CORUCHE, Portugal — The rhythmic noise of axes whacking timber echoes within the depths of the cork oak forest.
However in Coruche, a rural space south of the Tagus River often known as Portugal’s “cork capital,” the bang of timber falling to the bottom doesn’t comply with the sound of the ax strokes. As a substitute, skilled staff rigorously peel away the bark from the tree trunks.
This annual ceremony of extracting cork in the summertime months has been round for hundreds of years within the western Mediterranean. Egyptians, Persians, Greeks and Romans used the fabric to make fishing gear, sandals and to seal jugs, jars and barrels. As glass bottles gained reputation within the 18th century, cork turned the popular sealant as a result of it’s sturdy, waterproof, mild and pliable.
Now cork is experiencing a revival as extra industries search for sustainable alternate options to plastic and different supplies derived from fossil fuels. The bark is now used for flooring and furnishings, to make sneakers and garments and as insulation in homes and electric cars. Portugal’s exports reached an all-time excessive of 670 million euro ($728 million) within the first half of 2023.
However cork is greater than a classy inexperienced materials. Along with jobs, the forests the place it grows present meals and shelter for animals, all whereas sequestering carbon dioxide. And in contrast to most timber grown commercially, cork oaks are by no means minimize down, that means their carbon storage capability continues by means of the 200 years or extra they dwell.
How cork is harvested
With a agency swing, Fernando Tacha strikes the trunk of a cork oak, then twists his ax and makes use of the deal with to delicately prise the plank.
“I began chopping cork once I was solely 19. Now I’m 69. However I’ll do that so long as I can,” he says as he wipes the sweat from his brow. “It’s a tough job, however a stupendous one.”
A low, slow-growing evergreen tree, the cork oak is endemic to the Mediterranean. Probably the most intensive forests will be discovered on the Atlantic coast of the Iberian Peninsula. In Portugal, the world’s largest cork producer, the oaks are so cherished they have been chosen because the nation’s nationwide tree and are protected by regulation, so it’s forbidden to chop them. Spain is the second-largest producer, adopted by Morocco, Algeria, Tunisia, Italy and France.
The method of harvesting cork takes precision and years of observe. The stroke of the ax should be sturdy, but in addition delicate to keep away from hitting the internal bark and damaging the tree. As a result of it’s so specialised, it’s the most effective paying agricultural jobs in Portugal.
The bark can solely be harvested between late Might and August, when the tree is in its energetic part of development, which makes it simpler to strip the outer layer with out damaging the tree trunk.
The cork oak is exclusive in its skill to regenerate its bark. As soon as it’s eliminated, staff write the final variety of that yr with white paint on the uncovered golden brown trunk — a 3 means it was harvested in 2023. The bark will slowly develop again and be prepared for an additional harvest after 9 years.
Paula Salgueira, who has been working within the cork harvest in Coruche for 35 years, extends her hand to the touch an oak that was simply stripped. “It’s chilly,” she says as she caresses the sleek denuded trunk. Whereas axmen work in pairs eradicating the cork, Salgueira and some different girls collect the planks in piles for transportation.
The planks will then be stacked outside in storage areas uncovered to air and daylight. After six months of ageing to take away moisture, they are going to be sorted in keeping with their thickness and high quality, then boiled to scrub impurities and make the fabric softer and simpler to deal with.
From bottle stopper to inexperienced materials
Whereas most cork remains to be used for bottle stoppers, over the past decade completely different industries have been discovering new makes use of for it.
“We’re seeing a rising curiosity in cork as a sustainable materials,” says Rui Novais, a supplies professional on the College of Aveiro in Portugal. “In contrast with supplies like polyurethane foam [used for thermal insulation], merchandise made with cork require much less vitality and produce much less CO2 emissions.”
The cork oak’s thick bark tailored to defend the tree from hearth, making it a robust insulating materials that’s been used to protect gas tanks on NASA spacecraft and electrical automobile batteries. It’s additionally immune to water and oil, and may stand up to compression whereas retaining springiness.
“It’s a rare, renewable and biodegradable materials,” says Novais. “It’s additionally very sturdy. It has been demonstrated that cork merchandise stay nearly unchanged for greater than 50 years.”
A part of the carbon absorbed by cork oak timber is transferred to cork merchandise, which can be utilized for lengthy intervals, repurposed and recycled. A number of studies discovered that cork is carbon negative, that means it can store extra carbon than what’s required to provide it.
When cork planks are trimmed and punched to kind pure cork stoppers, the leftovers are floor into granules and pressed collectively to kind cork sheets or blocks. “Even cork mud is used to provide vitality,” says João Rui Ferreira, secretary common of the Portuguese Cork Affiliation. “It feeds the business’s boilers and powers a few of the manufacturing.”
Recycled cork can be crushed and composited to make different merchandise. In Portugal, Green Cork, a recycling program began by the environmental group Quercus, has collected and recycled greater than 100 million cork stoppers since 2009. An analogous initiative, ReCORK, exists in the US.
A pure manufacturing unit
A lot of the cork produced in Portugal grows within the gently undulating hills and plains within the south of the nation, in an historic agroforestry system often known as montado. This savannah-like ecosystem combines cork, holm oaks and olive timber with pastures, grazing livestock, crops and fallows.
“The soil in southern Portugal could be very poor, there’s little or no rain and temperatures are very excessive in the summertime,” says Teresa Pinto-Correia, a professor on the College of Évora in Portugal specializing in rural landscapes and agricultural techniques. “However this sort of system is productive even when assets are scarce and circumstances are tough.”
For hundreds of years, locals have preserved the montado as a result of cork supplied landowners with a supply of revenue. This mosaic of habitats helps a whole bunch of species, together with the Iberian lynx, the world’s most endangered wildcat, and the threatened Imperial eagle. One of many world’s oldest identified cork oak timber, planted in 1783 in Águas de Moura, is called “the whistler” as a result of so many birds go to its massive sprawling branches.
Iberian pigs feed on acorns and goats graze the interwoven pastures. Interspersing cork oak timber with animals and crops can increase manufacturing and biodiversity, but in addition construct soil, management erosion, retain water, fight desertification and sequester carbon, says Pinto-Correia.
Whereas the cork forests will help mitigate the results of local weather change, they’re additionally more and more in danger from it as drought and wildfires change into extra intense and extra frequent within the area.
“The tree is tailored to the Mediterranean local weather. The bark protects it from hearth,” says forest engineer Conceição Santos Silva. “However for the primary two years after cork is extracted, the timber are rather more weak to wildfires as a result of they don’t have this safety.”
But fires in cork groves, she says, stay uncommon due to cautious human administration. “The tree all the time regenerates,” says Santos Silva.
As a slow-growing tree, the cork oak takes a long time to offer shade and produce good high quality cork. However in Coruche, individuals nonetheless go by an outdated Portuguese saying: “Those that care about their grandchildren plant cork oak timber.”