Chapter 12: Harvested Wood Products

CHAPTER 12

HARVESTED WOOD PRODUCTS2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.1

Volume 4: Agriculture, Forestry and Other Land Use

Authors
Kim Pingoud (Finland) and Kenneth E. Skog (USA)
Daniel L. Martino (Uruguay), Mario Tonosaki (Japan), and Zhang Xiaoquan (China)

Contributing Author
Justin Ford-Robertson (New Zealand)

12.2

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood ProductsContents
12 Harvested Wood Products (HWP)
12.1

Introduction .........................................................................................................................................12.5

12.2

Methological issues .............................................................................................................................12.8

12.2.1

Choice of method ........................................................................................................................12.8

12.2.1.1

Tier 1......................................................................................................................................12.9

12.2.1.2

Tier 2: Using country data ...................................................................................................12.15

12.2.1.3

Tier 3: Country-specific methods ........................................................................................12.15

12.2.1.4

Estimating carbon release to the atmosphere from the HWP variables ...............................12.16

12.2.1.5

Estimating carbon released to the atmosphere in the form of CO2 ......................................12.17

12.2.2

Choice of emission factors ........................................................................................................12.17

12.2.3

Choice of activity data...............................................................................................................12.17

12.3

Uncertainty assessment .....................................................................................................................12.21

12.4

Quality assurance/ Quality control ....................................................................................................12.23

12.5

Completeness ....................................................................................................................................12.23

12.6

Reporting and Documentation...........................................................................................................12.24

12.7

Reporting Tables and Worksheets.....................................................................................................12.24

Annex 12.A.1 Some Approaches......................................................................................................................12.26
References...................................................................................................................................................12.32

Equations
Equation 12.1 Estimation of carbon stock and its annual change in HWP pools of reporting country.....12.11
Equation 12.2 Estimation of HWP products produced annaully from domestic consumption .................12.11
Equation 12.3 Estimation of HWP products produced annually from domestic harvest ..........................12.12
Equation 12.4 Estimation of annual change in carbon in HWP in domestic SWDS where HWPcame from domestic harvest ..............................................................................................12.14
Equation 12.5 Estimation of carbon release using HWP variables...........................................................12.16
Equation 12.6 Equation to estimate production, imports or export variables in Table 12.5
for years before 1961.........................................................................................................12.18
Equation 12A.1 Emissions from AFOLU by the Stock-Change Approach.................................................12.27
Equation 12A.2 Stock-Change Approach: HWP Contribution....................................................................12.27
Equation 12A.3 Emissions from AFOLU as by the Atmospheric Flow Approach .....................................12.28
Equation 12A.4 Atmospheric Flow Approach: HWP Contribution ............................................................12.29
Equation 12A.5 Emissions from AFOLU by the Production Approach......................................................12.30
Equation 12A.6 Production Approach: HWP Contribution.........................................................................12.30

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.3

Volume 4: Agriculture, Forestry and Other Land Use

FiguresFigure 12.1

Decision tree for reporting an HWP Contribution of zero or selecting a tier. ...................12.10

Figure 12.A.1 System boundary of the Stock-Change approach. .............................................................12.26
Figure 12.A.2 System boundary of the Atmospheric Flow Approach......................................................12.28
Figure 12.A.3 System boundary of the Production Approach. .................................................................12.29

Tables/Worksheets
Table 12.1

HWP Variables used to estimate annual HWP Contribution to AFOLU CO2emissions/removals..............................................................................................................12.8

Table 12.2

Default half-lives for “products in use” carbon pools and associatedfraction retained each year.................................................................................................12.17

Table 12.3

Estimated annual rates of increase for industrial roundwood production(harvest) by world region for the period 1900 to 1961......................................................12.18

Table 12.4

Default factors to convert from product units to carbon....................................................12.19

Table 12.5

UN FAO activity data needed for Tier 1 variables, and default conversion factors ..........12.20

Table 12.6

Uncertainty associated with activity data and paramenters (emission factors)
for the Tier 1 method to estimate the five annual HWP variables .....................................12.22

Table 12.7

Sectoral background data for AFOLU...............................................................................12.25

Table A12.1

Summary of How to compute HWP Contribution using varialbes in Table 12.7..............12.31

12.4

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products

12 HARVESTED WOOD PRODUCTS (HWP)
Currently there are several different approaches for reporting the storage of carbon in wood products and its
subsequent release as CO2 (see e.g., Brown et al., 1998; and Ford-Robertson, 2003; in Annex 12A.1). This
chapter does not prefer any of these and does not attempt to prejudge whether these, or any other approach,should be used to account for this storage and emission 1.
This guidance concentrates on some of the variables needed for particular approaches and shows how they canbe estimated from default data or more detailed country-specific data. Although some of these variables arestock-changes, this guidance should not be interpreted as implying that stock-change approaches are better orworse than any other approach, the variables discussed here are simply tools needed to estimate the quantities
required by differing individual reporting approaches.
The guidance here generally assumes that the amount of woody material in use declines following a first-orderdecay: again this is not the only assumption possible. Different possibilities include linear decay and moredetailed approaches based on studies of the real use of these materials. Again no preference on this choice isimplied.
This text:•

clarifies the option of reporting “zero”;•

provides default Tier 1 methods and guidance on higher Tiers; and•provides guidance on reporting whatever accounting approach is used.

The alternative approaches to estimate and report the contribution of HWP to annual AFOLU CO2 emissions/removals (which will be referred to as the HWP Contribution) that have been proposed differ in how they
allocate the HWP Contribution between wood producing and consuming countries, and what processes(atmospheric fluxes or stock changes) they focus on. They therefore give different results for the overall annual
emissions or removals of CO2 in AFOLU that a given country would report in a given year (see Annex 12A.1).
The differences are partly based on different interpretations of some key terms such as emissions/removals or
source/sink in the AFOLU reporting framework (Cowie et al., 2006). Estimation, reporting and accounting of the
HWP Contribution is under consideration by the UNFCCC.
The approaches that have been identified are mutually exclusive in the sense that a global or regional estimate ofannual HWP Contribution would only be correct if all the different countries provided estimates using the same
approach.

12.1

INTRODUCTION

Much of the wood that is harvested from Forest Land, Cropland and other types of land use remains in products
for differing lengths of time. This chapter provides guidance on how to estimate and report the contribution ofthese harvested wood products (HWP) to annual AFOLU CO2 emissions/ removals.
HWP includes all wood material (including bark) that leaves harvest sites. Slash and other material left at harvest
sites should be regarded as dead organic matter in the associated land-use category in Chapters 4, 5, 6, 8 and 9 of
the Guidelines and not as HWP. HWP constitutes a carbon reservoir 2. The time carbon is held in products willvary depending on the product and its uses. For example, fuelwood and mill residue may be burned in the year of
harvest; many types of paper are likely to have a use life in uses less than 5 years which may include recycling of
paper; and sawnwood or panels used in buildings may be held for decades to over 100 years. Discarded HWP
can be deposited in solid waste disposal sites (SWDS) where they may persist for long periods of time. Due to

1

SBSTA 21 noted “…the intent of the IPCC to develop for the purpose of compiling GHG inventories under the UNFCCC,
methods that are neutral in relation to potential accounting approaches for harvested wood products(FCCC/SBSTA/2004/13, pp 7-8, para 30.) The idea to develop an approach neutral set of HWP variables was suggested byparticipants at a HWP workshop requested by SBSTA that was held in Lillehammer, Norway. “…participants noted theneed to develop a set of methods that is neutral to the approaches, which could, for example, include methodologicalguidance on a minimum set of “quantities” required to estimate emissions and removals under any approach.” (UNFCCC,
2004).

2

Article 1 of the UNFCCC defines reservoirs as follows: "Reservoir" means a component or components of the climate
system where a greenhouse gas or a precursor of a greenhouse gas is stored.

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.5

Volume 4: Agriculture, Forestry and Other Land Use

this storage in products in use and in SWDS, the oxidation of harvested wood products in a given year could be
less, or potentially more, than the total amount of wood harvested in that year. Worldwide - according to a study
by Winjum et al. (1998) and a report by the UNFCCC secretariat (2003) - the amount of carbon held in
harvested wood products is likely to be increasing.
The 1996 IPCC Guidelines (IPCC, 1997) did not provide methods for estimating carbon held in HWP, andrecommended, for the purpose of basic calculations, a default assumption expressed as “… that all carbon
biomass harvested is oxidised in the removal [harvest] year” 3. This was based on the perception that HWP
stocks are not changing. That is, the annual carbon inflow and outflow for the HWP reservoir were assumed tobe equal and the oxidation from pre-existing wood products stocks could be replaced (and hence omitted) by an
implied oxidation directly after harvesting. More precisely therefore the IPCC default assumption was that inputs
to the HWP reservoir equals outputs. Since the only significant output is oxidation, this means that the amount ofoxidation equals the harvest, where the oxidation includes oxidation of some of the wood harvested in thecurrent year and oxidation of some of the HWP placed in use in prior years.
Given that inputs do not in general equal outputs and that carbon can remain stored in HWP for extended periodsof time, this storage time needs to be taken into account when providing guidelines for estimating thecontribution of HWP to AFOLU CO2 emissions/ removals.
This chapter also provides guidance on when a country may report a HWP Contribution as zero without
necessarily making detailed estimates. This guidance differs from that provided in earlier IPCC guidance.4
Estimates of HWP Contribution are designed to be consistent with those for other sectors of these guidelines,
specifically:
1.

All CO2 released from HWP is included in the AFOLU Sector;

2.

CO2 released from wood burnt for energy in the Energy Sector is not included in the Energy Sector totals(although CO2 emissions from biofuels are reported as a memo item for QA/QC purposes). CH4 and othergases from HWP used for energy is included in the Energy Sector;

3.

CO2 released from HWP in SWDS is not included in the Waste Sector totals although CH4 emissions from
HWP are included.

Methods in this chapter estimate release of carbon: this carbon may also be counted as methane emissions in the
Waste Sector. This potential double counting of carbon release to the atmosphere can be corrected by subtracting
the carbon emitted in the methane emissions from HWP in landfill from the carbon emissions estimated in thischapter (see guidance on how to make an optional correction in Section 12.2.1.5).
In order to make estimates of the HWP Contribution for the various approaches, there is a generic set of annual
variables that can be used to make the estimates. Using estimates of these annual variables, the HWPContribution can be estimated for any of the currently proposed approaches (see Annex 12.A1). While not all of
the data are required for every approach, the complete set would allow any of the proposed approaches to be
adopted. These “HWP Variables” are:1.

