The Common hazel (Corylus avellana) belongs to Betulaceae (the Birch family). It is a small deciduous tree that is native to Europe, including the British Isles and western Asia. It is an important component of the hedgerows that were the traditional field boundaries in lowland England. This tree is typically a shrub reaching 3-8 m tall, but can reach 15 m. The leaves are rounded, 6-12 cm long and across, softly hairy on both surfaces, and with a double-serrate margin. The flowers are produced very early in spring, before the leaves, and are monoecious with single-sex catkins. The fruit is a nut, and called hazelnut. Hazelnuts are rich in protein and unsaturated fat. This tree is cultivated for its nuts in commercial orchards in Europe, Turkey, Iran and Caucasus. The photos are a cultivar "Corkscrew hazel" (cv. Contorta).