* Metric Name: FRID Condition Class for Departure  

* Tier: 3  

* Data Vintage: 2021  

* Unit Of Measure: Integer, -3 to 3

This metric uses the mean percent FRID to a measure of the extent to which
contemporary fires (i.e., since 1908) are burning at frequencies similar to
the frequencies that occurred prior to Euro-American settlement, with the mean
reference FRI binned into another basis for comparison. Mean PFRID is a metric
of fire return interval departure (FRID), and measures the departure of
current FRI from reference mean FRI in percent.

* Creation Method: This is a condition class categorization of the data in the Mean PFRID field. MeanCC_FRI categorizes the percent differences calculated in Mean PFRID using the following scale:

  * 1 0 to 33.3%
  * 2 33 to 66.7%
  * 3 greater than 66.7%

Negative condition classes (i.e., where fires are burning more often than
under pre-Anglo-American settlement conditions) are categorized on the
negative of the same scale:

  * 1 0 to -33.3%
  * 2 -33 to -66.7%
  * 3 less than -66.7%

CC1 and CC-1 are mapped in the same class because they are both within 33% of
the mean pre-settlement value.

  

* Credits: Fire History (2021), CAL FIRE \--Department of Forestry and Fire Protection Existing Vegetation (CALVEG 2011), USDA Forest Service, Region 5, MARS Team \--Region 5 - Pacific Southwest Region