Approved VCS Module VMD0005

Version 1.0

REDD Methodological Module:

Estimation of carbon stocks in the long-term wood products pool (CP-W)

Sectoral Scope 14

I. SCOPE, APPLICABILITY AND PARAMETERS

Scope

This module allows for ex ante estimation of carbon stocks in the long-term wood products 

pool in the baseline case. Carbon stocks treated here are those stocks remaining in wood 

products after 100 years; the bulk of emissions associated with timber harvest, processing and 

waste, and eventual product retirement occur within this timeframe, and this module employs 

the simplifying assumption that the proportion remaining after 100 years is effectively 

“permanent1.”

Applicability

This module is applicable to all cases where wood is harvested for conversion to wood products

for commercial markets, for all forest types and age classes. This module is applicable in the 

baseline if the wood products pool is included as part of the project boundary as per 

applicability criteria in the framework module REDD-MF, specifically:

 Timber harvest occurs prior to or in the process of deforestation, and where timber is 

destined for commercial markets

 The wood products pool is determined to be significant (using T-SIG).

Parameters

This module produces the following parameter:

Parameter SI Unit Description

 

1

The proportion remaining after 100 years is effectively the amount sequestered in the wood products pool 

throughout the crediting period of any VCS REDD project (maximum crediting period = 100 years).
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CWP, i t CO2-e ha-1 Mean carbon stock in wood products pool (stock remaining in 

wood products after 100 years) from stratum i

CXB,i t CO2-e ha-1 Mean stock of extracted biomass carbon from stratum i

Frequency of update of oxidation factors

The approach outlined in this module employs emission factors (OF, SLF, and WW) derived by 

Winjum et al. 1998. In the event that new research findings updating or refining (e.g. for 

specific countries) OF, SLF and/or WW factors become available in the future (during the 

project crediting period), they will replace the factors included in the module, otherwise the 

factors in the module will remain valid. The use of this module requires that project proponents 

review research findings (that produce emissions factors compatible with the conceptual 

framework here) at least every 10 years to identify further refinements to the emission factors 

that are empirically-based and peer-reviewed. 

II. PROCEDURES

Ex ante estimation of carbon stocks in the wood products pool in the baseline

This module estimates carbon stocks in wood products resulting from timber harvest occurring 

prior to or in the process of deforestation. Accounting for such wood products should only take 

place at the time of deforestation. This module follows the conceptual framework detailed in 

Winjum et al. 19982, applying the simplifying (and conservative) assumption that all extracted 

biomass not retained in long-term wood products after 100 years is emitted in the year 

harvested, instead of tracking annual emissions through retirement, burning and 

decomposition.

All factors are derived from Winjum et al. 1998.

If approved timber harvest plans, specifying harvest intensity per strata in terms of volume 

extracted per ha, are available for the project area use Option 1. If approved harvest plans are 

not available use Option 2.

Option 1: Direct Volume Extraction Estimation

Step 1: Identify the wood product class(es) (ty; defined here as sawnwood, wood-based panels, 

other industrial roundwood, paper and paper board, and other) that are the anticipated end 

use of the extracted carbon calculated in Step 2. 

 

2 Winjum, J.K., Brown, S. and Schlamadinger, B. 1998. Forest harvests and wood products: sources and sinks of

atmospheric carbon dioxide. Forest Science 44: 272-284
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Step 2: Calculate the biomass carbon of the volume extracted by wood product type ty from 

within the project boundary:

)

12

44 * ( * * *1

1

, , , , , j

S

j

e x t y j i j

i

XB t y i V D CF

A

C 

(1)

Where:

CXB,ty,i Mean stock of extracted biomass carbon by class of wood product ty from 

stratum i; t CO2-e ha-1

Ai Total area of stratum i; ha

Vex,ty,j Volume of timber extracted from within stratum i (does not include slash left 

onsite) by species j and wood product class ty; m3

Dj Mean wood density of species j; t d.m.m-3

CFj Carbon fraction of biomass for tree species j; t C t-1d.m. 

j 1, 2, 3, ... S tree species 

ty Wood product class – defined here as sawnwood (s), wood-based panels (w), 

other industrial roundwood (oir), paper and paper board (p), and other (o)

44/12 Ratio of molecular weight of CO2 to carbon, t CO2-e t C-1

Step 3: Calculate the proportion of biomass carbon extracted that remains sequestered in longterm wood products after 100 years. 

