Corylus colurna - Turkish hazel

Corylus colurna, also known as a Turkish hazel, belongs to the family of Betulaceae. It is the only type of hazel that grows as a tree and not as a shrub, which makes it a remarkable peculiarity within the genus Corylus. Originally from Southeast Europe and western Asia, the tree has also established itself as an ornamental and useful plant in Central Europe. The species is characterized by its striking bark, its attractive tree shape and its edible nuts.

Morphology and appearance

Corylus colurna is a deciduous tree that can reach heights of up to 20 meters in its natural environment. It often remains smaller in cultivation, but still grows significantly higher than other hazel species. The trunk is straight and is covered by a characteristic, thick and corky bark that has cracks and furrows in old age. This bark is gray to brownish colored and gives the tree a robust and distinctive appearance.

The leaves of the Turkish hazel are heart -shaped and about 6 to 12 cm long. They have a serrated edge and are dark green on the top and colored a little brighter on the underside. In autumn they turn yellow and offer an attractive sight. As with other types of hazelnut, the leaves are slightly hairy, which gives the plant a rough texture.

The flowers of Corylus colurna appear in front of the leaf output in early spring. The male flowers are organized in long, yellow kittens that become 5 to 10 cm long, while the female flowers are inconspicuous and only show small red scars. The pollination is carried out by the wind, which is typical for hazel species.

The fruit is a nut that is characterized by its round shape and a harder shell than in the ordinary hazel (Corylus avellana). The nuts are about 1 to 2 cm tall and surrounded by a dense, bristly fruit cup that almost completely envelops them and offers protection against predators. The tire nuts are edible and tires in late summer until autumn.

Distribution and habitat

The natural spread of Corylus colurna extends from Southeast Europe to the Balkan Peninsula to the Caucasus and Asia Minor. The species in Turkey can be found particularly often, which is why it is often referred to as the "Turkish hazel". In Central Europe it was mainly introduced as an ornamental tree and is now widespread in parks and along streets.

The Turkish hazel prefers sunny to partially shaded locations and thrives on different types of soil as long as they are well permeable and not too wet. It is particularly adapted to dry and limed locations, which makes it resistant to the urban climate conditions that are common in Central Europe.

Use and meaning

Corylus colurna is primarily used as an ornamental and road tree. Their deep root and high tolerance to urban stress such as air pollution, soil compression and road salt make them ideal for urban plantings. In addition, the dense crown offers good shadows and gives public and private green areas an elegant appearance.

The nuts of the Turkish hazel are edible like that of the ordinary hazel and have a mild, sweet taste. However, since the shell is harder and the yield is lower compared to the ordinary hazel, the nuts of the Turkish hazel are rarely used commercially. In some regions, the nuts are nevertheless collected and marketed regionally.

Baumhasel plays a subordinate role in traditional medicine, but its bark excerpt in some cultures is used to treat skin diseases.

Ecological meaning

Corylus colurna makes a valuable contribution to biodiversity in urban and natural habitats. The kittens in spring offer an early source of food for insects, while the nuts in autumn are an important source of food for numerous animal species such as squirrels, mice and different bird species. The dense tree crown also offers habitat and protection for birds and smaller mammals.

The Turkish hazel also contributes to the soil improvement and, thanks to its deep roots, promotes ventilation and stabilization of the soil. It can make an important contribution to preventing soil erosion and is particularly suitable for slopes and locations at risk of erosion.