There are a multitude of different ways that wood and sustainable forestry practices can help our environment – trees soak up harmful CO2 from our atmosphere to fight climate change, forests promote biodiversity and are home to wildlife, and wood fits into a natural circular economic model as a renewable product. All these reasons are equally important and together make wood the ultimate sustainable material.
Conversation about wood, particularly its use in construction, is often centred around its ability to store carbon and reduce the embodied carbon value of a building. But wood products can also promote circularity in construction – and reducing waste and reducing carbon emissions go hand-in-hand when it comes to fighting climate change.
The Ellen McArthur Foundation says a circular economy “is underpinned by a transition to renewable energy and materials. A circular economy decouples economic activity from the consumption of finite resources. It is a resilient system that is good for business, people and the environment.”
One of the key principles of a circular economy model is to circulate products and materials. There are two fundamental cycles involved here – one is technical, which means keeping materials in use as a product for as long as possible. The second is biological – this means that when a biodegradable product is no longer used, it should be returned to the earth.
Wood fits nearly into both of the above cycles, it is an inherently circular product. Wood needs to be grown naturally and it can be easily replanted to create its material, unlike other construction materials that are often produced through the extraction of fossil fuels. As a product, it has the ability to be repaired, recycled and repurposed.
The forestry supply chain is circular too – once trees are grown and harvested to create wood products, trees are replanted in their place. Once a wood product does come to the end of its useful life, it can be returned to the earth or burned for energy, and many trees will have already been planted in its place by this stage.
The Department for Environment, Food & Rural Affairs (Defra) reported that 62% of total waste accumulated in the UK was down to construction, demolition and excavation. And the Circle Economy claims that global construction of housing and infrastructure has the largest resource footprint at 38.8 billion tonnes.
As a naturally circular product that is easily recycled, repaired and reused, timber seems like a natural solution to this problem. It is already common to see upcycled pallets used as furniture, floor boards that have been recycled from previous buildings used in new ones, and products such as chipboards are often made with recycled wood material too.
But there are industry innovators making wood go even further. They are finding solutions to making wood products last even longer and go further in their life as a useful product. We’ve highlighted some of the newest, exciting innovations currently underway.
MDF Recovery is a technology company that has designed a unique recycling technology which gives them the ability to recover high quality wood fibres from waste MDF. Historically, there has not been a viable and sustainable solution for MDF disposal, with it often being burned or thrown out at the end of its life – both resulting in carbon being released back into the atmosphere, and waste in our landfill sites.
The technology separates fibres from resin (glue) used in MDF production thereby reversing the manufacturing process. Independent studies conducted have shown that the quality of these resulting fibres are equal to that of virgin fibre equivalents. This allows the MDF manufacturing industry to access a new source of raw material, easing constraints on traditional linear supply chains, reducing waste and keeping MDF fibres embedded in products for generations to come.
The recovered fibres are also well suited to the growing natural fibre insulation market and can be used to produce high quality loose, flexible and rigid products.
It’s not just timber construction products that can be enhanced to create a more circular model. There are an estimated 250 million timber pallets in British circulation. That represents a huge amount of carbon captured. Pallets are used by a variety of different sectors including construction and retail. Every year around 18 million pallets are produced for the UK construction industry alone - but less than 10% are currently reused. This is in stark contrast to the FMCG retail sector where pallet reuse is estimated to be around 98%.
On a mission to change how UK construction uses pallets, The Pallet LOOP is a circular economy deposit-based service that supplies a range of distinctive green pallets that have been engineered to last and recovers them via a dedicated nationwide collection network. Through The Pallet LOOP, building material manufacturers pay a deposit per pallet in addition to an issue fee. As the pallets move through the supply chain, the deposit passes from manufacturer to merchant to end-user. Once materials reach their destination, the pallets are collected (from as little as 72 hours later), deposits are refunded and the team at Pallet LOOP ensures that the pallets are inspected, repaired if necessary, and then ‘looped’ back into use.
Due to be operational by the end of 2022, The Pallet LOOP has calculated that replacing 18 million single use pallets with a reusable alternative, has the potential to save the construction industry around £153 million in waste costs and 26,100 tonnes of CO2 emissions.
Commenting, Nathan Wride from The Pallet LOOP, said: "There is a growing consensus that linear ways of working are broken and that waste is a design flaw. The issue posed by pallet waste in the construction industry has proved problematic for years. Now is the time for change. We’ve created a really simple circular solution that will transform a practice that is dysfunctional and unsustainable. Eliminating avoidable pallet waste is a no-brainer for business and for the planet - and we’re having some great conversations across the sector with companies that are actively exploring how to implement The Pallet LOOP as part of their sustainability work.”
A project from Build-in-Wood has been researching how to create CLT with recycled wood products. The practical experiments used discarded slats that had been cleaned and planed before being glued into five-layered CLT prototypes. The prototypes have now been tested, showing positive results across a variety of characteristics including strength, adhesiveness and shear properties. Leader of the research group, Andreas Stenstad said that there was “no sign the wood had been used before.”
The research proves that recycled wood products are able to be used in mass timber products and systems. Historically, CLT is produced with primary virgin wood materials but this potential for using secondary recycled material allows CLT to become part of a circular economic model.
You can read more about the research here: https://www.build-in-wood.eu/post/used-wood-in-new-clt
If we want to embrace circularity in construction, it's clear that we need to start reusing more, wasting less and rethinking how we design our buildings. Wood is a great option for those looking to embrace materials made from recycled products and materials that are fundamentally cyclical.