We were not prepared for how simple and almost medieval the harvesting process was. The tree farmers removed cork bark from the tree in the same manner they did hundreds of years ago. And yet, the manufacturing of the cork was innovative, sophisticated, and state of the art.
Our experience in the cork forest together with our exposure to the wide variety of products was not only inspiring but it also forever changed our perception and understanding of cork. We’re happy to share our story of what we learned in Portugal with the hope that you, too, will be inspired.
The Cork Forest (called Forestal in Portuguese)
Our tour of the cork forest began west of Lisbon in the south part of Portugal called the Montado system which covers about 1.8 million acres. This is the largest and oldest cork forest in the world. It was planted hundreds of years ago. In Portugal, cork is the national tree and is protected by the government. No one is allowed to cut the trees down for use in construction, but the cork bark can be harvested. We visited a privately owned cork tree farm which is one of many that supply cork to Amorim.
The climate in Portugal was much like that of Napa Valley, California; hot and humid. On the way to the forest, we noticed that the quality of the soil looked sandy and completely different from the dark rich topsoil we were used to in Iowa. As we drove by, we noted Eucalyptus trees, a variety of fruit trees, and some vegetable crops that were irrigated.
The roads into the forest were like narrow winding logging roads in a jungle; no signs, very bumpy, and not made for normal vehicles. Even with an experienced driver and GPS, we got lost and had to backtrack twice until we luckily found our way to the right road.
The Farmers
When we finally arrived, we saw about 8-10 farmers sitting in circles eating lunch under the shade of huge cork trees. They were a mix of young to middle-aged men; strong and scrappy, wearing typical work clothing. Cork harvesting is a highly skilled family craft in Portugal that is passed down from generation to generation. These men are some of the highest paid agricultural workers in the world, making 150 Euros per day (equivalent to $163 U.S. Dollars).
Tools
Except for one old tractor, there was no expensive heavy equipment like you might expect. No chain saws either. In fact, the only tools were woodworking axes that looked like something from the middle ages. One of the workers was grinding the edge of his blade by hand with a small grinding stone. It was razor sharp.
Harvesting the Bark
Removal of the bark from the lower parts of the trunk and limbs does not hurt the tree. It naturally regenerates itself about 15-18 times over the course of its harvesting lifespan of 200+ years. The trees continue to live for another 300 + years and are never cut down.
Seed in Ground - Year 0
The first 25 years of the Cork Trees life allow for full maturation from planted seed, to full tree.
First harvest - Year 25
Cork must be harvested only during May through August; otherwise, the bark won’t separate from the trunk easily. The first “virgin” harvest is after 25 years of growth where the bark is very gnarly with irregular structure and extremely hard. It is not suitable for stoppers or flooring but is ground up and used for other purposes described below.
Second harvest - Year 34
After another 9 years (total of 34 years), the tree is considered a “young adult” and the bark is used for other purposes, but it’s still not suitable for wine stoppers.
Third and future harvests - Years 43 +
Finally after 9 more years of growth (total of 43 years), the tree matures and the density, porosity and texture of the bark becomes suitable for stoppers as well as flooring.
Before the trip I had requested to cut off a piece of cork bark by myself to prove that I was not making this story up...
The manager of the team demonstrated how they determine the optimum time to harvest the bark. He cut out a small 4” x 4” chunk of bark which exposed the inside of the trunk to show how deep I was supposed to cut. When he removed the small chunk of bark, I could smell the sweet sap of the tree and the exposed area under the bark was a little sticky to the touch.
The manager then handed me the ax to try cutting by myself. Not knowing how hard to swing, I only cut about ½” deep. Everyone laughed at my feeble first attempt. After three more swings, I finally got deep enough to twist the blade and pop the bark slightly off the trunk. The manager smiled with approval. He then put the 4”x4” piece of bark back into the tree as if it would grow back somehow. It does.
We were then summoned to proceed into the forest by foot. The old cork trees were hundreds of years old and very large; approximately 75-100’ tall x 60’ wide. The trunks were easily 2-3’ wide. They were planted randomly about 50-75’ apart from one another, but not in rows like a plantation. The canopy was so dense that it was dark and quiet underneath. It was also noticeably cooler in the shade where we watched the workers mount aluminum ladders and resume their workday of harvesting the bark.
