Annex 5: Considerations for defining sustainable forestry in LCA for biogenic carbon
Per Erik Karlsson, Eskil Mattsson, Martin Erlandsson
Summary
Renewable wood from sustainable forests is carbon-neutral, and when utilised in long-lived products in buildings, it creates biogenic carbon storage. This inherent characteristic of wood as a construction material can contribute to climate mitigation efforts. These aspects are not valid for wood from non-sustainable forests. Therefore, a definition of sustainable forest is needed to be defined in the context of life cycle assessment (LCA) and Environmental Product Declarations (EPD), as the forthcoming climate declaration for all new buildings in the EU as outlined in the new Energy Performance of Building Directive (EPBD) directive.
The proposed definition of sustainable forestry to be used in LCA, EPD, etc., is here suggested to be defined following the classification of forestry as applied in international climate reporting:
Wood from sustainable forests is equal to wood from managed forests on the remaining forest land
Non-sustainable forests are equal to forests with deforestation activities
The life-cycle GWP indicator for building declaration in the EPBD may be complemented with “information on carbon removals associated with the temporary storage of carbon in or on buildings”. This information might be reported as elementary carbon, as reported in the EPD for construction products (EN 15804). Nevertheless, in the future, the recommendation is that this biogenic carbon stored in the product and the forest carbon stock changes in relation to different forest management are accounted for in the climate indicator for land-use and land-use change: GWP-luluc. The biogenic carbon stored in Harvested Wood Products (HWP) is accounted for in international climate reporting.
In brief, the suggestion is that the same climate impact in LCA, EPD, and the EPBD life-cycle GWP indicator shall, as the first choice, follow the same methodology as defined in international climate reporting. The indicator should be applied at the landscape level for the entire land of productive forests under the control of the forest owner, not for single forest stands. If this is followed for climate neutrality and carbon removal, including these methodology settings for biogenic carbon in LCA will very likely align with the upcoming EU carbon removal certification framework that will set the rules for climate mitigation actions that can be accounted for as carbon removal.
Introduction
Biobased products originating from sustainably managed forests will ideally be carbon neutral over their life cycle, compared to fossil-based carbon that contributes to an increased concentration of carbon dioxide in the atmosphere. Moreover, if biobased products are used in long-lived products, e.g. in the construction sector, it results in a temporary carbon sink. This effect is accounted for in international climate reporting as Harvest Wood Products (HWP
IPCC (2019). IPCC Guidelines for National Greenhouse Gas Inventories. Tillgänglig: https://www.ipccnggip.iges.or.jp/public/2019rf/pdf/4_Volume4/19R_V4_Ch12_HarvestedWoodProducts .pdf
In the EU, future Carbon Removal Certification
Proposal for a REGULATION OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL establishing a Union certification framework for carbon removals. Brussels, 30.11.2022 COM(2022) 672 final.
- Nature-based solutions, e.g. restoring forests, soils, and innovative farming practices
- Technology, e.g. bioenergy with carbon capture and storage, or direct air carbon capture and storage
- Long-lasting products and materials, e.g. wood-based construction
According to the upcoming climate declaration according to the EPBD directive
Council of the European Union. Brussels, 14 December 2023. Proposal for a DIRECTIVE OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL on the energy performance of buildings (recast) - Analysis of the final compromise text with a view to agreement.
Besides this sink effect, when long-lived biobased products are used in society, the forest can also, through different silviculture strategies, contribute to increased carbon storage in the forest or, in a worst-case scenario, reduced net growth and, in the long run, a decrease in the carbon stock. Therefore, accounting for biogenic carbon storage fluxes in the forests and the context of an overall assessment based on a common methodology is also essential.
Biobased products in construction offer a potentially long-term storage of carbon. However, the climate benefits of long-term carbon storage in relation to different forest use scenarios need to be clarified regarding land use and land-use change (LULUC). The potential to use different forestry management strategies for different competing combinations of goals and their effect on the forest ecosystem carbon balance should also be part of an assessment of the harvested wood if all significant aspects should be accounted for. The same applies to validating the sustainability of forestry and reducing biodiversity loss.
