CEI-Bois
Biogenic carbon in life cycle assessment and environmental product
declarations
1. Climate change is happening now
During the thirty years between 1983 and 2012 we had the warmest period since 1400 years on Earth.
At least 60% of climate change can be attributed to CO2 emissions resulting from human activities mostly the burning of fossil fuels. Buildings are responsible for about 40% of energy consumption and
36% of EU CO₂ emissions1.
Around 85% of the energy necessary to run our societies comes from fossil fuels. A reduction in
emissions of this order would involve politically unacceptable cuts in our energy consumption. In short,
the efforts necessary to stabilize the concentrations of greenhouse gases are not consistent with our
current vision of development based on a steady increase in global consumption.
There are two ways to reduce CO2 in the atmosphere: either by reducing emissions, or by removing CO2
and storing it. The latter one leads to ‘carbon sinks’. Wood has the unique ability to do both.
2. Reducing emissions of carbon dioxide
2.1 Substitution of other materials
There is no other commonly used building material that requires so little energy to produce as wood.
Thanks to photosynthesis, with the energy of sunlight trees are able to capture CO 2 in the air and to
combine it - with the water they get from the soil - to the organic material, wood2. In most cases the
necessary energy for processing and transporting wood is less than the energy stored by photosynthesis
in the wood.
The production and processing of wood is highly energy-efficient, giving wood products an ultra-low
carbon footprint. Therefore wood can often be used to substitute for more energy intensive materials
like steel, aluminium, concrete or plastics. Every cubic metre of wood used as a substitute for other
building materials reduces CO2 emissions to the atmosphere by an average of 1 to 2.5 t CO23. In addition,
roughly 0.9 t of CO2 are stored in every cubic metre wood and temporarily removed from atmosphere.
Using wood also helps to save energy over the life of a building, as its cellular structure provides
outstanding thermal insulation.
Wood also leads to an energy substitution (scrap wood instead of fossil fuels): When wood cannot be reused or recycled, it can still produce energy through combustion. The energy gained this way is nothing
else than the use of stored solar energy. The amount of CO2 emitted from combustion is no more than
the amount previously stored. Burning wood is therefore carbon neutral. Wood industries are well
1
COM(2007) 860 final
This process of photosynthesis also produces oxygen; all the oxygen we breathe and on which all animal life relies on comes
from the photosynthesis activity of plants and trees.
3
Sathre & O‘Connor (2008), Werner & Richter (2007), Albrecht et al. (2009), Lundmark et al. (2014), Bafu (2007)
2
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aware of this beneficial property of wood: Up to 75% of the energy used to process wood derives from
wood by-products from the manufacturing process4.
3. Increasing carbon sinks
3.1 The carbon cycle
Carbon is present in our environment in a variety of different carbon reservoirs: dissolved in our oceans;
in the biomass of plants or animals, in the atmosphere (mostly as CO2), and in rocks such as limestone
and coal. This carbon is being exchanged continuously between the different carbon pools in a process
called the ‘Carbon Cycle’.
The imbalance between current CO2 emissions from the combustion of fossil fuels and the required
reductions from a climate perspective is so acute that it will not be enough simply to reduce CO2
emissions. Carbon sinks will also have to be increased. One of the simplest ways to increase carbon sinks
is to increase the use of wood.
3.2 Forests as a carbon sink
Thanks to photosynthesis, the trees in a forest can trap large amounts of CO2 and store it as wood. Some
0.9 t CO2 is trapped in every cubic metre of wood. Sustainably managed forests in combination with the
harvested wood products as carbon stores are more efficient carbon sinks than forests which are usually
left in a natural unmanaged state. Because younger trees, in vigorous growth, absorb more CO 2 than
mature trees, which will eventually die and rot, returning their store of CO2 to the atmosphere, while
most of the CO2 of the trees harvested from a managed forest continues to be stored throughout the
life of the resulting wood product.
