG) fire mapping efforts, and Protected Area Database (PAD) data. Event polygon data are provided to LANDFIRE by various local, regional, and national agencies and organizations. Disturbance type and year information is included as attributes for each polygon and transferred to the disturbance grids. Severity is determined by using dNBR (difference Normalized Burn Ratio) data classified into high, medium, and low severity levels based on a statistical comparison with the MTBS, BARC, and RAVG fire severity. Vegetation Tracker (VCT, Huang, et. al. 2010) algorithms are used to identify disturbances outside of LF 2001 Events. VCT data are developed for each year identifying disturbed areas and severity. Since disturbance type (i.e. causality) is not determined in the VCT process, a spatial analysis was done comparing the VCT output to buffered (1 kilometer) LF 2001 Events and PAD GAP land use characteristics. While not providing a precise type of disturbance, this analysis provides information useful for narrowing down the types of disturbance that could or could not typically occur. Each zone has ten disturbance grids, one for each year 1999 to 2007. Each grid is attributed with year, disturbance type (if known, otherwise a description of possible types), severity, and the data sources used to create the data.

LANDFIRE’s (LF) 2001 Vegetation Departure (VDep) product categorizes departure between current vegetation condition and reference vegetation condition, according to the methods outlined in the Interagency Fire Regime Condition Class Guidebook [FRCC Guidebook (Hann et al 2010)]. VDep differs from the FRCC Guidebook, however, because it is based on the departure of current vegetation condition only, whereas the FRCC Guidebook approach includes departure of current fire regimes for the reference period. For VDep, summary units are defined as a BioPhysical Setting (BpS) with identical reference condition values regardless of map zone. For example, when a BpS is present in map zone 1, 2, 4, 5, 6 and 8, the reference conditions for this BpS are identical in map zones 1, 2, 4, 5, and 8, those map zones become a summary unit for VDep computation. Since reference conditions are unique for this BpS in map zone 6, it is a separate summary unit for calculating VDep. Within each BpS summary unit, we compare the reference percentage of each Succession Class (SClass) to the current percentage, then the smaller of the two is summed to determine the similarity index for the BpS. This value is then subtracted from 100 to determine the departure value, VDep value is always between 0 and 100, with 100 representing maximum departure. Reference conditions are derived from quantitative vegetation dynamics models that mimic native, pre-European colonization disturbance regimes. The current conditions are derived from the corresponding LF 2001 SClass data for each BpS. The proportion of the landscape occupied by each SClass, in each BpS unit, within each summary unit represents current condition of that SClass in VDep calculation. VDep is based entirely on the remaining area of each BpS unit that is occupied by valid SClasses. Each pixel in a BpS within a summary unit has the same VDep value.