Appendix 3a.1

Appendix 3a.1 Harvested wood products:
Basis for future methodological development
3a.1.13a.1.1.1

Methodological Issues
R ELATIONSHIP TO THE IPCC GUIDELINES 1

The IPCC Guidelines (IPCC, 1997) provide an outline of how harvested wood could be treated in national
greenhouse gas (GHG) inventories. This section shows the relation of that outline to the approaches andestimation methods to be presented in this Appendix. Wood and paper products are referred to as harvested wood
products (HWP). It does not include carbon in harvested trees that are left at harvest sites. The issue of harvested
wood is discussed in Box 5 (IPCC Guidelines, Reference Manual, p. 5.17) as follows:“For the purposes of the basic calculations, the recommended default assumption is that all carbon
removed in wood and other biomass from forests is oxidised in the year of removal. This is clearly notstrictly accurate in the case of some forest products, but is considered a legitimate, conservative
assumption for initial calculations.”
and“...the recommended default assumption is that all carbon in biomass harvested is oxidised in theremoval year. This is based on the perception that stocks of forest products in most countries are notincreasing significantly on an annual basis.” The Guidelines go on to say “The proposed method
recommends that storage of carbon in forest products be included in a national inventory only in thecase where a country can document that existing stocks of long term forest products are in factincreasing. If data permit, one could add a pool to Equation (1) in the changes in forest and otherwoody biomass stocks calculation to account for increases in the pool of forest products. This
information would, of course, require careful documentation, including accounting for imports andexports of forest products during the inventory period.”
A note on the relationship between this discussion and this report: The IPCC Guidelines recommend that storage
estimates only be included in inventories if a country can document a method indicating that stocks are
increasing. This Appendix is intended to further the discussion as to when such methods may be available forcountries to determine and document increases in HWP stocks. This Appendix is based on the presumption thatan effort should be made to enable countries to determine if they may meet the “only if” condition of the IPCC
Guidelines.
The above outline in the IPCC Guidelines provides the starting point in the development of good practiceguidance for HWP estimation and reporting. The recommended default assumption – basically that harvested
wood is oxidised in the removal year – has the same effect as the case where there are no significant changes in
product stocks. In this case carbon flux of harvesting equals the decay flux of HWP into the atmosphere, butthere could still be a delay in emissions (and substantial but constant HWP stocks). This assumption is called the
IPCC default approach in the remainder of this section. The outline says that if data permit, positive stockchanges in HWP can be reported in national greenhouse gas inventories. There are two alternatives ways to do
this:Approach 1: Estimation of annual carbon stock changes of HWP in a country regardless of wood origin. This
would mean that:•

Wood carbon sources are not spatially specific – that is, product carbon comes from a number of land areas
including foreign forests but the carbon ends up in the reporting country.

•

Estimates of stock changes would be based on data for what happens to products in uses and waste disposal
within the borders of a country – it could include movements of products into and out of the country. Data
on uses and disposition would be found in one country.

1

The Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories (IPCC, 1997) is abbreviated as IPCC
Guidelines in this report.

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Chapter 3: LUCF Sector Good Practice Guidance•

Wood is from many sources and management activities – possibly outside the country. The change in stockcannot be linked to activities on one land area.

•

The approach may be used as part of an evaluation of the effect of factors on the accumulation and loss of
HWP carbon stored in a country.

•

There are several types of removals (or transfers to HWP) and emissions associated with the estimate of thechange in HWP stock in a country. These include the transfer of domestic harvest to products, the transfer ofimports to products, and the transfer of products to other countries, and the emissions from products to theatmosphere (see Figure 3a.1.1).

•

The positive carbon stock changes would be interpreted as removals or equivalently as negative emissions,expressed in Gg CO2/year in national greenhouse gas inventories.

Approach 1 is named as the Stock Change Approach.
Figure 3a.1.1 Carbon flows and stocks associated with forests and harvested wood products(HWP) to illustrate the Stock Change and Atmospheric Flow Accounting 2
Approaches.

ATMOSPHERE
NEE

E

Own country
Forestecosystems

PEX
H

HWP

PIM

Variable definitions:NEE= net ecosystem exchangeH= harvested wood transported from forestsE= emissions from HWP within country borders
PEX= exports of HWP including roundwood, wood-based waste and refined products
PIM= imports of HWP including roundwood, wood-based waste and refined products
Approach 2: Estimation of annual carbon stock changes of HWP where the carbon is from trees harvested in thereporting country. This would mean:•

Estimates of stock changes would be based on what happens to wood carbon that originated from one landarea – it could include movement of products out of the country and its disposition in other countries. Data
on uses and disposition would potentially be needed from different countries or assumptions may be needed
about disposition in other countries.

•

Consequently, the reporting boundary would not coincide with national borders.

•

Wood is from one land source and carbon stock change would be associated with management activities onthat land.

•This approach might be used as part of an evaluation of carbon storage changes associated with management
on certain land areas.

•

This approach could follow the life cycle of all wood carbon harvested from a specific land area.

2

Atmospheric Flow Approach is the Approach 3 in this section.

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Appendix 3a.1•

The positive carbon stock changes would be interpreted as removals or equivalently as negative emissions,expressed in Gg CO2/year in national greenhouse gas inventories.

•

There are several removals (or transfers to HWP) and emissions associated with the estimate of changes in
HWP stocks that came from timber in a country. These include the transfer of domestic harvest to productsin the country and to other countries, the emissions from HWP in the country that came from domestic
harvest and emissions from HWP in other countries that came from domestic harvest (see Figure 3a.1.2).

Approach 2 is named as the Production Approach.
Figure 3a.1.2 Carbon flows and stocks associated with forests and harvested wood products(HWP) to illustrate the Production Accounting Approach.