3.3 Wood products as a carbon store
Wood products are carbon stores, rather than carbon sinks, as they do not themselves capture CO 2 from
the atmosphere. But they play an important role in enhancing the effectiveness of the forest sinks, both
by extending the period that the CO2 captured by the forests is kept out of the atmosphere and by
encouraging increased forest growth.5
According to recent estimates, the average life of wood products varies between 2 months for
newspapers and 75 years for structural wood. The longer, the better for the environment, not least
because it makes better use of forest resources. So increasing the use of wood from sustainable sources
is one simple way of reducing climate change.
4. The role of wood products in supporting forest
Contrary to the commonly held belief that there is a direct causal link between using wood and the
destruction of forests, increasing the use of wood makes a positive contribution to maintaining and
4
nd
CEI-Bois (2011): Tackle climate change, use wood. 2 edition, CEI-Bois (Ed.), Brussels.
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It is tempting to add the substitution and the sink effects (the 1.0 to 2.5 tons CO₂ for the substitution of another material with
the sink of 0.9 ton CO₂) captured by wood. This is not recommended and could be misleading as the substitution is permanent
compared to the sink effect that is temporary.
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increasing forests. It is important, however, to make a distinction between tropical or sub-tropical
forests and temperate forests.
In the former, forest cover is indeed being reduced, for a number of reasons predominantly linked to
population growth, poverty and institutional weaknesses. In most of the cases where there is good
management, an increased wood use is not a direct contributory factor to deforestation. On the
contrary, a sustainable forest management and wood use creates a market value for the forests which is
a powerful incentive for local communities to conserve them.6
In all European regions, forest area has increased since 1990. Europe is the only region to have a positive
net change in forest area for the past 20 years7. Europe has gained 5.1 million ha of forest and other
forest land since 2005 and 16.69 million ha since 1990. The total standing volume in Europe in 2010
amounted to 96 252 million cubic meters of which 21 750 million cubic metres in EU 27 countries. The
net annual increment of EU 27 is estimated at 620 million cubic metres. In practice, however, just 64 %
of the net annual increment is harvested.8
The European forest-based sector is well aware that its own future is linked to the future of its forests.
This, together with regulations requiring the reforestation of harvested trees and the development of
certification schemes, gives the stability needed in order for the forests to continue to thrive.
5. CO2-Neutrality and the consideration of wood in international climate policy
Within the framework of the UN climate convention on climate change (UNFCCC) all annex-I countries
(basically all western industrialized countries) have committed to report and publish their humaninduced emissions of greenhouse gases on an annual basis in National Inventory Reports: this includes,
their removals of greenhouse gases by managed sinks (the absorption of atmospheric CO 2 during the
growth of living biomass).
For the purpose of reporting, all emissions (and removals) are grouped into six source groups. For
instance, all emissions related to the generation of energy are inventoried in source group 1. On the
other hand, emissions and removals from forests are inventoried in source group 5 – land use, land use
change and forestry (LULUCF).
The mandatory inventorying rules of the UN climate convention on climate change did not take into
account the delayed emissions from carbon storage in wood products. As a simplification, it was
assumed that the carbon pool in harvested wood products did not change significantly over time and
that therefore the inputs of wood (and stored carbon) did balance the outputs of wood (and stored
carbon). As a consequence no net sink or source effects did occur from the carbon pool of harvested
wood products.
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By the countries concerned conserving tropical forests is more often considered as an obstacle to their own development than
an ecological necessity. In providing energy, arable or pasture land, or simply more space, deforestation is frequently seen as a
solution rather than a problem. The saying that ‘a forest that pays is a forest that stays’ may be a simplification, but it illustrates
a simple truth: a forest’s survival depends, broadly speaking, on its economic value. Developing a market for wood helps
owners and governments to see forests in a different way and to recognize their contribution to local and national economies.
As soon as the prosperity of a local community is seen to be associated with the presence of a forest, the principles of
sustainable management begin to be respected.