Annual change in carbon stock in HWP in the reporting country, including HWP stocks from both domestic
harvest and imports (Gg of carbon per year)

2.

Annual change in carbon stock in HWP made from wood harvested in the reporting country including
annual change in carbon stock in HWP exported to other countries (Gg of carbon per year)

3.

Annual imports of all types of wood and paper material to the reporting country (Gg of carbon per year)

4.

Annual exports of all types of wood and paper material from the reporting country (Gg of carbon per year)

5.

Annual harvest for wood products in the reporting country 5 (Gg of carbon per year).

This chapter provides methods to estimate these HWP variables which can then be used, according to therequirements of different approaches, to estimate the HWP Contribution to AFOLU CO2 emissions / removals.
3

The 1996 IPCC Guidelines (Vol. III, p.5.17, Box 5)

4The 1996 IPCC Guidelines recommended that storage of carbon in forest products be included in a national inventory onlyin the case where a country can document that existing stocks of long term forest products are in fact increasing.

5

Annual harvest for products includes all wood and bark removed for products including fuel from all land categories notjust Forest Land. It does not include timber cut down and left at harvest sites. In some countries, other tree parts such as
branches and needles and roots or stumps are collected and used for bioenergy. All these tree parts should be included. See
Section 12.2.1.1 text on estimating harvest which indicates how it is linked to estimates of Lwood-removals and Lfuelwood in
Chapters 2 and 4.

12.6

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood ProductsThis chapter provides tiered methods that countries may use annually to estimate the HWP variables for any year
from 1990 to the current year. To do this, data from years before 1990 are needed as explained below. For Tier 1,
default values are suggested for all activity data and parameters required. Excel worksheets are provided to
implement the calculations and produce the Sectoral Background Table 12.7. This table indicates how thesevariables may be used to estimate the HWP Contribution under the alternate approaches. Table 12.7 shows the
HWP variables estimated in Gg C yr-1 and uses these values to compute HWP Contribution and converts thecontribution amount to Gg CO2 yr-1 by multiplying by −44/12. A negative HWP Contribution value decreases
overall emissions from AFOLU and a positive value increases overall emissions from AFOLU.
If countries provide all the HWP variables from Table 12.7 in AFOLU Background Reporting Table 3.10 then it
will be possible to calculate each country’s HWP Contribution for any of the different approaches.
Annex 12A.1 to this chapter provides examples of some approaches and how the HWP variables are used toestimate HWP Contribution. This chapter does not provide guidance on the selection of an individual approach
for a country to use. Section 12.6 indicates options for reporting the HWP Contribution in country inventory
reports. The options for reporting include reporting zero as the HWP Contribution.
In addition to indicating how to combine the HWP variables to estimate the HWP Contribution to AFOLU CO2emissions and removals, information is provided in Section 12.2.1.4 on how to compute annual carbon release to
the atmosphere from the five HWP variables.
Carbon release estimates from HWP are presented in order to indicate clearly the role annual carbon release from
HWP plays in the overall AFOLU system of carbon removals and release. Showing annual carbon release
explicitly demonstrates how it compares with annual harvest. Carbon release variables used in Section 12.2.1.4
are as follows:•↑CHWP DC = annual release of carbon to the atmosphere from HWP contained in the reporting country. This
includes carbon release from all wood harvested and retained in the country and from wood imports into thecountry but excluding exports, Gg yr-1. This amount of carbon release corresponds to (E + EW) in Annex
Figures 12A.1 and 12A.2.

•↑CHWP DH = annual release of carbon to the atmosphere from HWP that came from wood harvested in thereporting country. This includes carbon release from all wood harvested in the country including wood thatis exported but excluding imports, Gg yr-1. This carbon release amount corresponds to (EDOM + EEX DOM) in
Annex Figure 12A.3.

DEFINITION OF VARIABLES
Tier 1 and Tier 2 methods provide annual estimates for a set of five variables that can be used to estimate the
HWP Contribution for different approaches. Two of the variables have two parts – corresponding to annual
additions to a) HWP in “products in use”, and b) HWP in solid waste disposal sites (SWDS). Table 12.1
introduces the variables. While variables 1A, 1B, 2A and 2B are stock changes, this does not imply that any
reported HWP contribution, or any other data, should be a stock change: these are simply items that can be used
to calculate the desired results under different accounting approaches. Inventory compilers should also note thatmodified or new accounting approaches may change the HWP variables that are needed and how they are
estimated. For example, there could be changes in what is included in HWP or changes in how decay of stocks isallocated among reporting countries. For the approaches identified, Equation 12.5 shows the relationshipbetween these HWP variables and two estimates of release of carbon to the atmosphere from HWP. The
relationship among the variables may be seen in flow diagrams in the Annex Figures 12A.1, 12A.2 and 12A.3.

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.7

Volume 4: Agriculture, Forestry and Other Land Use

TABLE 12.1
HWP VARIABLES USED TO ESTIMATE ANNUAL HWP CONTRIBUTION TO AFOLU CO2 EMISSIONS/REMOVALS
Variable names
Variable definition

1. Annual change in carbon stock in a) HWP in use, and b)
in HWP in solid waste disposal sites in the reporting
country, this is wood carbon that came from domestic
consumption of products ,
∆CHWP

DC =

HWP in SWDS

Variable 1A

Variable 1B∆CHWP IU DC∆CHWP SWDS DC

Variable 2A

Variable 2B∆CHWP IU DH∆CHWP SWDS DH∆CHWP IU DC + ∆CHWP SWDS DC

2. Annual change in carbon stock in a) HWP in use, and b)
in HWP in solid waste disposal sites where the wood in the
products came from domestic harvest -- trees harvested in
the reporting country, this includes exported HWP to othercountries,∆CHWP

HWP in “products in
use”

DH =

∆CHWP IU DH + ∆CHWP SWDS DH

3. Carbon in annual imports of HWP to the reporting
country including all wood-based material - roundwood,
solidwood products, paper, pulp and recovered paper

PIM

4. Carbon in annual exports of HWP from the reporting
country including all wood-based material:- roundwood,
solidwood products, paper, pulp and recovered paper

PEX

5. Carbon in annual harvest of roundwood for products –wood removed from harvest sites in the reporting country,
including fuelwood

H

12.2

METHOLOGICAL ISSUES

12.2.1

Choice of method

This section provides:
1.

Guidance on when it is consistent with good practice to report a HWP Contribution value of zero; 6

2.

Guidance on when it is consistent with good practice to assume that the annual change in HWP carbon in
SWDS is zero (i.e., assume annual carbon release from SWDS is the same as HWP additions to SWDS);
and3.

Three tiers of methods to estimate the five HWP variables which may be used to compute HWPContribution. Figure 12.1 presents a decision tree as a guide in making these choices.

The HWP Contribution can be reported as zero if the inventory compiler judges that the annual change in carbon
in HWP stocks is insignificant. Either the stocks in the country (Variable 1A + Variable 1B), or the annualchange in carbon in HWP stocks originating from wood harvested in the country (including exported HWP)
(variable 2A + variable 2B) may be considered. The term ‘insignificant’ in this context means that the annualchange in carbon in HWP stocks, using one of the measures of carbon change above, is less than the size of any
key category. Countries are encouraged to use the Tier 1 methods to estimate HWP variables to aid in judging if
the annual change is insignificant. Parties that wish to report HWP contribution to AFOLU where the focus is on
carbon fluxes to and from the atmosphere may want to report HWP even where there is no significant stockchange.
If an inventory compiler judges that the annual change in carbon in total HWP stocks is significant, they may
still separately judge if the annual change of HWP carbon in SWDS is significant. If it is not significantly
increasing or decreasing it may be assumed to be zero (Variables 1B and 2B are zero). It is suggested that an
estimate be made if annual change in carbon in TOTAL HWP stocks is likely to be of a comparable size to other

6

This guidance replaces the guidance in the 1996 IPCC Guidelines on when to report HWP contribution of zero.

12.8

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products

key categories. Countries are encouraged to use the Tier 1 methods to estimate HWP variables to aid in judging
if the annual change in SWDS is insignificant.
If the annual change in HWP carbon stocks are judged to be significant, or a country chooses to make estimates,
then one of three tiers may be selected to make estimates of the five HWP variables to make an estimate of HWP
Contribution. Tier 1 uses forest products data from FAO (the default activity data) which are freely and easily
available to most countries. The Tier 1 method specifies that changes in carbon held in SWDS (Variables 1B) isto be calculated using the Waste Sector Tier 1 methods, default data, and worksheets. A Tier 1 method isprovided to estimated Variable 2B from Variable 1B.
The decision tree in Figure 12.1 indicates how to choose a Tier to estimate HWP Variables on the basis of data
availability. Default data are provided for Tier 1. Tiers 2 and 3 aim to improve the accuracy of the estimates byusing more accurate country-specific data and methods.
Until the Parties to the UNFCCC decide on the approach to be used, it will not be possible to identify
definitively whether or not HWP is a key category, since the magnitude of the HWP Contribution depends on theapproach chosen. Thus, whether or not the sector is a key category cannot be used to guide the choice of tier. In
order to facilitate current reporting and allow for future decisions, there are two options. First, they could elect touse a particular approach and determine if this is a key category in the normal way, according to guidance
provided in Volume 1, Chapter 4. Alternatively, they could use their judgment to determine if the source is likely
to have a significant (equal or greater than other key categories) impact on the national greenhouse gas emission
estimates. If the source is judged to be significant, then a Tier 2 or 3 method should be used.

