English Oak

English Oak

Description and Identification

English Oak Quercus robur, also known as Pedunculate Oak, is a large deciduous tree with twisted, spreading and heavy branches, forming a dense crown and can grow up to 38 metres in height (Johnson & More, 2015). Foliage is in arranged bunches and the bark is grey-brown with short but deep ridges. Leaves have deep and irregular lobes, with two small auricles at the base by the stalk, with hairless shoots and buds.
The other regularly occurring confusion species is Quercus petraea (Sessile Oak) however a key difference is that acorns on Q. petraea are practically stalkless and leaves have long stalks to separate the leaves from the branch (Johnson & More, 2015). Q. robur demonstrates the opposite of this, with acorns connected to the branch on long stalks (pedunculate) and grouped in cups of 1-3 (Cleave, 2015), and leaves connected to the branch by very small (5mm or less) stalks (Johnson & More, 2015).
Both male and female catkins (flowers) are produced in spring, with male catkins having a yellow colouration and hanging distinctively and female catkins being much smaller (Cleave, 2015).

English Oak field sketches, UEA, March 2019 (Max Hellicar)


Kingdom: Plantae
Division: Tracheophyta
Class: Magnoliopsida
Order: Fagales
Family: Fagaceae
Genus: Quercus
Species: Q. robur

Reasons for Presence

Quercus robur benefits the largest range of leaf-eating insects of any British plant species and has a lifespan of up to one thousand years (Johnson & More, 2015)!
Most woodland habitats are suitable for Q. robur to survive in (Cleave, 2015) and it is often dominant in old woodland. It is frequent across Britain and is tolerant to different soil conditions (i.e. clay, loam, sand) with the exception of chalky, marshy or very light soils (Johnson & More, 2015; RHS, 2018), preferring fertile soils and can tolerate flooding. UEA campus therefore, provides an ideal habitat for survival of this species, where it can be found frequently. Foliage is deciduous and this species prefers full sun or partial shade. It can grow in a range of pH conditions (alkaline, neutral and acidic) (RHS, 2018).
Quercus robur is often left as standards during coppicing of other woodland species (McShea & Healy, 2002) such as Hazel Corylus avellana and Hornbeam Carpinus betulus.

Family Characteristics

Fagaceae is a family of angiosperms including oaks and beeches, with 927 recognised species in eight genera (Christenhusz & Byng, 2016). This family consists of deciduous or evergreen trees and shrubs with simple leaves which are alternate, pinnate vein arrangement, flowers in the form of catkins, fruit in the form of cuples and calybia (McShea & Healy, 2002). The leaves of many species in this family are lobed, with stipules and petioles. Fruits of Fagaceae species generally do not have endosperms and the whole fruit may not be enclosed by the husk, for example the acorn and cup present on Q. robur (McShea & Healy, 2002). All of the circa 500 species of oak have acorns held in cups, with clustering buds at the tips of shoots which can dominate to the twisting and wide limbs present in many species. This family is one of high ecological importance, with Quercus species forming the foundations of temperate forests across the Northern Hemisphere (Last & Gardiner, 1981; McShea & Healy, 2002) and providing substantial food and habitat for a diverse range of wildlife.

References and Sources of Information

Christenhusz, M. J., & Byng, J. W. (2016). The number of known plants species in the world and its annual increase. Phytotaxa, 261 (3): 201–217.

Cleave, A. (2015). A Naturalist's Guide to Trees of Britain and Northern Europe. Oxford, UK: John Beaufoy Publishing.

Johnson, O., & More, D. (2015). Collins British Tree Guide. London, UK: William Collins.
Last, F. T., & Gardiner, A. S. (1981). Forest and Woodland Ecology. Cambridge, UK: Institute of Terrestrial Ecology.

McShea, W. J., & Healy, W. M. (2002). Oak Forest Ecosystems. Maryland, USA: Johns Hopkins University Press.

The Royal Horticultural Society. (2018). Quercus robur. Retrieved March 29, 2019, from The Royal Horticultural Society: www.rhs.org.uk/Plants/14294/Quercus-robur/Details