Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

The Wonder of Cork Oaks

Jean-Pol Grandmont
Wiki Commons

People have used cork for millennia. It's light, buoyant, and elastic, thanks to the 40 million air cells that occupy each cubic inch. Today, we use cork for fishing floats, floor tiles, and of course, bottle stoppers.

The tree that produces it is called cork oak. It has evolved a spongy bark to protect against fire and disease. Unlike other trees, its bark separates along the dead cork cambium so that the inner bark can regrow for many harvests.

Most of the 13 billion corks produced each year come from Spain and Portugal. Each cork oak lives for 250 years, and makes enough cork for 60,000 bottles of wine.

Skilled workers harvest the bark, slicing and peeling it into sheets the size of a yoga mat. The bark weathers for a year, and is then soaked, flattened and sorted. Wine corks are punched by hand, printed with logos and then sent off to candle-lit dinners in our homes and restaurants. The process provides jobs for some 30,000 people.

Cork forests also offer critical habitat for two endangered animals — the Iberian Lynx and the Iberian Eagle.

But recently, the wine industry has started using synthetic corks made from petroleum to reduce costs and the risk of contaminants. Cork oak forests are being replaced by pine plantations to make wood pulp, with negative impacts on centuries-old human and animal communities.

So, the next time you order a bottle of wine, let your server know you'd like a bottle with a real cork — from a real tree. As with so many of our actions, this seemingly simple decision can affect people and trees half a world away.

Dr. Nalini Nadkarni is an emeritus professor of both The Evergreen State College and the University of Utah, one of the world’s leading ecologists and a popular science communicator. Dr. Nadkarni’s research and public engagement work is supported by the National Geographic Society and the National Science Foundation. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation. @nalininadkarni
KUER is listener-supported public radio. Support this work by making a donation today.