Pedunculate Oak

The power and the beauty

In Western Europe the English oak is probably the tree that appeals most to the imagination. The trees are tall and can live for many centuries. The thick stems have a grooved bark and large branches support a full, dense crown with countless lobed leaves. In the autumn the tree makes an abundance of large, hard fruits each sitting in their own little cup: the acorns. In acidic, nutrient poor forests the oak may lose some of its splendour, whilst the tree given space can become especially large.

Painters from the 19th century Romantic period often depicted the mighty oak in their imaginative landscapes. The worship of this tree dates back to the Celts who regarded the tree as a symbol of strength (Latin: robur) and beauty (Celtic: quer). 

The space in and around the oak tree is rich in wildlife, especially insects and fungi. The tree provides shelter, hunting grounds, nesting and foraging sites. Oaks are very susceptible to mildew, a fungus that gets its food from the leaves. A suffering oak becomes a banquet table for the yellow, 22-spotted ladybird that feed on mildew rather than lice. Oak galls are also recognizable; these are nurseries for the gall wasp but sometimes for gall midges.

Economically, it was and is an important tree species. Western Europe was once covered with oak, most were felled at a time when the shipping industry across Europe was extensive (Spanish Armada etc.). The wood quality is excellent. It was once used to supply tannins (bark). It is excellent tree to plant along city streets to form tree-lined avenues, and also looks beautiful in parks.

Today oak cultivar seedlings are still selected for many reasons. Selection can be for winter hardiness, the shape of the tree or the leaves, or leaf colour. It can also be for the taste of the fruits for wildlife, the growth rate or resistance to different types of infestation, or the wood properties. Oak cultivars are propagated vegetatively, usually through grafting, whereas evergreen oaks are usually propagated via cuttings.

Oak cuttings are difficult, although this method works well with the American species. If an old tree is felled and suckers then appear, these can be used as cuttings. If these cuttings take, then more cuttings can be taken from them and so on.

A grafted oak will live for about 40-50 years unless there are problems arising through incompatibility with the rootstock.

Oak species native to the Netherlands include Quercus robur (the English-, pedunculate- or common oak) growing on low lying, nutrient-rich soils, and Quercus petraea (the sessile-, or durmast, oak) which occurs through Europe on higher, drier soils. Oak species cross easily so there are quite a few hybrid species. There are also very old oak trees of 1,000 years or more. A mature native oak of between 50 and 150 years produces 50,000 acorns annually. From a seedbank 60% will be true species and 0.5% will be hybrids.