*(1 )*(1 )*(1 )

, , , ,

, , , t y t y

t y s w oir p o

CWP i  CX B t y i W Wt y  SLF OF



(2)

Where:

CWP,i Carbon stock in wood products pool (stock remaining in wood products after 

100 years) from stratum i; t CO2-e ha-1 

CXB,ty,i Mean stock of extracted biomass carbon by class of wood product ty from 

stratum i; t CO2-e ha-1

WWty Wood waste. The fraction immediately emitted through mill inefficiency by 

class of wood product ty; dimensionless

SLFty Fraction of wood products that will be emitted to the atmosphere within 5 

years of timber harvest by class of wood product ty; dimensionless

OFty Fraction of wood products that will be emitted to the atmosphere between 5 

and 100 years of timber harvest by class of wood product ty; dimensionless
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ty Wood product class – defined here as sawnwood (s), wood-based panels (w), 

other industrial roundwood (oir), paper and paper board (p), and other (o)

i 1, 2, 3, ... M strata 

Option 2: Commercial inventory estimation

Step 1: Calculate the biomass carbon of the commercial volume extracted prior to or in the 

process of deforestation:

XB i AB tree i Pcomi

BCEF

C C *

1

,

 _ ,*

(3)

Where:

CXB,i Mean stock of extracted biomass carbon from stratum i; t CO2-e ha-1

CAB_tree,i Mean aboveground biomass carbon stock in stratum i; t CO2-e ha-1

BCEF Biomass conversion and expansion factor (BCEF) for conversion of 

merchantable volume to total aboveground tree biomass; dimensionless

Pcomi Commercial volume as a percent of total aboveground volume in stratum 

i; dimensionless

i 1, 2, 3, ... M strata 

Step 2: Identify the wood product class(es) (ty; defined here as sawnwood, wood-based panels, 

other industrial roundwood, paper and paper board, and other) that are the anticipated end 

use of the extracted carbon calculated in Step 1. 

Step 3: Calculate the proportion of biomass carbon extracted that remains sequestered in longterm wood products after 100 years. This module applies the simplifying (and conservative) 

assumption that all extracted biomass not retained in long-term wood products after 100 years 

is emitted in the year harvested, instead of tracking annual emissions through retirement, 

burning and decomposition. All factors are derived from Winjum et al. 1998. 



   

t y s w oir p o

CWP i CXB t y i WWt y SLFt y OFt y

, , , ,

, , , *(1 )*(1 )*(1 )

(4)

Where:

CWP,i Carbon stock in long-term wood products pool (stock remaining in wood 

products after 100 years) from stratum i post deforestation; t CO2-e ha-1

CXB,ty,i Mean stock of extracted biomass carbon by class of wood product ty from 

stratum i; t CO2-e ha-1
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WWty Wood waste. The fraction immediately emitted through mill inefficiency by 

class of wood product ty; dimensionless

SLFty Fraction of wood products that will be emitted to the atmosphere within 5 

years of timber harvest by class of wood product ty; dimensionless

OFty Fraction of wood products that will be emitted to the atmosphere between 5 

and 100 years of timber harvest by class of wood product ty; dimensionless

ty Wood product class – defined here as sawnwood (s), wood-based panels (w), 

other industrial roundwood (oir), paper and paper board (p), and other (o)

i 1, 2, 3, ... M strata 

III. DATA AND PARAMETERS NOT MONITORED (DEFAULT OR POSSIBLY MEASURED ONE 

TIME)

Data / parameter: BCEF

Data unit: Dimensionless

Used in equations: 1

Description: Biomass conversion and expansion factor for conversion of commercial 

wood volume per unit area to total aboveground tree biomass per unit 

area; note that BCEF as defined here, and in most applications, is not 

applied on a per stem basis

Source of data: Equations must have been derived using a wide range of measured 

variables (commercial wood volume per unit area and total aboveground 

biomass per unit area) based on datasets that comprise at least 30 trees. 