ATMOSPHERE
E

NEE

DOM

Own Country

Forestecosystems

EX OTH

Abroad
HWP

H

E

E EX DOM

EIM

HWP

in usein useor in waste sites

or in waste

sites

PEX
PIM

Variable definitions:NEE= net ecosystem exchangeH= harvested wood transported from forests
EDOM= emissions from HWP in own country made from wood harvested from domestic forests
EEX DOM = emissions from HWP in other countries made from wood exported abroad that were madefrom wood harvested from own country’s forests
EIM= emission from imported HWP in own country
EEX OTH = emissions from HWP in other countries made from wood harvested in other countries= exports of HWP including roundwood, wood-based waste and refined products
PEX
PIM= imports of HWP including roundwood, wood-based waste and refined products
Approaches 1 and 2 above were elaborated at an IPCC Expert Meeting on Harvested Wood Products (IPCC,
1998). If either approach was used by an inventory agency, the estimated annual change of HWP stocks would
be added to the estimated annual biomass change in Equation 1 in the IPCC Guidelines (Reference Manual, p.
5.19). Equation 1 in the IPCC Guidelines corresponds to the sum of Equations 3.2.1 and 3.2.21 in Chapter 3 ofthis report. Equation 3.2.1 indicates carbon change on forest land that remains forest land and Equation 3.2.21
indicates carbon change on non-forest land that is converted to forest land. The Production Approach would addchange in HWP carbon where the carbon came from trees in domestic forests (the land sources cited in
Equations 3.2.1 and 3.2.21). The Stock Change Approach would add the change in HWP carbon that is resident
in the country (includes imports, excludes exports).
A third approach, having no explicit reference in the IPCC Guidelines, was also elaborated at the abovementioned IPCC Expert Meeting.
Approach 3: Estimation of annual atmospheric fluxes between the atmosphere and forests/HWP within nationalboundaries. This would mean that:•

The viewpoint of the approach deviates from the previous ones. Instead of focusing on stock changes(Approaches 1 and 2), the focus is directly on carbon fluxes from and to the atmosphere. It considers theannual carbon removal by forests and emissions from the HWP.

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Chapter 3: LUCF Sector Good Practice Guidance•Instead of reporting the annual HWP stock change as in Approach 1, the annual emissions are reported in
Approach 3 (see Figure 3.a.1.1).

•

This approach could require modification of the existing reporting practice concerning forests. Instead ofreporting only the net annual forest biomass change as growth minus harvest (and the changes in carbon of
the other stocks in forest ecosystems), the annual net carbon flux into forest ecosystems (net ecosystem
exchange) would be reported along with the estimates of emissions from HWP (see Figure 3.a.1.1).

•

Estimates of emissions would be based on data for what happens to products in use and waste disposal
within the boarders of a country – it could include movements of products into and out of the country. Data
on uses and disposition would be found in the reporting country. In this sense it is similar to Approach 1 (seeFigures 3a.1.1 and 3a.1.3.)•

Wood is from many sources and management activities – possibly outside the country. The emissions arelinked to the location of emissions but not to the land the wood carbon came from. The latter is analogous toApproach 1.

•

This approach may be used to evaluate the effect of all the factors that influence the emissions from woodcarbon in a country.

•

There are several removals (or transfers to HWP) and emissions associated with the estimate of theemissions from HWP stock in a country. These include the transfer of harvest to products, the emissions
from HWP remaining in the country, and the emissions from products imported to the country (see Figure
3a.1.1).

•

The carbon flux E in Figure 3a.1.1 would be interpreted as an emission, expressed in Gg CO2/year innational greenhouse gas inventories.
Approach 3 is named as the Atmospheric Flow Approach.

Figure 3a.1.3 Carbon flows and stocks when products both in use and in solid waste disposalsites (SWDS) are considered (Stock change and Atmospheric flow accounting
approaches).

ATMOSPHERE
E

NEE

EW

Own country

Forestecosystems

HWP
in use

H

PIM

W

HWP
in SWDS

PEX

Variable definitions:
HWP= harvested wood products
NEE= net ecosystem exchangeH= harvested wood transported from forestsE= emissions from HWP in use within country borders
PEX= exports of HWP including roundwood, wood-based waste and refined products
PIM= imports of HWP including roundwood, wood-based waste and refined products
W= HWP carbon disposed into SWDS
EW
= emissions from HWP in SWDS within country borders

Objective of this Appendi xThis appendix provides information on possible methods to estimate stock changes consistent with the advice in
the IPCC Guidelines, if data are available. In addition, it would be relevant for any of the three approaches just

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Appendix 3a.1

outlined, or potentially for other approaches, depending on decisions from the COP and/or COP/MOP on thismatter.3

The issue of how to account f or carbon in w ood-based w aste
One additional issue to be resolved when deciding on methods is whether or not changes in HWP stocks in solid
waste disposal sites (SWDS) should be included in emission/removal estimation and reporting. And if so, howshould such stock changes be included? There are several questions to consider:•First, should assumptions about decay of wood in SWDS be consistent between the Waste Sector and theForest Sector? That is, if the Waste Sector estimates that a portion of wood carbon stocks in SWDS is notdecaying, should the Forest Sector assume the same?

•

Second, should the Waste Sector keep track of HWP stored in SWDS sites? If so, how would that bereflected in accounting for HWP in the Forest Sector? The Waste Sector currently accounts for andestimates methane emissions from Solid Waste Disposal Sites (SWDS) (including emissions from wood andpaper) but does not estimate corresponding changes in the carbon stock in SWDS.

The above mentioned questions are not resolved in this section but suggestions are presented on methods for
estimating changes in HWP carbon stored in SWDS.

