Sessile refers to the absence of a stalk (peduncle) for this species’ acorn, while its species epithet petraea means ‘growing amongst rocks’, which is apt given its preferred habitat. Also known as Irish Oak or Durmast Oak.
Native to most of Europe, from southern Scandinavia to northern Iberia and southern Italy. Native to Britain and Ireland and widespread, though generally less frequent in a swathe across England between the Severn Estuary and the Wash, and in central Ireland.
Monoecious, with drooping male catkins and tiny red female flowers. A pioneer, thanks to palatable acorns dispersed by birds and mammals. It produces a second summer flush, Lammas growth. Heavy seed years (mast crops) occur every three to four years. Long-lived, several specimens exceeding 1,000 years across north-west Europe.
Stately and tall (35-40m) on fertile sheltered sites, with an upright form and straight branching, but twisted and stunted at altitude. Bark brown-grey with shallow short ridges. Leaves elliptic, with at least five regular shallow triangular lobes, no intercalary veins, stellate hairs beneath, a wedge-shaped base without auricles, on a long petiole (10-25mm). Acorns sessile. Pedunculate Oak differs: backward auricles, short petiole, intercalary veins, stalked acorns.
Grows on many soils and is quite drought-tolerant. Light-demanding. It regenerates well naturally, but only where deer numbers are controlled. Foresters often consider it better suited to forest conditions than Pedunculate Oak; some celebrated oak woodlands, such as the Forest of Bellême in Normandy, are dominated by Sessile Oak grown on 200-year cycles. In Britain and Ireland it is often a standard over Hazel coppice.
With Pedunculate Oak it supports the richest wildlife of any tree in the region: some 2,300 species across all groups are closely associated, including obligates such as the Purple Hairstreak butterfly (Favonius quercus). In the rare Atlantic oakwoods (a temperate rainforest) of western Britain and Ireland, Sessile Oak dominates, its limbs festooned with mosses, liverworts and ferns.
Detailed under Pedunculate Oak.
Its heartwood is durable and strong, desired for boat-building, house framing, furniture and joinery. Otherwise, it was often coppiced for charcoal-making, especially in remoter areas.