Equations must be based on statistically significant regressions and must 

have an r2that is ≥ 0.8.

The source of data shall be chosen with priority from higher to lower 

preference as follows:

(a) Existing local forest type-specific;

(b) National forest type-specific or eco-region-specific (e.g. from national 

GHG inventory);

(c) Forest type-specific or eco-region-specific from neighboring countries 

with similar conditions. Sometimes (c) might be preferable to (b);

(d) Global forest type or eco-region-specific (e.g. IPCC 2006 INV GLs 

AFOLU Chapter 4 Table 4.5)

The project volume data to which the selected BCEF is applied must 

conform to the data the BCEF was originally derived from, in particular, it 
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must match forest type, stand structure, minimum DBH, and cover the 

range of potential independent variable values (commercial volumes)

likely to be encountered in the project area.

Care must be taken to ensure that the selected BCEF does not account for 

non-commercial species not represented in commercial volume estimates 

(i.e. is restricted to expanding merchantable volumes to account for only 

non-merchantable tree components).

Measurement 

procedures (if any):

Any comment: Alternatively, BCEF, where not directly available, can be calculated as 

wood density (t dry mass m-3green volume) * BEF (Biomass Expansion 

Factor = ratio of aboveground biomass to biomass of the commercial 

volume).

If using BCEFs developed outside the project country (cases (c) and (d) 

above under Source of data), it is necessary to validate the applicability 

of BCEFs used. Validation is performed by:

1. Limited Measurements

 Select at least 20 plots in the project area covering a wide range of 

commercial volumes.

 Obtain tree measurements (e.g. DBH, height to a 10 cm diameter top) 

from which to calculate commercial volume and total biomass.

 Calculate commercial volume per unit area (e.g. using Smalian’s 

formula) and total biomass per unit area (using the biomass 

equation(s) selected for application in CP-AB) for each plot

 Calculate BCEF for each plot (biomass (t) / commercial volume (m3)

 Graph the plot-level estimates of BCEF versus commercial volume 

along with the BCEF equation (predicted) to be validated. If the 

estimated BCEFs of the measured plots are distributed both above and 

below the predicted value the BCEF equation may be used. The BCEF 

equation may also be used if the measured plots have a BCEF 

consistently lower than that predicted. If graphing the BCEF of the 

measured plots indicates a systematic bias to overestimation of BCEF 

(>75% of the plots below the predicted value) then another BCEF 

equation must be selected or developed anew.

Data / parameter: CFj

Data unit: t C t-1 d.m.

Used in equations: 4
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Description: Carbon fraction of dry matter in t C t-1d.m. for species j

Source of data: Species- or family-specific values from the literature (e.g. IPCC 2006 INV 

GLs AFOLU Chapter 4 Table 4.3) shall be used if available, otherwise 

default value of 0.47 t C t-1 d.m. can be used.

Measurement 

procedures (if any):

Any comment: Where new species are encountered in the course of monitoring, new 

carbon fraction values must be sourced from the literature or otherwise 

use the default value.

Data / parameter: Dj

Data unit: t d.m. m-3

Used in equations: 4

Description: Basic wood density in t d.m. m-3for species j

Source of data: The source of data shall be chosen with priority from higher to lower 

preference as follows:

(a) National species-specific or group of species-specific (e.g. from 

National GHG inventory);

(b) Species-specific or group of species-specific from neighboring 

countries with similar conditions. Sometimes (b) may be preferable to 

(a);

(c) Global species-specific or group of species-specific (e.g. IPCC 2006 INV 

GLs AFOLU Chapter 4 Tables 4.13 and 4.14).

