Stock Change Approach


Organization Boundaries Emission
Figure 12.A.1 System boundary of the Stock-Change approach.

Note: NEE = net ecosystem exchange of carbon, E = carbon release to the atmosphere from HWP in use, EW = carbon release to the atmosphere from HWP in SWDS, H = carbon transfer in the form of harvested wood biomass transported from harvest sites, W = carbon transfer in the form of wood waste into SWDS, Pex = carbon transfer in the form of HWP exports, PIM = carbon transfer in the form of HWP imports, O = possible other cross-border carbon transfers from rest of AFOLU (assumed zero here).

The Stock-Change Approach (SCA) estimates changes in wood carbon stocks in the forest pool (and other wood producing lands) and wood-products pool in the reporting country. Changes in carbon stock in forests and other wood producing land categories are reported by the country in which the wood is grown, referred to as the producing country. Changes in the products pool are reported by the country where the products are used, referred to as the consuming country. Because the stock changes actually occur in the reporting country the report indicates when and where the stock changes occur.

The system boundary of the Stock-Change Approach and the carbon pools under consideration are shown in Figure 12A.1. In the Stock-Change Approach all the national annual C-stock changes in biomass pools of the AFOLU Sector are summed up and the national carbon dioxide emissions are approximated using Equation 12A.1:

Equation 12A.1 Emissions from AFOLU by the Stock-Change Approach

Annual CO2 emissions from AFOLU = -44/12 • [A(AFOLU without HWP) + A(HWP in use) +

= -44/12 • [A(AFOLU without HWP) + AChwp iudc+AChwp swdsdc]

= -44/12 • [A(AFOLU without HWP) + H + Pm - Pex - TChwp dc]


A means annual change in carbon stock of the pool within the brackets. Note that the variables AChwp iuDcand AChwp swdsdc are defined in Table 12.1.

Figure 12A.2 may be used to express Equations 12A.3 and 12A.4 using either carbon stock change variables

(AChwp iudc+AChwp SWDSDC ) or carbon release variables and carbon transfer variables (|CHWP DC, H, PIM, PEX).


H = Harvest of wood to be used for HWP (including fuelwood)

E = carbon release to the atmosphere from HWP in use

EW = carbon release to the atmosphere from HWP in SWDS. (Note that here the carbon release is not considered as a sum of C-stock changes as in the Stock-Change and Production approaches. HWP in use include all harvested wood products consumed in the reporting country and HWP in SWDS include all wood-based waste disposed into the solid waste disposal sites (including both open dumps and landfill sites) of the reporting country).

PEX = carbon transfer in the form of exported wood-based biomass

PIM = carbon transfer in the form of imported wood-based biomass

As the quantity = -44/12 • A(AFOLU without HWP) is already reported in the rest of AFOLU, the HWP

Contribution to be reported in the HWP module is given by Equation 12A.2:

Equation 12A.2 Stock-Change Approach: HWP Contribution

HWP Contribution to AFOLU Net CO2 emissions SCA = -44/12 • [ACHWP IU Dc+ ACHWP SWDS ]

HWP Contribution to AFOLU Net CO2 emissions sca = -44/12 • [ H + Pm - Pex - TChwp dc ]

In the specific case when stock change of carbon in the HWP pools is zero, HWP Contribution is reported as zero (Equation 12A.2).

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