Sustainability impact assessments of forestry are extremely complex and may include widely different aspects, particularly regarding biodiversity issues. Discussions concerning Nordic forestry are characterised by strong polarisation and conflicts. In the forestry sector, the concept of sustainability has transitioned from a narrow emphasis on sustainable wood production to a broader assessment of climate, environmental, social, and economic sustainability across entire value chains
Karvonen, J., Halder, P., Kangas, J. et al. Indicators and tools for assessing sustainability impacts of the forest bioeconomy. For. Ecosyst. 4, 2 (2017). https://doi.org/10.1186/s40663-017-0089-8
It is evident that forestry’s impact on all aspects of sustainability will not be fully optimised. Consequently, there is a tremendous need for standardising methods and target values to assess sustainability for Nordic forestry in broad dialogue with various stakeholders at the national and international levels. Various aspects of sustainability need to be quantified, compared, and linked to the production of forest resources and their products because there are increasing demands from consumers for environmental performance disclosure for a product. In particular, there are potential conflicts between the aim to increase the carbon sequestration in Nordic forests while promoting the conditions for improved biodiversity.
Managed forests are typically assessed on the landscape scale across a mosaic of forest stands in different states of the rotation cycle and assessed as a dynamic system. Hence, forest management is based on a long-term overall strategy for all available productive forests within the property of the forest owner. Consequently, all forestry in all available productive forest lands should be assessed, not only the specific forest stands from which a specific timber originates
Eliasson, P.; Svensson, M.; Olsson, M.; Ågren, G.I. Forest carbon balances at the landscape scale investigated with the Q model and the CoupModel—Responses to intensified harvests. For. Ecol. Manag. 2013, 290, 67–78.
Cintas, O.; Berndes, G.; Cowie, A.L.; Egnell, G.; Holmstrom, H.; Ågren, G.I. The climate effect of increased forest bioenergy use in Sweden: Evaluation at different spatial and temporal scales. Wiley Interdiscip. Rev. Energy Environ. 2015, 5, 351–369.
In the context of systems analysis, a reference scenario typically aims to assess how the studied “system” influences the aspects of interest. One perspective is that sustainability indicators should help accurately assess the system’s impact over time based on the long-term goals one aims to achieve.
The overarching system analytic question asked for in a climate declaration of building is to assess the influence of selecting different technical solutions and their material choices. Thus, this kind of assessment is necessary for the building climate assessment, not covering aspects of optimal use of forestry or alternative uses of biomass.
Forestry can be associated with a wide range of sustainability aspects. On a basic level, there are important forestry-based principles, such as that the rates of harvests must not exceed the forest gross growth rates. Besides these basic principles, four important sustainability aspects of forestry may be suggested:
- Impact on biodiversity
- Impact on climate change, separated into fossil and biogenic origin
- Impact on social values, e.g. the recreational values of the forest and reindeer husbandry
- Impact on the economic values, e.g. national economic values, economic revenues for the forest owner, and job opportunities
However, several more aspects may be considered for forestry, e.g. air pollutant emissions from forestry operations, delay or reversal of recovering surface waters affected by acidification, and the discharge of nitrogen and mercury into surface waters. However, it is also important to emphasise that forestry can contribute positively to the environment, such as providing sources for clean drinking water.
Definitions of sustainable forestry
The most common system analytic tool is a life cycle assessment (LCA); the framework is described in an internationally agreed-upon and commonly used framework (ISO 14044). LCA constitutes a tool to assess ecological sustainability and other dimensions of sustainability need to be covered by other measures and assessment methods if the goal is to account for three pillars of sustainability. The result of an LCA depends on the goal, scope, and settings made by its practitioners. When LCA shall be used for quantifying ecological sustainability from a legal perspective, it is needed to set common goals and scope to match the purpose of the decision support the LCA shall be used for.
In this process, it is noticed that the development of the Environmental Product Declarations (EPD) (ISO 14025) can be reused and constitute the basis for stricter implementation of LCA, where the settings shall guarantee the same assessment result independent of the practitioner who calculates the result. This development will be part of the EU’s so-called Digital Product Passport (DPP), which, in future European legislation, will mean all products will have a climate declaration.
Introduction to EPD
In the context of reporting the environmental performance of products so-called Environmental Product Declarations (EPD) are widely used. EPDs are internationally standardised in ISO 21930 and EN 15804 and used for business-to-business and business-to-consumer communication. Compared to a traditional LCA, EPDs are divided into different information modules that can be added to a full life cycle.