Species-specific wood densities may not always be available, and may be 

difficult to apply with certainty in the typically species rich forests of the 

humid tropics, hence it is acceptable practice to use wood densities 

developed for forest types or plant families or species groups.

Measurement 

procedures (if any):

N/A

Any comment: Where using wood densities developed outside of the project country 

(cases (b) and (c) above under Source of data), wood densities must be 

validated with either limited destructive sampling or direct measurement 

of wood hardness (e.g. with a Pilodyn wood tester) in the field and 

correlating with wood density. Samples or measurements should be from 

20-30 trees. For validation of mean forest type or species group wood 

densities, representation of species in the sample should be proportional 

to their occurrence in terms of basal area or volume in the project area 

(not abundance or stem density). Samples should provide representation 
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across the length of the tree.

Wood samples are cut in discs and thickness and diameter measured to 

calculate green volume. Samples are oven dried (70oC) to a constant 

weight in the laboratory, and density calculated as dry weight (g) per unit 

green volume (cm3). 

If the density of the samples/measurements (or mean density in the case 

of forest type or species group means) is within ±10% of the selected 

density values, then the selected density values may be used. Otherwise, 

a new density value must be developed with more extensive sampling, 

using the validation samples as a base.

Where new species are encountered in the course of monitoring, new 

wood density values must be sourced from the literature and validated, if 

necessary, as per requirements and procedures above.

Data / parameter: OFty

Data unit: Dimensionless

Used in equations: 2,4

Description: OF = Fraction of wood products that will be emitted to the atmosphere 

between 5 and 100 years after production by class of wood product ty;

Winjum et al. 1998 gives annual oxidation fractions for each class of wood 

products split by forest region (boreal, temperate and tropical). This 

methodology projects these fractions over 95 years to give the additional 

proportion (OF value) that is oxidized between the 5th and 100th years 

after initial harvest:

Wood Product Class OF

Boreal Temperate Tropical

Sawnwood 0.36 0.60 0.84

Woodbase panels 0.60 0.84 0.97

Other industrial 

roundwood

0.84 0.97 0.99

Paper and paperboard 0.36 0.60 0.99

Source of data: The source of data is the published paper of Winjum et al. 19983

 

3 Winjum, J.K., Brown, S. and Schlamadinger, B. 1998. Forest harvests and wood products: sources and sinks of 

atmospheric carbon dioxide. Forest Science 44: 272-284
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Measurement 

procedures (if 

any):

Any comment: Parameter values to be updated if new empirically-based peer-reviewed 

findings become available. Every 10 years, project proponents should 

review research findings to identify further refinements to the emission 

factors that are empirically-based and peer-reviewed

Data / parameter: Pcomi

Data unit: Dimensionless

Used in equations: 1

Description: Commercial volume as a percent of total aboveground volume in stratum 

i. 

Source of data: The source of data shall be chosen with priority from higher to lower 

preference as follows:

(a) Direct forest inventory of the project area, distinguishing 

commercially viable stocks on the basis of species and tree size, 

referencing local expert knowledge or a participatory rural assessment 

(PRA) of harvest practices and markets;

(b) Forest inventory from a proxy area in the same region, representing 

the same forest type and age class, distinguishing commercially viable 

stocks on the basis of species and tree size, referencing local expert 

knowledge of harvest practices and markets National and forest typespecific or eco-region-specific (e.g. from National GHG inventory).

Measurement 

procedures (if any):

This parameter is updated at baseline renewal when aboveground 

biomass is re-inventoried as per module CP-AB (at least every 10 years).

Any comment: Updated at the time of baseline revision (at least every 10 years).

