Facts and History of the Cork Oak

The cork oak is a magnificent tree to behold. Known botanically as Quercus suber, the cork oak is native to the Mediterranean regions of Europe and North Africa where it has been grown and cultivated for centuries.

In comparison to other species of oak, the cork oak is a relatively medium sized tree at maturity, with a height that typically tops out at 65 feet tall. It has wide spanning branches that dip and arch to the ground, similar to that of the Live oak (Quercus virginiana) but not nearly as wide. The leaves of the cork oak are dark green and oval shaped with scalloped edges, rather than the typical lobed shaped, and are also evergreen and retained on the branches for two years. As with all oaks, the cork oak produces seeds in the form of acorns that are 1 to 1.5 inches long with caps that cover approximately half of the acorn. Acorns are produced once a year in the fall and provide food for wildlife.

The most distinguishing feature of the cork oak is its bark which is very thick and durable and is what most readily comes to mind when describing this tree. The bark of this oak, unlike most other types of trees, can regenerate itself after being removed. The cork is then used to make various products such as  wine bottle corks, bulletin boards, shoe insoles and as insulation. Cork can be taken from trees that have reached at least 20-25 years in age and then harvested again every 9-12 years as it takes time for the oaks to re grow their bark. Most cork oaks have a life span of 100-200 years and can be harvested multiple times. New trees are produced through the germination of acorns which are then cared for in nurseries before being planted out in the fields. The largest production of cork occurs in Portugal where acres of cork oaks are grown, cared for and harvested to produce some of the finest  wine bottle corks in the world.  Although there are now alternatives being manufactured as stoppers for wine bottles, natural cork still remains the prevalent material for wine bottles.

An attractive tree in its own right, the cork oak can be grown as an ornamental, given the correct growing conditions. Growing requirements include full sun, ample room to spread its branches, ample amounts of water and well draining soil. Listed as able to grow in USDA zones 7-11, the best climates for growing these trees are similar to that of the Mediterranean, such as California, where temperatures remain balmy year round. When grown as an ornamental that is not used in cork harvesting, the bark becomes quite thick and will display patterns of cream and gray on its heavily textured surface.

The cork oak is a great representation of a tree that has both natural beauty and also produces  a sustainable product. As long as humans continue to make wine or need a natural material that is both light and extremely durable, the cork oak will always be a tree used in cultivation as well as a symbol of rugged endurance.