For more than 150 years, Corticeira Amorim SA has thrived by buying slabs of bark stripped from cork trees in Portugal and transforming them into stoppers. The company annually produces billions of seals for the planet’s wine and champagne bottles.

As annual sales have hit records, the challenge now for the world’s biggest cork maker is ensuring it has enough supply to meet growing demand outside the drinks industry.

“There is currently no shortage of supply in today’s market, but we need to start producing more of this raw material to respond to greater demand in the future,” Chief Executive Officer António Amorim said in an interview last month.

Today the light, spongy material is found in everything from clothing to insulation used in cars and high-speed trains as well as even space shuttles. It’s more sustainable than lumber as it’s harvested from trees that don’t need to be cut down. This means the trees can continue to serve as long-lasting carbon sinks.

The only thing standing in the way of the cork market exploding is it takes decades to grow and regrow the material. That’s something Amorim hopes to change.

Amorim is looking to shorten the time of the first harvest from 25 years to about 10 years through the use of drip irrigation. It’s a practice that’s been used for years to speed up the harvest of a variety of crops such as olive trees but it’s rarely been applied to cork farming because these trees are predominant in Portuguese and Mediterranean regions where there are recurrent droughts and long dry summers. Cork also isn’t a crop grown in a field, but rather a forest, which many farmers wouldn’t normally irrigate.Until recently, Corticeira Amorim didn’t own any cork oak forests. In 2018 the Mozelos, Portugal-based company began buying land to develop irrigated cork oak plantations, with as many as eight times more trees per hectare than normal.

Portugal, which produces around 50% of world’s cork supply, has seen the size of these forests decline by 3.6% between 1995 and 2015, according to the latest available data compiled by the government’s national forestry inventory.

For some farmers the long waiting period that it takes for a cork oak tree to grow enough product hasn’t made planting them worth it. A newly planted tree requires at least 25 years before a cork stripper can remove the outer bark from the trunk with his bare hands. It then takes nine years for the bark to regenerate itself and another nine years to produce cork that’s good enough for bottle stoppers, which account for the bulk of Corticeira Amorim’s sales.

The decades long waiting period has prompted farmers to invest in crops like olive trees or vineyards that generate faster financial gains.

“Today, when people consider planting a cork tree, they think they are doing it for their grandchildren,” said Amorim, whose great grandfather founded the company in the northern Portuguese town of Mozelos in 1870. “We need to show that it’s possible to plant cork oak trees for our generation as well.”

Amorim said the idea to speed up the harvesting process came to him over a decade ago when a family friend in a small town in central Portugal decided to test drip irrigation on cork trees.

Francisco Almeida Garrett, planted two hectares of cork oak trees in his farm in Avis, a town in central Portugal, in 2003 using a similar irrigation process that he used on his olive trees.

“Eight years later, I noticed that some of these trees were ready to be harvested instead of the usual 25 years,” said Almeida Garrett, who has since planted another 40 hectares of irrigated cork oak trees. “It was incredible.”

In 2010, Amorim, a long-time family friend of Almeida Garrett, visited this farm to see for himself the results of his experiment, which paved the way for a new chapter in Corticeira Amorim’s growth strategy. At the time, cork stoppers were starting to regain market share from artificial bottle closures after Corticeira Amorim found a way to virtually eliminate so-called “cork taint” — a contaminant that could render the finest vintage undrinkable.Today, cork stoppers are used in about 13 billion bottles of wine out of a total of 20.5 billion produced every year. The remaining bottles are sealed with screw caps, plastic and other stopper types. Corticeira Amorim sells about 6.1 billion cork stoppers every year.

“I told Francisco: ‘You changed my life,’” Amorim said. “Once I saw what he did, I decided that we couldn’t just stand there and do nothing.”

Amorim quickly contacted the University of Evora in southern Portugal and helped fund a research program that could verify the findings at Almeida Garrett’s Herdade do Conqueiro Estate. Soon, the two hectares of irrigated cork trees at the Conqueiro Estate, roughly the size of two soccer fields, were turned into an open-air lab. Three different types of drip irrigation techniques were used on hundreds of trees equipped with sensors to monitor their growth and water use as drones flew overhead to track their development. A control group of non-irrigated trees was also evaluated to compare progress.“We’ve proven that drip irrigating will cut the waiting time until the first harvest by around half,” said Nuno de Almeida Ribeiro, a professor at the University of Evora who heads the Regacork research project that is today backed by several agricultural estates and companies alongside Amorim. “Not everyone will be able to do this as you need access to water and energy and an adequate soil to grow these trees.”

That’s no easy task for most cork producers in Portugal, where the biggest concentration of cork forests is in the southern Alentejo and Algarve region — a vast area of undulated plains and hills with mild winters and hot and dry summers. The cork oak’s deep root system allows it to extract water from the subsoil and cope well with drought.

Ana Cristina Coelho, a professor at the University of the Algarve in Portugal, who has done research on the decline of the cork oak forest, estimates that only a very small percentage of landowners will be able to carry out drip irrigation. “This type of irrigation is only possible in areas close to rivers, lakes or dams where there is an abundance of water and where you don't compete for water supplies that could be used for drinking water or other important food crops,” said Cristina Coelho.Still, Amorim estimates that if 50,000 hectares of these new cork oak forests are planted — just 7% of a total of 730,000 hectares of them in Portugal — the country could increase its production by as much as 40%.

Corticeira Amorim recently acquired Herdade de Rio Frio, a huge forest estate near Lisbon. It’s there, in an area with about 5,200 hectares covered with cork oak trees alongside two large dams and manmade channels used to transport water from the River Tagus to be used for irrigation that Amorim is developing a central part of its so-called forest intervention program.

“We currently have about 50 trees per hectare. But there is room to plant a lot more trees in the same area,” Nuno Oliveira, who oversees Corticeira Amorim’s forest properties, said as he walked along several cork oak trees at Herdade de Rio Frio.

The company will use drip irrigation in newly planted cork oak tree plantations until their first harvest in about 10 years. Once the trees are harvested, drip irrigation can stop, and the regular nine-year cycle of growth and harvest can continue. Corticeira Amorim aims to plant as many as 400 cork trees per hectare instead of the usual 50 and use plants cloned from trees that are considered to be stronger and produce better quality cork than others to increase the rate of success, he said.

Planting cork oak trees closer to one another will lead trees to grow more evenly upwards, said Oliveira, a forest engineer. This will make it easier to use technology to speed-up the removal of the bark from the trees, which is currently extracted by hand, using a single instrument — the axe — and applying techniques that have been passed down within communities and families for centuries.

“We’re changing the way the cork sector works,” said Oliveira.

If it works, Amorim hopes other landowners will follow his lead and invest in irrigation systems for new cork plantations with more trees. One extra incentive for them, Amorim said, is that these trees are natural carbon sinks and could potentially be used to offer carbon credits that will help landowners pay for their investment.

For now, however, Corticeira Amorim is focused on the end product. The company posted a record 1 billion euros ($1.11 billion) in revenue in 2022 and expects demand for cork to continue to increase in the coming years as consumers opt for more sustainable products.

“My hope is that others are inspired by what we are doing,” Amorim said. “All we want is to have more cork to continue to grow in the future.”

--With assistance from Joao Lima.