In many applications, only the cradle-to-gate data (A1-3) is used from EPD in an LCA calculation; the other information modules are just illustrative examples (i.e. not representative) of what a full life cycle can look like. EPD for construction products is suggested to be mandatory for all products that fall within the forthcoming constructing product regulation (CPR) and in an LCA for new buildings, according to the new Energy Performance Declaration Directive (EPBD) to be launched in 2024. This kind of communication product is based on an attributional LCA, which theoretically allows for aggregating environmental impacts from, e.g. all new buildings based on the LCA result A1-5. The sum will be the same as in national statistics for the building sector if a life cycle approach is used in that statistic.
The current impact assessment of climate impact in EPD used for construction products and buildings (EN 15804 and ISO 15978) is not rigorously scientifically endorsed since the impact assessment of Global Warming Potential (GWP), besides characterisation factors based on radiative forcing integrated over 100 years is also complemented with a life cycle inventory flow of biogenic carbon. This GWP-biogenic indicator accounts for greenhouse gases that arise from biogenic carbon and the carbon stored in the assessed product and its packaging material. However, the general rule says such inherent properties cannot be allocated away. Thus, the ‘real GWP indicators’ are based on radiative forcing added with the biogenic carbon stored in the product and its packaging, which is reported as a negative CO2e when sequestrated through photosynthesis and then as a numerical positive emission at the end-of-life (inapproachable if combusted or recovering). This implies that the sum of biogenic carbon in the product and its packaging material shall always be zero when summed over the full life cycle. If not, an error is made in the calculation and needs to be corrected. Altogether, this means the modular approach in EN 15804 is lost, and it is no longer possible with this GWP indicator to compare the contribution to the climate impact module by module, but only if a full life cycle is considered since this biogenic carbon is then balanced out.
EN 15804
The construction industry is a forerunner, leading in publishing EPD; now, almost 20 000 EPDs are valid on the European market. The DPP for construction products will be based on the core product category rules (PCR) EN 15804, which is valid for all construction products. The PCR EN 15804 establishes rules for the direct evaluation of construction products or is a foundation for developing more intricate PCR tailored to specific product categories. Essentially, EN 15804 outlines the procedures for collecting, reporting, verifying, and presenting data for EPDs. It also incorporates the elements of an LCI: guidelines for a life cycle impact assessment (LCIA) and inventories (LCI).
Complementary PCR rules (i.e. a cPCR) for wood and wood-based products are defined in the standard (EN 16485) that complements the core PCR for all construction products and services established in EN 15804. This cPCR for wood is being revised. One important issue to be covered in this cPCR is the definition of the term ‘sustainable’ in the context of forestry. The basic idea is that renewable material from a non-sustainable forestry will be considered fossil, and the carbon emitted as carbon dioxide will to climate impact (1 kg non-sustainable CO2 = 1 kg CO2e).
The suggested standard sent for inquiry (dated June 2023) gives the following specifications on sustainable forest management under 6.3.5.1.1 and instead refers to forestry certification that must be fulfilled to be defined as sustainable; see below (EN 16485: 2023 June):
“Resulting from the fundamental principle of sustainable forest management to preserve the production function of forest[s], total forest carbon pools shall be considered stable (or increasing) under sustainable forest management. This is due to the fact that temporal decreases of forest carbon pools resulting from harvesting on one site are compensated by increases of carbon pools on the other sites, forming together, at the landscape level, the forest area under sustainable forest management.
Effects on forest carbon pools related to the extraction of slash, litter or roots shall not be attributed to the material use of wood and are, therefore, not considered in this document.
NOTE 1 In accordance with European policies, forests are understood as a natural system with multiple functions, the production function of timber being one of them. The existence of forests as natural systems is protected by European and national legislation.
NOTE 2 Harvesting operations lead to temporal decreases in forest carbon pools in the respective stand. Impacts on forest carbon pools resulting from the sustainable or unsustainable management of forests, however, cannot be defined or assessed on [the] stand level but requires the consideration of carbon pool changes on [the] landscape level, i.e. the level based on which management decisions are made.
NOTE 3 It is acknowledged that excessive extraction of slash, litter or roots for the purpose of bioenergy generation can lead to decreases in forest carbon pools. These activities, however, are not causally linked to the extraction of timber for the material use of wood.”