The issue of how to account f or harvested w ood use f or energy production
Currently wood energy emissions are noted but not included in emissions accounting for the Energy Sector orother sectors that produce wood energy. These emissions are assumed to be accounted for in the Land Use
Change and Forestry (LUCF) Sector. That is, they are part of the emissions from harvested wood. A
consideration for an accounting approach for HWP may be that it properly accounts for emissions from woodenergy in a country. The Stock Change and Atmospheric Flow Approaches both account for all emissions fromwood burned for energy in a country but the Production Approach may not account for all wood burned forenergy if some wood is imported and later burned for energy. Such emissions are not accounted for because
imported wood (including amounts burned after being imported) is not included in the Production Approach.

Proposed Tier struct ure
Three tiers of estimation methods are suggested:
Ti er 1
IPCC Guidelines Default estimation method is the way of making the Tier 1 estimate. This tier or method
assumes that all carbon in biomass harvested is oxidised in the removal year. This would correspond to an
estimate of no change in HWP carbon stocks for both the Stock Change Approach and the Production Approach.
Ti e r 2 : F i r st o r de r de c a y ( a f l u x met ho d)
Estimates are made of stock changes of HWP carbon in products in use and – in the case where waste is included
in reporting – HWP carbon in SWDS. The estimates are made by tracking inputs to and outputs from these poolsof carbon (also called input and output fluxes). Data beginning a number of decades in the past up to the present
time are used to estimate 1) additions to HWP in use, 2) removals from use, 3) additions to HWP in SWDS, and
4) decay from SWDS. This procedure is needed to obtain an estimate of the existing HWP stock accumulated
from historical wood use and current year emissions from those stocks as they go out of use (also termed“inherited emissions”).
If HWP in SWDS is included, data used for Tier 2 is intended to be consistent with data used for the Tier 2
method used for the Waste Sector (Chapter 5, Waste, GPG20004). The numerical factors a country uses to3

Decisions about how to treat harvested wood products have been deferred. The Conference of the Parties decides that any
changes to the treatment of harvested wood products shall be in accordance with future decisions of the COP(FCCC/CP/2001/13/Add/1, page 55, paragraph 4). The SBSTA, in FCCC/SBSTA/2003/L.3, recalled decision 11/CP.7,
paragraph 4, and noted the possible inclusion of methods to estimate the change in carbon stored in harvested wood
products as an annex or appendix to the IPCC report on good practice guidance for LULUCF. The purpose of the Appendix
is to support the decisions of the Subsidiary Body for Scientific and Technological Advice. Because SBSTA has requested
that the UNFCC Secretariat “…prepare a technical paper on harvested wood products accounting…” this section focuses
on methods that the authors suggest may be used whatever is developed concerning accounting (FCC/SBSTA/2001/8, 4
Feb 2002).

4

IPCC Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories (IPCC 2000) is
abbreviated as GPG2000 in this report.

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Chapter 3: LUCF Sector Good Practice Guidancecompute the methane emissions from SWDS should be consistent with the numerical factors used to computeamounts of HWP carbon retained in SWDS.
Ti er 3: Co unt ry- Sp ecif ic M etho d s
Change in HWP carbon in products in use and HWP carbon in SWDS (if agreed for inclusion) can each becomputed by separate methods. These methods may apply to some but not all of the accounting approaches(Flugsrud et al., 2001).
Method A – Estimate Change in inventories (stock methods)
Use inventories of HWP in use or HWP in waste disposal sites at two or more points in time and calculate thechange in carbon stored. The HWP pool of products in use in building structures is normally a major part of thetotal HWP pool. The amount of HWP carbon can be estimated, for example, by multiplying the average HWP
content per square metre of floor space times the total floor space for several types of buildings. Change incarbon may be estimated by noting the change between inventories estimated at different points in time.
Examples of such inventories are reported in Gjesdal et al., 1996 (for Norway) and in Pingoud et al., 1996, 2001
(for Finland). In this case no procedure for integration of the existing HWP stock from historical wood use datais needed, which is an advantage compared to the flux methods (Tier 2 and Tier 3/Method B). Similarly, it has
been suggested that the change in HWP carbon in SWDS could be estimated using information about the area,
average depth, and average wood and paper carbon content per cubic metre in these sites, although no examplesof this method have been reported in the literature.
Method B – Track input and output flows using detailed country data (flux methods)
Use detailed country data beginning a number of decades in the past and estimate each year, up to the present
time, (i) additions to pools of HWP in use, (ii) removals from use, (iii) additions to pools of HWP in SWDS, and(iv) decay from SWDS. Estimates for SWDS may use survey estimates of the amount of HWP placed in SWDS
each year rather than the amount of HWP going out of use and the portion going to SWDS.
Method C – Combine Method A and Method B estimates
An example of combining methods is 1) to use changes in inventory to estimate carbon changes in buildings andfurniture and 2) to use input and output flows to estimate changes of carbon in paper products (see example for
Norway, Flugsrud et al., 2001).

3a.1.1.2

C HOICE OF METH OD

With default data and country-specific estimates for some parameters, countries can use Tier 2 to makepreliminary estimates to evaluate changes in HWP stocks and whether counted increases in stocks would be a
key category. If country information is available it is suggested to use Tier 3 custom country methods, such aschange between actual inventories of wood products stored in long-lived pools for these purposes. If HWP is a
key category it is suggested that work would be done to develop national data for Tier 2 or Tier 3 estimates. If
HWP is not a key category, the Tier 1 method may be applied.

3a.1.1.3

C HOICE OF ACTIVITY DATA AND FACTORS I N
CALCULATIONS

Ti er 1: IP C C Gu id e li ne s D ef a u lt
Under Tier 1 the recommended default assumption is that all carbon in biomass harvested is oxidised in theremoval year. This is based on the perception that stocks of forest products in most countries are not increasingor decreasing significantly on an annual basis.
Ti e r 2 : F ir st o r de r de c a y me t h o d ( F O D)This method is termed the first order decay method because carbon in each of the carbon pools (products in use
and products in SWDS) is estimated to leave the pool at a constant percentage rate. The Tier 2 method for the
Waste Sector uses this technique to estimate methane emissions from SWDS (see Chapter 6, Waste, of the IPCC
Guidelines; and Chapter 5, Waste, of GPG2000).
The Tier 2 method is divided into two parts – Tier 2a to estimate HWP carbon changes for products in use andTier 2b to estimate HWP carbon changes in SWDS (see Figure 3a.1.3). Tier 2b is omitted if carbon changes in
SWDS are not included in reporting.

