The quantity of carbon stored in a forest depends on factors like geographical location, mix of species, silvicultural management, soil type, and climate.
The Gold Standard Afforestation/Reforestation (A/R) methodology, which applies to projects that plant trees (it is understood by trees also bamboo, palms and shrubs; by planting it is also considered assisted natural regeneration), requires biomass in plantations to be measured via a forest inventory. The A/R methodology requires following the BioCarbon Fund – Winrock’s Sourcebook for LULUCF Projects to conduct a forest inventory.
The process of measuring biomass up to issuance of Gold Standard Verified Emission Reduction (GS-VER) from an A/R project can be summarised as:
- Division of the project area in modeling units (MUs) that represent planted areas with homogenous characteristics.
- MUs are then sampled following a random sampling approach (sample points can be permanent plots) to measure tree biomass.
- Below-ground biomass is calculated based on root-to-shoot ratio coefficient obtained from literature sources demonstrated to be applicable to the project plantation.
- Above-ground and below-ground biomass is added at the sample plot level and expanded to the MU level. The sum of the total biomass in all MUs represents the biomass in the project area.
- Total biomass is converted to metric tons of CO2-equivalent (tCO2e).
- Baseline, leakage and project emissions, both in tCO2e, are deducted from the tCO2e from total biomass. This gives the net tCO2e sequestered by the project.
- Net tCO2e in the project area is adjusted by discounting uncertainty above 20% error from the mean at 90% confidence level.
- The resulting adjusted net tCO2e is used to issue GS-VERs. One (1) tCO2e represents one (1) GS-VER.