12.2.1.1

T IER 1HWP Variables 1A, 2A, 1B and 2B are estimates of annual changes in stock of HWP carbon which are eachestimated using a flux-data method with lifetime-analysis. The decay of HWP is assumed to be of first-order 7.
This means the annual loss from the stock of products is estimated as a constant fraction of the amount of thestock. Estimates of change of carbon held in “products in use” (Variables 1A and 2A in Table 12.1), are made bytracking inputs to and outputs from the “products in use” carbon pool. The carbon inflow to the pool is estimatedfrom historical production or consumption rates of HWP. Waste Sector Tier 1 methods are used to estimatechange in HWP carbon stock in SWDS (Variable 1B) (see Volume 5, Chapter 3). A Tier 1 method is provided toestimated Variable 2B from Variable 1B.
In the case of the “products in use” pool, the outflow from the pool is calculated based on estimated half-life andassociated decay rates of HWP from use assuming first-order decay rates.
The intent is to provide valid estimates of the total release of carbon from HWP for any UNFCCC reportingyear. This requires knowledge of change to the total existing HWP pool. In the absence of surveys or census dataof HWP in use, it is recommended that inputs to and outputs from HWP stocks since 1900 are used in order tomake valid estimates for recent years. Excluding current year carbon release or stock change associated with
HWP placed in use in years prior to the reporting period would overestimate current year net additions to HWP
carbon stocks (underestimate current year carbon release), and would therefore not be consistent with the Good
Practice Guidance objective to neither over- nor under-estimate as far as can be judged. 8
Data beginning in 1900 are used to estimate additions to HWP in use while the discard from use of this HWP isestimated assuming a first order decay. This procedure is needed to produce an estimate of the existing HWP
stock accumulated from historical wood use, and hence the current year carbon release from the total stock as itgoes out of use (also termed “inherited emissions”).
HWP Variables 3, 4 and 5 (i.e., PIM, PEX, and H, respectively) are estimates of carbon in annual product imports
and exports, as well as carbon in annual harvest for products and fuelwood. They are estimated by adding
together – aggregating – various forest products variables from the FAO database.

7

Other decay profiles have been suggested (Ford-Robertson, 2003) and these could be used in place of the FOD assumption.
In this case the estimation procedure would differ from Equation 12.1 and the decay of each year’s Inflow would betracked individually up to the current year. The remaining discussion about default data would still apply.

8

The year 1900 was chosen based on the judgement that contributions to the current year HWP Contribution due to products
entering the product pool prior to 1900 would be insignificant, therefore to exclude years prior to 1900 would not violate
good practice neither over- nor under-estimate as far as can be judged.

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.9

Volume 4: Agriculture, Forestry and Other Land Use

Figure 12.1

Decision tree for reporting an HWP Contribution of zero or selecting a tier.

Start

Is theannual change
in HWP stocks insignificant?
See Section 12.2.1.

Yes

Report HWP Contribution is zero.
(See guidance in Section 12.10 about preparing
Sectoral Background Table 12.7.)

Yes

In Background report Table 12.7, set variables
1B and 2B to zero. Prepare estimates of variables 1A,
2A, 3, 4, 5 using Tiered methods below.

Yes

Use country-specific data and a Tier 3 method
to estimate HWP variables to estimate HWPContribution to be reported . Tier 3 methods
may be used to estimate variables 1A, 2A, 2B, 3,
4, & 5, and use WASTE SECTOR Tier 1 orhigher Tier to estimate carbon change
in SWDS variable 1B (Volume 5, Chapter 3).

No

Is theannual change in
HWP stocks in SWDS insignificant?
See Section 12.2.1

NoAre
country-specificmethods or detailed historicalcountry-specific data on wood products
stocks and flows
available?

Box 3: Tier 3NoAre
country-specificactivity data or discard rates from use(half lives) available?

Yes

Use Tier 1 equations and country data toestimate variables 1A, 2A, 2B, 3, 4, & 5,
and use WASTE SECTOR Tier 1 with country
data to estimate variables 1B (Volume 5, Chapter 3).
Box 2: Tier 2

No

Use Tier 1 equations and default data to estimate
variables 1A, 2A, 2B, 3, 4, & 5, and use
WASTE SECTOR Tier 1 with default
data to estimate variables 1B (Volume 5, Chapter 3)
Box 1: Tier 1

12.10

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products

GENERAL METHOD TO ESTIMATE VARIABLES 1A AND 2A -- ANNUAL
CHANGE IN CARBON STOCK IN “PRODUCTS IN USE”
Estimation of changes in carbon stock in “products in use” may be obtained by using Equation 12.1:
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





( A)

 1  e k 
C (i  1)  e  k  C (i )    Inflow(i ) k ( B)

C (i )  C (i  1)  C (i )with C (1900)  0.0

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

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

Estimating Variable 1a – Annual change in carbon stock in “product in use” inthe reporting country
Equation 12.1 is used to estimate carbon change in each of two pools in the Tier 1 spreadsheets (discussed
below). The two pools are:1.

Solidwood products in use; and2.

Paper products in use.

Where products in use are held in the reporting country, more than one pool is used because it is believed there isa significant difference in half-life of products in use between the two pools. Annual change in these two carbon
pools, when added together, gives Variable 1A. The carbon Inflow variable to these pools is from annual
consumption in the reporting country of semi-finished wood products, including sawnwood, wood panels andother solidwood products or paper and paperboard. Consumption equals domestic production plus imports minus
exports as shown in Equation 12.2. The rate at which solidwood or paper is lost from the pools in a given year is
specified by a constant loss rate (k) and for convenience is also specified by half-life in years. A half-life is thenumber of years it takes to lose one-half of the material currently in the pool. Production, imports and exports ofsolidwood or paper are converted from cubic meters or air dry Gg to tonnes of carbon (see Table 12.4).

EQUATION 12.2
ESTIMATION OF HWP PRODUCTS PLACED IN USE ANNUALLY FROM DOMESTIC CONSUMPTION
InflowDC  P  SFPIM  SFPEX

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 thisincludes sawnwood, panels, and other industrial roundwood. For paper products this includes paper
and paperboard, Gg C yr-1

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.11

Volume 4: Agriculture, Forestry and Other Land Use

In order to make estimates of change in these pools for the reporting year, the method uses data on Inflow(Product Consumption = Production + Imports – Exports) back to 1961 from the FAO database 9. For the periodprior to 1961 back to 1900, it is assumed that change in consumption prior to 1961 was the same as change inindustrial roundwood production for the region the country is in. Data and parameters used are as follows:•

FAO variables used to estimate product consumption are shown in Table 12.5.

•

Default factors to convert solidwood and paper from volume units to carbon units is shown in Table 12.4.
Countries are encouraged to estimate factors using wood densities in Tables 4.13 and 4.14 in Chapter 4(Forest Land).

•Regional rates of change in industrial roundwood production prior to 1961 are show in Table 12.3.

•

Half-lives for products in use are shown in Table 12. 2

The rest of harvested wood material transported from the harvest site − any material except the semi-finishedproducts noted above − is assumed to be oxidized in the year of harvest, and it is thus not transferred to the HWP
pools.

Estimating Variable 2a – Annual change in carbon stock in “products in use”
where wood came from harvest in the reporting country (includes exports)
General Equation 12.1 is used again to estimate carbon change in each of two pools (as for Variable 1A) in the
Tier 1 spreadsheets to estimate the annual change of carbon in solidwood and paper products in use separately
where wood to make the products came from wood harvested in the reporting country (domestic harvest). This
includes products exported and held in use in other countries. Annual change in carbon stock in solidwood
products in use and paper products in use reservoirs when added together give Variable 2A. The Inflow variable
to these pools is the production of all products from wood harvested in the reporting country.
This annual carbon inflow variable is estimated using Equation 12.3. If the ratio in parenthesis is <1 then the
country is a net importer of industrial roundwood (IRW), wood chips and wood residues that are used to makeproducts and less than the full amount of HWP produced (P) would have used domestically harvested IRW. If
the ratio in parenthesis is >1, then this means there is a net export of IRW, chips, and residues by the country.
The HWP production inflow calculated by the equation needs to be greater than HWP production (P) in this casebecause exported wood is used to make products in other countries. The implicit assumption being used is thatthe importers of the exported IRW, chips and residues will use them to produce solidwood or paper products inthe same proportion as in the reporting country.
EQUATION 12.3
ESTIMATION OF HWP PRODUCTS PRODUCED ANNUALLY FROM DOMESTIC HARVEST⎡⎤
IRWHInflowDH = P • ⎢⎥⎣ IRWH + IRWIM − IRWEX + WCH IM − WCH EX + WRIM − WREX ⎦Where:
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. Notethat paper product production includes wood fibre and excludes non-wood fibre. An equation toestimate 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 makesolidwood 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 yr-1
Just as for Variable 1A, estimates of annual change in the two product-in-use pools require data on total productproduction, and industrial roundwood production, imports and exports from the current year back to 1900. As for9

See http://faostat.fao.org/

12.12

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products

Variable 1A, FAO data are used back to 1961 and data back to 1900 is estimated by assuming the annual rate ofchange from 1900 to 1961 is the same as the annual rate of change in industrial roundwood production between
1900 and 1961.
The half-life values for product-in-use pools are assumed to be the same as for variable 1A and the carbon
conversion factors are assumed to be the same. Data and parameters used are as follows:•

FAO variables used to estimate total product production and industrial roundwood production, imports andexports are shown in Table 12.5.

•

Default factors to convert solidwood and paper from volume units to carbon units are shown in Table 12.4.
Countries are encouraged to estimate factors using wood densities in Tables 4.13 and 4.14.

•

Regional rates of change in industrial roundwood consumption prior to 1961 are shown in Table 12.3.

