Harvesting Cork

Cork oaks, Quercus suber, are amazing. Not only are they beautiful, stunning trees but they are icons for sustainability. The bark is harvested once the oak is at least 20-25 years old and can be harvested again and again every nine to twelve years until the tree reaches 200 years old! It is generally thought that the bark evolved as a protection from forest fires and other extreme conditions in its environment. The cork contains a unique waxy substance called suberin (hence the Latin name) that is virtually impermeable to liquids and gases which also prevents it from rotting. This explains why cork has successfully been used for wine stoppers for over 400 years.

Robert Hooke in the mid 1660s was fascinated with the structure of cork under the microscope noting that it resembeled a “honey-comb” structure and was much like the “cells” where monks prayed and slept. This story is told in the book To Cork or Not to Cork and the author contends that Hooke called the structures cells due to this likenss and coined the term cells “given to the building blocks of all living things” (p6).

Cork Oak forests support a diverse ecosystem in themselves, and because people have become attuned to the parameters of harvesting with the trees, it can be seen as an impressive symbiotic relationship that has developed between people and the oaks. They are native to Spain, Portugal, North Africa, France and Italy and cover vast areas in these countries. Although folks have attempted to grow them in the states (California), the bark did not create the desired cork properties and basically failed for the purposes of harvesting proving that indeed some things cannot be replicated outside their natural geographic environment.

Amazingly, harvesting the cork does not harm the tree. This is especially impressive because due to the biological make up of trees, removing large strips of bark can sometimes result in a fatal injury or severe damage compromising the health of the tree. Just underneath the bark, the layers of a tree support the entire plant because food and water is moved through transportation systems housed in these layers.

There are some videos available online showing the harvesting of cork, but I liked this one best: Cork Harvest in Catalonia.

References and additional Resources
Cork and the Cork System
How Stuff Works
Absolute Astronomy
Jelinek
World’s Largest Cork Tree