Materials – The Cork Oak

By: Christian Watson

Materials – The Cork Oak

By: Christian Watson

An Introduction


C ork has been used as a material for thousands of years – from the Ancient Greeks and Romans, to the present day. Having only stumbled into using it ourselves as the seat for the No.04 chair in our new ‘Two Element Collection’, we thought we would share some interesting facts about its history, its current uses and what we love about it. So here we go…

Quercus suber, commonly called the Cork Oak, is a medium-sized, evergreen (keeps its leaves throughout the year, ever…green…) oak tree. Native to southwest Europe and Northern Africa (the Mediterranean basin) scientists have been able to carbon date fossilised Cork Oak back to the Geologic period, the bracket of which is between 66 million years ago and 2.58! In Ancient Greece, the Cork Oak was used a symbol for Freedom and Honour; in the Roman Empire, they used it for Beehives, and archaeologists have even found cork stoppers in Egyptian tombs.



How is it harvested?


C ork, as we know it, is harvested by peeling the thick bark away from the trunk and then placed into manufacturing processes. For the purposes of cork harvesting, each tree must reach between 25-30 years of age before the first ‘virgin’ harvest can take place, before then waiting between 9-13 years before the bark has re-grown to an appropriate thickness. Each tree should harvest around 40-60KG of cork.

The sustainability of the process stems from the fact that the bark can be removed without damaging the tree trunk itself. The extraction of the bark is a very delicate process, with the ‘extractors’ careful not to damage the trunk while peeling.

This is a highly sustainable process, especially given that each Cork Oak should last around 300 years, that’s an average of between 33 and 23 harvests! In ecology, the Cork Oak has many uses besides its cork; the bark is generally thick enough to withstand high temperatures during forest fires, usually coming out of them unscathed. While it loses its bark and canopy during the fire, it has the ability to regrow its branches, produce its canopy quickly therefore giving the undergrowth protection, and time to recover. This coupled with the fact that certain species seem to enjoy its forests and use it for habitats, for example the highly endangered Iberian Lynx, with only an estimated 150 adults left as well as the endangered Iberian Imperial Eagle and the Black Stork.



The Whistler Oak


N ow. This everything but a normal Cork Oak. This is the world’s biggest Cork Oak (above). In fact, it’s so big, been around for so long, produced so many harvests, that it has been submitted for protection as a UNESCO world heritage site.

Named after its canopy of songbirds and planted in 1783, the same year Great Britain declared peace with France and Spain (it didn’t last long), ended the revolutionary war and saw the Montgolfier brothers design the hot air balloon! It stands 14 meters high (45 feet) and boasts an almost 5 meter wide trunk.

On average, a healthy Cork Oak, will produce between 45-60KG per harvest, in 1991 the Whistler Oak produced a whopping 1200KG (2650lbs), and it has been harvested 20 times! It’s last harvest was in 2010 with its next stripping coming up soon.
It was included in the 2018 tree of the year competition (I know you all voted) and won by a margin. On a slight side note, the tree of the year competition is fantastic competition helping to protect natural forests and raise awareness of our environment. Focusing on the story and impact on society of each tree submitted, each entered gets attention and care and hundreds of thousands of admirers. Over the last 20 years, it has raised over £8 million to donate to forestry charities. With 13 countries in Europe involved, it is getting bigger every year.



Where and what?


T he majority of world cork production is based in Portugal, where it takes up 23% of their natural forests and where they produce around 50% of the worlds cork (sources differ). We ourselves source our cork from a Portuguese company, specialising in cork production with a strong belief in their environmental impact. So, let’s delve into some environment facts quickly – a harvested tree absorbs between 3-5 times more CO2 than an unharvested one, giving us an incentive to harvest, while the Cork Oak located in the Iberian Peninsula (Spain and Portugal) absorbs 20 MILLION tonnes of CO2 a year. To put that in context, the amazon rainforest absorbs roughly 430 MILLION tonnes a year – not bad considering it’s about 160 times smaller.

Cork is used in a variety of products all over the globe, from cricket balls, baseballs, and insulation, exterior bricks, and incredibly in space craft heat diffusers. Most famously however is the ‘wine-stopper’ or, to most of us, just ‘the cork’. During the 17th century, wine production was mainly based in France, where the alternative to the cork as we know it, was an oil-soaked rag!! Since then, we have favoured the cork stopper over all other alternatives and still accounts for roughly 60% (figures differ) of cork stoppers worldwide. It is the only natural material to have the unique seal created by the pressure in the bottle, as well as the only material to preserve, as well as enrich the wine as it ages.



A new method of using waste and recycled cork by combining it with a binding agent was developed by a German company in 1890. This meant it could be rolled into sheets and cut into any shape imaginable. Natural, sustainable, recyclable, and versatile, it’s no wonder that cork remains such a sought after material.



We, however, use it to produce the aforementioned seat in our No.04 chair, pictured below. It’s a beautiful material to work with; its pliable, strong, has high elasticity, is durable and waterproof. While personally I think its look is stunning, it varies in look with each batch we get which gives me the same feeling that all wood-lovers get, when each board has its own character. Its reliable, environmentally friendly, sustainable and abundant. For us moving forward, it is definitely a material we will endeavour to use more frequently and holds many possibilities yet unexplored.

As always, we’d love to hear what you have to say. So let us know what you think or if you have any questions or comments! You can email me or a member of the team via the website contact page or at

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