•

Half-lives for products in use are shown in Table 12. 2

Estimating Variables 1B and 2B - Annual change in carbon stock in SWDS in
the reporting country; and Annual change in carbon stock in SWDS where
wood came from harvest in the reporting country
Tier 1 methods are provided to estimate accumulation of HWP carbon in SWDS because a number of studies
have indicated very long storage times for HWP carbon in SWDS in some cases (NCASI, 2004; Gardner et al.,
2002; Micales and Skog, 1997).
Variable 1B, ∆CHWP SWDS DC, i.e., the carbon stock change of HWP from domestic consumption discarded to
SWDS of the reporting country is estimated directly by the Waste Sector Tier 1 methods and spreadsheets(Volume 5, Chapter 3, Section 3.2.1.1 “Spreadsheet model” and Section 3.4). The Waste Sector guidelines
explain how to use Waste Sector default data and parameters to estimate the amount of solidwood and paper
carbon that accumulates in SWDS in the reporting country. A key point about the Waste Sector Tier 1 estimate isthat it estimates carbon change in SWDS by identifying the portion of carbon discarded to SWDS in the current
year which is judged to have originated as HWP. It is assumed that HWP carbon equates to the “garden”,“wood” and “paper” waste categories. The spreadsheet gives the amount of “long-term” stored carbon from
HWP in the “HWP” sheet. The individual waste type sheets give the amount of decomposable, degradableorganic carbon stored. Together these give the change in the amount of stored HWP carbon. No carbon release to
the atmosphere is reported from this long-life pool in the SWDS Chapter.
To estimate Variable 2B, ∆CHWP SWDSDH, it is necessary to estimate the portion of Variable 1B that is fromdomestic harvest. The Tier 1 estimate of Variable 2B is limited to estimating the carbon change in domestic
SWDS only. It is judged that potential Tier 1 methods to estimate carbon change in SWDS in other countries
could lead to substantial over- or under-estimates so it is best to not include an estimate of carbon change in
SWDS in other countries.
The portion of Variable 1B that is from domestic harvest is approximated by multiplying by the fraction of woodcarbon consumed in the country in the current year that came from domestic harvest (Equation 12.4). This ratio
will be a reasonable approximation of the fraction of HWP carbon discarded to SWDS that came from domestic
harvest if imported wood material has been a relatively stable fraction of all wood consumed over a period ofyears.

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.13

Volume 4: Agriculture, Forestry and Other Land Use

EQUATION 12.4
ESTIMATION OF ANNUAL CHANGE IN CARBON IN HWP IN DOMESTIC SWDS WHERE HWP CAMEFROM DOMESTIC HARVEST⎡ ⎛⎞⎤Imported wood material⎟⎟⎥
ΔC HWP SWDS DH = ΔC HWP SWDS DC • ⎢1 − ⎜⎜⎣ ⎝ Produced wood material + Imported wood material ⎠⎦⎡ IRWIM + WCH IM + WRIM + SawnWIM + WPanIM + ⎤Imported wood material = ⎢⎥⎣ P&PBIM + WPulp&RecPapIM⎦
Produced wood material = IRWH

Where:∆CHWP SWDSDH = Variable 2B = annual change in carbon in HWP in domestic SWDS where HWP camefrom domestic wood harvest, Gg C yr-1
∆CHWP 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
Data to be used for Equation 12.4 are FAO variables shown in Table 12.5.

Estimating Variables 3, 4, and 5 – Annual imports and exports of HWP to andfrom the reporting country, and annual HWP harvest
Estimates of annual imports, exports and harvest for Variables PIM, PEX, and H are needed for the most recent
years only (see Annex Equations 12A.3 and 12A.4). No data are needed for years before the reporting period.
Default import, export and harvest data may be obtained from the FAOSTAT database. The specific FAO
variables that are needed are shown in Table 12.5. Factors to convert from cubic meters or air dry tonne ofproduct are shown in Table 12.4.
H (Variable 5), total annual HWP harvest, is defined here as all wood and bark that leaves harvest sites including
fuelwood. It is intended to include the total of the Lwood-removals and Lfuelwood values as defined in Volume 4,
Chapter 2, Equations 2.12 and 2.13. Guidelines for estimation of Lwood-removals and Lfuelwood for Forest Land is in
Volume 4, Chapter 4, Section 4.2.1. Default estimate for this variable is the FAO database value for industrial
roundwood times a bark expansion factor plus the FAO database value for fuelwood. A default bark expansion
factor is shown in Table 12.5, Note 4.

Spreadsheet MODELS: step by step guidance
The IPCC Harvested Wood Product Model: Estimating Variables 1A, 2A, 2B, 3, 4,
and 5
The model may be used to estimate the HWP variables and produce Table 12.7 which may be used to fill in
AFOLU Sectoral Background Table 3.10. Default parameters are already included to make Tier 1 estimates or
may be changed to make Tier 2 estimates. Variable 2B may be estimated if Variable 1B has been estimatedusing the Waste Sector Tier 1 spreadsheets.

12.14

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products

Here are general instructions on how to use the model spreadsheet to estimate the HWP variables and generate
Table 12.7 and AFOLU Sectoral Background Table 3.10. Please see detailed instructions under the“Instructions” tab of the model spreadsheet.
1.

Download country activity data (wood and paper products production, imports and exports) from the
FAOSTAT web site and place in columns of one of the “Data” sheets (years 1961 to reporting year).

2.

Transfer estimates of carbon stored in SWDS from the Waste Sector Tier 1 Model spreadsheet to the lasttwo columns of the same “Data” sheet (years 1990 to reporting year as needed).

3.

Type the country name in cell A1 of the Data sheet.

4.

Check / change default parameters as needed that are shown in yellow in the “Parameters” sheet.

5.

See results in a completed Table 12.7 on the sheet named “Result”. Results from this table may betransferred to the AFOLU Sectoral Background for Harvested Wood Products in Table 3.10.

6.

See detailed results in tables, graphs, and diagrams in “Parameters” and “Result” sheets.

Waste Sector Tier 1 Model: Estimating Variable 1B
To prepare the estimate of carbon stored in HWP in the reporting country that can be inserted in the model
spreadsheet, see Volume 5, Chapter 3, Section 3.2.1.1 “Spreadsheet model” and Section 3.4. In Section 3.2.1.1
there is a link to the spreadsheet model. Details on how to use the model can be found in the “Instructions”
spreadsheet.

12.2.1.2

T IER 2: U SING COUNTRY DATA

Tier 2 uses country-specific data to improve estimates of annual carbon change in “products in use” and in
SWDS. Improved data could include country data on:•

annual production, imports and exports by product types and wood species;•

factors to convert activity data to carbon;•

rate at which products are discarded from use (half-life). If information indicates various wood products
have different half-lives (e.g., sawnwood versus panels) then Equation 12.1 can be used to track carbonchange for separate pools and not just solidwood and paper products;•

Waste Sector annual activity data and parameters for Waste Sector Tier 1 method including DOCf - thefraction of wood and paper that decays in SWDS.

12.2.1.3

T IER 3: C OUNTRY - SPECIFIC METHODSCountries may wish to develop more complex, detailed country-specific methods to estimate Variables 1A, 1B,
3, 4, and 5. Typically these will be more complex models and will be focused on a single approach (Flugsrud etal., 2001). Tier 3 models could also use decay functions other than first order decay – e.g., linear decay. It is
more difficult to develop Tier 3 methods for Variables 2A and 2B which require data on the lifecycle of exported
HWP for countries where most of its products are exported. Estimates for Variables 2A and 2B could be
improved by obtaining decay information for countries where most products are exported.

METHOD A – ESTIMATE ANNUAL CHANGE IN INVENTORIES (STOCKMETHODS)
Inventories of HWP in use or HWP in waste disposal sites, at two or more points in time, could be used toestimate the annual change in carbon stock – Variables 1A and 1B. The HWP pool of products in use in building
structures is frequently a major part of the total HWP pool. The amount of HWP carbon can be estimated, forexample, by multiplying the average HWP content per square meter of floor space times the total floor space forrelevant building types that use wood taking into account when the buildings were constructed and changes inwood use per square meter over time. Annual change in carbon stock could be estimated by noting the change
between inventories estimated at different points in time. Examples of such inventories are reported in Gjesdal etal., 1996 (for Norway); Pingoud et al., 1996, 2001 (for Finland); and Hashimoto and Moriguchi, 2004 (forJapan). In this case, no procedure for adding up wood use data from historical data is needed to estimate theexisting HWP stock or annual change in stock, which is an advantage compared to the flux methods (Tier 1 andTier 2).

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.15

Volume 4: Agriculture, Forestry and Other Land Use

METHOD B – TRACK INPUT AND OUTPUT FLOWS USING DETAILEDCOUNTRY DATA AND DECAY PATTERNS
Use detailed country data beginning with a number of decades in the past and estimate each year, up to thepresent time, including (i) additions to pools of HWP in use, (ii) discards 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. This method is also based on flux data and lifetime analysis just as for Tier 1 and Tier 2 methods, but therate at which products are discarded from use may differ from the first-order decay assumption used in Tiers 1
and 2.

METHOD C – FLUX DATA METHOD WITH DIRECT OUTPUT ESTIMATES
Instead of the flux-data method with lifetime analysis, a flux-data method using direct estimates of the output of
the HWP pool could also be used in principle. Examples would be information on carbon wood burned forenergy each year or carbon contained in buildings demolished in a year. The advantage of this method is thatlong historical input data for the HWP pool are no longer required. On the other hand, the method would have aserious disadvantage - the outflow and oxidation data of HWP are much more uncertain than the input data andare likely to be underestimated, as a result a significant part of decay would not be identified and net additions tocarbon held in HWP would be overestimated (see Flugsrud et al., 2001; Pingoud et al., 2003).

METHOD D – COMBINE METHODS A, B AND C
An example of a combined method that uses the most accurate information available about different products is:1) to use changes in inventory to estimate carbon changes in buildings and furniture; and 2) to use input andoutput flows to estimate changes of carbon in paper products (see example for Norway, Flugsrud et al., 2001;
and for Japan, Hashimoto and Moriguchi, 2004). Or alternatively, the inherited carbon stock of HWP in somerecent year could be estimated by direct inventory, Method A − instead of estimating it from historicalconsumption rates as in Method B and Tier 1. Then taking this carbon stock as initial value, carbon stock andstock changes in subsequent years can be estimated by using decay rates from Method B. HWP inventory data
could also be used to help determine the half-life parameters in the first-order decay method. Instead of using
default half-lives these parameters could be chosen to obtain the best fit of the first-order decay method (or otherdecay function) with the real inventory data (see e.g., Pingoud et al., 2001).

12.2.1.4

E STIMATING CARBON RELEASE TO THE ATMOSPHERE
FROM THE HWP VARIABLES

Annual carbon release to the atmosphere from HWP may be estimated for two cases using the five HWPvariables as follows:
EQUATION 12.5
ESTIMATION OF CARBON RELEASE USING HWP VARIABLES
For annual carbon release from wood stocks in the reporting country( A)↑ C HWP DC = H + PIM − PEX − ΔC HWP IU DC − ΔC HWP SWDS DC

For annual carbon release from wood harvested in the reporting country( B)↑ C HWP DH = H − ΔC HWP IU DH − ΔC HWP SWDS DH

The carbon release variables are defined in Section 12.1. These equations may be used to compute CO2 release
to report in Table 12.7 and AFOLU background reporting Table 3.10 as described in Section 12.7. If estimates ofcarbon release are available these equations may be solved for the total stock change amounts (∆CHWP IU DC +∆CHWP SWDS DC or ∆CHWP IU DH - ∆CHWP SWDS DH ) and the resulting equation could be used to calculated these total
stock changes using the carbon release variables.

