Going circular to close the materials loop

19 March 2019

To ensure timber supply can meet growing consumption without depleting the forest resource, the sector needs to develop new approaches on reuse and recovery says Dan Ridley-Ellis, head of the Centre for Wood Science and Technology at Edinburgh Napier University

There’s little doubt that wood will increase in importance as population growth and increasing standards of living put ever greater demands on raw materials globally. Forests are not the only source of renewable, sustainable, materials but they are the one with the greatest potential to deliver the volumes we need for a future, less fossil-dependent, more biologically based economy.

But, of course, renewable and sustainable are not the same as unlimited, and so we really ought to think more strategically about how we make use of what we have. We can happily declare that everything we get from a barrel of oil we can get from wood, but we must keep in mind that the world currently uses a larger volume of oil than it produces of harvested roundwood, even when including wood used for fuel.

The timber construction sector is growing, and innovative, with new methods of building and new engineered wood products, composites and treatments.

Large volumes of wood are going into buildings and the quantity used is frequently seen as a virtue – as sequestered carbon. Given that wood is limited in supply – especially that of the species and quality used in such buildings – we should pause to consider whether it’s not better to use the same amount of wood to do more. We should, at least, be giving serious thought to the end-of- life of these buildings so that these large volumes of wood can be used for something else.

For this reason, Edinburgh Napier University is soon to partner on an ambitious European collaborative project under the Forest Value funding scheme. The “InFutUReWood”project (Innovative Design For the Future – Use and Reuse of Wood) asks the question “How should we build today to be able to circulate tomorrow?”

Where we cannot find solutions, we aim to at least avoid creating future problems.

To answer this, we need to know how we should design timber buildings, and wood-based construction products, from the perspective of reuse and recoverability.

Crucially, to better understand how design and construction impact on material reuse and recirculation, we need to know how choices made in the past are affecting current practice in renovation and demolition.

This will inform us about what problems are likely with current methods of building. By closing this knowledge loop, we aim to better close the materials loop.

We will also look at the potential for reuse of current reclaimed wood, and other timber not presently entering the circular economy, in new construction. We will also address the need to be more efficient about use of the forest resource, bringing a wider range of virgin wood into the value chain. Edinburgh Napier will lead the work to assess how to grade this timber, without expensive testing programmes. And while our supply chains and processing paths will remain largely dependent on a small number of commercial species, we still need to adapt to a changing timber supply. Because wood properties are heavily influenced by forest management and climate, even familiar species, like spruce and pine, are going to be different in future.

Dan Ridley-Ellis