Carbon Storage

Latest Score:


in 2021

Weight: 8%
score trend is up over time

Carbon storage is the amount of carbon stored by trees in forests. Through photosynthesis, trees convert atmospheric carbon dioxide (CO2) into sugars and wood, sequestering large amounts of carbon in their roots, trunks, and branches. Carbon is stored not only in live trees, but in soils, downed logs, and standing dead trees. While trees release some CO2 through the natural processes of respiration and decay, they store far more carbon then they release. Here we use Forest Inventory and Analysis Phase 2 plot data1 to assess the total, annual forest carbon storage, expressed in metric tonnes (equivalent to 1,000 Kg). The role of forests in carbon sequestration is critically important in moderating the effect of greenhouse gas emissions. A high score means that carbon storage is staying high over time. 

1 USDA Forest Service. Forest Inventory and Analysis Program. Available at:

-- Expert interpretation for Carbon Storage is not available--

The score is calculated using a target value and the historical range of the the entire long-term dataset. The higher the score, the closer this year's value is to the target.

Once the score is computed for each year, the trend in scores over time is calculated. If the trend is significantly positive or negative, the long-term trend is marked as increasing or decreasing respectively.

Component Description
Scored as

Distance between minimum and maximum (scaled 1-5)

Target value

Data maximum + 10% of range

Directionality of scores

Higher values in the data are better.

Minimum value used in scoring

Data minimum - 10% of range

Maximum value used in scoring

Data maximum + 10% of range

Data on carbon storage were extracted from the USFS Forest Inventory and Analysis Program EVALIDator1. We used an FIA-established query (“0103 Forest carbon total: all 5 pools, in metric tonnes, on forest land”) accessed by the FIA EVALIDator1. This query computed the total carbon storage (in MgT) on FIA plots across all carbon pools. The first available year of data was 1997. The data target was set at the maximum value in the dataset plus 10% of the range. The annual score was computed as the difference between the lower scoring bounds (either the minimum value in the data minus 10% of range or 0, whichever was greater) and the target, scaled between 1 and 5.

1USDA Forest Service. 2019. FIA EVALIDator. Available at: