- Metric Name:  Sawtimber

- Data Vintage:  2021

- Unit Of Measure: Dry weight tons/acre

This metric expresses the amount of total existing, aboveground, live tree stem biomass measured in dry weight tons per acre. This metric can be used to assess the sawtimber volume present at the 30m cell level.- Creation Method:  The F3 model generated raster surfaces to provide an estimate of the total aboveground live tree stem biomass (ABGDLVSM).

2019 to 2021 Update:  Values for 2021 were adjusted using the Ecosystem Disturbance and Recovery Tracker (eDaRT), described in the Introduction. All eDaRT events beginning August 1, 2019 through November 30, 2021 were identified, and the corresponding Mortality Magnitude Index (MMI) values for these events was summed, giving the estimated fractional canopy cover loss per 30m pixel over that time period. The MMI value for canopy cover loss was used as a direct proxy to estimate biomass loss, using the formula:

2021 ABGDLVSM = 2019 ABGDLVSM – (2019 ABGDLVSM * MMI/100)

Although the assumption of direct correlation between canopy cover and biomass should be viewed with caution, it serves as a reasonable approximation for representative mixed conifer forests in the Sierra Nevada affected by the recent drought (Slaton et al. 2022).

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