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Appendix 3a.1

The proposed method for estimating changes in carbon stored in HWP utilizes data on production andinternational trade of primary HWP (saw wood, panels and paper). Only primary products are used because data
are available for virtually all countries. Data on secondary products such as furniture may also be used if
available but care is needed to avoid double counting of HWP carbon5. Data on input flows and output flows
over several decades is used to calculate current year change in the pool of HWP carbon. The input flow to thepool in a country is calculated by adding imports to the national production of primary products, and subtracting
the exports. The output of the pool or decay is assumed to be of first order. That is, a constant fraction of eachpool is lost each year. The pool of primary products will include wood used in all its final uses. Wood-basedmaterial that is not accumulated into the stocks of HWP in use (or HWP in SWDS) in a country is assumed toform emissions. These calculations are valid for Stock Change Approach and may also be used to computecarbon flows for the Atmospheric Flow Approach. Stock Change and Atmospheric Flow Approaches in the case,where both products in use and in SWDS are included, are illustrated in Figure 3a.1.3. The Production Approachrequires additional approximations, as typically only a part of the HWP in a country are of domestic origin and,in addition, HWP of domestic origin might be exported (see Figure 3a.1.2).
The Tier 2 equations for the three approaches are as follows:
Tier 2a: Change in HWP carbon in products in use
EQUATION 3a.1.1
ANNUAL CHANGE IN HWP CARBON IN PRODUCTS IN USE AND THE ASSOCIATED CO2 EMISSIONS(1A) ∆CHWP IU SCA = PA – PL
CO2 emissions/removals SCA = ∆CHWP IU SCA ● 10-3 ● 44/12 ● (-1)(Stock Change Approach)(1B) ∆CHWP IU PA = PHA – PHL
CO2 emissions/removals PA = ∆CHWP IU PA ● 10-3 ● 44/12 ● (-1)(Production Approach)(1C) E = – ∆CHWP IU SCA + H – PEX + PIM – W
CO2 emissions/removals AFA = E ● 10-3 ● 44/12(Atmospheric Flow Approach)

Note 1: The quantity E estimated is the real flux of C from HWP stock into the atmosphere within
the borders of the reporting country (see Figures 3a.1.1 and 3a.1.3). The forest sector
should then report the real flux of carbon from atmosphere into the forest ecosystems(NEE) or the sum of stock changes in forest ecosystems + H, which is a deviation fromthe existing reporting practice in which only stock changes are reported (NEE – H).
Note 2: Each term has a year subscript t – omitted to simplify the format; each term on the righthand side of the equations has at least two parts: at least one for solidwood products andat least one for paper products.
Note 3: The changes in carbon in HWP are as a rule estimated as tonnes C yr-1 and converted to
Gg CO2 for reporting by multiplying with 10-3 ● 44/12. The emissions are reported as
positive and removals as negative – hence the multiplication with -1 (see also Section
3.7.1 and Annex 3A.2 Reporting Tables and Worksheets).
Where:∆CHWP IU SCA = annual change in carbon stored in HWP in use in the country, tonnes C yr-1
∆CHWP IU PA = annual change in carbon in HWP in use from wood harvested in the country (includes
carbon in exports and excludes carbon in imports, tonnes C yr-1
E = carbon flux from HWP into the atmosphere within the borders of the reporting country, tonnes C yr-1
H = current year wood carbon harvested and removed from sites to be processed into forest products(including fuelwood), tonnes C yr-1
W = current year HWP carbon disposed into SWDS (in case HWP in SWDS is included in reporting,otherwise W = 0), tonnes C yr-1

5

Use of wood products forms a chain and flow of carbon from round wood through primary and secondary products to finaluse. Double counting in estimation of the C input flow to the HWP pool is possible if, for instance, the consumption ofround wood and primary products or primary products and secondary products are summed up. In the proposed Tier 2amethod the consumption of primary products is assumed to form the input to the HWP pool.

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Chapter 3: LUCF Sector Good Practice GuidanceEach variable below has at least two parts – at least one for solidwood products, and at least one for paper products.
PA = current year additions to HWP carbon in use from domestic consumption calculated on the basis of
the primary products carbon flux, tonnes C yr-1
See Table 3a.1.1 for information on data for these values, tonnes C yr-1
PL = current year loss of HWP carbon from uses (placed in use in current or prior years) , tonnes C yr-1
PHA = current year additions to HWP carbon from wood harvested in the country calculated on the basisof the primary products carbon flux, tonnes C yr-1
See Table 3a.1.1 for information on data and calculating PHA, tonnes C yr-1
PHL = current year loss of HWP carbon in use (place in use in current or prior years) from wood harvested
in the country, tonnes C yr-1
PEX = exports of wood and paper products including roundwood, chips, residue, pulp, and recovered(recycled) paper, tonnes C yr-1
PIM = imports of wood and paper products including roundwood, chips, residue, pulp, and recovered(recycled) paper, tonnes C yr-1.
The procedure to calculate ∆CHWP IU SCA and ∆CHWP IU PA uses a recursive process shown below rather thancalculating losses from HWP use, PL or PHL, for the current year directly.
Beginning in, say j = year 1900, compute the following equation recursively6 for each year up to the current year t.
Or

CHWP IUSCA (j) = (1 / (1 + fD )) ● (PAj + CHWP IUSCA(j – 1))(Stock Change Approach)

