BARKing Mad & Little Chambers - Cork Tree
Hello and welcome to another week of Rooted where this time i wanted to talk about a tree you’ve maybe never heard of, despite using pretty often- CORK
I had no idea corks literally grew on trees (well, I guess the whole tree is really one big cork) until we got to visit one at the Natural History museum here in LA, which made me ask about a million questions like “how long does it take to grow a tree that can make cork? How often can you harvest and what is THAT like? How do you get into cork farming? With that in mind, this week I wanted to answer those questions for myself and take you along for the ride!
For starters Cork comes from cork oak, or quercus suber, which is an evergreen oak with a native range spanning from europe to the mediterranean. While it’s a kind of narrow band, it does make sense because this tree is OOOOOOOLD. We’re talking dated back to the tertiary period, each tree can live up to 200 years old, and much like older adults, they just need specific conditions to thrive okay?
These conditions are specifically not too crowded, not too much light, not too cold, and with enough humidity and nutrients in the soil to just kinda chill..and like, can we blame them?
This makes the absolute best spot for them Portugal and Spain, with Portugal actually producing about 50% of the world's entire cork.
As far as looks go, this tree is pretty tall, maxing out at about 50 feet (15 meters, and growing to a diameter of 39 inches- which is actually pretty thick for a tree! Their leaves are described as being leathery, toothy ovals that grow on slender sticks that become huge knotty branches as they age. The bark starts smooth, but gets craggly and kind of spongey looking with age, which we will tough on in a second.
Like most oaks, these guys produce acorns, and while they are technically edible with enough leaching, from what I have read it’s a lot of work for very little pay off, so you’d be better off finding a different acorn with more sugars to snack on.
Now back to that bark- this is actually going to be our main focus, since as you might have guessed, this is where we get the actual cork material from. And, it;s kind of a process- but I think the best way to take you through it is to go through it in terms of the life of the tree.
SO from the ages of 1-25, the ONLY thing cork oaks are doing is staying alive and growing. And as they start reaching maturity, they put on a whole bunch of extra layers of cambium. This protects them from the fires known to spread in their region, and helps them to retain moisture and stay cool in the hotter dry months.
After 25 years, we’re ready for our first cork harvest, which has to be done ENTIRELY by hand, and by people who know what they are doing. This first harvest tends to be a little wonky and the densities can vary a lot, with some having less room for air pockets and some layers having more or big gaps while the tree was getting established. THis is normal, but it does mean it’s not the best quality, so this cork is referred to as “male cork” and will probably only be used for links like mats and other industrial/building uses.
After this harvest, the tree will be cared for and tended to for another 9-12 years before its cork could be harvested again without harming it. The reason it’s 9-12 is because farmers will typically only harvest once every 3 years to be able to manage any pests or infections that might come to these oak forests more frequently if they did it every year.
The second harvest is generally better the first, but it isn;t until year 3 that the cork is consistent enough to be used in wine and other food products, with this harvest and the 4th being generally the best of the best, and the start of the so called “female bark”
Most cork oaks will only be able to be harvested 20 times at the most, so farmers really have to make each harvest count. Interestingly, cork farming is typically a family farming practice, with most of the trees staying under the care of the same family for generations- some for their entire lives.
And this makes sense when you consider how specific the work is, and how much knowledge goes into it. While it’s something you CAN learn, the work is grueling and sort of inconsistent with that 3 year break between. Many of these farms would say cork farming is the main source of income, but is very unlikely to be their only crop.
Another interesting fact about cork farmers is that they aren’t actually paid by volume or units like most farmers, but are instead paid around $150 an hour for their skills- making them on average some of the best paid farmers in the world.
But before we all jump into dreaming of cork farming, let’s go over what exactly these people are DOING all day during the harvest. For every tree that have to first, very carefully, remove the bark with a sharp knife, then with a different knife and up to 5 people per tree, they must make clean, long cuts to remove as much bark in as thick and uniform layers as possible, being careful not to cut too deeply and risk harming the tree. Then, in the months that follow they have to careful look over the trees to be sure they don't get infected with a gnarly canker or eaten by spongey moth larva while they grow their bark back….and when you consider that these trees don’t like to be too close together, and every one has to be harvested by hand- it’s a crazy amount of work to do in one season!
Additionally, location really matters here- the only cork used is grown and produced in the fertile crescent, a it’s the only place with the exact right conditions for the buoyant, airy, water tight corks the wine industry NEEDS to make sure their products are sealed properly- kind of a big job even without risking the wrath of 10000 wine moms if you mess up!
Portugal takes its trees seriously, and rightfully so- all of them are protected legally, so it’s a felony to cut one down or intentionally harm one. In fact, these forests are so widely loved that they are referred to as the Amazon forest of Europe, and create very unique conditions for biodiversity! Lots of the photos have baby lynx hiding behind them, but all kinds of birds, bugs, fungi, and other critters rely on these guys for food, shelter, and safety, so they play a vital role in keeping the ecosystem functioning, especially in times where fires disrupt the landscape.
Outside of being useful in beverages and biodiversity, cork is actually how we discovered cells! Okay well it’s how we started piecing it together, when biologist Robert Hooke took a peak at a piece of these bad boys and saw all the chambers, which he called cells, which in latin means “little rooms” and as we kept getting better microscopes the rooms just kept getting smaller and smaller!
As far as folklore goes, the Greeks are said to have viewed cork oaks as a symbol of respect and resilience, but that was about all I could find on them specifically! There is some folklore around oaks, but I am going to save that for a more general oak episode when we can really dig deep into that, galls, and all kinds of other fun oaky things!
If you ever find yourself somewhere that has a cork oak, do yourself a favor and go stare at it for a bit! They are such an interesting tree, and absolutely not something most of us see every day!
That’s all I’ve got for this week, but I’ll be back next week with a deep dive on the History of Houseplants to celebrate PlantCon Orlando being next weekend! See you then!
Source:
https://en.wikipedia.org/wiki/Quercus_suber
https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=c943
https://annforsci.biomedcentral.com/articles/10.1007/s13595-012-0197-0
