- Metric Name:  ABOVEGROUND LIVE TREE CARBON (F3)

- Data Vintage:  2021

- Unit Of Measure: Mg C/ha

A recent paper (Bernal et al., 2022), suggests that due to drought/temps expected beyond 2040, the Sierra Nevada may not be able to support carbon loads of aboveground live trees over 20 Mg C/ha (note that they report biomass values, not carbon values). Carbon values are generally assumed to be half of biomass (See CAL FIRE’s “AB 1504” methodology, Christensen et al., 2019). 

Creation Method:  The F3 model generated a raster surface from the Fire and Fuels Extension of the FVS Carbon Report to estimate the total aboveground live trees, including stems, branches, and foliage but not including roots (Abovegroun), to provide the Tons C per acre. Conversion from short tons per acre (the default F3 output units) to Mg/ha requires multiplication by 2.2417023114334.
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 Carbon loss, following the formula:
2021 Abovegroun = 2019 Abovegroun – (2019 Abovegroun * MMI/100)
The assumption of direct correlation between canopy cover and Carbon should be viewed with caution.
This layer for Aboveground Live Tree Carbon metric is derived from F3 layers (2021) using the following formula:
[Abovegroun]*2.2417023114334]


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 Carbon loss, following the formula:
2021 Abovegroun = 2019 Abovegroun – (2019 Abovegroun * MMI/100)
The assumption of direct correlation between canopy cover and Carbon should be viewed with caution.
This layer for Aboveground Live Tree Carbon metric is derived from F3 layers (2021) using the following formula:
[Abovegroun]*2.2417023114334]



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