CHWP IUPA (j) = (1 / (1 + fHD )) ● (PAj + CHWP IUPA(j – 1))(Production Approach)For the initial year, e.g. j = 1900, the value of C HWP IUSCA = 0 or C HWP IUPA = 0
For the current year calculate
Or∆CHWP IUSCA (t) = CHWP IUSCA (t) – CHWP IUSCA (t – 1)

(Stock Change Approach)∆CHWP IUPA (t)(Production Approach)= CHWP IUPA (t) – CHWP IUPA (t – 1)

Where:∆CHWP IUSCA = annual change in carbon stored in HWP in use in the country, tonnes C yr-1
∆CHWP IUPA = annual change in carbon in HWP in use from wood harvested in the country (includes
carbon in exports and excludes carbon in imports), tonnes C yr-1
PA = current year additions to HWP carbon in use from domestic consumption calculated on the basis of
the primary products carbon flux, tonnes C yr-1
t = current year
j = year of data, starting in, for example, 1900, which is long enough in the past so that current decay isvery small from HWP placed in use in the early years
fD = fraction of HWP carbon in use in a country in a given year that is discarded in that year (discarded
products include those that are recycled)
fHD = fraction of HWP carbon in use in a country in a given year (includes exports) that is discarded inthat year (discarded products include those that are recycled).

6

The recursive formula above for stock change approach is equivalent to the equation:(CHWP IU
– CHWP IU (j – 1)) / ∆t = PA – fD ● CHWP IU, where ∆t is 1 yr.
SCA(j)SCAj

SCA(j)

This implicit Euler method (see Burden and Faires, 2001), is used as an approximation of a constant rate of decay from a
HWP pool specified by the differential equation dCHWP IU /dt = PA – fD ● CHWP IU .
SCA

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Appendix 3a.1

TABLE 3a.1.1
FAO DATA, AND FACTORS TO ESTIMATE PA AND PHA FOR TIER 2 EQUATION 3a.1.1
FAO Product Data
(Solidwood products data are in m3;
pulp and paper products are in Gg )Roundwood harvest (Coniferous)
Roundwood harvest (Non-Coniferous)
Saw wood (Coniferous)
Saw wood (Non Coniferous)
Veneer sheets
Plywood
Particle board
Fibreboard Compressed
Hardboard
MDF

Default conversion factors(Gg of oven dry product per m3
or Gg of product)

Time period
for data

Equation variables(see footnotes)

1961-2000

H

1961-2000

PDP (solidwood)
PIM (solidwood)
PEX (solidwood)

Roundwood harvest data
0.45 (Gg/ m3)
0.56 (Gg/ m3)
Solidwood products data
0.45 (Gg/ m3)
0.56 (Gg/ m3)
0.59 (Gg/ m3)
0.48 (Gg/ m3)
0.26 (Gg/ m3)
1.02 (Gg/ m3)
1.02 (Gg/ m3)
0.50 (Gg/ m3)
Pulp, paper and paperboard data

1961-1994
1995-2000

PDP (paper)
Paper and paperboard

0.9 (Gg/ Gg)

1961-2000

Recovered paper(Values set to zero from 1900 to 1969)

0.9 (Gg/ Gg)

1970-2000

Wood pulp

0.9 (Gg/ Gg)

1961-2000

Recovered fibre pulp

0.9 (Gg/ Gg)

1998-2000

Other fiber pulp

0.9 (Gg/ Gg)

1961-2000

PIM (paper)
PEX (paper)
RP
IM (RP)
EX (RP)WP
IM (WP)
EX (WP)
IM (RFP)EX (RFP)OFPIM (OFP)EX (OFP)

Industrial roundwood data
Industrial roundwood (Coniferous)

0.49 Gg/ m3)

Industrial roundwood (Non-Coniferous)

0.56 Gg/ m3)

Industrial roundwood (Coniferous)

0.49 Gg/ m3)

Industrial roundwood (Non-Coniferous)

0.56 Gg/ m3)

1961-2000

IRW
IM (IRW)

1990-2000

EX (IRW)

Sources: For FAO data see: http://apps.fao.org/page/collections?subset=forestry
Source of Conversion factors: Solidwood factors (Haynes et al. 1990, Tables B-7 and B-6)
NOTES:
Paper and pulp factors – One tonne of paper or pulp air dry are assumed to have 0.9 tonne of paper or pulp oven dry.
The equations below indicate how to compute PA and PHA for Equation 3a.1.1 using FAO data.
PA (solidwood) is the sum of solidwood products production; PA (paper) is the sum of paper products production.
PA (solidwood) = PDP (solidwood) + PIM (solidwood) – PEX (solidwood)
PA (paper) = [PDP (paper) + PIM (paper) – PEX (paper)] ● WPratio
Where WPratio is the fraction of all pulp that is wood pulp (excludes other fiber pulp).
WPratio = [(WP + IM (WP) – EX (WP))/ ((WP + IM (WP) – EX (WP)) + (OFP + IM (OFP) – EX (OFP))]PHA (solidwood) = PA (solidwood) ● IRW / (IRW + IM (IRW) – EX (IRW))PHA (paper) = [(PA (paper) + EX (WP) – IM (WP) ● WPratio + EX (RP) – IM (RP) + EX (RFP) – IM (RFP)] ● IRW / (IRW + IM (IRW)– EX (IRW))
Convert tonnes of dry products PA and PHA to tonnes of carbon by multiplying by 0.5 (tonnes carbon / tonnes product).

