Quercus robur - English Oak

Probably the best-loved British native tree, the English Oak is a familiar sight in parkland and the countryside. Its spreading, rugged shape, massive trunk and distinctive lobed leaves have all become a symbol for the British nation, and its seed, the acorn, is a logo for the National Trust. Long-lived, and with the highest conservation value of any of our native trees (it supports over 400 different species of insect) the English Oak is an essential part of our natural heritage.

Site and soil

Prefers heavy clay soils, but will do well on lighter soils which do not dry out. Good on exposed windy sites.

Height and spread

Below are the approximate stages of growth, assuming sited in suitable conditions for this species;

After 10 years: 4m x 3m
After 20 years: 9m x 5m

Leaf and bark

The almost stalkless leaves have 4-5 lobes and reach about 12cm in length. They turn brown before leaf fall in late autumn. The bark is grey and deeply fissured.

Flower, seed and fruit

The yellowish-green flowers are borne on the end of new growth in May; the male flowers and long catkins, the females small and inconspicuous. The fruit, the acorn, develops on the end of long stalks, the smooth oval green seed being held in a rough-textured cup. It ripens in autumn.

Uses

Woodland, parkland, specimen tree, commemorative tree.

The English Oak slows its growth down as it matures, producing a timber which is both very hard and very durable. Famously, it was used for building warships from Tudor times, and Nelson urged the government to plant more oak woodlands for this purpose during the Napoleonic Wars.

Oak was also used extensively in buildings and for furniture, and the bark was used for tanning leather. Oak sawdust and oak galls were used for making dyes and ink, and the bark has been used medicinally to treat lung disorders, as an antiseptic and in the treatment of diarrhoea. The acorns were a valuable food for pigs – and for humans in times of famine. The oak was the sacred tree of the Druids, and in some areas country customs such as tree dressing still survive. The oak is also the derivation of many place-names, for example Okehampton, Sevenoaks.

Wildlife

Over 400 species of insect depend upon the oak – more than any other native tree. Jays and small mammals eat the acorns. The oak comes into leaf late, allowing wild flowers and mosses to flourish. Older trees often develop hollow trunks, giving shelter to mammals and birds.