7
Asia, which had a net loss of forest in the 1990s, reported a net gain of forest of more than 2.2 million hectares per year in
the period 2000-2010, primarily due to the large-scale afforestation reported by China (FAO 2010)
8 MCPFE, 2011
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In this regard, it was assumed that the CO2 balance of the sector ended after wood harvesting. As the
carbon emissions in the forest from harvesting were inventoried implicitly under the LULUCF source
group already, they could not be inventoried again in the energy source group when using wood as an
energy source, as this would have led to double counting of emissions. Therefore, the use of wood as an
energy source was considered as “carbon neutral”. This, however, is only true, if the carbon balance of
the forest where the wood originates from is in equilibrium at the least. If wood is sourced from
countries where the forest carbon inventory is decreasing or from countries that do not report their
national inventories in the context of the UNFCCC, carbon neutrality of wood cannot a priori be
assumed.
Additionally to the annual reporting under the UN climate convention on climate change some countries
had committed in the Kyoto Protocol to reduce their greenhouse gas emissions within the so-called first
commitment period (2008 – 2012, compared to a base year of 1990). For the forestry sector, according
to Art. 3.3 of the Protocol, all greenhouse gas emissions that related to land use change – notably
afforestation, reforestation and deforestation – had to be reported on a mandatory basis. Furthermore,
Art. 3.4 of the Protocol provided the option to report the net emissions/removals of “forest
management” activities on a voluntary basis. The intention of this rule was to incentivise the reduction
of greenhouse gas emissions from forest management.
At the 2012 Durban Conference of the Parties (COP 17) it was agreed that the Kyoto Protocol should be
extended. At the same time some rules were revised and amended with regard to the inventorying and
accounting in the forestry and wood sectors. Specifically of relevance to this paper, the reporting and
accounting of forest management became mandatory and the temporary dynamic and related changes
in the carbon pool of harvested wood products will now be explicitly taken into account.
The carbon pool of harvested wood products is defined as contributions from the use of sawn timber,
wood-based panels and paper. Wood used in the construction sector - one of the most important
consumers of wood and wood-based products - is thereby included. Apart from a more realistic
consideration of the carbon flows related to the use of wood, it also reinforces the use of wood in long
lasting wood products in the construction sector and incentivises the positive substitution effects
related to the use of wood in national climate policies.
Furthermore, because of the carbon neutrality assumption explained above only wood that originates
from domestic forests, where the carbon balance is inventoried can be accounted for as a contributor
to the carbon pool of harvested wood products. Consequently, wood stemming from deforestation is
excluded from the accounting.
These accounting rules agreed in Durban have been recognised and given a legal framework in Decision
No. 529/2013/ of the European Parliament and Council.
6. The quantification of the contribution of wood products to the mitigation of climate change
Life cycle assessment (LCA) is a well established method for the quantification of environmental impacts
of a product. LCAs allow a way to compare the environmental effects between different products. Such
information is key to integrate the beneficial climate effects of wood into the context of decision
making.
LCA assesses the environmental impacts of a building component right the way through its life. It is
becoming increasingly important as more and more specifiers are considering (mandatory and
voluntarily) the environmental impacts of the products and materials they select. The process takes into
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account where the material comes from, how it is used or converted into a product and its use in a
building, right through to its disposal or re-use/recycling.
The factually correct consideration of the complex carbon flows related to growth processes, forestry
operations, production of wood products, temporary carbon storage in wood products as well as end of
life options are key for an unbiased and appropriate quantification of the environmental profile of wood
products, particularly their Global Warming Potential (GWP). Several initiatives are currently trying to
define rules on how biogenic carbon flows should be considered in life cycle assessment and carbon foot
printing. Such initiatives include standardisation initiatives including:
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CEN TC 175, specifying the product category rules EN 15804 for wood products in the context of
the elaboration of environmental product declarations (EPDs);
CEN TC 411, specifying rules for LCA of bio-based materials;
ISO TC 207 to elaborate rules for the quantification of a carbon footprinting of products;
European Commission, specifying rules for the “environmental footprint” of products.
The following principles should followed in all these initiatives in order to avoid methodological
differences in depicting biogenic carbon flows related to wood products:

Environmental impacts of the management of a renewable resource can only be assessed on
the level, where management decisions are taken in order to reflect whether a renewable
resource is not exploited at a higher rate than its recovery rate as the basic principle for the
sustainable management of a renewable resource; in the case of forestry, impacts on forest
carbon pools have to be considered on landscape level, i.e. on the level of a forestry unit9 or at
higher scales, for example on regional or country level. Only at this level, can it be assessed
whether a forest is managed in a sustainable manner (implying as one of the core concepts of
sustainable forest management a constant (or increasing) commercial volume and hence
indirectly creating stable or increasing carbon pools.