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Chapter 3: LUCF Sector Good Practice Guidance

Tier 2b: Change in HWP carbon in Solid Waste Disposal Sites (SWDS)
If included in reporting, stock changes of HWP in SWDS could be calculated in similar manner as HWP in use:
EQUATION 3a.1.2
ANNUAL CHANGE IN HWP CARBON IN SWDS AND THE ASSOCIATED CO2 EMISSIONS(2A) ∆CHWP WSCA = WAP + WAD – WL
CO2 emissions/removals SCA = ∆CHWP W SCA ● 10-3 ● 44/12 ● (-1)(2B) ∆CHWP WPA(Stock Change Approach)= WHAP + WHAD – WHL

CO2 emissions/removals PA = ∆CHWP W PA ● 10-3 ● 44/12 ● (-1)(Production Approach)(2C) ∆CHWP W AFA = WAP + WAD – ∆CHWP WSCA = WL
CO2 emissions/removals AFA = ∆CHWP W AFA ● 10-3 ● 44/12(Atmospheric Flow Approach)

Note 1: Each term has a year subscript t – omitted to simplify the format.
Note 2: Each term on the right hand side of the equations has at least two parts – at least one forsolidwood products and at least one for paper products)
Where:∆ C HWP WSCA = annual change in carbon stored in HWP in SWDS in the country, tonnes C yr-1
∆C HWP WPA= annual change in carbon in HWP in SWDS from wood harvested in the country (includes
carbon in exports and excludes carbon in imports), tonnes C yr-1

∆CHWP WAFA = carbon emissions from HWP in SWDS, tonnes C yr-1
Each variable below has at least two parts – at least one for solidwood products, and at least one for paper
products
WAP = amount of current year additions of HWP carbon to SWDS which are permanent (no decay)7,
tonnes C yr-1
WAD = amount of current year additions of HWP carbon to SWDS which decay over time (note that WAP+ WAD = W in Tier 2a), tonnes C yr-1
WL = loss of HWP carbon from SWDS (placed in sites in current or prior years)
WHAP = amount of current year additions of HWP carbon to SWDS that are permanent (no decay) (fromwood harvested in the country), tonnes C yr-1
WHAD = amount of current year additions of HWP carbon to SWDS which decay over time (from wood
harvested in the country), tonnes C yr-1
WHL = loss of HWP carbon from SWDS (placed in sites in current or prior years) (from wood harvested
in the country), tonnes C yr-1
We do not provide detailed equations and data to estimate storage in SWDS because more development isneeded on default data and methods and this development needs to be coordinated with guidance provided for
the Waste Sector on how to calculate emissions from SWDS.
In general terms, estimation of the HWP carbon storage in SWDS requires data on:

7(i)

The fraction of discarded HWP carbon that goes to SWDS each year;(ii)

The fraction of HWP carbon going to SWDS that goes to anaerobic conditions (versus aerobic
conditions);(iii)

The fraction of HWP carbon going to anaerobic conditions in SWDS that decays (a portion does
not decay as indicated by the good practice guidance for the Waste Sector (GPG2000);(iv)

The rate of decay for the portion of HWP carbon (in anaerobic conditions) that does decay; and(v)

The rate of decay for HWP carbon in aerobic conditions.

Only a portion of degradable organic carbon in SWDS decays as indicated in the IPCC Guidelines for the Waste Sector(see variable DOCF in IPCC Guidelines, Reference Manual p 6.5).

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Appendix 3a.1

Information on default data for items 2 through 5 above are indicated in the good practice guidance for the Waste
Sector (GPG2000). Country-specific data are needed for item 1 above – the fraction of discarded HWP carbon
that goes to SWDS each year.
Ti er 3: Cu st o m co u ntry met ho ds
EQUATION 3a.1.3
ANNUAL CHANGE IN CARBON IN HWP (EXAMPLE OF A CUSTOM COUNTRY METHOD)(3A) ∆CHWP BLDG SCA = (ABLDG t ● fC BLDG t) – (ABLDG t -1 ● fC BLDG t-1)

(Stock Change Approach)(3B) ∆CHWP W SCA = (VHWP SWDS t ● fC SWDS t) – (VHWP SWDS t-1 ● fC SWDS t -1)(Stock Change
Approach)

Where:∆CHWP BLDG SCA= annual change in HWP carbon contained in buildings, tonnes C yr-1
∆CHWP W SCA = annual change in HWP carbon contained in SWDS, tonnes C yr-1
ABLDG = floor area of buildings, m2
fC BLDG = HWP carbon in buildings per unit of floor area, tonnes C m-2
VHWP SWDS = Volume of HWP waste in disposal sites, m3
fC SWDS = HWP carbon in SWDS per unit volume of SWDS, tonnes C m-3
Data so u rce s fo r th e Ti er 2 met ho d
The following bullet points summarise how to obtain the data needed for Tier 2 calculations, identifying defaults
which are available in many cases.
Data for variables PA (carbon in HWP consumed in a country) and PHA (carbon in HWP products produced by acountry) are as follows:•

Default data for HWP production, imports and exports are available in the United Nations FAOSTATForestry database since 19618 (see Table 3a.1.1). Separate PA values need to be computed for solidwood andpaper products as indicated in the notes to Table 3a.1.1 to allow for different lifetimes in use and disposal
patterns.

•

Data to convert units of solidwood products to carbon content are shown in Table 3a.1.1.

•

Data prior to 1961 can be estimated using a trend in growth back to 1900.

For each forest product in Table 3a.1.1, the values before 1961 can be estimated by:
EQUATION 3a.1.4
EQUATION TO ESTIMATE PRODUCTION AND TRADE FOR YEARS BEFORE 1961
Vt = V1961 ● e ( r ● ( t – 1961))

Where V is value of the forest product in question, t is a year before 1961 and r is the estimated growth rate prior
to 1961. Default r values for growth between 1900 and 1961 are indicated in columns 7 and 8 in Table 3a.1.2.
•

See Table 3a.1.1 for factors to convert product amounts from volume or weight measure to tonnes of carbon.

Data for parameters fD and fHD (the fraction of HWP carbon put in use in year t that goes out of use in each year)•

Separate fD and fHD values are needed for solidwood products and paper products.

•

The average fD and fHD values for solidwood products could be the weighted average of fD and fHD for
lumber, panels and other industrial roundwood.

