Cork oak (Quercus suber)

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The cork oak is a medium sized evergreen oak native to southwest Europe and northwest Africa. It can grow up to 20m tall and can live for up to 250 years. It is one of the most highly renewable and eco-friendly resources to be found on our planet today. Mostly recognised for its use as wine bottle stoppers it has many other uses including insulation, flooring and decorative and fashion items such as bags and shoes. Cork is a raw material that is very light, compressible, has an elastic memory, is impermeable to liquids and gases, provides both thermal and acoustic insulation, is fire retardant as well as highly abrasion-resistant, hypoallergenic, plus it is completely biodegradable, renewable and recyclable.

The thick insulating bark may have been the cork oak’s evolutionary answer to forest fires. After a fire while many other tree species regenerate from seeds or re sprout from the base of the tree. The cork oak’s branches protected by cork quickly re sprout and reform the tree canopy.

The European cork industry produces 300,000 tonnes of cork a year and employs 30,000 people. Portugal has the world’s largest cork oak forest area and accounts for 50% of the worlds cork harvest.  Cork is harvested in a process called stripping. No trees are cut down in the process, but the bark is extracted in the summer months using nothing more than an ax. A cork is first stripped at around 25 years old and then every 9 years or so. After stripping the planks of cork are left outside for at least six months to allow the cork to stabilise.

As well as being found in forests cork oaks are sometimes planted as individual tress and are becoming more and more popular in the UK. They were first brought to Britain by botanists in the 17th and 18th centuries. They can withstand the conditions in this country and the leathery wrinkled texture gives the tree a lot of character. Unfortunately we can’t harvest the bark in this country as the trees don’t grow quick enough. One of the oldest specimens in the UK is in Painhill Park, Surrey and has occupied its position on the top of a slope in the park for about 250 years!

Cork oak forest is also important with regard to our ecosystem and supports various endangered species. In Portugal and Spain the forests are home to the Iberian lynx which with only around 300 left in the world is the most critically threatened feline. In the forests of north west Africa cork oaks are also home to the Barbary macaque. A small population of this species was introduced from Morrocco to Gibraltar so is now the only population of wild monkeys in Europe.

Tree of the Month: November’16
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