In recent years several research initiatives have proposed assessments on a per hectare or even
on a per tree basis, linking temporal decreases in forest carbon pools to natural re-absorption
processes in vegetation or in oceans. Other sources have linked the life time of wood products
to the rotation period, claiming an over-exploitation of forests. Such approaches come to
misleading conclusions as they ignore the fact that, while forest carbon pools are decreased due
to harvesting operations (or other forest management operations such as thinning), forest
carbon pools under the same management regime are growing in other areas of the forest,
compensating for these losses. To a large extent it is the relationship between the amount of
wood extracted compared to the growing volume, which determines whether carbon pools
have decreased due to harvesting.
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Impacts on forest carbon pools, e.g. related to deforestation shall be calculated in addition to
the consideration of the effect of carbon storage and emissions of biogenic carbon related to
wood products. Only in this way can a transparent and comprehensive quantification of the
GWP be undertaken for wood products, allowing the conceptual linkage to the national
reporting and accounting framework of the UNFCCC.
Or as the combination of several (small) forestry units which generate a regular annual wood flow from a forest area that is
managed sustainably.
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To both reflect the storage of biogenic carbon and to counter-balance emissions of biogenic
carbon within a product system for wood products under study, biogenic carbon shall be treated
as a material inherent property of wood. The amount of carbon stored in wood entering a
product system from nature shall be characterised in the quantification of the GWP as an input
of stored biogenic carbon in CO2-equivalent, counter-balancing biogenic carbon emissions
within the product system under study. The characterisation factor to be applied on the
biogenic carbon stored in wood depends on whether wood is coming from sustainably managed
forests or not (see below). In analogy, wood flows leaving a product system as a co-product or
as a material for recycling or energy recovery will be characterised in the quantification of the
GWP as an output of stored biogenic carbon.
These considerations are particularly relevant for product life cycles that are divided into several
modules and where wood is entering or leaving other product systems.
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When assessing the impact of forest management on forest carbon pools, all five forest carbon
pools – above-ground biomass, below-ground biomass, litter, dead wood and soil organic
carbon shall be considered. It is not appropriate to concentrate on selected carbon pools as
carbon stocks in forest carbon pools are interdependent.
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In the case of wood sourced from sustainable forestry, it can be assumed that forest carbon
pools are stable or increasing. It can even be assumed that temporally decreasing forest carbon
pools in forests under sustainable forest management are due to natural adjustments (e.g. the
age structure of forests or larger decreases due to natural occurrences such as large-scale
windfall resulting from storm events or forest plagues in over-aged forests with inappropriate
age structure). Generally speaking temporary impacts on carbon pools from wood from
sustainably managed forests are counter-balanced by re-growth and therefore need not be
taken into account in LCA.
For the characterisation of biogenic carbon stored in wood that enters a product system from
nature, this implies a negative GWP for the carbon stored in wood, expressed in CO2-equivalent.
This ensures carbon neutrality of wood over its life cycle if sourced from sustainably managed
forests.
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In the context of LCA, simple robust indicators need to indicate to a LCA practitioner, whether
wood is sourced from sustainable sources. While there exist no direct indicators, proxy
indicators serve to identify wood from sustainably managed sources while maintaining the
environmental integrity of the assessment, including:
a.
b.
wood from forests managed to the requirements of schemes such as FSC or PEFC,
preferably with a chain of custody certificate to ensure that wood originates from a
sustainably managed forest;
wood from countries that have committed to report impacts of forest management on
forest carbon pools according to Article 3.4 of the Kyoto protocol. Under such
circumstances it can be assumed that the wood originates from forests with increasing
forest carbon pools because profiting from increasing forest carbon pools for the national
accounting was the key driver for the commitment of such countries. In such cases where
there are decreasing forest carbon pools, environmental integrity would be maintained as
carbon losses from forestry would need to be compensated by respective offsetting
measures. Currently, the forest carbon pools in all major European countries are increasing.
