## Equations For Harvested Wood Products

Equation 12.1

Estimation of carbon stock and its annual change in HWP pools of the reporting

COUNTRY

Starting with i = 1900 and continuing to present year, compute

Note: For an explanation of technique used in Equations 12.1A to estimate first-order decay see Pingoud and Wagner (2006).

Where:

C(i) = the carbon stock of the HWP pool in the beginning of year i, Gg C

k = decay constant of first-order decay given in units, yr-1 ( k = ln(2) / HL, where HL is half-life of the HWP pool in years. A half-life is the number of years it takes to lose one-half of the material currently in the pool.)

Inflow(i) = the inflow to the HWP pool during year i, Gg C yr-1

AC(i) = carbon stock change of the HWP pool during year i, Gg C yr-1

Where:

InflowDC = carbon in annual consumption of solidwood or paper products that came from wood harvested in the reporting country (that is, from domestic harvest), Gg C yr-1

P = carbon in annual production of solidwood or paper products in the reporting country, Gg C yr-1

SFPim and SFPEX = imports and exports of semi-finished wood and paper products. For solidwood, this includes sawnwood, panels, and other industrial roundwood. For paper products, this includes paper and paperboard, Gg C yr-1

Equation 12.3

Estimation of HWP products produced annually from domestic harvest

InflowDH = P •

" irwh '

IRW h + irwIM - irwEX + wchIM - WCHEX + WRm - wrEX _

InflowDH = carbon in annual production of solidwood or paper products that came from wood harvested in the reporting country (that is, from domestic harvest), Gg C yr-1

P = carbon in annual production of solidwood or paper products in the reporting country, Gg C yr-1. Note that paper product production includes wood fibre and excludes non-wood fibre. An equation to estimate the wood fibre in paper products production is shown in Note 1 of Table 12.5.

IRWh = industrial roundwood harvest in the reporting country. This is the harvest of wood to make solidwood and paper products including IRW for export. [The FAO variable is called Industrial RW Production], Gg C yr-1

IRWim , IRWex = industrial roundwood imports and exports, respectively, Gg C yr-1

WCHIM, WCHEX = wood chip imports and exports, respectively, Gg C yr-1

WRim, WRex = wood residues from wood products mills imports and exports, respectively, Gg C

 Equation 12.4 Estimation of annual change in carbon in HWP in domestic SWDS where HWP came FROM DOMESTIC HARVEST AChwpswdsdh = achwp swdsdc • 1 | Imported wood material | ^ Produced wood material + Imported wood material J Imported wood material = ~IRWim + WCHim + WRIM + SawnWIM + WPanIM +" P&PBim + WPulp&RecPapIM Produced wood material = IRWH AChwp swds^tt = Variable 2B = annual change in carbon in HWP in domestic SWDS where HWP came from domestic wood harvest, Gg C yr-1 ACHWP swds DC = Variable 1B = annual change in carbon in HWP in SWDS in the reporting country, Gg C yr-1 IRWH and IRWiM = industrial roundwood harvest in the reporting country and industrial roundwood imports, respectively, Gg C yr-1 WCHIM = wood chip imports, Gg C yr-1 WRIM = wood residues from wood products mills imports, Gg C yr-1 SawnWIM = sawn wood imports and, Gg C yr-1 WPanIM = wood panel imports, Gg C yr-1 P&PBIM = paper and paperboard imports, Gg C yr-1 WPulp&RecPapIM = wood pulp and recovered paper imports, Gg C yr-1 Equation 12.5 Estimation of carbon release using HWP variables For annual carbon release from wood stocks in the reporting country (A) t CHWP DC = H + PIM - PEX - ACHWP1U DC - ACHWPSWDSDC For annual carbon release from wood harvested in the reporting country Equation 12.6 Equation to estimate production, imports or export variables in Table 12.5 for years before 1961 Where: Vt = annual production, imports or exports for a solidwood or paper product for year t, Gg C yr-1 t = year V1961 = annual production, imports or exports for a solidwood or paper product for the year 1961, Gg C yr-1 U = estimated continuous rate of change in industrial roundwood consumption for the region that includes the reporting county between 1900 and 1961 (see Table 12.3), yr-1 Appendix 1