12.16

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products

12.2.1.5

E STIMATING CARBON RELEASED TO THE ATMOSPHERE IN
THE FORM OF CO 2

Carbon that is released in the form of CO2 may be calculated if the methane emitted from HWP in landfills isknown as follows:•↑CHWP DC CO2 = ↑CHWP DC - EW CH4. Annual release of carbon to the atmosphere as CO2 from HWP accounting
for carbon emitted as methane emitted from HWP in SWDS. EW CH4 is the carbon in CH4 emitted from thedecomposition of HWP in SWDS in the year concerned. It can be estimated using the methodology in
Chapter 3, Section 3.2 of Volume 5. The IPCC Waste Model spreadsheet estimates this automatically for the“Waste Composition” option (it is the sum of the carbon in CH4 emitted in the inventory year from wood,
paper and garden waste on the HWP sheet).

•↑CHWP DH CO2 = ↑CHWP DH - EEX DOM CH4. Annual release of carbon to the atmosphere as CO2 from HWP thatcame from wood harvested in the reporting country, accounting for carbon emitted as methane emitted from
HWP in SWDS. EEX DOM CH4 is the carbon in CH4 emitted from SWDS (as carbon) from domestic harvest
whether in country or exported. It can be estimated using the methodology in the Chapter 3, Section 3.2 ofVolume 5. To use the IPCC Waste Model spreadsheet, the waste inputs into the SWDS would need to be
adjusted to account only the HWP from domestic harvest including domestically harvested HWP exported
and put into SWDS in other countries.

12.2.2

Choice of emission factors

Tier 1 and Tier 2 use the assumption that HWP are discarded from use at a constant rate, k, applied to the carbon
present in the pool. This constant rate of discard can be specified by an associated half-life in years for productsin the pool. The half-life is the number of years until half of the amount goes out of use. Default half-life values,
and associated discard rates (k) are provided in Table 12.2 for solidwood products and paper products.

TABLE 12.2
DEFAULT HALF-LIVES FOR “PRODUCTS IN USE” CARBON POOLS AND ASSOCIATED FRACTION RETAINED EACH
YEAR

Solidwood products

Paper products

Half-life (years)

30

2

Decay rate k (k = ln(2)/ half-life)

0.023

0.347

Source: Based on values used in previous studies summarized in HWP Appendix Table 3a.1.3 of the IPCC report on GPGLULUCF (IPCC, 2003). Table 3a.1.3 gives values for more product categories.

12.2.3

Choice of activity data

ACTIVITY DATA FOR TIER 1 VARIABLES
FAO datasets needed to estimate production, imports and exports of solidwood and paper products needed toestimate HWP Variables 1A, 2A, PIM, PEX, and H, for 1961 to the present, including default conversion factors,
are provided in Tables 12.4 and 12.5. In order to include current year carbon release from HWP placed in use
many decades ago, estimates are needed for HWP data prior to 1961. In order to estimate total harvest (VariableH) including bark, multiply the FAO estimate of harvest for products (Table 12.5) by a default bark expansion
factor of 1.13 (Jenkins et al., 2003).
In order to estimate the variables in Table 12.5 prior to 1961, they are extrapolated backward to 1900 using
Equation 12.6. Equation 12.6 uses a rate of change variable U to estimate values prior to 1961.10 The rate of
10

Countries formed after 1961 may not have data in the FAO database back to 1961. A way to extend more recent
production, import and export data back to 1961 is to look at data back to 1961 for the “old” country that the “new”

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.17

Volume 4: Agriculture, Forestry and Other Land Usechange taken to approximate change in production, imports and exports prior to 1961 is the rate of change inindustrial roundwood production. Default values for U are shown in Table 12.3 for major world regions.
EQUATION 12.6
EQUATION TO ESTIMATE PRODUCTION, IMPORTS OR EXPORT VARIABLES IN TABLE 12.5 FORYEARS BEFORE 1961
V =V
• e [ U • (t −1961) ]t

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

TABLE 12.3
ESTIMATED ANNUAL RATES OF INCREASE FOR INDUSTRIAL ROUNDWOOD PRODUCTION (HARVEST) BY WORLDREGION FOR THE PERIOD 1900 TO 1961
RegionAnnual Rate of Increase U

World total

0.0148Europe0.0151USSR

0.0160

North America

0.0143Latin America

0.0220Africa0.0287

Asia

0.0217

Oceania

0.0231

Source: See Table 3a.1.2 in HWP Appendix of GPG-LULUCF (IPCC, 2003).
Note: For each region the average rate of change over the period 1900 to 1961 is formed by combining a documented actual
rate of change from 1950 to 1961 and an estimated rate of change from 1900 to 1950. The estimated rate from 1900 to 1950
is formed by adding together the annual percent change of population growth from 1900 to 1950 and one half the annual
percent change in industrial roundwood harvest per capita for the period 1950 to 1975.

country was a part of (e.g., Czechoslovakia for the Czech Republic and Slovokia) and extend “new” country variables backto 1961 using the rate of change in each variable for the “old” country back to 1961.

12.18

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products

TABLE 12.4
DEFAULT FACTORS TO CONVERT FROM PRODUCT UNITS TO CARBON
Roundwood, industrial roundwood,
sawnwood, ,other industrial
roundwood, pulpwood, chips,
particles, wood fuel, wood residues

1. Density (oven-dry
tonnes per m3 ofsolidwood product oroven dry per air dry
tonne of pulp or paper
product)
2. Carbon fraction(tonnes carbon peroven dry tonne ofwood material)
3. Carbon factor(tonnes carbon per m3
of product or per air
dry tonne of product)

Charcoal

Averagefor wood
panelsPaper and
paperboard, pulp,
recovered fibre
pulp, recovered
paper

Temperate
species

Tropicalspecies

0.45

0.59

0.9

oven-dry tonnem-3

oven-dry
tonne m-3

oven-dry
tonne (airdry tonne)-1

0.5

0.5

0.85

0.468

0.5

A = 0.225 tonne
C m-3

A = 0.295

B = 0.765

C = 0.294

D = 0.450-3tonne C (airdry tonne)-1

tonne Cm-3

tonne C (air-dry
tonne)-1

tonne C m

0.628
oven-dry
tonne m-3

0.9
oven-dry tonne(air dry tonne)-1(row 1) x (row 2)
Source: Temperate species density: Average from Table 4.14, Volume 4, Chapter 4; Tropical species density: Average from Table 4.13,
Volume 4, Chapter 4.

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.19

Volume 4: Agriculture, Forestry and Other Land Use

TABLE 12.5
UN FAO ACTIVITY DATA NEEDED FOR TIER 1 VARIABLES, AND DEFAULT CONVERSION FACTORS
Carbon factor
Time period
FAO database variables needed to compute(Gg carbon per m3 for(Inv. Yr =aggregate variablewood products or per
Aggregate variable
Inventory3(m for wood
Gg for paper & pulp)
reporting
Gg for pulp and paper)(see Table 12.4 foryear)
values)Variable 1A – Consumption of solidwood or paper products
Other industrial roundwood
1961- Inv. yr.
A
Production of solidwood
Sawnwood
1961- Inv. yr.
Aproducts

Imports and exports ofsolidwood products

Production of paper andpaperboard from wood [seenote 1 below]
Imports and exports of paper
and paperboard

Wood panels

1961- Inv. yr.

C

Other industrial roundwood

1961 - 1989

A

Sawnwood

1961- Inv. yr.

A

Wood panels

1961- Inv. yr.

CPaper and paperboard – production (PPAPER)

1961- Inv. yr.

D

Other fibre pulp – production (OFPP), imports(OFPIM), and exports (OFPIM)

1961- Inv. yr.

D

Paper and paperboard

1961- Inv. yr.

D

Variable 2A – Production of solidwood and paper products from wood harvested in the reporting country

Production of solidwood
products from domestic
harvest [ see note 2 below]

Production of paper andpaperboard from domestic
harvest [see note 3 below]

Production of solidwood products as for Variable
1A above (PSW)

1961- Inv. yr.

A

Industrial roundwood harvest (IRWH), imports(IRWIM), exports (IRWEX)

1961- Inv. yr.

A

Chips and particles imports (CPIM ), and exports(CPEX)

1961-Inv. yr.

A

Production of paper and paperboard products fromas for Variable 1A above (PPAPER)

1961- Inv. yr.

DIndustrial roundwood harvest (IRWH), imports(IRWIM), exports (IRWEX) – same as above

1961- Inv. yr.

A

Other fibre pulp – production (OFPP), imports(OFPIM), and exports (OFPIM)– same as above

1961- Inv. yr.

DExports of wood pulp, recovered paper andrecovered paper pulp (PPEXPORTS )1961- Inv. yr.

D

Variables 3 and 4 – Imports and exports of all solidwood and paper products and wood fiber
Roundwood (includes fuelwood)

Imports and exports

1961- Inv. yr.

A

Chips and particles

1961- Inv. yr.

A

Wood residue

1961- Inv. yr.

ACharcoal

1961- Inv. yr

B

Sawnwood

1961- Inv. yr.

A

Wood panels

1961- Inv. yr.

D

Wood pulp

1961- Inv. yr.

D

Recovered paper

1961- Inv. yr.

D

1961- Inv. yr.

A

Variable 5 – Harvest for products
Harvest for products [seenote 4 below]

Industrial roundwood (IRWH), fuelwood

Notes:
1. Production of paper and paperboard from wood = PPAPER - (OFPP + OFPIM - OFPEX )2. Production of solidwood products from domestic harvest = PSW * IRWH / (IRWH + IRWIM - IRWEX + CPIM - CPEX )3. Production of paper products from domestic harvest = (PPAPER+PPEXPORTS - (OFPP + OFPIM - OFPEX )) * IRWH / (IRWH + IRWIM IRWEX + CPIM - CPEX )4.Variable H = IRWH * BF + Fuelwood, BF (bark factor) default value = 1.13 ; Softwoods (1.11), Hardwoods (1.15) (Jenkins et al.,2003)
Source of variables and data: FAOSTAT Forestry database (FAO 2005).