Also, specifications concerning the accounting of LULUC can be found in the latest standard:
“GWP-luluc is 0 for countries that have decided to account for Art. 3.4 of the Kyoto Protocol or for wood originating from forests, which are operating under established certification schemes for sustainable forest management.”
The cPCR that is in its final stage after the inquiry suggests that a sustainable forest is defined, as in international climate reporting, where each county will classify forests where the harvested wood can be classified as:
Wood from sustainable forests: managed forests on remaining forest land
Wood from non-sustainable forests: forests with deforestation activities
In this draft after the enquiry is the definition of sustainable wood:
“In order to assess whether the wood being used in the defined product system originates sustainably managed forests and/or managed forests on remaining forest land (i.e. land that is categorized as forest in line with REGULATION (EU) 2018/841 and REGULATION (EU) 2023/839) and/or IPCC (2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Chapter 4: Forest Land), two alternative verification options can be chosen:
- by checking the share of the land use category of the respective country and/or countries of origin for the raw wood material used in the construction product. The country and/or countries of origin shall be determined during the data collection as set out in 6.4.1.
- by chain of custody certification demonstrating that the used wood feedstock originates from relevant forest certification schemes for sustainable forest management, whereby the proportion of wood certified as sourced from sustainably managed and certified forests must be at least 95%.”
It is also noticed that in this version, the soil carbon is unaccounted for: “Effects on the forest carbon pools below-ground biomass (roots), litter (related to the extraction of slash) or dead wood shall not be attributed to the material use of wood and are, therefore, not considered in this document.” It should be noted that the final cPCR text is not known when this paper is published, thus describing the state of discussion.
To understand the importance of this system boundary for a tropical forest, we have calculated for the forest land GHG balance for a major pulp and paper factory in Indonesia. The factory used timber from acacia plantations on mineral and peat soils and set aside forests for conservation purposes. The calculated GHG balance describes the consequences before and after the company took responsibility for the forestry land.
The GHG emissions from plantations on peatland are very high – up to 60 t CO2e/ ha/ yr. This did not include GHG emissions from the transfer to the plantation, which involved ditching of the land, among other things. In comparison, GHG emissions from Swedish forests on drained peatland in southern Sweden can be estimated to 5–16 tonnes CO2e / ha/ yr.
One might question why LCA for harvested woods fails to consider forests’ contribution to climate change mitigation through carbon sequestration from different management intensity strategies.
FSC and PEFC
Two important systems for certifying sustainable forestry in Sweden are the Forest Stewardship Standard of Sweden (FSC) and the Programme for the Endorsement of Forest Certification (PEFC). The FSC was developed by international environmental movements while the PEFC was originally developed within the family-owned forest sector.
The FSC and PEFC focus on the performance of the forest owner and the management of the total area of productive forest.
The FSC was first published in 1998; the most recent revision was published in January 2020. Certified forest owners have their own certificate or are certified through a group entity. The whole area of the management unit, including wetlands and small water bodies, is included in the certified area. The requirements can differ depending on the size of the landholding.
The FSC has numerous overarching principles:
PRINCIPLE 1: COMPLIANCE WITH LAWS
PRINCIPLE 2: WORKERS’ RIGHTS AND EMPLOYMENT CONDITIONS
PRINCIPLE 3: INDIGENOUS PEOPLES’ RIGHTS
PRINCIPLE 4: COMMUNITY RELATIONS
PRINCIPLE 5: BENEFITS FROM THE FOREST
These principles focus mainly on social and economic values and deal with basic forestry principles, such as keeping harvest products from the management unit at or below a level that can be permanently sustained.
PRINCIPLE 6: ENVIRONMENTAL VALUES AND IMPACTS
This principle states that the forest owner shall maintain, conserve, and/or restore ecosystem services and environmental values of the management unit and shall avoid, repair, or mitigate negative environmental impacts. Examples of the most important criteria under this principle are that Woodland Key Habitats are exempt from all management activities other than the management required to maintain or promote natural biodiversity. It should be mentioned that the registration of Woodland Key Habitats by the Swedish Forest Agency is controversial and has been intensively debated and subject to legal conflicts.
