Large Tree Carbon

Large trees in this metric were calculated as the sum of branch and stemwood plus foliage for trees over 20 inches in diameter. This is intended to represent the most stable (possibly other than soil) component of the carbon pool, and can be an indicator of the carbon stock's resilience/stability. For this metric, higher values generally indicate more stability, and upward trends in this value may be interpreted as generally increasing resilience of the aboveground C pool.

Data and Resources

Additional Info

Field Value
Last Updated January 17, 2025, 06:42 (UTC)
Created January 17, 2025, 06:42 (UTC)
category /Carbon Sequestration/Stability
collection_name California Landscape Metrics
creation_method This data layer currently exists only for the Sierra Nevada region. Efforts are underway to explore development of F3 data for the rest of California. The [F3 model](https://docs.google.com/document/d/15tXCMkEzUEgQKHoXL74cftwtLuz3z-Rm/edit#heading=h.1t3h5sf) generated several different raster surfaces to estimate the biomass of stemwood in non-overlapping predefined size classes (BMSTM_x) and for the branchwood, foliage, and the unmerchantable portion of stemwood above 4" in the same non-overlapping predefined size classes (BMCWN_x). 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). 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](https://docs.google.com/document/d/15tXCMkEzUEgQKHoXL74cftwtLuz3z-Rm/edit#heading=h.2s8eyo1). 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, following the formula: _2021 BMCWN_x = 2019 BMCWN_x '€“ (2019 BMCWN_x * 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). The assumption that canopy cover loss as estimated using eDaRT MMI was equitably distributed among the predefined size classes may result in over- or under-estimates of actual large tree biomass, depending on location. Values for each of the non-overlapping, predefined, large tree size class for stemwood (BMSTM_x) rasters and for branchwood, foliage, and unmerchantable portion of stemwood above 4" (BMCWN_x) rasters were adjusted for 2021 following the same procedure using eDaRT MMI. This layer for the Large Tree Carbon metric is derived from F3 layers (2021) using the following formula: _[(sum(BMCWN_25, BMCWN_35, BMCWN_40, BMSTM_25, BMSTM_35, BMSTM_40)/2)* 2.2417023114334]_
data_resolution 30m Raster
data_units Mg C/ha
data_vintage 2021
encoding utf8
file_name SNV_LargeTreeCarbon_202111_202209_T2_v5
format GeoTiff
harvest_object_id d163f919-d5f7-4a1f-903c-d452012c3647
harvest_source_id a2637971-af12-457f-ae4a-831d2202a539
harvest_source_title WIFIRE Commons
maximum_value 340.2
metric_definition_and_relevance Large trees in this metric were calculated as the sum of branch and stemwood plus foliage for trees over 20 inches in diameter. This is intended to represent the most stable (possibly other than soil) component of the carbon pool, and can be an indicator of the carbon stock's resilience/stability. For this metric, higher values generally indicate more stability, and upward trends in this value may be interpreted as generally increasing resilience of the aboveground C pool.
minimum_value 0.0
spatial {"type": "Polygon", "coordinates": [[[-122.2883616476824, 35.05769372687348], [-117.5563290826801, 35.05769372687348], [-117.5563290826801, 42.00332292672577], [-122.2883616476824, 42.00332292672577], [-122.2883616476824, 35.05769372687348]]]}
tier 2