12.20

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products

12.3

UNCERTAINTY ASSESSMENT

Uncertainty in the five HWP variables using Tier 1 methods arises in two ways:
1.

More accurate country data may differ from the default data in Tables 12.2, 12.3, 12.4 and 12.5; and2.

The estimation method is a simplification of real world processes.

The uncertainty associated with using default product production and trade (the activity data) and parameters areprovided in Table 12.6. The uncertainty estimates are based on published studies and expert judgment. If
national data and parameters are used, uncertainties should be evaluated consistent with the guidance in Volume
1, Chapter 3.
Some FAO activity data – such as Other Industrial Roundwood Production – needed in calculation of Variables
1A and 2A may have high uncertainty.
An estimate of the effect of the uncertainty in the default data on each of the five HWP variables could beobtained by using the error propagation approach or the Monte Carlo simulation approach as discussed inVolume 1, Chapter 3.
There is also uncertainty in the estimates because the calculations simplify a more complex real world process ofadditions to and discards from “products in use” and SWDS. One simplification for Tier 1 and Tier 2 methods isthe tracking of additions and discards only in the form of semi-finished products (solidwood and paper). Ideally
it would be possible to track additions and discards of carbon in end-uses (such as buildings, furniture, books,etc.). The end-use pools (such as buildings, books, etc.) are assumed to be included in these semi-finishedproduct pools. Additional simplifications include the assumptions that there are two stocks of products in use(solidwood and paper) and that discards are a constant fraction of the contents of the product pools in use overtime. If country information is available to indicate more product stock groups with differing discard patterns,
including variation in discards over time, then a Tier 3 method is recommended allowing for a different discard
pattern.
Given the potential differences between the default data and actual country data estimates for Variables 1A, 1B,
2A and 2B estimates using Tier 1 methods could have uncertainties of ± 50% or more.
There will be higher uncertainties associated with estimation of Variables 2A and 2B than Variables 1A and 1B
because of the practical difficulties to estimate changes in carbon pools in countries where HWP are exported.
The simplified assumption for Variable 2A (carbon stock changes in HWP pools from domestic harvest) is thatthe lifecycle of harvested wood in the importing countries is similar to that for domestic use. The simplified
assumption for Variable 2B is that there is no significant storage of exported products in SWDS after their use inother countries. The uncertainty in Variables 2A and 2B will be greater for countries that have higher levels ofexports and/or imports. To reduce the uncertainties concerning Variable 2B a conservative estimate is madewhich includes only carbon stock changes in domestic SWDS.
Uncertainties in Variables PIM, PEX, and H are associated with the accuracy of this default country data and theirconversion factors into amounts of carbon − not with such modeling uncertainties as in case of Variables 1 and2.
Amounts of wood-based materials in international trade of final products (e.g., prefabricated houses, furniture,books, etc.) are not included in FAO statistics and in order to avoid double-counting those could not be used in
the Tiers 1 and 2 methods that are focused on semi-finished products (e.g., lumber and paper).
For a discussion of the uncertainty associated with the Waste Sector Tier 1 method see Volume 5, Chapter 2.
Even though the uncertainty associated with Tier 1 estimates using default data could be high, working throughsuch estimates can be the first step in identifying ways to improve them. Initial improvements can be made using
Tier 2, including use of country data, and use of validation steps suggested in the next section on quality control
and quality assurance.

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.21

Volume 4: Agriculture, Forestry and Other Land Use

TABLE 12.6
UNCERTAINTY ASSOCIATED WITH ACTIVITY DATA AND PARAMENTERS (EMISSION FACTORS) FOR THE TIER 1 METHOD TO ESTIMATE THE FIVE ANNUAL HWP VARIABLES
Description of data or parameter
Roundwood harvest (wood harvested and removed
from sites for products including fuelwood)

Uncertainty range – possible difference fromdefault for individual countries

Data or parameter

ValuesH in Table 12.5

FAO database- Country-specific for FAO data

HWP production, imports and exports – FAO data

See Table 12.5

FAO database- 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

Product volume to product weight factors

See Table 12.4

See Table 12.4

~ ±25%Oven dry product weight to carbon weight

See Table 12.4

0.5

~ ±10%

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

Decay (or discard) rate for solidwood and paper fromthe “products in use” pool2006 IPCC Guidelines for National Greenhouse Gas Inventories

U (in Table 12.3)

K

See Table 12.3

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

See Table 12.2

- For estimating Variable 1A , uncertainty in halflife ~ ±50% , k = ln(2)/ (half-life); (preliminary –further study needed, half-life likely to vary overtime)
- For estimating Variable 1B, uncertainty in halflife of products in use would be greater given theextra uncertainty of discard rates for exported
products on other countries.

12.22

Chapter 12: Harvested Wood Products

12.4

QUALITY ASSURANCE/ QUALITY CONTROLThis section suggests steps to improve estimates of the five HWP variables including checking and revising data
for the Tier 1 method and improvements for Tier 2 estimates.
1.

Check that country data in the FAO database (Table 12.5) agree with best available country sources of dataon production and trade, or use country data in place of FAO data. (this can improve Variables 1through 5).

2.

Check for country sources for densities of wood and paper products to revise the values in Table 12.4.
Review wood density information provided in the IPCC Emission Factor Database (EFDB) and in relevant
Tables 4.13 and 4.14 in Chapter 4 (Forest Land) of these guidelines (this can improve Variables 1through 5).

3.

Use the following steps to validate the estimate of Variable 1A - Annual change in carbon stock in HWP
products in use in the reporting country – by comparing two estimates of amounts of wood and paper
deposited in SWDS.

4.

(i)

Use the Waste Sector Tier 1 method and Excel worksheets (or other Waste Sector methods and data)
to estimate of the amount of solidwood and paper products deposited in SWDS for several years (e.g.,
1961 to the present).

(ii)

Prepare a second estimate of the amount of solidwood and paper products deposited in SWDS in thefollowing way:a.

Use the HWP Tier 1 Excel worksheets to estimate the amount of solidwood and paper
products in use that are discarded each year for 1961 to the present.

b.

Reduce the amount of paper discards each year by the amount of paper that is recovered forrecycling each year using FAO data on amount of recovered paper produced.

c.

Obtain an estimate of the portion of discarded wood and paper (excluding recovered amounts)that is sent to SWDS. This would likely be the fraction not burned.

d.

Estimate the amount of solidwood and paper deposited in SWDS each year by multiply thediscard amount (after recovery for recycling) by the fraction that goes to SWDS.

(iii)

Compare the yearly deposit estimates from the Waste Sector Tier 1 method and the method based on
HWP Tier 1 discard data.

(iv)

To reconcile differences in estimates, it is recommended that changes be made to HWP Tier 1
parameters so that the SWDS deposit estimates based on HWP numbers match the SWDS deposit
from the Waste Sector estimates. HWP parameters to change include: 1) half-life for solidwood andpaper products in use (Table 12.2), or 2) factors to convert HWP product data to carbon units (Table
12.4).

An additional step to help verify Variable 1A - annual change in HWP carbon in products in use - would be
to use Equation 12.2 to make separate estimates of annual change in solidwood carbon held in buildings,
such as residential buildings and separately for all other uses. A different half-life would be used forsolidwood products in residential buildings. Compare this estimate of carbon change in residential buildings
to a second estimate made in the following way. Compute the total carbon held in residential buildings at
two points in time. For each point in time multiply the number of residential buildings, times average square
meters per building, times cubic meters of solidwood use per square meter of house, times carbon per unit ofsolidwood. Take the difference in carbon in residential buildings between the two points in time and divideby the number of years to estimate carbon change per year. To reconcile the two estimates of annual change
in solidwood carbon, adjust the half-life assumed for solidwood use in residential buildings.

12.5

COMPLETENESS

Tiers 1 and 2 methods, for estimating Variables 1A and 1B (annual change in HWP carbon in products in use
and in SWDS, respectively, in the reporting country), include carbon additions in the form of all semi-finishedwood and paper products that are consumed. By doing so, they include carbon in any secondary wood products
made in the country from those semi-finished products. If the country is a notable exporter or importer of
secondary wood products, such as furniture or wooden crafts, then methods may need to be adapted to adjust
HWP consumption to exclude exports of secondary products and/ or include imports of secondary products.

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.23

Volume 4: Agriculture, Forestry and Other Land Use

Tiers 1 and 2 methods to estimate Variables 2A and 2B (annual change in HWP carbon in products in use fromdomestic harvest) are likely to include all semi-finished and secondary product carbon from domestic harvest(sawnwood, panels and paper) unless some wood is used directly for secondary products (e.g., furniture) and notincluded first in a semi-finished product amounts reported in the FAO or country data (e.g. sawnwood ). If somesawnwood is used directly to make furniture (and not included in FAO country data on sawnwood) then theTiers 1 and 2 methods would underestimate the inflow of carbon to products in use and products in SWDS.
The methods provided in these guidelines do not include estimates of HWP carbon storage associated with CO2that is captured after biomass burning and held as part of a solid chemical or as a gas.

12.6

REPORTING AND DOCUMENTATION

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

12.7

REPORTING TABLES AND WORKSHEETSTo report the HWP Contribution an approach should be selected. It is good practice to report the following in the
AFOLU sectoral background Table 3.10 (see Table 12.7 and Table A12.1):•

The HWP Contribution•

The approach used to estimate the HWP Contribution. If the HWP Contribution is assumed to be zero
(Section 12.2.1) then the reason for this should be stated instead of the approach chosen,•

The amounts harvested, imported and exported should be given in Table 12.7 even if the HWP Contribution
is assumed to be zero.

•CO2 release to the atmosphere from HWP --- (44/12*↑C HWP DC) and/or (44/12*↑C HWP DH) as appropriate.

•

Any other HWP variables used to estimate the reported HWP Contribution should also be given.

The inventory compiler is encouraged to report additional information that would increase the comparability andtransparency of the report. This could include:•

Any of the remaining HWP variables defined in Table 12.1 not covered above.

•

Other additional items may also be reported for specific approaches if an inventory compiler believes thiswould add to the transparency of the inventory.

