Timber Structures

New research calls for cross-sectoral coordination to maximize net zero benefits of wood recycling

Whilst less than 1% of waste wood goes to landfill in the UK, a new study published in Nature Communications proposes further efficiencies. A team of researchers from Bangor University, the University of Galway in Ireland and Woodknowledge Wales, analysed the whole life cycle of the current timber value chain. They believe collaboration and system change is needed to achieve even longer sequestration of the carbon locked within timber already in use within the supply chain.

The full paper, Circular wood use can accelerate global decarbonisation but requires cross-sectoral coordination [1], was written by Eilidh Forster, John Healey, Gary Newman and David Styles. It was published online by Nature Communications on 25 October 2023 and is open access. The original press release can be read via Bangor University’s news page. [2]

“The UK is currently able to produce only a fraction of the wood it requires yet recovered wood ‘waste’ is an under-valued resource. Improved transparency, reporting and management of recovered wood could create a multitude of circular business opportunities.” Eilidh Forster, lead author and PhD researcher, Bangor University

Enhancing the benefits of timber towards net zero

Wood harvested from sustainably managed forests is an important source of renewable biomaterial and global demand for wood is forecast to increase by up to 170% by 2050. In 2022, UK timber imports cost £11.5 billion.

Carbon captured during tree growth is retained in wood from harvested trees. The manufacture of timber products already tends to minimise greenhouse gas emissions relative to the manufacture of materials such as concrete and steel. Additionally, timber products are excellent carbon stores throughout the full life cycle of those products.

The benefits of timber towards net zero can be enhanced further by applying the principles of the circular economy. By identifying new ways to use, then reuse timber, before reusing that wood again – perhaps in the form of chipboard or wood fibre – there is huge potential to extend the service life of wood. By doing so, that captured atmospheric carbon is stored within that wood. Additionally, reusing wood in this ‘cascading’ manner (a concept introduced and explained in detail in Forster et al’s first paper [3]) brings down the demand for fresh supplies. As a result, there are also increased net carbon sequestration gains from reduced harvesting of virgin wood and reduced transport costs for timber imports.

A circular or cascading wood flow as shown in the reproduced Figure above, delivers multiplied efficiencies in the journey to net zero. The report presents results that indicate a circular approach to recycling medium-density fibreboard (MDF) in the UK alone could deliver ‘75% more cumulative climate-change mitigation by 2050’ when compared with the current, ‘business-as-usual’ single-use approach. In combination with the complementary, if slower, long-term benefits of planting new forests for wood production, the cumulative effects of these two approaches alone could mitigate 258.8 million tonnes of carbon dioxide equivalent (CO2e) emissions. Which equals 61% of the total of net territorial emissions of the UK in the single year of 2021.

“Planting new production forests to meet future wood demand is a very important priority for achieving net zero, however it will take several decades for this benefit to be realised, and we can’t afford to wait that long to reduce the current rate of global warming. Therefore, we also need to act urgently to increase the efficiency with which we reuse current wood products to reduce the pressure that we are placing on global forests to meet our needs.” John Healey, study co-author and Professor of Forest Sciences, Bangor University

System change needed to maximise potential benefits of timber

The new research highlights that, while there are many potential benefits for net zero to be leveraged further, the current UK timber manufacturing system incorporates significant barriers that will first need to be overcome. The aims of the paper were to highlight these barriers and propose solutions that might enable maximum efficiency towards net zero across the timber value chain.

The researchers cite uncertainty of land-use subsidies, poor transparency of material flow through the value chain, and a lack of agreed circularity metrics among other barriers. They also note that low public awareness means the industry isn’t under social pressure and that this, in turn, has enabled conservatism towards change. To resolve these issues, the authors recommend industry collaboration towards cross-sector co-ordination, government intervention on matters such as compulsory deconstruction planning requirements for the built environment, and extended responsibility from manufacturers across the entire life cycle of their products.

“To substantially increase the efficiency of the whole system will require some significant changes in the wood using industries in UK, backed-up by better-targeted government policies, to substantially improve their co-ordination from afforestation to better wood recovery and reuse.” David Styles, study co-author and Associate Professor in Agri-sustainability, University of Galway.

Use, reuse, and reuse again before end-of-life biomass

Currently, a huge proportion of our out-of-service timber products are burnt as biomass to generate heat or electricity. The research team point out that there is opportunity to re-use or recycle these products several times prior to what should be perceived only as a final, end-of-life use as biomass.

There are already several pioneering projects here in Wales that do employ circular thinking to timber reuse with great success. Particleboard manufacturers are increasing their use of recycled wood chips and innovative methods are being used to recover wood fibres from MDF board recovered from residential demolition. Recovered wood fibres can then be used as insulation, locking in the carbon for many more tens of years again within new build homes. If installed with recovery in mind, this same insulation might then be recoverable for further use in the next generation of new builds. This circular thinking can extend the use of the original harvested tree for hundreds more years.

“Moving to a circular economy is difficult but essential if we are to meet both our decarbonisation targets as well as our future resource needs. This paper shows the size of the win and makes practical suggestions for how we might get there. Woodknowledge Wales is an experiment in the kind of cross-sector coordination advocated by this research.” Gary Newman, study co-author and Chief Executive of Woodknowledge Wales.

References

1: Forster, E. J., Healey, J. R., Dymond, C. & Styles, D. , Circular wood use can accelerate global decarbonisation but requires cross-sectoral coordination. Nature Communications, 14:6766, (2023) DOI 10.1038/s41467-023-42499-6

2: Recycling used wood can make a big contribution to net zero but it needs much better coordination, Press Release, https://www.bangor.ac.uk/news/ [Accessed 26 October 2023]

3: Forster, E. J., Healey, J. R., Dymond, C. & Styles, D. Commercial afforestation can deliver effective climate change mitigation under multiple decarbonisation pathways. Nature Communications, 12:3831 (2021) DOI 10.1038/s41467-021-24084-x

Further reading

• W Howard and MDF Recovery agree UK and Ireland licensing deal
• Kronospan: Making circularity a reality