By Isla Quinn
An axe. A cut around the trunk. Then a plank of bark comes away, and the tree stands there, bare and orange, and carries on living.
How it is taken
Wikipedia’s article on cork says extractors use an axe to make a horizontal “crown” cut around the trunk and vertical “rulers” cuts, then pry the planks free by pushing the axe handle into the rulers. The extractor must avoid damaging the phellogen, or the tree can be harmed. The planks are stacked to dry before shipping. Amorim, a cork producer, says on its own FAQ page that the work is done by hand by specialised professionals with a single tool, an axe, and that “the trees do not have to be cut down”.
Both sources give the same season: May to August. Amorim adds that this is when the tree is growing most actively and the bark is easiest to remove.
The wait
This is where the numbers wander. The first harvest comes when the tree is about 25 years old, says Wikipedia’s cork article, while another passage on the same page says 25 to 30. Amorim says 25. The trunk size is given three ways: about 24 inches (60 centimetres) in circumference on the cork page; a trunk diameter of about 70 centimetres on the Quercus suber page; and a 70-centimetre perimeter, measured 1.5 metres from the ground, from Amorim. Diameter and circumference are not the same measurement, and we report all three without choosing.
The gap between harvests is also given several ways. Wikipedia’s cork article says about every nine years, up to thirteen if the bark is slow. Its Quercus suber article says every nine to twelve years, every eight in warm conditions. Amorim says at least nine. The Spanish tourism board page for Los Alcornocales says every nine years, while Wikipedia’s article on that park says every ten to twelve.
How long the tree lives
Here too. Wikipedia’s cork article says trees live about 300 years. The Quercus suber article says more than 400 years, with harvested specimens typically 150 to 200 years old. Amorim says an average of 170 to 200 years. A tree can be harvested about 17 times, says Amorim, and five to seventeen times, says the Quercus suber article, which also gives a yield of 40 to 60 kilograms per harvest.
Thick enough to survive fire
The Quercus suber article says the thick, insulating bark protects the tree from forest fires, and that after a fire it regrows branches to refill the canopy. It describes an evergreen oak, 10 to 15 metres tall and occasionally up to 25, native to southwest Europe and northwest Africa. In Spain it grows mostly below 600 metres and is common in the southern half.
A park built around it
Los Alcornocales Natural Park lies in southern Spain, in Cádiz and Málaga provinces. Wikipedia says it was established in 1989, covers 1,677 square kilometres and has the most extensive cork oak forest in Spain. The Spain.info tourism page gives 173,619.52 hectares, which does not match 1,677 square kilometres (167,700 hectares), and we show both. It says the cork forests grow mainly between 200 and 900 metres, that the park holds the largest cork oak forest on the Iberian Peninsula, and that about 30 per cent of Spain’s cork production comes from the area. The highest peak it names is the Aljibe, at 1,091 metres.
Who makes it
Wikipedia’s cork article says the Mediterranean cork oak forest covers about 2,200,000 hectares and yields about 300,000 tons a year. By its figures Portugal produces 49.6 per cent and Spain 30.5 per cent, while Portugal holds 34 per cent of the forest and Spain 27 per cent. The Quercus suber article says Portugal produces about half the world’s cork. It names the extensively managed woodlands with cork oaks dehesas in Spain and montados in Portugal.
What is made from it
Wikipedia lists bottle stoppers as the most common use, about 60 per cent of cork-based production, and then gaskets, insulation, bulletin boards, floor and wall tiles, fishing floats, shuttlecocks and the seams of musical instruments. A separate passage says natural cork closures were used on about 80 per cent of 20 billion bottles produced yearly and about 60 per cent of stoppers in 2016. Those figures measure different things, and a reader could easily confuse them.
Dates in order
- 25 years: first harvest, according to Amorim and Wikipedia.
- May to August: the season, according to Wikipedia and Amorim.
- Every nine years and up: the cycle, according to Wikipedia, Amorim and Spain.info.
- 1989: Los Alcornocales Natural Park established, according to Wikipedia.
Side by side
| Question | Source one | Source two |
|---|---|---|
| Harvest cycle | nine years (Spain.info) | ten to twelve (Wikipedia, park article) |
| Park size | 1,677 square kilometres (Wikipedia) | 173,619.52 hectares (Spain.info) |
| Tree lifespan | about 300 years (Wikipedia, cork) | over 400 years (Wikipedia, Quercus suber) |
What kind of sources these are
Three Wikipedia articles, one national tourism page and a producer’s FAQ. The producer has a commercial interest in cork, and we use its page for the harvest practice and not for any claim about quality. Our reading: where sources differ on years, they may be describing different trees, regions or definitions. No source says so.
Questions a buyer would ask
Is the product natural cork, or an agglomerate? Where was the bark harvested, and how long ago? What does the maker say about the gap between harvests? We name no maker and no product, and we make no claim about sustainability beyond what the pages say.
What we left out
We left out the carbon figures on the cork page, because its own numbers do not match its own multiples. We left out an East Asian oak that Wikipedia names as a poorer source, to keep this piece to the Iberian tree. We left out the unfinished question of legal protections, which the cork page does not describe.
Roam first. Shop later.