True climate act: slowing down the carbon flows in forest-based bio-cycles

The average lifespan of a building is often around 50-60 years (1). However, as wooden buildings can also be in use for over 700 years, like Stålekleivloftet in Norway (2), using wood as a building material has the potential to act as a substantially long time carbon storage.

On average log trees grow in commercial Northern forests for 80 years, and for that time they sequester carbon. Once the logs are harvested, the stored carbon remains in them. The longer the wood products are being used and re-used before turning into bioenergy and biogenic CO2 at their end of life, the longer the carbon is stored (3). This means that slowing down the carbon flow plays a big role in mitigating climate change. The carbon stored in bio-based products can act as a temporary reservoir with positive climate effects (4). Simply put: we need to extend the service lifetime of wood products from sustainably managed forests and encourage to reuse of products to keep carbon stored longer.  

The carbon benefits of wood construction can also be quantified as substitution impacts. It is estimated that one tonne of carbon in wood construction products substituting a non-wood construction product on average displaces emissions of approximately 2.1 tonnes of carbon or roughly 3.9 t CO2 eq (5).

Northern solutions and cutting-edge technologies to extend the life cycle of a tree

Innovations have been developed to reuse wood products, but there is still a long way to go to re-engineer the entire life cycle of a tree. A study done at Aalto University concluded that reusing structural components of timber can result in a significant reduction of the environmental burden (6) and therefore contribute to slowing down climate change. So while traditionally wood products have been viewed only for one-time use that efficiently going to energy recovery (7), the future of reusing timber for other purposes may be much brighter, and longer, than thought.

Already taking advantage of that technology combined with high-quality material is The Nautical Coordination Centre in Amsterdam focusing on circularity and is built entirely with Kerto® LVL (8). All materials used in the building are fully circular, and sustainability and long use life are at the core of the building. The Kerto LVL elements can be reused further for other purposes as the elements can be and reused, and the entire buildings can be moved to another location if necessary. When planned ahead, using demountable construction components also enables the reuse of construction components and the reconstruction of buildings.

Dutch housing company Sustainer. home uses Kerto LVL products from Metsä Wood for their building system for modular housing using primarily wood. Their products offer design flexibility and advanced 3D models they are able to create scalable, sustainable and affordable buildings. The supporting structure in the buildings is LVL, and it offers the same performance as solid wood construction, but with the effective use of materials of traditional timber frame construction. The building modules can also be demounted and used again and again for new purposes if need be, thanks to Kerto LVL being a durable material.

Circular economy supports sustainability

Most of the wood Metsä Group uses comes from family-owned Nordic forests, and all the used wood is traceable and comes from certified or controlled forests. When buildings are built with circularity in mind, it allows the same amount of wood to serve more purposes, to truly offer more, and be in use for longer periods of time. As long as Kerto LVL product is in use, carbon stays stored. Kerto LVL stores carbon 783 kg CO2 eq/m3. Reuse and recycling ensure prolonged carbon storage. Compared to other products, Kerto LVL is efficient, as it is dense and durable, and makes for a great building material. The sustainability of Kerto LVL raw material and production is documented in Kerto LVL’s environmental product declaration(9).

Our built environment uses almost half the materials extracted globally every year and is a significant contributor to greenhouse gas emissions.  For a sustainable future we need to rethink the way we design and utilize construction materials. Metsä Wood is one of the forerunners in the field: Kerto LVL can be used in demountable construction solutions supporting circularity. Reuse slows down the carbon flows in forest-based bio-cycles and thus reinforces the positive climate impacts of wood construction.

At the end of the day, extending the life cycle of wood material is truly a climate action, as it slows down how carbon is released. The longer we can keep wood in circulation before it is used for energy, the more tools we have for combating climate change. Metsä Group is already here to offer a viable solution to extend the carbon cycle.


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    Sources of articles

    (4) Sustainable carbon cycles for a 2050 climate-neutral EU Technical AssessmentAccompanying the
    Communication from the Commission to the European Parliament and the Council Sustainable Carbon Cycles, 15.12.2021 EU Commission
    (5) (Source: Sathre R. et al (2010), Meta-analysis of greenhouse gas displacement factors of wood product substitution)