It is a large tree, native to most of Europe and western Asia, and is widely cultivated in other temperate regions.

It grows on soils of near neutral acidity in the lowlands and is notable for its value to natural ecosystems, supporting a very wide diversity of herbivorous insects and other pests, predators and pathogens.

[5][6][7] The leaves are arranged alternately along the twigs and are broadly oblong or ovate, 10–12 centimetres (4–4+1⁄2 in) long by 7–8 cm (2+3⁄4–3+1⁄4 in) wide, with a short (typically 2–3 millimetres or 1⁄16–1⁄8 inch) petiole.

The male flowers occur in narrow catkins some 2–4 cm (3⁄4–1+1⁄2 in) long and arranged in small bunches; the female flowers are small, brown with dark red stigmas, about 2 mm in diameter and are found at the tips of new shoots on peduncles 2–5 cm long.

[5] Turkey oak is also sometimes confused with it, but that species has "whiskers" on the winter buds and deeper lobes on the leaves (often more than halfway to the midrib).

[16] The populations in Iberia, Italy, southeast Europe, and Asia Minor and the Caucasus are sometimes treated as separate species, Q. orocantabrica, Q. brutia Tenore, Q. pedunculiflora K. Koch and Q. haas Kotschy respectively.

It is a long-lived tree of high-canopy woodland, coppice and wood pasture, and it is commonly planted in hedges.

When compared to sessile oak, it is more abundant in the lowlands of the south and east of Britain, and it occurs on more neutral (less acid) soils.

Sometimes it is found on the margins of swamps, rivers and ponds, showing that it is fairly tolerant of intermittent flooding.

[8] One of the most distinctive galls is the oak apple, a 4.5 cm diameter spongy ball created from the buds by the wasp Biorhiza pallida.

[23] The most common caterpillar species include the winter moth, the green tortrix and the mottled umber, all of which can become extremely abundant on the first flush of leaves in May, but the oak trees do recover their foliage later in the year.

[8] The acorns are typically produced in large quantities every other year (unlike Q. petraea, which produces large crops only every 4-10 years)[8] and form a valuable food resource for several small mammals and some birds, notably Eurasian jays Garrulus glandarius.

[citation needed] Quercus robur is planted for forestry, and produces a long-lasting and durable heartwood, much in demand for interior and furniture work.

There are rays of thin (about 0.1 mm or 1⁄256 in) yellow or light brown lines running across the growth rings.

[26] Additionally, although bitter due to their high tannin content, the acorns can be roasted and ground into a coffee substitute.

[27] In the Scandinavian countries, oaks were considered the "thunderstorm trees", representing Thor, the god of thunder.

[28] A Finnish myth is that the World tree, a great oak which grew to block the movement of the sky, sunlight and moonlight, had to be felled, releasing its magic, thus creating the Milky Way.

After the announcement of General Charles de Gaulle's death, caricaturist Jacques Faizant represented him as a fallen oak.

[32] In Germany, the oak tree can be found in several paintings of Caspar David Friedrich and in "Of the life of a Good-For-Nothing" written by Joseph Freiherr von Eichendorff as a symbol of the state protecting every citizen.

The naval associations are strengthened by the fact that oak was the main construction material for sailing warships.

[43] This is based on research by Aljos Farjon at the Royal Botanic Gardens, Kew, who found that there were 115 oaks (of both species) in England with a circumference of 9 m or more, compared with just 96 in Europe.