•

The average for fHD would be a weighted average of fD (for the home country) and for countries where
exports are used and later discarded. Weights would be the portion of PHAt that is from domestic use and the
portion of PHAt that is exported. A starting point would be to assume fD equals fHD.

8

See http://apps.fao.org/page/collections?subset=forestry

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Chapter 3: LUCF Sector Good Practice Guidance•fD and fHD values may also be converted from estimates of the half life for products in use or from theaverage life of a product. The half-life is the number of years until one-half of the products have gone out ofuse. The average life is the average number of years a product is in use.
fD = ln 2 / (half life in years) = 0.693 / (half life in years)
fD = 1 / (average life in years)
average life in years = 1 / fD•

Half life values of various products used in recent studies, including suggested default values, are shown in
Table 3a.1.3. Each country needs to determine values appropriate for their country.

3a.1.2Completeness

The Tier 2 methods include all primary wood and paper products. By doing so they include the carbon in any
secondary wood products made from those primary products. But the methods do not include the effect on stockchanges of carbon in imports and exports of secondary wood products, such as furniture or wooden crafts.
Methods may need to be adapted to include imports and exports of secondary wood products if HWP is a key
category and amounts of secondary wood product traded are notable in comparison to amounts of primary
products produced or consumed. The Tier 2 method also omits any estimates of the amount of waste wood that
goes from primary or secondary wood and from paper mills directly to SWDS. If these amounts are significant
then separate direct estimates may be needed for these wood waste flows to SWDS.

3a.1.3

Uncertainty Assessment

Uncertainty estimates for variables and parameters for the Tier 2 method are shown in Table 3a.1.4. The
estimates are based on published studies and expert judgement. If national values are used for variables andparameters, uncertainties should be evaluated consistent with the guidance in Section 5.2, (Identifying andQuantifying Uncertainties) of this report.
The only firm estimates of uncertainty likely to be available are those associated with national surveys of woodand paper products production and trade. For these, the error can be relatively low.
For the Tier 2 method, the effect of uncertainty in production and trade several decades in the past is relatively
less if the half-life of products in use and the half-life in SWDS is relatively short. This means that with longer
use life, it becomes more important to use country-specific data on production and trade before 1961.
Uncertainty in Tier 2 estimates could be quite large particularly if country-specific uncertainty is large inestimates over time in 1) fraction of discarded wood and paper going to SWDS, and 2) proportion of products in
SWDS undergoing anaerobic decay. Because of these uncertainties it is desirable to use Tier 3 national level
inventory surveys of wood stored in stocks such as housing, if possible. Such surveys may have relatively low
uncertainties. Estimating uncertainties associated specifically with the Production Approach would include
estimating the uncertainty of decay of products exported to other countries. Overall, uncertainties for Tier 2 orTier 3 methods may be estimated using Tier 3 (Monte Carlo) methods discussed in Section 5.2, (Identifying andQuantifying Uncertainties). Further work is needed to specify a simpler method to evaluate uncertainties – that is
equations that could use uncertainties from Table 3a.1.4 directly to estimate the overall uncertainty rather than to
use the Monte Carlo simulation method. Use of the Tier 2 methods with default data, that is, without countryspecific data, is unlikely to produce estimates with uncertainly less than ± 50%.

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0.0226
0.01930.03590.05480.04920.0412Latin America

AfricaAsia

Oceania

0.01730.00740.01550.02550.00540.00160.00870.012

0.00490.01550.00780.01020.01630.01480.00610.00590.0085(1900-1950)(4)

Population

0.01930.01930.0226

0.02680.01700.01730.00800.0182(1900-1950)(5)=(2)IPCC Good Practice Guidance for LULUCF

Column 4 – 1900-1950: (UN Pop Div 1999)

Population – 1950-1960: (UN Pop Div. 1998), 1961-1975: (UNFAO 2002b)

Column 3 – Industrial roundwood - 1950-53: (UNFAO 1957), 1954-1960: (UNFAO 1965), 1961-1975: (UNFAO 2002a)

Column 2 – 1950-1960: (UN Pop Div 1998), 1961: (UNFAO 2002b)

Industrial
roundwood

Industrial
roundwood

Industrial
roundwood

Industrial
roundwood

0.02290.02330.03570.02170.01640.01480.01790.0134(1900-1950)(6)=(3)+(4)0.02330.02470.02840.02850.01550.02160.01190.0208(1900-1961)(7) see note

0.02620.02800.03910.02430.01500.01960.02000.0169(1900-1961)(8) see note

3.269

Production with
Production with
Production with
Production withproduction per
production per
production per
production percapita deceasing at
capita fixed at 1950 capita deceasing at capita fixed at 1950
1950 to 1975 ratelevel
1950 to 1975 ratelevel before 1950
before 1950

Data Sources: Column 1 -- 1950-53: (UNFAO 1957), 1954-1960: (UNFAO 1965), 1961: (UNFAO 2002a)

Note:Column 8 is ln ( EXP(col 6*50)*EXP(col 1*11) )/ 61

Note:Column 7 is ln ( EXP(col 5*50)*EXP(col 1*11) )/ 61

0.01930.02680.01700.04120.0085USSR

North America

0.01820.00800.03260.0296(1950-1975)(3)(1950-1961)(1)

EuropeProduction percapitaIndustrial
roundwood

Production(1950-1961)(2)

Population

World total

World region

Industrial
roundwood

TABLE 3a.1.2
ESTIMATED ANNUAL RATES OF GROWTH FOR INDUSTRIAL ROUNDWOOD PRODUCTION (HARVEST) BY WORLD REGION, FOR SELECTED PERIODS 1900 TO 1961.
(Columns 7 and 8 are rates that may be used to project wood and paper products production and trade data backward in time from 1961 using equation 3A.1.4)