Furthermore, a selection of the productive forest land area, covering a minimum of 5% of the productive forest land area, has to be set aside and exempt from measures other than management to maintain and promote natural biodiversity or biodiversity conditioned by traditional land use practices. Moreover, at least 5% of the productive forest land area has to be managed with long-term protection and enhancement of conservation and/or social values as the primary objective. Hence, the set-aside areas comprise at least 10% of the productive forest land area.
Several more restrictions apply to forest management operations, e.g. harvesting, protecting surface waters, ditching of wetlands, etc. Furthermore, the forest owner may not convert natural forests to plantations. The definition of plantations is similar to that of Norway spruce forests on former agricultural land in southern Sweden.
There are more principles, 7–10, which are not described here.
The PEFC was formed in 1998 because small-scale family forest owners, mainly in Finland, Germany, France, Norway, Austria, and Sweden, together with some industry partners, did not approve some of the criteria in the FSC. Generally, the PEFC is organised similarly to the FSC, but the PEFC has somewhat less strict regulations than the FSC. For instance, the FSC has a criterion that 10% of the forest owner’s productive forest area should be set aside for purposes other than wood production based on clear-cut forestry, while the PEFC requires only 5%.
GHG inventories
Forests play a vital role in the climate change abatement strategies. On the global scale, forests represent a sink for approximately a quarter of the total GHG emissions. Forest carbon sequestration also has a critical role in the EU climate change abatement strategies, which is expressed in the EU directive on land use, land-use change, and forestry (LULUCF) directive
EU, 2018. REGULATION (EU) 2018/841 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 30 May 2018 on the inclusion of greenhouse gas emissions and removals from land use, land-use change and forestry in the 2030 climate and energy framework, and amending Regulation (EU) No 525/2013 and Decision No 529/2013/EU.
GHG inventories generally do not include general forestry sustainability assessments. However, for reporting the LULUCF sector, the EU has stated that each country has to report a Forest Reference Level (FRL) for reporting GHG sources/sinks for the activity Managed Forests. The FRL shall be based on the continuation of sustainable forest management practices. Each member state has to submit a national forestry accounting plan that describes how the different EU countries aim to maintain sustainable forestry to mitigate climate change, represented by the FRL. Hence, the national forestry accounting plans, at least partially, describe each country’s forestry sustainability policy.
The Swedish GHG inventory for the land use sector, LULUCF, is described in Figure 1 below.
Figure 1 An illustration of the Swedish GHG inventory principles for the land use sector, LULUCF
Karlsson, P.E., Lundblad, M., Josefsson Ortiz, C., Wikberg, P.-E., Gustafsson, T. 2023. Kartläggning av inhemska biogena koldioxidutsläpp i Sverige. SMED Rapport Nr 3 2023.
The annual sink of CO2 in the Swedish land use sector was estimated to be 35 M tonne CO2e for 2019. The total annual emissions from all other sectors in Sweden in the same year were 51 M tonnes of CO2e (Naturvårdsverket, 2021). The dominant sink in the Swedish LULUCF sector was the ”forest land remaining forest land”, with the main sink in the living biomass carbon stocks. The main reason is that the total gross growth in Swedish forests consistently exceeds the total yearly removals.
Figure 2 A, Yearly balance of GHG in different parts of the Swedish forest ecosystems in Sweden, ”forest land remaining forest land”, until 2019. Negative values represent the removal of GHG from the atmosphere to the forest. Source: “National Inventory Report” (NIR), Swedish submission to the climate convention. B, Yearly gross growth (including the growth of harvested trees in the same year), yearly harvests, and yearly natural removals for the total Swedish forests 1956–2014. Formally protected forests are not included. Running 5-year mean values. Source: Skogsdata, 2018. SLU, Institutionen för skoglig resurshushållning.
Workshop
General information
In the context of WP1 in the project ‘Nordic Harmonization of Life Cycle Assessment’, an online expert consultation workshop on considerations for defining sustainable forestry was held on Thursday, January 18th, 2024. The workshop aimed to gather essential viewpoints that need to be considered in defining sustainable forestry, particularly regarding the LCA rules for biogenic carbon.
Agenda of the workshop
- Welcome, practicalities, and tour de table
- Introduction to the project
- Why and how information on sustainable forestry is needed in LCA rules for biogenic carbon
- Definition of sustainable forestry in EN15804
- Definition of sustainable forestry in FSC and PEFC certification
- Definition of sustainable forestry in GHG inventories
- Discussion with the following lead questions:
- What are the essential viewpoints in defining sustainable forestry in LCA in construction works?