Note that application of the commercial percentage of total volume 

introduces the simplifying assumption (and conservative, as it is only 

used in the ex ante baseline calculations) that all commercial stocks are 

extracted (i.e. perfect efficiency).

Data / parameter: SLFty

Data unit: Dimensionless

Used in equations: 2,4

Description: SLF = Fraction of wood products that will be emitted to the atmosphere 
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within 5 years of production by class of wood product ty

Winjum et al. 1998 give the following proportions for wood products 

with short-term (<5 yr) uses after which they are retired and oxidized 

(applicable internationally):

Sawnwood 0.2

Woodbase panels 0.1

Other industrial roundwood 0.3

Paper and Paperboard 0.4

The methodology makes the assumption that all other classes of wood 

products, and where wood product class ty is unknown, are 100% 

oxidized within 5 years.

Therefore SLF, by wood product class, is equal to: 

Wood Product Class SLF

Sawnwood 0.2

Woodbase panels 0.1

Other industrial roundwood 0.3

Paper and paperboard 0.4

Other classes of wood 

products

1.0

Source of data: The source of data is the published paper of Winjum et al. 19984

Measurement 

procedures (if any):

Any comment: Parameter values to be updated if new empirically-based peer-reviewed 

findings become available.

Data / parameter: WWty

Data unit: dimensionless

Used in equations: 2,4

Description: WW = Fraction of extracted biomass effectively emitted to the 

atmosphere during production by class of wood product ty

Winjum et al. 1998 indicate that the proportion of extracted biomass 

 

4 Winjum, J.K., Brown, S. and Schlamadinger, B. 1998. Forest harvests and wood products: sources and sinks of 

atmospheric carbon dioxide. Forest Science 44: 272-284
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that is oxidized (burning or decaying) from the production of 

commodities to be equal to 19% for developed countries, 24% for 

developing countries. WW is therefore equal to CXB,ty multiplied by 0.19 

for developed countries and 0.24 for developing countries.

Source of data: The source of data is the published paper of Winjum et al. 19985

Measurement 

procedures (if any):

Any comment: Parameter values to be updated if new empirically-based peer-reviewed 

findings become available.

IV. DATA AND PARAMETERS MONITORED

Data / parameter: Ai

Data unit: ha

Used in equations: 3

Description: Total area of stratum i

Source of data:

Measurement 

procedures (if any):

Monitoring 

frequency:

At a minimum every time the baseline is updated (at least every 10 years) 

QA/QC procedures:

Any comment: Ex-ante it shall be assumed that strata area will remain constant

Data / parameter: Vex,i

Data unit: m

3

Used in equations: 3

Description: The volume of timber in m3extracted from within the stratum (does not 

include slash left onsite), reported by wood product class and preferably 

species.

 

5 Winjum, J.K., Brown, S. and Schlamadinger, B. 1998. Forest harvests and wood products: sources and sinks of 

atmospheric carbon dioxide. Forest Science 44: 272-284
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Source of data: Timber harvest records and/or estimates derived from field 

measurements or remote assessments with aerial photography or 

satellite imagery.

Measurement 

procedures (if any):

Monitoring 

frequency:

At a minimum every time the baseline is updated (at least every 10 years)

QA/QC procedures:

Any comment: Note that this volume does not include logging slash left onsite. Data 

compilers should also make sure that extracted volumes reported are 

gross volumes removed (i.e. reported volume does not already discount 

for estimated wood waste, as is often the practice in harvest records). 

Assignment of volume extracted to wood product class(es), must be 

substantiated on the basis of participatory rural appraisal (PRA) findings 

(also used to assess potential for degradation in module M-MON) or 

records of timber sales. Assignment of volume extracted to species, must 

be substantiated on the basis of either PRA findings, harvest records, or a 

commercial inventory.

Baseline removals will be known ex-ante. With project removals are 

classed as project emissions and where expected shall be detailed exante alongside evidence on expected harvested volumes.