Why the humble cork is reinventing itself


Cork is now used in electric cars to protect batteries from heat and vibration, and its heat-absorbing properties have protected space rockets from the Space Shuttle program to NASA’s new Artemis spacecraft which has Portuguese cork in its nose cone. Cork dust waste is also burned as an alternative to fossil fuels to power some of the production lines.

Cork stoppers can also be collected, recycled, granulated and used for many of these different uses, with cork recycling schemes having been introduced around the world, including Recorked in the UK and ReCORK in the US.

Materials scientists at Amorim’s iCork lab are also experimenting with combining cork with rubber and bio-based or biodegradable polymers to develop other new uses, including injection molding.

“His [got] the advantages of cork mixed with the advantages of plastic,” says Álvaro Batista, who is prototyping new materials to replace the aluminum stopper on wine bottles, to enable the use of cork sheet rolls and for injection molding. We get a lot of materials from other industries…to mix with cork to improve cork properties and of course reuse raw materials…to help address sustainability issues,” he says.

The cork oak is Portugal’s national tree, protected since 1209, and cutting one down or even pruning it without permission could land you a hefty fine.

Twenty years ago, the symbiotic relationship between ecosystem and industry was threatened by the rise of plastic caps, aluminum screw caps and the dreaded cork taint. The problem now is getting enough cork – demand is growing and the value of Portuguese exports hit a record high of €1.13bn (£921.29m/$1.09bn) in 2021.

The biggest threats to trees are intense wildfires and drought which are increasingly a risk amid extremes of climate change. Global warming is also changing the threat posed by diseases caused by moths, beetles and weevils, which burrow into the bark carrying fungi and bacteria.

So while cork oaks could help fight climate change, they are also under threat. In the absence of incentives or a viable carbon market, other threats related to cattle ranching and urban sprawl could also cause the valuable montado landscape where the oaks grow to wither.

The Whistler itself is a sign of what could be lost. The axe-wielding men have left him untouched this year, but his next cut will be the 21st in his long life. They estimate this could exceed the tree’s record yield in 1991, which was over 1,200 kg of cork, enough for 100,000 corks. The carbon of nearly a decade of growth will be locked inside them.

* Alastair Leithead is a former BBC foreign correspondent who is now trying to live off the grid in Portugal on a 17-acre (seven-hectare) plot that includes cork oaks, olive trees, pines and eucalyptus trees. He also keeps a blog about wine in Portugal.

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