- Which existing definitions of sustainable forestry are applicable/relevant for biogenic carbon LCA, and which are not?
- Should biodiversity be included in the sustainable forestry definition for biogenic carbon LCA? If yes, how?
- Should the leaching of nutrients and solid matter into water bodies be included in the sustainable forestry definition for biogenic carbon LCA? If yes, how?
- How should the biogenic carbon flows in forestry be accounted? Is (mineral and organic) soil carbon included, and how?
- What are reasonable data requirement demands for biogenic carbon LCA? What do the suggested requirements mean for the forest owners?
- Closing of the workshop.
Presentations
Janne Pesu, Finnish Environment Institute, SYKE introduced the project’s overall objective and workstreams. Pesu explained that the work supports Nordic common understanding and harmonisation of LCA data, including generic databases.
Martin Erlandsson, IVL Swedish Environmental Research Institute, continued to explain different approaches to measuring climate benefits of wood construction and why and how information on sustainable forestry is needed in LCA rules for biogenic carbon.
Questions emerged after his presentation, as there is no common understanding of how GHG inventory should be carried out in LCA regarding biogenic carbon. Also, different LCA standards provide different guidance. A key issue is how the reference land use is defined and how this relates to the question we would like to respond to, which is related to the temporal scope of the system.
Martin Erlandsson, IVL Swedish Environmental Research Institute, further elaborated on various approaches to accounting for sustainable forestry in relation to EN15804. In short, a native forest can be considered equal to fossil emissions.
In the ensuing discussion, the issue of a reference system was raised. For example, if a reference system is not applied, then the coherent application of an LCA is limited. For example, comparing wooden and non-wooden systems does not provide useful information without applying a reference system, which makes sense. A key question is for which purposes do we use an LCA based on in “absolute GHG emissions and removals”? The current praxis is too simplified, and the potential to improve it could be to include a more sophisticated approach in the new product category rules for wood-based products prEN16485.
Per Erik Karlsson, IVL Swedish Environmental Research Institute gave a presentation on the definition of sustainable forestry in FSC and PEFC certification.
In the following Q&A session, it was raised that certification is voluntary and market-based. Also, the fact that the forest sink in Finland and Sweden has decreased over the last years with regional differences due to declining growth in the forest and the high levels of logging in recent years was discussed, which have implications for baselines (there can be many). A European standard for the sustainability of construction works is proposed on how to handle mass balances and change of custody, such as mixed products (CEN/TC 350). This might also affect how forest certifications can be used in LCA assessment.
Sampo Pihlainen, Finnish Environment Institute, SYKE, presented how sustainable forestry is defined in EU Taxonomy, which is referred to in his presentation on the EU Taxonomy guide – a simple and practical guide for users; see https://ec.europa.eu/sustainable-finance-taxonomy/home. From forest management in a climate change mitigation aspect, Sampo focused his presentation on the substantial contribution criteria.
After the presentation, similarities between EU Taxonomy and the EU Carbon Removal Certification Framework (CRCF) were mentioned. It was argued that these initiatives must be coordinated in some way, as there are two criteria for the same carbon sink. EU Taxonomy has a wider scope, as the CRCF strongly focuses on carbon removal and has no effect on other environmental factors. It is debated whether one could use regional baselines, as CRCF is based on agriculture. Hence, one must model the carbon because most of the carbon is in the soil. Many are concerned about using regional baselines because there will be winners and losers. In forestry, most carbon is accumulated in the living biomass and is more straightforward to measure. In this case, sustainability must be compared to something – to the surrounding areas or the activity itself. Someone also emphasised that the taxonomy criteria are defined in political processes, not on scientific evidence.
Workshop discussion
After the presentations, the lead questions above were discussed. These discussions were categorised into the topics (sub-headings) below.
Purposes and scales
The purposes for which we use LCA results are important to consider. We should always clarify who should use these results and for what. The goal and scope are key but are overlooked in many cases. We influence carbon stocks if we use a lot of material; if we want to use biomass, we could use that to study those consequences and, in that case, monitor the consequences closely whether they are from sustainable forests (editor’s comment, see purpose with LCA here given in heading “Introduction”).
