Quercus robur
A long-lived oak supporting high biodiversity across Europe and Asia.
Quercus robur, also called pedunculate oak, European oak, or English oak, belongs to the Fagaceae family, which includes beeches and oaks. This large tree is native to Europe and western Asia and is widely planted in other temperate areas. It thrives in lowland soils with near-neutral acidity and is ecologically important, hosting many herbivorous insects, acorn-eating mammals and birds, and fungi. The name "pedunculate oak" comes from its acorns growing on a stalk, or peduncle. English oaks can become very old, often living over 500 years, with some specimens thought to exceed 1,000 years. Their bark is thick and deeply fissured.
This deciduous tree usually reaches about 20 meters in height at maturity, sometimes up to 40 meters, with a stout trunk typically up to 4 meters in girth (circumference at breast height), occasionally exceeding 10 meters, and reportedly 14 meters in pollarded individuals. Older trees are often pollarded, with a main trunk about 3 meters long, and tend to live longer and grow stouter than unpollarded ones. The crown is spreading and unevenly domed, often with massive lower branches. The bark is greyish-brown with close grooves and vertical plates. Large burrs on the trunk frequently produce many small shoots. Oaks do not produce suckers but recover well from pruning or lightning damage. Twigs are hairless, and buds are rounded, brownish, and pointed. Leaves are arranged alternately, broadly oblong or ovate, 10–12 cm long by 7–8 cm wide, with a short petiole (2–3 mm). They have a cordate (auricled) base and 3–6 rounded lobes that do not cut more than halfway to the midrib. Leaves are usually hairless or have a few simple hairs underneath, dark green above and paler below, and often develop small disks of spangle gall by autumn.
Flowering occurs in spring (early May in Northern Europe), with wind-pollinated flowers. Male flowers appear in narrow catkins 2–4 cm long, arranged in small bunches. Female flowers are small, brown with dark red stigmas, about 2 mm across, and sit at the tips of new shoots on peduncles 2–5 cm long. Acorns grow in clusters of 2–3 on a long stalk (4–8 cm). Each acorn is 1.5–4 cm long, ovoid with a pointed tip, starting whitish-green, turning brown, then black. They sit in a distinctive shallow cup, useful for identification. This species bears large acorn crops every other year.
Chemically, Q. robur contain
- scientific_name
- Quercus robur
- family
- Fagaceae
- native_range
- Europe and western Asia
- typical_height
- up to 20 m, sometimes 40 m
- lifespan
- often over 500 years, some over 1,000 years
- common_names
- pedunculate oak, common oak, European oak, English oak
Lore & Background
Quercus robur is a deciduous tree, typically maturing at up to 20 m in height, sometimes reaching 40 m, with a stout trunk up to 4 m in girth, occasionally exceeding 10 m, and reportedly 14 m in pollarded specimens. Older trees tend to be pollarded, with boles about 3 m long, and often live longer and become more stout than unpollarded trees. The crown is spreading and unevenly domed, with massive lower branches, and the bark is greyish-brown, closely grooved with vertical plates. The leaves are broadly oblong or ovate, 10–12 cm long, with a cordate base and 3–6 rounded lobes, dark green above and paler below. Flowering occurs in spring, with wind-pollinated male flowers in narrow catkins and small female flowers at the tips of new shoots. The acorns are borne in clusters of 2–3 on a long peduncle 4–8 cm long, each acorn 1.5–4 cm long, ovoid with a pointed tip, starting whitish-green and becoming brown then black.
Reader's Guide
Quercus robur is valued for its importance to insects and other wildlife, famously supporting the highest biodiversity of insect herbivores of any British plant, with at least 400 species. In 2019 it was estimated that 2,300 species of insect, bryophyte, lichen, bird, mammal or other species are associated with Q. robur in the UK. The acorns form a valuable food resource for small mammals and birds, notably Eurasian jays, which were overwhelmingly the primary propagators of oaks before humans began planting them commercially. The species is planted for forestry and produces a long-lasting and durable heartwood, much in demand for interior and furniture. It is the type species of the genus Quercus and was named by Carl Linnaeus in Species Plantarum (1753). Its genome was completely sequenced, with the first version published in 2016, comprising 12 chromosome pairs, about 26,000 genes and 750 million base pairs.
Did You Know?
- The common name pedunculate oak refers to the acorns being borne on a peduncle, or stalk.
- English oaks can live for over 500 years, with some specimens believed to be over 1,000 years old.
- The species supports at least 400 species of insect herbivores, the highest of any British plant.
- Jays were the primary propagators of oaks before humans began planting them commercially.
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