- Metric Name:  Total Dead/Down Fuels

- Data Vintage:  2021

- Unit Of Measure: Short tons/acre

Stephens et al. (2022) note that total dead/down values over 20 (short) tons/ac (40 Mg/ha) resulted in high severity in 56% of the pixels. Higuera and Abatzoglou (2020) note that fuel and fuel aridity, where fuel is “non-limiting”, are a primary control on area burned at interannual to millennial timescales. Thus, it is more important than ever to define fuel limitation and map where it is on the landscape as a fundamental metric for where, even under hotter climates, low to moderate severity fire is still a strong likelihood.- Creation Method:  The F3 model generated several different raster surfaces of fuel loading estimates of the coarse woody debris by non-overlapping predefined size classes; including 1, 10, 100, 1000-hour fuels (FLOAD_1-5). The model also produced estimates for coarse woody debris of heavy fuels by non-overlapping predefined size classes which are greater than the 1000-hour fuel size (greater than or equal to12”; FLOAD_6-9) and for litter and duff. 

2019 to 2021 Update:  No adjustments were made for 2021 due to uncertainties in conversions based on the limits with which change detection information can quantify the individual components of this metric. For areas with disturbance 2019-2021 (defined as eDaRT MMI greater than or equal to 10% canopy cover loss), total dead/down fuel values are not represented for 2021 (i.e., NULL). For areas undisturbed 2019-2021, it is a reasonable assumption that total dead/down fuels did not change significantly over the course of two years.

This layer for the Total Dead/Down Fuels metric is derived from F3 layers (2021) using the following formula: 

sum(FLOAD_1-9, LITTER, DUFF)

- Credits:  F3 data outputs, Region 5, MARS Team
USDA Forest Service - Region 5 - Pacific Southwest Region