A report by global design, engineering and architecture firm Arup, Rethinking Timber Buildings: Seven perspectives on the use of timber in building, states that global carbon dioxide emissions have increased by almost 50% since 1990, with the global construction industry alone producing around 15% of these emissions. Furthermore, an estimated two-billion square metres of new building stock are needed every year between 2019 and 2025, especially for housing.
When you consider the findings of the recent Intergovernmental Panel on Climate Change Assessment Report which states that climate change is widespread and rapidly intensifying, the built environment holds the key for swift climate action, backed by a natural material.
How? By using more wood.
South Africa has 1.2-million hectares of farmed trees. With only 10% harvested (and replanted with new trees each year), it makes wood a renewable resource. Sustainable forestry also maintains trees in an active growing phase, optimising carbon storage.
Some 0.9 tonnes of carbon are sequestered by one cubic metre of wood, and carbon is stored for longer when the trees used for the production of harvested wood products.
Roy Southey, executive director for Sawmilling South Africa, says, “There is no doubt that concrete, steel and stone are good building materials but it takes something special to match wood’s environmental credentials.”
Using wood combats deforestation
The consumption of sustainable wood can actually help combat deforestation and local plantations are managed to stringent environmental criteria, especially in terms of water and biodiversity impacts.
“For many years, wood has been viewed as inferior and reserved either for the very poor, or engineered for the ultra-rich. It’s perceived as a fire hazard, weak or the cause of deforestation,” explains Southey.
For professionals and architects who are drawn to the wonders of wood, the sky is quite literally the limit. The world’s tallest mass timber building is the 18-storey Brock Commons Student Residence in Vancouver, Canada. In 2018, Sumitomo Forestry announced its plans to build a 70-storey hybrid timber skyscraper to mark its 350th anniversary in 2041. Dubbed W350, this lofty tower of lumber reflects a growing global trend to take wood to new heights in the built environment.
Timber ticks the boxes
“Along with design flexibility, longevity and superior insulating properties, timber structures are often prefabricated off-site and lighter to transport, reducing both construction times and associated costs and emissions,” Southey points out, adding that local production capacity for engineered wood will require greater investment, knowledge and training before its use can become commonplace.
“Locally, we have enough forestry and timber resources to build more than 55 000 houses a year,” states Dr Philip Crafford from Stellenbosch University’s Department of Forest and Wood Science who co-authored a study with Dr Brand Wessels. This study revealed that our local log resource is sufficient for a sustainable wood residential building market.
As the Arup report rightly asserts: “The use of timber alone will not solve our many challenges, but it could form a vital component of how we choose to design and build, and underpin a more resilient built environment.”
The timber sector can not only rethink how it creates living and work spaces, but should act against climate change and create a greener building economy using one of the oldest, most intelligent and beautiful materials known to humankind.