Making a strong case for wood in tall architecture, Michael Green’s recent TED talk emphasised the notion that steel and concrete are “old world” materials and the future is, and needs to be, in wooden skyscrapers.
The Vancouver-based Green refers to wood as the most technologically advanced material available and believes people react differently to the aesthetic of wood in his projects than they do to concrete or steel.
“Just like snowflakes, no two pieces of wood can ever be the same anywhere on earth - that’s a wonderful thing,” Green said. “I like to think that wood gives Mother Nature fingerprints in our buildings. It’s Mother Nature's fingerprints that make our buildings connect us to nature in the built environment.”
Green believes that if a tree is cut down, it must be turned into something valuable and respected particularly for its innate ability to store carbon.
“One cubic metre of wood can store one tonne of carbon dioxide,” says Green.
Enter the wooden skyscraper – an ambitious initiative Green believes can contribute to two of society's and architects’ greatest climate challenges today: to reduce carbon and to house the more than one billion people that live in slums and the more than 100 million people who are homeless around the world.
Beyond the worldwide housing shortage, the growing population is a major driver for implementing wood into high-rise architecture.
With half of the population currently living in cities and that number set to grow by 75 per cent by 2040, 40 per cent of the world - or three billion people - will need a new building built for them in the next 20 years, Green says.
"Cities and density mean that our buildings are going to continue to be big and I think there is a role for wood to play in cities,” he said.
In his talk, Green commended the use of steel and concrete in the past referring to them as great materials, but he also revealed the alarming statistic that steel represents about three per cent of man’s greenhouse gas emissions while concrete emits over five per cent. This, he says, creates a sense of urgency to rethink buildings and their materials.
“Almost half of greenhouse gases [are] related to the building industry and energy is same story,” said Green, adding that in the United States, the building industry is responsible for 47 per cent of carbon dioxide emissions.
“The problem I see that ultimately the clash of how we solve that problem of serving those three billion people that need a home and climate change are a head on collision to happen, or already happening,” he said.
In terms of building a solution, Green noted that building codes in the United States and other areas of the world that put height restrictions on wooden buildings are limiting very possible opportunities for sustainable structures.
He referenced local forests in Vancouver and red gum forests in California that are growing trees up to 40 storeys tall while many of the wooden buildings around the world stand at a humble four storeys.
Green wants to see wooden skyscrapers engineered to stand 30 storeys or more in height using the available and flexible system that applies mass timer panels to a building.
He also addressed two of the most common concerns raised with wooden skyscrapers - fire and deforestation.
In terms of fire, Green compared a wooden building to trying to light a large log with a match.
“It’s hard to start them on fire, they burn extraordinary predictably and we can use fire signs in order to predict and make these buildings as strong as concrete and as strong as steel,” he said.
To avoid deforestation, Green referred to models for sustainable forestry and cutting down the “right” trees. He noted that trees with fast growth cycles are ideal, stating that 20 North American forests can grow enough wood for a 20-storey building every 13 minutes.
When used to build a typical 20-storey building, Green noted that concrete emits 1,215 tonnes of carbon dioxide while wood sequesters 3,150 tonnes of the gas for a net difference of 4,365 tonnes.
“That's the equivalent of about 900 cars removed from the road in one year,” said Green. “We are at the beginning of a revolution, I hope, in the way we build, and this is the first new way to build a skyscraper in probably 100 years or more.”
Green believes the challenge is not in engineering wooden skyscrapers but in changing society’s perceptions regarding the material.
“It just happens to be that Mother Nature holds the patterns and we don’t really feel comfortable with it,” he added.
In his talk, Green referred to current wood high-rise projects, including Melbourne’s own world tallest timber apartment building, Forté. Standing at 10 storeys, the building features 760 panels of certified and manufactured cross-laminated timber.
London's nine-storey residential building Stadthaus, meanwhile, is built from prefabricated cross-laminated timber.
In British Columbia, Canada, the Wood Innovation and Design Centre has partnered with Green and his firm Michael Green Architecture (MGA) to develop a 27.5-metre building wooden building and in June, a 34-storey wooden skyscraper was proposed for Stockholm.
Today, Green is searching for an “Eiffel Tower” moment for wooden skyscrapers, reminiscent of when the Parisian icon changed the skylines of the world.
“That Eiffel tower moment will break the arbitrary ceilings of height and allow wood buildings to join the competition and I believe the race is ultimately on,” Green said.
Here is the full TED video in its entirety: