In IFTDSS you may choose to edit your landscape using your own custom rules, or default rules meant to replicate landscape treatments or disturbances. The default rules often have additional options that specify the severity or breadth of the treatment or disturbance.
In IFTDSS you may choose to edit your landscape by adding you own editing rules, or using Default Fuel Treatment / Disturbance Edit Rules. Default Fuel Treatment and Disturbance Edit Rules use previously existing LANDFIRE Lookup tables (LFLUs) and Fuel Model Lookup (FMLU) tables. The LFLU tables were created in an effort to improve the LANDFIRE fuels layers between versions. The LFLU tables are used to adjust the fuel attributes of cells, including: fuel model, canopy cover, stand height, canopy base height, and canopy bulk density, based on the type and intensity of treatment or disturbance and the time that has elapsed since that treatment or disturbance. The rules work by taking into account Existing Vegetation Type (EVT), Existing Vegetation Cover (EVC), and Existing Vegetation Height (EVH) and then using the LANDFIRE Look Up (LFLU) table as a crosswalk to account for changes in vegetation attributes, based on treatment or disturbance type, intensity and timing. The resulting vegetation is then crosswalked to one of the 40 fuel models. In the continental US, only 36 of the 40 fuel models are used, the 4 fuel models that aren’t used are 109, 164, 201, and 202. As of now the LFLU rules are not available in AK or HI.
To streamline the process of making a landscape representative of the current conditions and gaming out potential treatments, the IFTDSS team has made the LFLU tables available to IFTDSS users. These rules are an improvement over previous methods of landscape edits in that each pixel is updated independently based on EVT, EVC, and EVH. This allows for the rules to apply differently based on the known responses of a particular EVT to a particular disturbance or treatment. A user may apply Default Fuels Treatment / Disturbance Rules based on a mask (polygon) or on the full extent of the landscape.
Below we have outlined the details describing the specific treatment or disturbance details associated with each default rule:
Light Thinning; Pile Burn - Thins the stand to ~80% of present density by removing understory up to 8" DBH. Subsequent pile burning of thinned material.
Heavy Thinning; Pile Burning - Thins the stand to ~35% of present density with no upper diameter limit.
Moderate Thin; Lop and Scatter - Thins the stand to ~45% of present density by removing understory up to 6" DBH. Thinned material left on site and spread evenly.
Moderate Thin; Masticate - Thins the stand to ~25% of present density by removing understory up to 6” DBH. Thinned material crushed, chipped, and left on site.
Heavy Thin; Masticate - Thins the stand to ~10% of present density by removing understory up to 8” DBH. Thinned material crushed, chipped, and left on site.
Clearcut and Broadcast Burn - This treatment consists of removal of 100% of overstory with subsequent prescribed burn covering 100% of the area.
Low Severity Fire: Fire with resulting mortality of above ground vegetation <25%.
Moderate Severity Fire: Fire with resulting mortality of above ground vegetation from 25-75%.
High Severity Fire: Fire with resulting mortality of above ground vegetation from 75 to 100%.
This assumes that the fuel treatment or disturbance occurred the previous year. This time period assumes a minimum reaccumulation of fuel post disturbance or treatment but recognizing that this reaction will vary depending on Existing Vegetation Type (EVT), disturbance or treatment intensity, and local factors of the LANDFIRE zone.
This time period assumes a median of 4 years. Utilizing the Forest Vegetation Simulator (FVS), the LANDFIRE team utilizes the median of this period to model vegetation recovery and fuel accumulation for the purposes of informing the local workshops of local experts to determine an appropriate new EVT and resulting fuel model.
This time period assumes a median of 8 years. Utilizing the Forest Vegetation Simulator (FVS), the LANDFIRE team utilizes the median of this period to model vegetation recovery and fuel accumulation for the purposes of informing the local workshops of local experts to determine an appropriate new EVT and resulting fuel model.
The use of the Default Fuel Treatment or Disturbance Edit rules can greatly increase the efficiency of your landscape updates, calibrations and projections. To make the best use of these default rules it is critical to have an understanding of how landscape edits are being applied to your landscape. If you are new to an area or are working in an unfamiliar vegetation type, these rules helpful as well because the LFLU tables are using the best current knowledge in relationship to the most representative edits to show fuel attribute changes post treatment/disturbance.
See Landscape Edit Rules Technical Documentation for more detail on Landscape Edit Rules