Hazel (Corylus avellana)
|Size||Height: up to 12 m (2)|
The hazel is classified as Least Concern (LC) on the IUCN Red List (1). It is widespread and common in the UK (3).
Hazel (Corylus avellana) belongs to the same family of trees as the birch (family Betulaceae), however it is often described as a bush rather than a tree, as it tends to produce several 'trunks' or shoots rather than just one (3). The brown bark is shiny, and tends to peel away in horizontal strips. The twigs are covered in short hairs (2); the roundish leaves have serrated edges, reach ten centimetres in length, and are also hairy (4). The male flowers are in the form of pendulous pale yellow catkins, which are known as 'lamb's-tails' (5); they open in February, a time when most other trees are leafless, and are one of the first harbingers of spring (3). The female flowers appear on the same branches as catkins, they are small red tufts on swollen bud-like structures, and it is these that develop into hazel nuts after fertilisation. The edible nuts grow in groups of up to four; they reach two centimetres in size and are sheathed by papery modified leaves (3). The English name for this tree derives from the Anglo-Saxon 'haesel knut'; haesel means cap or hat, and refers to the papery cap of leaves on the nuts (6).
Hazel has a wide distribution throughout Europe, reaching as far east as the Ural Mountains in Russia, and from Scandinavia in the north to Spain, Italy and Greece in the south. It is also found in North Africa, Turkey, Iran and the Caucasus region of south west Russia (3).
Throughout its range, hazel tends to occur as an understory species in deciduous woods, particularly oak woodlands (3). In Britain it is a common feature of hedgerows, where it is coppiced (2).
Pollination of hazel is by wind, and only takes place between different trees (a tree cannot pollinate itself). The catkins appear in February, but the leaves do not grow until April; they turn yellow before falling in October (3). The nuts are an important source of food for many animals, including red squirrels (Sciurus vulgaris), woodpeckers, dormice (Muscardinus avellanarius) and wood mice (Apodemus sylvaticus). Some nuts that are hoarded may germinate, and so these animals aid in the dispersal of the hazel (3).
Hazel lives for 50 to 70 years, but the ancient technique of coppicing can dramatically extend the life-span (3). This species has been employed by humans for a variety of uses during the past 6,000 years (5). Hazel poles, which result from coppicing, can be split lengthways, and can be twisted without breaking. They were used during the Neolithic to make wattle (hazel strips woven into a lattice), for the construction of wattle and daub houses. Wattle fencing has been used in more recent times as sound screens beside motorways (5). Hazel wood was (and still is) used to make staffs, crooks, walking sticks, and baskets. It is also the wood of choice for divining rods. Hazel leaves were used to feed cattle, and hazelnuts were an essential part of the diet of prehistoric humans. In Celtic mythology, hazel nuts were believed to represent concentrated wisdom (5).
Throughout Britain, there has been a prolonged decline of traditional forms of woodland management, particularly coppicing. At present, however, this ancient woodland skill is undergoing a revival in many areas.
The hazel has been rather neglected in terms of conservation when compared to other native trees. However, its importance has now been recognised, and steps are underway to conserve this species (3).
For more on the hazel, see the Trees for Life species profile:
For more on the wealth of folklore surrounding the hazel, see Trees for Life: Mythology and folklore of the hazel
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- Coppiced: traditional form of woodland management in which trees are cut close to the base of the trunk. Re-growth occurs in the form of many thin poles. Woodlands are cut in this way on rotation, producing a mosaic of different stages of re-growth.
- Deciduous: a plant that sheds its leaves at the end of the growing season.
- Fertilisation: the fusion of gametes (male and female reproductive cells) to produce an embryo, which grows into a new individual.
- Germination: the beginning of growth, usually following a period of dormancy and in response to favourable conditions. For example, the sprouting of a seedling from a seed.
- Neolithic: a cultural period of the Stone Age, which began around 10,000 B.C. The Neolithic is characterized by the making of polished stone tools and the development of agriculture.
IUCN Red List (April, 2011)
- Humphries. C.J., Press, J.R. & Sutton, D.A. (2000) Hamlyn guide to trees of Britain and Europe. Hamlyn, London.
Trees for life: restoring the Caledonian forest. Species profile: hazel. (Feb 2003):
- Press, B. (1996) Collins Wild Guide: Trees. Harper Collins Publishers, London
- Mabey, R. (1996) Flora Britannica. Sinclair-Stevenson, London.
Trees for Life: restoring the Caledonian forest. Mythology and folklore of the hazel. (Feb 2003):