Appendix 3a.1

Chapter 3: LUCF Sector Good Practice Guidance

Table 3a.1.3
HALF LIFE OF HARVESTED WOOD PRODUCTS IN USE – EXAMPLES FROM STUDIESCountry/
regionDefaults

FinlandFinlandFinlandNetherlands

UnitedStatesHalf life in use(years)Fraction loss each year (f D j )(ln(2) / Half life in years)

Saw wood
Veneer, plywood and structural
panelsNon structural panels

35

0.019830

0.023120

0.0347

Paper
Saw wood and plywood (based onchange in inventory of products)
Saw wood and plywood average

20.346630

0.023150

0.0139Paper from mechanical pulp average

70.0990Paper from chemical pulp average

5.3

0.1308Average for paper

1.80.3851

Newsprint, household, sanitary paper
Linerboard fluting and folding
boxboard
80 % of printing and writing paper

0.51.38631

0.6931

10.6931

Reference

Pingoud
et al. 2001
Karjalainen
et al. 1994

Pingoud
et al. 1996

Nabuurs
1996

Skog and
Nicholson
2000

HWP category

20% of printing and writing paper

100.0693Paper

20.3466

Packing wood30.2310Particleboard

20

0.0347

Saw wood average

35

0.0198Saw wood – spruce & poplar

18

0.0385

Saw wood – oak & beech

45

0.0154

Saw wood

40

0.0173Structural panels

45

0.0154

Non structural panels

23

0.0301

Paper (free sheet)

60.1155

Other paper

10.6931

Note: It is recommended that use of these estimated half lives be accompanied with verification of the resulting stock change estimatesas indicated, for example, in Section 3a.1.5. Adjustments in half lives may be needed as a result.

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WCr (in Equation 3a.1.4)

fD (solidwood)fHD (solidwood)fD (paper)fHD (paper)

HWP production, imports and exports – FAO data

Product volume to product weight

Oven dry product weight to carbon weight

Growth rate of production, imports and exports prior
to first year of FAO data

Fraction of solid wood products discarded from use
each year

Fraction of paper products discarded from use eachyear

IPCC Good Practice Guidance for LULUCF

Table 3a.1.1

PDP ,PIM , PEX WP, IM(WP), EX (WP)
OFP, IM(OFP), EX(OFP)
RP, IM(RP), EX(RP)
IM(RFP), EX(RFP)
Amount of products produced, imported andexported

Table 3a.1.3

Table 3a.1.3

Table 3a.1.2, columns 7
and 8

0.5 (Table 3a.1.1)

Table 3a.1.1

Table 3a.1.1

H

Roundwood harvest (wood harvested and removed
from sites for products including fuelwood)

ValuesParameter

Description of Parameter

Half life in years =( 0.693 / fD (paper))
Uncertainty in half life = ±50%
Uncertainty is greater for fHD depending on thesize and destination of exports

Half life in years =( 0.693 / fD (solidwood))
Uncertainty in half life = ±50%
Uncertainty is greater for fHD depending on thesize and destination of exports

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Rate of increase in production prior to 1961 ±15%
for a region, larger for country within a region.
Rate of increase in trade prior to 1961 ±50% for aregion, larger for country within a region.

±10%

±15%

Country-specific for FAO data
Production and trade – for countries withsystematic census or surveys - ±15% since 1961
Production and trade – for countries without
systematic census or survey ±50% since 1961

Country-specific for FAO data

Uncertainty Range

TABLE 3A.1.4
PARAMETERS, AND ESTIMATES OF UNCERTAINTIES ASSOCIATED WITH DEFAULT VALUES FOR THE TIER 2 METHOD FOR ESTIMATING CHANGE IN CARBON STORAGE IN HWP IN USE

Chapter 3: LUCF Sector Good Practice GuidanceChapter 3: LUCF Sector Good Practice Guidance

3a.1.4

Reporting and Documentation

It is suggested to document and archive all information used to produce national estimates of stock change. This
includes wood and paper production and trade data, parameters used. Changes in parameters to make estimatesof stock change from one year to the next should be documented. The national inventory report should containsummaries of methods used and references to source data so that the steps used in making the estimates could be
retraced.

3a.1.5Inventory Quality Assurance/Quality Control

Regardless of whether or not HWP are a key category it is suggested to conduct quality control checks asoutlined in Section 5.5 (Quality Assurance and Quality Control), for data and parameters used for the method
selected. If HWP is a key category it is suggested to use additional Tier 2 quality control checks from Section 5.5,
(Quality Assurance and Quality Control), particularly development and expert review of data and parameters,
and develop, as necessary, national level estimates of data and parameters using national data sources and using
expert judgement as outlined in Section 6.2.5, Expert Judgement (GPG2000 ).
One suggestion to aid in quality control (to verify stock or stock change estimates) if Tier 2 is used, is to makeseparate estimates of total carbon storage or annual change in specific product groups, e.g., lumber or panels inbuildings. The lumber and panels in buildings would be a portion of all lumber stored. The Tier 2 method could
be used to estimate the total amount of lumber and panels in buildings, or the change in lumber and panels stored
in a recent year. One would need to have an estimate of the portion of wood and panels going to buildings overtime. These estimates could be compared to separate estimates of wood in buildings, or change in wood inbuildings as follows. The current total of wood and panels in buildings could be calculated as square metres offloor area in buildings times the lumber content per square metre. The change in lumber in buildings could be
calculated as square metres of buildings built in a given year times the lumber content per square metre.
Another suggestion, if Tier 2 is used, to aid in checking half life of buildings is to use historical information on
the number and age of buildings over time. Data would be needed on the number of buildings of a given age (orage range) at a certain time in the past and the number of those buildings that are standing at more recent points
in time. These figures could be used to estimate the fraction loss of buildings per year. The percentage loss per
year could be used to estimate a half life. See Table 3a.1.3 for the relation between half life and fraction loss per
year under the assumption that a constant fraction is lost each year).

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