There are about 600 species of oak, native to most countries in the northern hemisphere. Although in the UK we tend to think of the common oak as a quintessentially ‘English’ tree, we only have two species: the sessile oak (Quercus petraea) and the pedunculate oak (Quercus robur). The evergreen Holm oak (holm means holly), Quercus ilex (ilex is the holly genus) is native to the Mediterranean but was introduced to England in the 16th century. But there are lots of oaks from North America, including some of the most handsome, over 100 species that are found only in Mexico and another 100 or so from China. With so many species from so many countries it stands to reason that they vary hugely in size and shape but one thing that is constant is the fruits; that rounded fruit in the distinctive cup.

Although oaks are commonly valued for their timber possibly the most commercially important species is Quercus suber, the cork oak. This is an evergreen species found around the Mediterranean and grows well in climates with hot summers. It has been cultivated for centuries and has a long history of use, the corky bark making it useful for sandals and floats before it was used as corks for bottles. Today cork is grown commercially in Spain, France and Morocco but Portugal is the most important country and it produces 50% of the world’s cork. But cork production is under threat as synthetic corks gain in importance.

This is a shame because cork can be produced sustainably. The small trees are ready for their first harvest when about 25 years old. The bark is split and peeled off the trees without harming them. From then on the bark, when it has fully regrown, can be harvested about every ten years and a tree can be ‘cropped’ about a dozen times. But trees can live to twice that age, to about 250 years. The trees have other uses and the acorns are used to feed pigs. Cork oak trees and forests are legally conserved in Portugal and it is illegal to fell the trees.

This tree was at the JFK Arboretum near New Ross which I visited last weekend. I will post about the arboretum soon.

cork oak, pedunculate oak, quercus petraea, quercus robur, Quercus suber, sessile oak, what is cork, where does cork come from