The Turkish Hazel (Corylus colurna) is a tree native to southeast Europe and southwest Asia, from the Balkans through northern Turkey to northern Iran. It is the largest species of hazel, reaching 35 m tall, with a stout trunk up to 1.5 m diameter; the crown is slender conic in young trees, becoming broader with age.
The bark is pale grey-buff, with a thick, corky texture. The leaves are deciduous, rounded, 6-15 cm long and 5-13 cm across, softly hairy on both surfaces, and with a coarsely double-serrate to shallowly lobed margin.
The flowers are produced very early in spring before the leaves, and are monoecious, with single-sex catkins, the male pale yellow and 5-10 cm long, the female very small and largely concealed in the buds, with only the bright red 1-3 mm long styles visible. The fruit is a nut 1-2 cm long, surrounded by a thick, softly spiny and bristly involucre (husk) 3-4 cm diameter, which encloses all but the tip of the nut; the nuts are borne in tight clusters of 3-8 together, with the involucres fused at the base.
Turkish Hazel is widely cultivated as an ornamental tree in Europe and North America; this species does not conform to the typical stereotype of hazels as being shrubs, instead being a large tree with a single straight, stout, trunk.
Trunk-scope: from 12 - 14 cm