The Great New Green Building Material Is…Wood?
A recent article on The Conversation has made the argument that of all the major building materials – concrete, brick, aluminum, steel – wood is by far the most green. The article’s author, Chad Oliver is the Pinchot Professor of Forestry and Environmental Studies, and Director of Global Institute of Sustainable Forestry at Yale University, admits that his conclusion may be counter-intuitive, but insists the evidence is there.
The modern building materials that we employ each year are energy intensive to produce and account for 16% of the fuel production for the entire planet. Wood is renewable and only requires a portion of the world’s forestry resources.
Oliver cites his research published in the Journal of Sustainable Forestry. They estimate that the world’s forest contain 385 billion cubic meters of wood with an additional 17 billion cubic meters growing every year. Oliver argues that with a 3.4 billion cubic meters harvested each year, mostly for fuel, that other building products for wood would make for renewable building that would not harm biodiversity if done correctly.
Oliver and his team of researchers have evaluated scenarios in which wood is burned for energy, used for construction, or forests are left untouched. What they found was that the wood harvested each year accounts for only 20% of new annual growth. Increasing the wood harvest by 14% and creating less concrete and steel would reduce global CO2 by 14-31% and an annual of 12-19% of fossil fuel consumption would be saved.
Harvesting forests for wood production only temporarily disrupts a forest ecosystem, and would ultimately serve to preserve the forest as a precious natural resource. Placing emphasis on wood for construction would help to preserve forests and end the practice of clear cutting and converting the area to farmland. Oliver notes that new styles of building construction, such as cross-laminated tinder, have overcome some of the barriers of working with wood, making it a viable and green alternative to traditional modern materials.
To read the original article, head over to The Conversation.
By using efficient harvesting and production techniques, more CO2 is saved through the avoided emissions, materials, and wood energy than is lost from the harvested forest – yet another reason to appreciate forests, and to protect them from endless deforestation for agriculture. Clearing trees for harvest is temporary, but converting forests to farmland is a permanent loss of all forest’s resources and biodiversity.
If transport and assembly is taken into account, the 16% of global fossil fuels used to manufacture steel, concrete and brick is closer to 20-30%. These potential fuel and carbon emissions savings, already substantial, will become increasingly critical as demand for new buildings, bridges and other infrastructure surges with economic development in Asia, Africa and South America.
Wood construction for bridges in Quebec (A, photo Jean-Marc Dubois), Stadthaus in London (B, photo Will Pryce), aircraft hanger in Montreal, Quebec (C), and 20-storey wooden building (photo by Michael Green Architecture). Jean-Marc Dubois/Will Pryce/Michael Green Architecture
At the same time, new construction techniques have made wood even more effective as a building material for anything from bridges to mid-rise apartment buildings. The cross-laminated timber increasingly used in new buildings, made from alternating layers of perpendicular, wood pieces has strength approaching that of steel.
In 2009 a nine-storey building, Stadthaus, in London, was built with CLT instead of steel construction and in Stockholm a 34-storey wooden building has been given planning permission. There are many others, already built and in the pipeline.
Harvesting also reduces a forest’s likelihood of suffering a catastrophic wildfire, and improves its ability to withstand it. Maintaining a mix of forest habitats and tree densities in non-reserved forests would help preserve the varied biodiversity in ecosystems worldwide. Harvesting wood will save fossil fuel and CO2, and provide jobs – giving local people more reason to ensure the forests’ survival.