Cork is a true underdog when it comes to sustainability. Unknown to many, cork is an incredibly sustainable and versatile material. Cork has been used for centuries as the stopper in wine bottles, but it was used by ancient Egyptians, Romans and Greeks for building, footwear and ships. Today, the legacy of cork is being revitalised in a world where the search for sustainable alternatives is growing!
What is cork and how is it made?
Cork comes from the bark of cork oak trees. These trees must first be allowed to grow for 25 years before they are harvested and once reaching maturity, cork can only be harvested once every 9 or so years. The lifetime of a cork oak tree can be up to 300 years!
Cork is manually harvested from the oak tree by skilled labourers who peel the cork using sharp axes - it is then boiled, cleaned, flattened and graded to be cut into workable pieces.
What is amazing about this process is that harvesting cork creates no damage to the tree itself - they are not cut down and the people harvesting the cork ensure the living part of the tree remains untouched. This is a completely regenerative process! Old cork oak forests are found in Portugal, Spain, Italy, the south of France, Morocco, Tunisia, Algeria and Turkey. Portugal is the largest producer in the world - more than half of the world's cork comes from the montados of Portugal.
The cork oak trees are not only regenerative, but they do not require fertiliser, pesticides, irrigation or pruning. In Portugal, cork oaks store 17,500 tonnes of carbon in above and below ground biomass. Once the bark is harvested, the tree actually absorbs up to 5 times morecarbon dioxide than usual to help the restoration process. The stripped trees release so much oxygen they are referred to in Portugal as the 'lungs' of the environment.
Cork oak plantations and forests 'are some of the most bio-diverse environments on earth'. Endangered species such as the Iberian lynx and the Barbary deer are dependent on the cork ecosystem. WWF says 'Cork oak forests support one of the highest levels of biodiversity among forest habitats, as well as the highest diversity of plants found anywhere in the world.' Cork as a material is completely natural and biodegradable.
Qualities and versatility
So what products are made using cork? What first springs to mind is probably the memory of using a corkscrew for the first time, or the satisfying pop of the cork flying out of the bottle. A decade ago, the Portuguese cork industry supplied most of its cork for use in wine bottles, as it had done for centuries. But as plastic and metal screw-tops became increasingly popular, corked wine bottles were facing a crisis. This reduced demand led Portugal to recalibrate the cork industry by focusing on market diversification and increasing awareness about its environmental benefits.
Cork's adaptability as a material has created a long list of uses. It has thermal and acoustic properties, is free from synthetic resins and carcinogenic materials, resistant to abrasion and actually acts as a fire retardant. Cork has a weather-resistant quality and is extremely waterproof. Its aesthetic qualities give buildings natural patterning and earthy tones, with intriguing textural elements.
These hard-wearing properties have seen cork sneaking into buildings, such as the checkerboard flooring of the Library of Congress and the insulation of NASA space shuttles. As a natural insulator, floors made of cork regulate the temperature throughout seasons and reduce energy bills, and it is also fantastic for sound insulation. In terms of longevity, cork can be sanded and polished over and over to treat scratches and wear.
Cork is being used to make a wide range of products such as insulation panels, floor and wall tiles, sound-proofing, engine gaskets and bulletin boards. Cork paper is used in printing, book covering, and other handicrafts like clothes manufacturing, cork maroquinerie, woodwind instruments and model trains. It is used to make baseballs, cricket balls, badminton shuttlecocks and handles of fishing rods. It is used in shoe heels, and other footwear items such as cork clogs and cork thongs/flip flops. It's unique elastic and impermeable properties mean cork can be used as a leather substitute for handbags and wallets.
What about Australia?
Living halfway across the world from Portugal and other producers raises the question of whether cork is as sustainable here in Australia? Would the emissions involved in transporting cork to Australia balance out the environmental benefits?
More and more Australians are seeking out eco-friendly building materials, and cork is
becoming more popular. And Australian companies like Portugal Cork Co are partnering with Portguese cork industries to bring a vast range of products to Australia.
However, in Australia's capital city Canberra, there is a 100-year-old cork plantation that many do not know about. It is located within the National Arboretum, but existed many years before the arboretum was created. Canberra's dry climate was trialled in 1917 as a potential area for growing cork oaks and the trees have been successfully harvested 5 times since then!
Even so, cork is definitely more accessible and sustainable in those regions close to the main producers. The distance imported cork must travel to reach Australia and other far-away locations casts a shadow on its sustainability advantages.
Cork is a dark horse of sustainable materials! It's environmental benefits are unbeknown to many. Cork is a model of versatility and sustainability, and becoming an increasingly attractive building material. An increase in demand for cork, if regulated properly, will benefit the environment as the cork industry plants more trees, these ecosystems flourish and then consume more carbon dioxide!
Written by Grace Robinson-Tagg
Grace Robinson-Tagg is a final year university student who is passionate about sustainability, climate action and environmental justice. She also loves music, the beach and watching vegan cooking videos. She is currently interning with 1 Million Women.