Fire Return Interval Departure (Frid) - Mean Percent - Since 1908

This metric, mean percent FRID, is 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 as the 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.

Data and Resources

Additional Info

Field Value
Last Updated January 17, 2025, 06:42 (UTC)
Created January 17, 2025, 06:42 (UTC)
category /Fire Dynamics/Functional Fire/Fire Return Interval Departure (FRID)
collection_name California Landscape Metrics
creation_method The current FRI is calculated by dividing the number of years in the fire record (e.g., 2019-1908=112 years inclusive) by the number of fires occurring between 1908 and the current year in a given polygon plus one (CurrentFRI = Number of years/Number of fires +1). The mean reference FRI is an approximation of how often, on average, a given PFR likely burned in the three or four centuries prior to significant Euro-American settlement. This measure does not return to zero when a fire occurs, unlike FRID values used in some other analyses (e.g., NPS FRID Index). Instead, the following formulas are used to calculate Mean PFRID: When current FRI is longer than reference FRI (the common condition in most coniferous PFRs) the formula is: _[1-(MeanRefFRI/CurrentFRI)]*100_ When current FRI is shorter than reference FRI (common in some shrub dominated PFRs, and areas in the Wildland Urban Interface) the formula is: _-{[1-(CurrentFRI/MeanRefFRI)]}*100_ For areas dominated by PFRs with a mean reference FRI greater than 112 years, and that have not burned in the period of historical record considered in this analysis (i.e., since 1908), the FRID is assumed to equal zero.
data_units Percent
data_vintage 2022. Includes disturbances through the end of 2022.
encoding utf8
file_name FRID_MeanPrct_19082022_202401_T1_v5
format GeoTiff
harvest_object_id 1dfac65b-b46c-4329-b05c-65e3054568e6
harvest_source_id a2637971-af12-457f-ae4a-831d2202a539
harvest_source_title WIFIRE Commons
maximum_value 90.4
metric_definition_and_relevance This metric, mean percent FRID, is 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 as the 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.
minimum_value -98.4
spatial {"type": "Polygon", "coordinates": [[[-124.5090833859125, 32.4242698701859], [-113.49380570277376, 32.4242698701859], [-113.49380570277376, 42.1119747450123], [-124.5090833859125, 42.1119747450123], [-124.5090833859125, 32.4242698701859]]]}
tier 1