With the built environment responsible for approximately 40% of global energy-related carbon emissions[i], sustainable timber and engineered wood have the unique potential to decarbonise the built environment both quickly and at scale while supporting urban development, rural economies and innovation.
Emissions from the built environment come from two main sources: the energy consumed within buildings for heating, cooling and power (operational emissions) and the emissions associated with the extraction, processing and manufacture of building products (embodied emissions)[ii].
A report by Arup – Rethinking Timber Buildings: Seven perspectives on the use of timber in building design and construction – says around two billion square metres of new building stock will be required globally, every year between 2019 and 2025 alone, to keep up with urban development and population growth.
The impact of urbanisation has seen sustainability experts, architects and engineering professionals looking to greener solutions – including wood.
“South Africa is ripe for scaling up the use of timber in construction, however many people perceive wood as rudimentary or weak, and reserved for log cabins and tool sheds. But for mass timber structures, there is significant opportunity for innovation, localisation and employment creation,” says Roy Southey, executive director of Sawmilling South Africa.
“The construction of homes and buildings with timber is becoming more feasible as architects, construction engineers, and timber manufacturers employ modern tools and digital design to engineer an age-old material into modern functional structures.”
Using timber in buildings creates an opportunity to reduce the country’s carbon footprint and provide new opportunities for manufacturing, skills development and unemployment. It is for this reason that the promotion of timber is part of the Commercial Forestry Masterplan, which outlines plans to encourage sector growth, invest in job creation, and competitiveness.
The green factor
In South Africa, wood for structural timber comes from sustainably cultivated pine or eucalyptus trees, otherwise known as commercial timber plantations or planted forests.
It is a myth that timber production causes deforestation. Southey explains, “Deforestation is the removal of trees or clearing of forests for commercial development, housing, firewood or agriculture without replanting whereas sustainable forestry sees to it that trees are planted, grown and harvested in line with stringent environmental policy, international certification and local legislation.”
According to Forestry South Africa, less than 10% of the country’s total plantation area of 1.2 million hectares is harvested annually. Felled trees are replaced in the same year by saplings, often at a ratio of 2:1. This means there is a constant supply of trees for productive purposes for years to come.
South Africa’s plantations also remove a significant amount of carbon dioxide from our atmosphere during their rotations of seven to 20 years. Southey adds: “All mass timber products – whether a timber pole, a plank, plywood or cross-laminated timber – keep the carbon locked up.”
The conservation factor
Unlike Sweden or Canada, South Africa is not a tree-rich country, with only half a million hectares of indigenous forests – this is roughly 0.4% of the total land area.
“If it weren’t for the commercial planting of trees in the early 1900s, the country’s indigenous forests would have been eliminated many years ago for our fuel, furniture and fibre needs,” notes Southey.
However, a forestry landscape is far more complex and diverse than simply rows of planted, monoculture trees. Only 70% of forestry-owned land is planted to trees, with a significant unplanted proportion reserved for biodiversity conservation, natural corridors, riverine habitats, indigenous flora and wetlands.
The cost factor
Timber-based buildings can be pre-manufactured at a facility off-site and then require semi-to unskilled labour to assemble on-site. “From manufacturing to assembly, using timber will benefit foresters, communities and small and medium businesses and the greater supply chain,” says Braam de Villiers, owner of Earthworld Architects.
Timber structures may cost about 10% more to build, but they can be constructed in half the time. A recent master’s study by Fanie van der Westhuyzen from the University of Stellenbosch – A development cost comparison between a multi-storey mass timber and reinforced concrete building in South Africa – showed that an eight-storey timber building would cost R115 691 000 as opposed to the reinforced concrete alternative at R105 118 000. But the timber construction would take 21 weeks as opposed to 42.
Wood is versatile and lightweight, making it ideal for modular volumetric prefabrication of low-income housing as well as larger homes and multi-storey buildings.
The local factor
The forestry value chain contributes R69 billion to the local economy annually with sawmilling supporting approximately 30,000 people in predominantly rural communities.
Timber promotion seeks to upskill workers and create new jobs through the development of a circular bioeconomy. New areas such as modern renovation and prefabrication require different skillsets and knowledge bases while developing and improving traditional manufacturing in wood industries.
South Africa also has top quality structural wood. “South Africa is one of two countries in the world where the quality of structural timber is assured by compulsory, continuous strength testing at the grading facility. The introduction of a new South African National Standards (SANS) timber quality standard will ensure that our timber structures remain amongst the safest in the world,” says Prof Brand Wessels from the Department of Forest and Wood Science at Stellenbosch University.
The happy factor
Biologist and author Edward Wilson first popularised the ‘biophilia’ hypothesis that “humans have an innate tendency to seek connections with nature and other forms of life”.
According to Workplaces: Wellness+Wood=Productivity Report[iii], weaving wood into workplace design can be a major driver of wellbeing, job satisfaction and productivity. Wood and natural materials deliver a certain degree of wellbeing, happiness and comfort that other materials can’t match.
All factors considered, wood brings something special but it can have a greater purpose – to reduce carbon emissions and provide us with durable built environments.
Sawmilling South Africa, along with its value chain partners such as the South African Wood Preservers Association, have been hosting a series of webinars on the timber in the built environment.
[i] Global Alliance for Buildings and Construction. 2020, Global Status Report For Buildings And Construction, 4.
[ii] Time for Timber, Wood Manifesto, 2021.
[iii] A report prepared for Forest & Wood Products Australia by Andrew Knox, Howard Parry-Husbands, Pollinate