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Unsustainable forest management practices can lead to decreases in forest carbon pools due to
degradation processes or deforestation. Whenever possible, the decreases in forest carbon
pools resulting from unsustainable forest management practices shall be attributed to the
causal drivers of the respective processes. Under such conditions, carbon-neutrality of wood
cannot be assumed and a neutral GWP for the carbon input stored in wood, expressed in CO 2equivalent shall be assumed. This ensures that wood from unsustainable forest management is
not considered carbon neutral, while the attribution of decreases in forest carbon pools due to
forest degradation or deforestation shall be calculated avoiding double-counting, taking into
account the characterisation of the carbon stored in wood as outlined above.

The consideration of the effect of temporal carbon storage in wood products in established
carbon foot printing schemes is encouraged.
7. Summary of CEI-Bois position on Biogenic Carbon

Climate change requires urgent actions to avoid socially undesired consequences. Solely relying
on the reduction of CO2 emissions from the combustion of fossil fuels would be politically
unacceptable. Climate Change therefore must be tackled through multi solutions in multiple
sectors including carbon sequestration and storage. The forestry & timber industry already
naturally does this and therefore, using wood is one of the most efficient ways to tackle climate
change.
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Wood has the unique ability to both reduce the production of CO2 emissions (by replacing fossil
fuels that create CO2) and remove it from the atmosphere through carbon sinks. Once removed,
wood in use is also an efficient carbon store.

All the oxygen we breathe and on which all animal life relies comes from the photosynthesis
activity of plants and trees. So, from every molecule of CO2, photosynthesis produces two key
components essential to life: carbon, around which all living materials are built and oxygen on
which all animal life relies.

Every cubic metre of wood used as a substitute for other building materials reduces CO 2
emissions to the atmosphere by an average of 1 to 2.5 t CO2.

During the whole life of a wood product, 0.9 t CO2 per cubic metre of wood are taken from the
atmosphere and stored in wood.
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The woodworking industry uses up to 75% of the energy to process wood from wood byproducts.
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Additionally at the end of its productive life, wood can substitute the use of fossil fuels as a
source for energy.

Contrary to the commonly held belief that there is a direct causal link between using wood and
the destruction of forests, increasing the use of wood makes a positive contribution to
maintaining and increasing forests.
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Given all of the above facts and statements, the production and use of durable wood products
and the substitution of energy intensive materials with wood products provides the greatest
potential to make the required CO2 reductions to avoid the worst impacts of climate change.
References:
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Hellwig (2009): ÖkoPot - Ökologische Potenziale durch Holznutzung gezielt fördern. Abschlussbericht zum BMBF-Projekt
FKZ 0330545. Universität Stuttgart, Universität Hamburg, Hamburg.
BAFU (2007): CO2 Effects of the Swiss Forestry and Timber Industry. Environmental Studies No 0739, Federal Office for the
Environment (BAFU), Bern.
FAO (2010): Global Forest Resources, Assessment 2010, main report. FAO Forestry Paper 163. Food and Agriculture
Organization of the United States, Rome.
Lundmark, T., J. Bergh, P. Hofer, A. Nordin, B. C. Poudel, R. Taverna, F. Werner and R. Sathre (2014): Potential Roles of Swedish
Forestry in the context of Climate Change Mitigation. Forests(5): 557-578.
MCPFE (2011 : ‘State of Europe’s Forest 2011 – Status & Trends in Sustainable Forest Management in Europe’, Forest Europe Liaison Unit Oslo, Oslo, 2011
)
Sathre, R. and C. O'Connor (2008): A Synthesis of Research on Wood Products & Greenhouse Gas Impacts. Technical Report No.
TR-19, B.C. FPInnovations – Forintek Division, Vancouver.
Werner, F. and K. Richter (2007): Wooden building products in comparative LCA; a literature review. International Journal for
Life Cycle Assessment, 12(7): 470-479.