Demand for timber across the world is rising, not least because so many economies see the deployment of timber as a vital weapon in the battle to reach net zero – and new uses for timber are only accelerating that growth. In fact, asset manager Gresham House, which specialises in forestry investment, forecasts that global timber consumption will rise by 170% over the next 30 years.
Last year in the UK, demand for hardwoods rose by 26%, softwoods by 21% and plywood by 13% compared to 2020, according to Timber Development UK. Meanwhile, the Timber Trade Federation reported that a record 11.7 million m3 of timber was imported into the UK in 2021.
This is reflective of the changing and evolving attitudes of not only architects, developers and contractors but also building users who want to live and work in more environmentally-friendly spaces.
What is sustainable forestry?
To meet this growing demand for timber, we need to grow more trees. But forestry is often confused with deforestation, which, understandably, comes under much scrutiny for its negative effects on the environment. However, sustainable forestry is, in fact, a way of growing, felling and replenishing trees to create an ongoing supply of timber that can be used in construction while simultaneously protecting the environment. Sustainable forestry seeks to provide a balance between environmental, economic and social benefits.
Moreover, timber production is just one of the benefits that UK woodlands provide to local communities and businesses. They also provide a home for a range of outdoor sports and activities, community and educational facilities, flood protection, conservation and woodland and connected rural businesses.
Certified best practice
There are two main global certification schemes for sustainable forests: the FSC (Forest Stewardship Council) and the PEFC (Programme for the Endorsement of Forest Certification), which were set up in 1993 and 1999, respectively. Both have two components, certifying forest management practices and the supply chain or ‘chain of custody’.
FSC sets its own principles for forest management, to which any local standards have to conform. PEFC, on the other hand, is an umbrella body that endorses individual forest certification schemes. There are around 50 different national certification programmes, many of which fall under the PEFC umbrella.
The UK Woodland Assurance Standard (UKWAS) is based on the requirements of FSC and PEFC, as well as the UK Forest Standard, a new version of which is currently out for consultation.
Globally, the percentage of forests that are certified as sustainable is around 10%. In the UK, around 44% or 1.42 million hectares is certified.
The rise of the timber building
Across Europe, Governments are putting policies in place to increase the use of timber in construction. In the UK, however, there is much more to be done. While 85% of Scottish homes are already built using timber, only 22% of English new-build homes are currently timber framed.
Meanwhile, engineered timber takes the properties of timber to new levels, increasing its strength, flexibility and durability. This positions timber as a firm alternative to concrete and steel for many projects, dramatically reducing the carbon footprint of offices, schools and low-rise residential buildings.
The Department of Education-led GenZero project is one example that aims to develop and test ideas for the next generation of school buildings. Prototypes were developed using a kit of parts to enable maximum standardisation and minimise carbon. The only option that met the low-carbon targets was a hybrid with 85% timber, designed with panellised cross-laminated timber (CLT), together with glulam and volumetric steel-frame modules.
Engineered timber also lends itself perfectly to the regeneration and retrofit of existing buildings. One such example is General Projects’ Technique, designed by Buckley Gray Yeoman with structural engineer Heyne Tillett Steel, creating a bright and airy office space extended with lightweight CLT and glulam. The result is a 43% reduction in carbon emissions compared to concrete or steel.
Managing supply and demand
Building with timber is sustainable in several ways, not least because it involves using a naturally-renewable material. However, its supply is not without limits.
Boosting the supply of home-grown timber is considered another important element of our route to net zero. In the UK, Scotland and Wales are leading the way in this area, with 19 and 15% of their land given over to forestry, respectively. The UK Committee on Climate Change ‘Land use: Policies for a Net Zero UK’ report recommends increasing this by 4%, hence the Government’s target of 30,000 hectares of tree planting per year.
However, official statistics released in June this year showed that we are not on track to hit those targets. In the 12 months to March 2022, the UK planted fewer than 14,000 hectares of woodland – three-quarters of which were in Scotland.
It is clear there needs to be a balance between growing enough timber in a sustainable way and increasing the use of timber for construction to help reduce the carbon emissions produced by the built environment. Policies that promote tree planting and timber production alongside regulatory requirements to reduce the operational and embodied carbon in buildings are needed in tandem if we are to take the necessary steps to achieve this aim.