If the Simple Decay approach is used for reporting, the compiler should indicate in the Documentation Box of
Background Table 3.10 (Table 12.7) which of the following options is used: 1a) CO2 equivalent of carbon in
annual harvest of HWP is retained with (deducted from) the net emission/ removals estimate reported separately
for each land area [e.g., ( -44/12 * H ) for Forest Land], and 1b) HWP Contribution entered in Table 3.10 equals
the CO2 release from harvest in the country ( 44/12* ↑CHWP DH); OR 2) HWP Contribution in Table 3.10 equals[-44/12* (H -↑C HWP DH )].

12.24

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products
TABLE 12.7 SECTORAL BACKGROUND DATA FOR AFOLUANNUAL CARBON HWP CONTRIBUTION TO TOTAL AFOLU CO2 REMOVALS AND EMISSIONS AND BACKGROUND INFORMATION
Variable number
Inventory
year

1A

1B

2A

2B

3

4

5

6

7

8

9

Annualchange instock of
HWP in use
fromconsumption

Annualchange instock of
HWP inSWDS fromconsumption

Annualchange instock of
HWP in use
producedfromdomestic
harvestAnnualchange instock of
HWP inSWDS
producedfromdomestic
harvestAnnualimports ofwood, andpaper
products +wood fuel,pulp,
recoveredpaper,
roundwood/chips

Annualexports ofwood, andpaper
products +wood fuel,pulp,
recoveredpaper,
roundwood/chips

Annualdomestic
harvestAnnualrelease ofcarbon to theatmospherefrom HWP
consumption(fromfuelwood &products in
use andproducts in
SWDS)

Annualrelease ofcarbon to theatmospherefrom HWP(including
fuelwoood)
where woodcame fromdomestic
harvest (fromproducts in
use andproducts in
SWDS )

HWP
Contribution
to AFOLU
CO2
emissions/removals

Approachused toestimate
HWP
Contribution1∆CHWP IU DC∆CHWP SWDS DC∆C HWP IU DH∆CHWP SWDS DH

PIM

PEX

H

↑CHWP DC↑CHWP DH

Gg C yr-1

Gg CO2 yr-1

1990
…..
Report Col 6 or 7 as needed for the approach used. Col 6 or 7 may be computed using Cols 1 through 5 or by a Tier 3 method. Always report Cols 3, 4, and 5. Report Cols 1A, 1B, 2A, 2B if they are used.
The HWP Contribution and approach should be reported in Cols 8 and 9 together with a description of the approach chosen and main assumptions in the Documentation Box.
Additional variables calculated and used should be reported to enhance the transparency of the results (e.g., CH4 from SWDS if this was used). Add additional columns if needed.
Note: ↑C HWP DC = H + PIM – PEX - ∆C HWP IU DC - ∆C HWP SWDS DC AND ↑C HWP DH = H - ∆C HWP IU DH - ∆C HWP SWDS DH
Documentation
Box:

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.25

Volume 4: Agriculture, Forestry and Other Land Use

Annex 12.A.1 Some Approaches
This annex provides descriptions of some approaches for HWP. The descriptions included here are based on theoriginal descriptions of the approaches (Brown et al., 1998; and Ford-Robertson, 2003) and are provided here asadditional background information for inventory compilers. The inclusion of an approach here does not imply
any endorsement of that approach or any guidance on what approach to use. The special inventory terms"emissions", "removals" and "sinks" are used without any judgment that they are correctly used given their
special definitions.

S TOCK -C HANGE A PPROACH

ATMOSPHERE

NEE

EW

E

System boundary

AFOLU
without
HWP

O

Figure 12.A.1

HWP
in use

H

PEX

W

PIM

HWP
in SWDS

National boundary

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 theatmosphere 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 otherwood 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 thereport 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:

12.26

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products

EQUATION 12A.1
EMISSIONS FROM AFOLU BY THE STOCK-CHANGE APPROACH
Annual CO2 emissions from AFOLU = −44/12 ● [∆(AFOLU without HWP) + ∆(HWP in use) +∆(HWP in SWDS)]= −44/12 ● [∆(AFOLU without HWP) + ∆CHWP IUDC+∆CHWP SWDSDC]
or= −44/12 ● [∆(AFOLU without HWP) + H + PIM – PEX - ↑CHWP DC]
Where:∆ means annual change in carbon stock of the pool within the brackets. Note that the variables∆CHWP IUDCand ∆CHWP 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(∆CHWP IUDC+∆CHWP SWDSDC ) or carbon release variables and carbon transfer variables (↑CHWP DC, H, PIM, PEX).
Where:
H = Harvest of wood to be used for HWP (including fuelwood)↑CHWP DC = E + EW
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 notconsidered 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 ● ∆(AFOLU without HWP) is already reported in the rest of AFOLU, the HWPContribution 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 ● [∆CHWP IU DC+ ∆CHWP SWDS DC]orHWP Contribution to AFOLU Net CO2 emissions SCA = −44/12 ● [ H + PIM – PEX - ↑CHWP DC ]In the specific case when stock change of carbon in the HWP pools is zero, HWP Contribution is reported aszero (Equation 12A.2).

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.27

Volume 4: Agriculture, Forestry and Other Land Use

A TMOSPHERIC F LOW A PPROACH
ATMOSPHERE

NEE

System boundary

AFOLU
without
HWP

Figure 12.A.2

EW

HWP
in use

H

O

E

W

PIM

PEX

HWP
in SWDS

National boundary

System boundary of the Atmospheric Flow Approach.

Note: NEE = net ecosystem exchange of carbon, E = carbon release to the atmosphere from HWP in use, EW = carbon release to theatmosphere from HWP in SWDS, H = carbon transfer in the form of harvested wood biomass transported from harvest sites, W = carbon
transfer 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 Atmospheric Flow Approach (AFA) estimates fluxes of carbon to/from the atmosphere for the forest pool(and other wood producing lands) and wood products pool within national boundaries, and reports where andwhen these emissions and removals occur. A country includes in its estimate of emissions/ removals the grossremovals of carbon from the atmosphere due to tree biomass growth in forests and other wood producing land
categories (net of decay within forests), and the carbon release to the atmosphere from oxidation of harvested
wood products that are consumed in their country. The carbon release to the atmosphere from harvested wood
products includes carbon release from imports to the reporting country.
The system boundary of the Atmospheric Flow Approach and the carbon pools under consideration are shown in
Figure 12A.2. The pools are the same as in the Stock-Change Approach. The difference is that the Atmospheric
Flow Approach estimates the atmospheric carbon exchange of the AFOLU Sector of the reporting country rather
than stock changes within the country. The national carbon dioxide emissions are given by Equation 12A.3:
EQUATION 12A.3
EMISSIONS FROM AFOLU AS BY THE ATMOSPHERIC FLOW APPROACH
CO2 emissions from AFOLU = −44/12 ● (NEE − E − EW) = −44/12 ● (NEE − ↑CHWP DC )= −44/12 ● [∆(AFOLU without HWP) + ∆CHWP IUDC+∆CHWP SWDSDC+ PEX − PIM ]or= - 44/12 ● [∆(AFOLU without HWP) + H - ↑CHWP DC ]Figure 12A.2 may be used to express Equations 12A.3 and 12A.4 using either carbon stock change and carbon
transfer variables (∆CHWP IUDC, ∆CHWP SWDSDC PIM, PEX) or carbon release variables and carbon transfer
variables ( ↑CHWP DC, H).
Where:
NEE = net ecosystem exchange of C
E, EW, ↑CHWP DC , PEX, PIM and H are define above

12.28

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products

As the quantity −44/12 ● ∆(AFOLU without HWP) is reported elsewhere, the HWP Contribution to be reported
is given by Equation 12A.4:
EQUATION 12A.4
ATMOSPHERIC FLOW APPROACH: HWP CONTRIBUTION
HWP Contribution to AFOLU Net CO2 emissions AFA = −44/12 ● [∆CHWP IUDC+ ∆CHWP SWDSDC +PEX − PIM + O]orHWP Contribution to AFOLU Net CO2 emissions AFA = -44/12 ● [H - ↑CHWP DC]

In the specific case when stock change of carbon in the HWP pools is zero the carbon imports minus carbon
exports must still be reported as the HWP Contribution to AFOLU net CO2 emissions (see Equation 12A.4).

P RODUCTION A PPROACH
ATMOSPHERE

NEE

EDOM

EIM

EEX DOM

System boundary

AFOLU
without
HWP

O

H

HWP
in use orin SWDS

HWP
in use orin SWDS

domestic imported

from dom. rw.
in export markets

National boundary

PIM

PEX

Figure 12.A.3

System boundary of the Production Approach.

Note: NEE = net ecosystem exchange of carbon, EDOM = carbon release to the atmosphere from the pools of domestically grown HWP in use
and in SWDS, EIM = carbon release to the atmosphere from the pools of imported HWP in use and in SWDS, EEX DOM = carbon release to theatmosphere from the pools of domestically grown but exported HWP in use and in SWDS, H = carbon transfer in the form of harvested woodbiomass transported from harvest sites, PEX = carbon transfer in the form of HWP exports, PIM = carbon transfer in the form off HWP
imports, O = possible other cross-border carbon transfers from rest of AFOLU (assumed zero here). Note: Only those HWP in the export
markets that are produced from domestic roundwood are within the system boundary, not those only processed in the reporting country but
made from imported roundwood. The transfer PEX can in principle include both.

