The rise of wooden skyscrapers
"The world's tallest wooden house!" reads a huge poster on the side of a building under construction in the Norwegian municipality of Brummundal.
The house doesn't have any scaffolding; cranes and an outdoor elevator are used to transport the building material to where it's needed. The wood is sourced from Norwegian forests.
When it's finished in March 2019, the wooden house will be 81 meters (265 feet) tall, and will have 18 stories with 27 apartments that ranging from 67 to 149 square meters (720 to 1,600 square feet) as well as a swimming pool, a hotel, offices and restaurants.
Timber skyscrapers: an international trend?
But despite the declaration on the poster, this is not actually the world's tallest wooden house after all. Vienna is currently working on an 84-meter-tall wooden building 24 stories tall (with a staircase made out of cement).
The building in Vienna will also combine apartments with offices, shops and a spa.
Ask the Austrians and they will tell you they're the ones who came up with the concept of using wood as an industrial product. Austria is the world's largest producer of cross-laminated timber.
And though that may sound unsustainable, it's done under the number-one rule of Austria's lumber industry: Never log more than can grow back.
In the Parisian district of Terne, an entire building complex is being built from cross-laminated timber and glass.
The rooftops of the structures — which will be nine stories tall — will be accessible to the public, and are supposed to encourage citizens to engage in urban gardening.
In Germany, an eight-story wooden house was built on an area that used to belong to the United States army in the Bavarian town of Bad Aibling. It is a current showpiece for energy-efficient construction.
'Wooden buildings aren't profitable yet'
Berlin architects Kaden+Lager are building Germany's tallest building, the Skaio building in Heilbronn, using mostly wood. It will have 10 stories and be 34 meters tall.
Renowned architect Tom Kaden told German magazine Das Haus that he wants to make wooden houses affordable for everyone. That's why he uses metal rather than wooden nails. It's all about making the most of each material, he says.
Kaden teaches architecture and wooden construction at a university in Austria. There aren't more wooden houses yet because every architect and every carpenter has to create new models every time. This is not efficient, he points out.
"Today, we have hundreds of different ways of building timber houses. That's not profitable."
What's more, local planning and building laws often limit construction with wood. Germany has no country-wide regulations yet, and often individual permits are necessary, which are time-intensive and costly.
It's not surprising then that projects for the most spectacular wooden buildings only exist on paper so far.
Environmentally friendly alternative
Architects and researchers at the University of Cambridge created a concept for London's first wooden skyscraper. The wooden frame of the 80-story-high "Oakwood Towers" is supposed to rise 300 meters into the sky.
"Using wood as a construction material could change the way we build in this city," says architect Kevin Flanagan. "Wooden houses have the potential to create a more visually appealing, relaxing and creative experience."
A wooden high-rise planned for Tokyo will stand at 70 stories and 350 meters tall.
Ever more people are moving into cities. By using wood as a construction material for houses, nature can re-enter urban spaces.
And wood can be an environmentally friendly choice as well. Wood is a renewable resource — it grows back after being logged — and growing trees remove the greenhouse gas CO2 from the atmosphere.
As long as a wooden building stands, that carbon dioxide is locked away from contributing to climate change.
What's more, wood-based materials use less energy to create compared to steel or cement. And even thin wooden walls suppress sound.