Furthermore, when using building products, there are agreed-upon limitations on what we consider sustainable forestry. We need to look holistically at raw material sustainability, and the criteria we should set are important for all segments.
Emphasis was placed on the notion that this is a challenging topic. For example, the time aspect will greatly impact the result. Forestry is planned with a time horizon of several decades, which means the assessment periods must also cover several decades. Also, the increasing/decreasing carbon stock depends on the area. Our results could differ In the landscape from those of northern and southern Sweden. Should we look at a country as a whole? Substitution affects what we think, as long-lived products today might change someday and how long they exist in the system.
Definition of sustainable forestry in relation to an LCA
The question of whether the definition of sustainable forest management (SFM) is necessary in an LCA was also posed. An LCA should support climate mitigation; in that sense, the reference situation is important. Also, one could argue that we need a definition of SFM to determine whether a building is carbon neutral if the materials were taken from sustainably managed forests. Simply, if we are considering temporary storage in a building, we should also measure its impact in the forest; however, measuring carbon in the forest (averages could be formulated) is difficult. Many uncertainties exist at the building level. Can we improve the system? For example, we must now justify renewables as they are counted as zero. Discounting ideas were suggested to be easy to grasp in relation to an LCA. Also, in principle, SFM entails harvesting less than the growth, but this cannot be sustained indefinitely and is a factor to consider. Many countries in Europe have already become saturated with living biomass.
Fairness could also be considered. How is sustainability defined? The terminology of sustainability is sometimes confusing. What implications would arise from the absence of this dichotomy between sustainable and non-sustainable? Someone argued that we should stick with carbon to avoid complexity. Other instruments and certification systems could be used to account for other environmental pressures.
Accounting for other sustainability impacts and materials
If we want to use more wood for construction, that will be a conflict with biodiversity, which we will have to deal with. Otherwise, a large part of the sustainability criteria will be lost. Sustainability implies a broader implication than just carbon. You can deal with sustainability in different ways, e.g. measuring or considering do no significant harm (DNSH) principles for example. New indicators for biodiversity are being developed but will not be included for now as input data are mainly based on land use management for agriculture. New biodiversity indicators should be tested and accounted for as they are being developed.
It was also observed that materials other than wood have an environmental impact in relation to an LCA for construction works. Forest owners and authorities should be included this discussion. The position of wood construction will change when other energy sources of hydrogen increase. Emissions from forestry biomass will be less of an issue then. The industry is looking at practical solutions. Here, more research is needed on climate’s impact on biobased products and other materials.
Another participant emphasised the importance of determining why we intend to use the methodologies. If they are for policymaking, simplification is necessary when implementing them.
Views regarding carbon measurements across scales
It was proposed that a development stock change in the forest and the building should be included in the inventory. Some say it is too complicated to measure, but have we tried calculating it this way?
One participant clarified that many desire to attribute the carbon in the forest to their credit, e.g. the landowner. One can only account for the carbon sinks once, and once one has attributed the carbon to the landowner, one cannot take these benefits into the building. In many cases, carbon removal is also attributed to an organisation, but how could it be attributed to a product? That is an open question. Once again, understanding the intended use of an LCA is crucial. Clarity regarding the context is essential to achieve the desired impact. We should also consider the risk of double accounting. When the forest owner sells his or her timber, he or she should sell a certificate of the carbon with a similar methodology for other environmental factors.
Who owns the carbon? Distributing the carbon stock change, starting with the forestry, is needed to sort out the degree of the carbon balance of a proper system there, continuing with the storage downstream of the value chain. If one has a net growth, some of the carbon can stay within the forest domain and have a certain value. If it continues to be a product, it has a certain market value that needs to be calculated in an LCA. If an LCA reveals a carbon sink element in the building’s construction, safer storage could be outside the forest. Results can be used to develop a product’s value chain without a carbon footprint. This should also connect to the EU carbon removal certification framework (CRCF) process. These processes could help each other.
Suggestion for a new method
Forestry assessment in an EPD as an additional indicator
Assessing the degree of sustainable forest is needed when only a climate declaration is requested. Traditionally, an LCA accounts for ecological sustainability but not a social or economic assessment. Moreover, a current LCA does not cover all impact categories or include biodiversity. EPD can include other information not based on an LCA to handle the other dimensions of sustainability as a complement to the LCA result. No system analytics-based indicator quantitatively established accounts for all dimensions of sustainability. In the climate declaration of buildings, the primary focus naturally revolves around the GWP indicator. The fact is that decision support for climate mitigation is the most important aspect to account for and address in a climate declaration for forestry and wood-based products.