The Production Approach (PA) estimates changes in carbon stocks in the forest pool (and other wood producing
lands) of the reporting country and the wood products pool containing products made from wood harvested in
the reporting country. The wood products pool includes products made from domestic harvest that are beexported and stored in uses in other countries. This approach inventories carbon in wood products fromdomestically harvested wood only and does not provide a complete inventory of wood carbon in national stocks.
Because some of the stock changes reported by a country may occur in other countries (where exports are held),the stock change report indicates when changes occur but not where they occur.
The system boundary of the Production Approach and the carbon pools under consideration are shown in Figure
12A.3. The national carbon dioxide emissions are approximated using Equation 12A.5:

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.29

Volume 4: Agriculture, Forestry and Other Land Use

EQUATION 12A.5
EMISSIONS FROM AFOLU BY THE PRODUCTION APPROACH
CO2 emissions from AFOLU = −44/12 ● [∆(AFOLU without HWP) + ∆CHWP IU DH +∆CHWP SWDSDH]
or= - 44/12 ● [∆(AFOLU without HWP) + H - ↑CHWP DH]

Figure 12A.3 may be used to express Equations 12A.5 and 12A.6 using either carbon stock change and carbon
transfer variables (∆CHWP IUDH, ∆CHWP SWDSDH) or carbon release variables and carbon transfer variables ( ↑CHWP
DH, H). Where variables ∆CHWP IUDH and ∆CHWP SWDSDH are defined in Table 12.1 and ↑CHWP DH = EDOM + EEX
DOM.
As the quantity = −44/12 ● ∆(AFOLU without HWP) is reported in the rest of AFOLU, the HWP Contribution
to be reported in the HWP module is given by Equation 12A.6:
EQUATION 12A.6
PRODUCTION APPROACH: HWP CONTRIBUTION
HWP Contribution to AFOLU Net CO2 emissions PA = −44/12 ● [∆CHWP IUDH+ ∆CHWP SWDSDH]orHWP Contribution to AFOLU Net CO2 emissions PA = −44/12 ● [H - ↑CHWP DH]
In the specific case when stock change of carbon in the above HWP pools is zero, and the HWP Contribution to
net CO2 emissions HWP is reported as zero (Equation 12A.6).

S IMPLE D ECAY A PPROACH
This approach estimates and reports the net emissions or removals of carbon to/from the atmosphere when, but
not where they occur if wood products are traded. Removals of carbon from the atmosphere due to forest growth,and emissions resulting from oxidation of harvested wood products are reported by the producing country.
This approach to estimate and report from HWP (simple decay) has been proposed by Ford-Robertson (2003).
Just as the Production Approach differs from the Stock-Change Approach (for the production approach all stockchanges are accounted for and reported by the producer and for the Stock-Change Approach all stock changes
are reported by the country where they occur) the Simple Decay Approach (SDA) is similarly related to the
Atmospheric Flow Approach (for the Simple Decay Approach all CO2 release is reported by the country where
the HWP was harvested and for the Atmospheric Flow Approach all CO2 release is reported by the country
where the release occurs). The Simple Decay Approach differs from Production Approach in that HWP pool isconsidered to be related to activities in the forest and hence does not assume instant oxidation of wood in theyear of harvest. This means the amount of harvest in a year (Variable H, remains part of the AFOLU carbon pool(e.g., forest or other land area) and not counted as a part of emissions. The amount estimated for simple decay isthe amount of emissions from HWP each year (↑CHWP DH ). This suggestion to include and report annual harvest
as part of the land area CO2 removals, and report the HWP Contribution as (44/12*↑C HWP DH ) is only a proposal atthis point. For these guidelines, compilers are requested to report the HWP Contribution for Simple Decay
Approach as [-44/12* (H -↑C HWP DH )].

12.30

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products

TABLE A12.1
SUMMARY OF HOW TO COMPUTE HWP CONTRIBUTION USING VARIALBES IN TABLE 12.7
How to estimate HWP Contribution using
HWP Variables 1-5

How to estimate HWP Contribution using carbon
release estimates (Variables 6 and 7) and HWP
Variables 3-5

StockChange-44/12 ● ∆CHWP DC, [i.e. -44/12 ● (Var 1A +Var 1B)]-44/12 ● (H + PIM – PEX – ↑C HWP DC), [i.e. -44/12 ●(Var 5 + Var 3 – Var 4 – Var 6 )]AtmosphericFlow-44/12 ● (∆CHWP DC + PEX – PIM), [i.e. -44/12 ●(Var 1A + Var 1B – Var 3 + Var 4)]-44/12 ● (H – ↑C HWP DC ), [i.e. -44/12 ● (Var 5–Var 6)]

Production-44/12 ● ∆CHWP DH, [i.e. -44/12 ● (Var 2A +Var 2B)]-44/12 ● (H –↑C HWP DH ), [i.e. -44/12 ● (Var 5– Var 7)]

SimpleDecay

NA

Under these guidelines report HWP Contribution as

Approach-44/12 ● (H –↑C HWP DH ), [i.e. -44/12 ● (Var 5– Var 7)]
Proposal for a change in reporting
report ( -44/12 ● H ) as part of the AFOLU land area
(forest or land area) removals
report HWP Contribution as CO2 release from HWP(44/12 ● ↑CHWP DH )2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.31

Volume 4: Agriculture, Forestry and Other Land Use

References
Brown, S., Lim, B. and Schlamadinger, B. (1998). Evaluating Approaches for Estimating Net Emissions ofCarbon Dioxide from Forest Harvesting and Wood Products. Report of a meeting sponsored by the IPCC
held in Dakar, Senegal, 5-7 May, 1998. http://www.ipcc-nggip.iges.or.jp/public/mtdocs/pdfiles/dakar.pdf
and http://www.ipcc-nggip.iges.or.jp/public/mtdocs/dakar.htm
Cowie, A., Pingoud, K. and Schlamadinger, B. (2006). Stock changes or fluxes? Resolving terminologicalconfusion in the debate on land use change and forestry, Climate Policy, Vol. 6, No. 2.
Flugsrud, K, Hoem, B., Kvingedal, E. and Rypdal, R. (2001). Estimating net emissions of CO2 from harvested
wood products. SFT report 1831/200. Norwegian Pollution Control Authority, Oslo 47 p.
http://www.sft.no/ publikasjoner/luft/1831/ta1831.pdf
Food and Agriculture Organization (2005). FAOSTAT Forestry data. Web site http://faostat.fao.org/faostat/collections?subset=forestry accessed January 3, 2005.
Ford-Robertson, J.B. (2003). Implications of Harvested Wood Products Accounting - Analysis of issues raised
by Parties to the UNFCCC and development of a Simple Decay approach. MAF Technical Paper No
2003/5,30p.
Ministryof
Agriculture
andForestry,
Wellington,
New
Zealand.
http://www.maf.govt.nz/forestry/ publications/index.htm
Gardner, W.D., Ximenes, F., Cowie, A., Marchant, J.F., Mann, S. and Dods, K. (2002). Decomposition of wood
products in the Lucas Heights landfill facility. Presented at the Third Australian Conference on 'Life
Cycle Assessment – “Life Cycle Decision-making for Sustainability”. Queensland, Australia, 17 – 19
July, 2002. State Forests of New South Wales, Sydney, Australia. (http://www.greenhouse.crc.org.au/
crc/ecarbon/enews/gardner.pdf)
Gjesdal, S.F.T., Flugsrud, K., Mykkelbost, T.C. and Rypdal, K. (1996). A balance of use of wood products in
Norway, Norwegian Pollution Control Authority SFT, Report 96:04, 54 p.
Haygreen, J.G. and Bower, J.L. (1989). Forest Products and Wood Science – An Introduction, 2nd edition. Iowa
State University Press. Ames, Iowa. 500 p.
Hashimoto, S. and Moriguchi, Y. (2004). Data Book: Material and carbon flow of harvested wood in Japan.
CGER-D034-2004. National Institute for Environmenal Studies, Japan. Tsukuba. 40p. http://wwwcger.nies.go.jp/publication/D034/D034.pdf
IPCC (1997). Revised 1996 IPCC Guidelines for National Greenhouse Inventories. Houghton J.T., Meira Filho
L.G., Lim B., Tréanton K., Mamaty I., Bonduki Y., Griggs D.J. Callander B.A. (Eds). Intergovernmental
Panel on Climate Change (IPCC), IPCC/OECD/IEA, Paris, France.
IPCC (2003). Good Practice Guidance for Land Use, Land-Use Change and Forestry. Penman J., Gytarsky M.,
Hiraishi T., Krug, T., Kruger D., Pipatti R., Buendia L., Miwa K., Ngara T., Tanabe K., Wagner F.
(Eds).Intergovernmental Panel on Climate Change (IPCC), IPCC/IGES, Hayama, Japan.
Jenkins, J.C., Chojnacky, D.C., Heath, L.S. and Birdsey, R.A. (2003). National-scale biomass estimators forUnited States tree species. Forest Science. 49(1):12-35. http://www.fs.fed.us/ne/newtown_square/publications/other_publishers/OCR/ne_2003jenkins01.pdf
Micales, J.A and Skog, K.E. (1997). The decomposition of forest products in landfills. International
Biodeterioration and Biodegradation 39(2-3): pp. 145-158
National Council for Air and Stream Improvement, Inc. (NCASI). (2004). Critical Review of Forest Products
Decomposition in Municipal Solid Waste Landfills. Technical Bulletin No. 0872. Research Triangle Park,
NC: National Council for Air and Stream Improvement, Inc. http://www.ncasi.org/publications/
Detail.aspx?id=97
Pingoud, K., Perälä, A.-L. and Pussinen, A. (2001). Carbon dynamics in wood products. Mitigation and
Adaptation Strategies for Global Change, Vol. 6, No. 2, pp. 91-111, 2001.
Pingoud, K., Savolainen, I. and Seppala, H. (1996). Greenhouse impact of the Finnish forest sector including
forest products and waste management. Ambio 25:pp. 318-326.
Pingoud, K., Perälä, A.-L., Soimakallio, S. and Pussinen, A. (2003). Greenhouse gas impacts of harvested wood
products. Evaluation and development of methods. VTT Research Notes 2189, 138 p.
http://www.vtt.fi/inf/pdf/tiedotteet/2003/T2189.pdf.
Pingoud, K. and Wagner, F. (2006). Methane emissions from landfills and decay of harvested wood products:
the first order decay revisited. IIASA Interim Report IR-06-004

12.32

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 12: Harvested Wood Products

UNFCC Secretariat (2003). Estimation, reporting, and accounting of harvested wood products - Technical paper.
FCCC/TP/2003/7 27 October 2003. Bonn, Germany. http://unfccc.int/resource/docs/tp/tp0307.pdf
UNFCCC Secretariat (2004). Report on the workshop on harvested wood products [held in Lillehammer,
Norway, from 30 August to 1 September 2004.] FCCC/SBSTA/2004/INF.11 25 October 2004. Bonn,
Germany http://unfccc.int/resource/docs/2004/sbsta/inf11.pdf
Winjum, J. K., Brown, S. and Schlamadinger, B. (1998). Forest harvests and wood products: Sources and sinks
of atmospheric carbon dioxide. Forest Science 44 (2):272-284.

2006 IPCC Guidelines for National Greenhouse Gas Inventories

12.33