The farmers began carefully cutting the bark at the bottom of the tree in sections ranging from 4’ to 8’ long, tearing off each section with a raw wood-splitting sound. After they cut the bark, they do a quick twist with their ax blades which pops the bark off the trunk slightly. Then they take the opposite ends of the ax and shove it underneath the bark to help push the rest of the bark off the tree.
They worked their way up in a straight line vertically until they reached the first branches. Usually they stopped there unless the trees were large enough to use the bark on the limbs as well. In this case they were, so they climbed out on the limbs about 8-10 feet and removed that bark too. The sound of constant chopping and splitting could be heard throughout the forest with large chunks falling to the ground in a big pile.
Washing
These large pieces of cork bark lay one inside the other until they were picked up and shipped to the processing factory in Porto three hours north. When we arrived at the first factory we saw thousands of piles of cork bark, each pile 15’ tall, spread out over an area as far as our eyes could see.
These cork piles sit and season for several months outside. Then they are washed and boiled in water until they naturally become soft and flattened out. These cork carcasses are then delivered to their final processing plants where they would be turned into cork stoppers.
Sorting and Grading
The next step was to cut the large flattened pieces into smaller and narrower strips 4-5” wide and then grade each piece for caliber, classification, and defects. The pieces are first inspected by a worker visually and then sent through a high-tech piece of equipment that measures their width, length, porosity and density. Each and every piece was graded and then sorted into bins. The highest grades were used for cork stoppers, lower grades were used for flooring and veneers, and the rest were ground up into large, medium, and tiny granules.
How Stoppers are Made
At Amorim they make stoppers the old school way; by cutting them out piece by piece. The workers use a drill press by stepping on a pedal. This causes the cutting bit to drill through the edge of the bark to create the stopper shape.
While a cork stopper is created every 5-10 seconds, it goes through several more steps to produce the finished product.
The cork stoppers are sent again for evaluation where they were automatically inspected by a special machine for size, shape, and color. The tolerances must be precise in order to fit perfectly and snugly into different size wine bottles.
According to Amorim, they produce about 5 million stoppers per day and more than a billion per year! They supply about 70% of all the cork stoppers in the world.
Every Bit of Cork is Used
Only about 20% of the bark is used for stoppers and there’s a considerable amount of cork left over. The rest is either veneered into thin layers for flooring or ground up and agglomerated, i.e. pressed together into a mass of cork—much like a cork bulletin board.
In addition, the cork dust and excess granules are burned to create 60% of the heat and power for the factory. Amorim’s goal is to achieve net zero carbon emissions by 2025.
Cork Composites
The agglomeration process is handled by an Amorim subsidiary called Cork Composites. They utilize all of the waste cork to make hundreds of products from underlayment to shoes, purses, furniture, children’s toys, gaskets for automobile engines, filler for synthetic grass on sports fields, vibration controllers for commercial construction and railroads, surfboards, and, of course, bulletin boards and coasters…to name just a few.
Cork Insulation
There is another whole division dedicated to the production of acoustical and thermal insulation for residential and commercial buildings. This includes the fabrication of insulation for NASA and SpaceX space shuttles.
Amorim and Wicanders Cork Flooring
Finally, there’s the flooring division where they make several types of resilient flooring and wall coverings for commercial and residential use. The tour of this factory was of special interest to our team because we wanted to see, smell and touch every phase of the process—and we did.
Being in a clean factory with almost no odor other than that of cork was refreshing. We watched as they applied the veneers and pressed them directly onto the different waterproof cork or HDF cores using only heat and pressure. We then saw how those waterproof pieces were 3D printed directly on the surface. They were then finished in a different location.
From the agglomerated cork backing, to the waterproof cork core, to the veneered cork or 3D printed surface; we witnessed the entire sequence as workers and robots combined all these components into beautiful finished flooring.
Every part of the cork bark gets used in some way. Bits and pieces get ground down to cork granular, and what is too small for that gets collected as cork dust and gets converted to biofuel and powers over 60% of the manufacturing process.
Our relationship with Amorim has grown over the years and we expect that will continue as we take on new products and continue to educate our customers on the versatility and amazing benefits of cork.
From L to R: Aaron Hirshberg, Antonio Amorim (President), Joel Hirshberg
Shop Amorim Wicanders Cork Flooring
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Joel Hirshberg
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