Climate neutrality is not the same as carbon neutrality since forestry can affect the climate in several ways besides impacting the carbon balance. Such impacts involve, in particular, the forest balance of other important greenhouse gases, e.g. methane and N2O. In addition, the emission of organic compounds from the forest may induce the formation of particles in the atmosphere, which has important climate impacts.
There is a data gap in the current LCA methodology described above. An alternative approach is described here and its first development step. This approach is basically the same as described in Karlsson et al. (2023)
Karlsson P E, Erlandsson M, Mattsson E, Nilsson Å :Klimatpåverkan från skogsbruk inom Sveaskogs produktiva skogsmark. Biogen och fossil påverkan (komplement). IVL Svenska Miljöinsitutet på uppdrag av Mistra Digital Forest, IVL rapport C 741, Jan 2023.
A basic starting point to assess an individual forestry owner position(s) and its management is to consider the yearly net balance of harvested wood, gross forest growth, and soil carbon change. If this ratio is calculated, a figure equal to 1 means forestry management where there is a carbon balance, if larger than 1, an increase in bio stock, and the reverse if less than 1; see Figure 3 to get an illustrative example of what it could look like on a landscape level.
Figure 3 Harvested volume and mortality divided by data from the National Forest Assessment. Götaland and Svealand account for two-thirds of the entire annual felling in Sweden.
(Ref: /www.aftonbladet.se/debatt/a/gEMxO5/forskare-avverkning-och-skogsdod-ar-storre-an-tillvaxten)
(Ref: /www.aftonbladet.se/debatt/a/gEMxO5/forskare-avverkning-och-skogsdod-ar-storre-an-tillvaxten)
This approach can be directly adopted in LCA and EPD, where the biogenic carbon stock loss of 10% results in a GWP-luluc of 0.1 kg CO2e per kg biogenic carbon stored in the harvested wood. An extreme is a native forest that is the final cut, where the GWP-luluc will then be 1 kg CO2e per kg biogenic carbon stored in the harvested wood. In a well-managed forest, the reverse will be the case with a net increase in the forest ecosystem carbon stocks, and the GWP-luluc will result in a numerical negative number, which, in this context, shall be evaluated as a positive climate aspect and increased net carbon storage.
Since the evaluation is made yearly, the running balance is always correct from a bookkeeping perspective. A purchaser of wood can compensate for wood from non-balanced forestry with forestry with a surplus. In the long run, a relationship between the yearly carbon stock attributed to the harvested wood and the CE certification scheme is needed. Since this system is not in force, we can start using such indicator as it is and then make the needed additions and adoptions when the EC certification system is launched. Note that the system is operational for a large forestry owner or when different smaller forestry owners cooperate and can be assessed as a group. The approach described here must be further elaborated on if it is valid for small forestry owners or alternatively, the regional figures that are ready to use for small forestry owners.
Figure 4 Conceptual illustration of all parts of the expanded GWP indicators suggested here exemplified for planed boards, divided in fossil, biogenic excluding stored in the product, HWP and luluc for sawn boards
The GWP-fossil in Figure 4 represents 1 m3 planed boards that are about 35 kg CO2e/m3. The GWP indicators suggested here are based on EN 15804, with the difference being that if biogenic carbon stored in the product is from a sustainable forest, GWP-biogenic is directly balanced out (set to zero), and the emissions of methane, etc., from the manufacturing of the planed wood is the only GHG accounted for. HWP follows the approach of calculating HWP as used in LFM30 (Erlandsson, 2020), where 1 kg of biogenic CO2 stored equals 0.5 kg CO2e. The indicator results for GWP luluc is not set to zero as in EN 15805 but is divided into two components:
- net biogenic carbon balance valid for the year the wood was harvested
- other luluc emission, e.g. from soil carbon
If the biogenic carbon in the wood does not originate from sustainable forests, pEN 16485 suggests that this carbon, when emitted, will be accounted for in GWP-biogenic calculation (and 1 kg CO2 emitted is then equal to 1 kg CO2e).