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  • Built in 607AD in Nara, Japan

  • Horyu-ji Temple is the world's oldest surviving wooden building.

  • Five storeys high, it's still standing firm

  • despite being made from cypress trees felled over 1,400 years ago.

  • And Horyu's great age reveals a message for our future -

  • building with timber can be durable, beautiful and practical

  • and it can even help tackle climate change.

  • Here's why.

  • If we made 90% of our new buildings from wood

  • rather than concrete and steel

  • we could reduce our global carbon emissions by 4%.

  • That's more than the total climate footprint of flying.

  • So why does building with wood do such good?

  • First, trees absorb carbon dioxide from the air as they grow.

  • This is naturally stored in the beams and panels of buildings,

  • a process known as carbon capture.

  • So the timber in Horyu Temple

  • contains CO2 absorbed from the planet's atmosphere

  • in the 7th Century.

  • Of course, using wood means felling trees,

  • but so long as you're not chopping down ancient forests,

  • you're maintaining the wildlife, replanting,

  • and putting wood to long-term use, it's sustainable.

  • In the last 15 years, in the northern Hemisphere

  • total forest cover has increased by an area of around 242,000 sq km,

  • about the size of the United Kingdom.

  • In fact, every seven seconds the sustainable woodlands of Europe

  • yield enough timber to build a four-person family home.

  • And it's not just Europe -

  • Canada can harvest enough trees every year to house about a billion people.

  • An equally important carbon reduction comes from what you're not using -

  • construction with natural materials demands far less concrete and steel

  • and these are massive climate culprits.

  • Steel-making accounts for around 8% of total global CO2 emissions

  • and cement accounts for a further 6%.

  • OK, not all of this is going into buildings,

  • but they are a big customer.

  • It's the combination of stored carbon and avoided emissions

  • that really tips the climate scales for timber,

  • and a recent innovation has made wood much more user-friendly.

  • CLT, or cross-laminated timber,

  • is made by layering conifer planks at 90 degrees to each other

  • in three to seven tiers and then gluing them together

  • producing a kind of chunky plywood.

  • These panels are suitable for walls, floors, roofs, even lift shafts.

  • and their strength-to-weight ratio is often better than concrete.

  • CLT can be used in schools, offices and warehouses

  • and now there's a race to the sky

  • with 85m 'plyscrapers' recently completed

  • in Austria and Norway.

  • So why are wooden buildings still the exception?

  • Mainstream construction is a risk-averse industry

  • and changing this takes radical action.

  • One approach is law - the French government has decreed

  • that at least 50% of every new public building must be made of wood.

  • This not only allows those structures to store more carbon

  • but also encourages a generation of builders

  • to learn a timber-friendly skillset.

  • But how safe are wooden buildings, you may ask?

  • Remembering the Great Fire

  • that gutted the medieval centre of London in 1666?

  • In fact, tests of CLT panels in a blaze

  • have shown they tend to form a charcoal layer

  • that protects the core

  • and when combined with heat-resistant glues and claddings

  • they can match or exceed the fire resilience of conventional buildings.

  • There are other benefits too.

  • Studies suggest that wooden schools

  • can actually lower the heart rate of pupils.

  • Even looking at a wooden wall can reduce blood pressure.

  • So wood is not only renewable, safe and climate-friendly,

  • it can also make you feel good.

  • Or to put it another way, using wood is really good.

Built in 607AD in Nara, Japan

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Will we all live in 'plyscrapers' in the future? | BBC Ideas

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    Summer posted on 2021/06/03
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