Hazel has great cultural importance, providing essential materials, food and fuel since the dawn of civilisation; many woodlands were managed for it, and it is now valued for conservation. The Old English 'hæsel', meaning a cap or head-dress, refers to the frilly involucre surrounding the seed, the hazelnut.

Native to all of northern Europe, absent only from far-northern Scandinavia, ranging east to the Urals and into favourable spots in Turkey and Georgia. In Britain and Ireland it is very widespread and common except on waterlogged soils, often a woodland understorey and in hedgerows, banks, cliffs and gullies. In a few western Scottish and Irish sites it forms Atlantic hazelwood, an extraordinarily rare temperate rainforest variant.

Monoecious. Wind-pollinated. Seeds (hazelnuts) dispersed by small mammals and birds.

A small (15m), usually multi-stemmed tree, continually producing basal shoots and often coppiced into straight 'rods'. Bark bronze, smooth and burnished, peeling in fine shreds, fissuring with age. Twigs brown with long stiff hairs; buds green, oval. Leaves round to obovate, downy both sides, slightly lobed and coarsely double-toothed, abruptly pointed. Male catkins (7-9cm) open yellow in early spring; female tiny with red stigmas. Filbert differs: more lobed, shiny leaves, nut fully enclosed.

Grows in all but waterlogged and strongly acidic soils, tolerating sun and shade, and unharmed by late frosts. Commonly coppiced on 6-9-year cycles to produce straight, fork-free shoots, often as coppice-with-standards beneath oak. Useful in hedgerows for wildlife. Commercial 'cobnut' varieties (the same species) include 'Kentish Cob', 'Butler' and 'Merveille de Bollwiller'; 'Contorta' is corkscrew hazel. Its pollen commonly causes early-season allergy and oral allergy syndrome.

An important food plant for many insects, birds and mammals, including the endangered Hazel Dormouse (Muscardinus avellanarius). Many fungi associate with it, such as the rare Hazel Gloves (Hypocreopsis rhododendri) and Spring Hazelcup (Encoelia furfuracea), both found on trees in Atlantic hazelwoods.

Generally free from pests and diseases. Foliage is highly palatable to deer.

There are innumerable uses for hazel products, from woven fences and pea sticks, to thatching spars. Commercially, many hazelnuts are grown in southern Europe, but cobnut orchards can be found in south-east England.