There are many cultivars of the hazel cultivated for its nuts and others as ornamental plants. In Italy, the second hazelnuts producer after Turkey in the world, the hazel is intesively cultivated in few regions: Piedmont (cultivar Tonda Gentile Trilobata), Lazio (cultivar Tonda Romana), Campania (cultivar Tonda di Giffoni, Camponica, Mortarella e San Giovanni) and Sicily (cultivar "Nostrale" or "Sicilian"). Its fruit, the hazelnut, is edible and rich of oil, and it is utilized as food as it is, in the confectionery industry, in the cosmetics market and in the varnishes industry. 
The hazel (Corylus avellana L.
is a deciduous tree or large shrub reaching 5-8 meters tall and belongs to the Betulaceae family. Hazel has simple, rounded leaves with double-serrate margins. Each cultivar is self-sterile and needs to be pollinated by another cultivar. The fruit (hazelnut) is with an outer fibrous husk surrounding a smooth shell. The nut falls out of the husk when ripe. It is native to Europe and western Asia, naturally distributed from hill to middle mountain areas. Even if hazel prefers temperate locations - not too hot and dry - it is a colonizing plant without any particular needs, and easily adaptable to many different environmental conditions.