Hazelnut

In 1995, evidence of large-scale Mesolithic nut processing, some 8,000 years old, was found in a midden pit on the island of Colonsay in Scotland.

The evidence consists of a large, shallow pit full of the remains of hundreds of thousands of burned hazelnut shells.

The many cultivars of the hazel include 'Atababa', 'Barcelona', 'Butler', 'Casina', 'Clark', 'Cosford', 'Daviana', 'Delle Langhe', 'England', 'Ennis', 'Halls Giant', 'Jemtegaard', 'Kent Cob', 'Lewis', 'Tokolyi', 'Tonda Gentile', 'Tonda di Giffoni', 'Tonda Romana', 'Wanliss Pride', and 'Willamette'.

To enhance the possibility for mechanization and to prevent suckering, a single-trunk tree can be formed by grafting a scion of the desired variety on a Corylus colurna rootstock.

It has a 2 m (6 ft 7 in) belt attached to the front that rotates to sweep leaves, nuts, and small twigs from left to right, depositing the material in the center of the row as it drives forward.

On the rear of the sweeper is a powerful blower to blow material left into the adjacent row with air speeds up to 90 m/s (300 ft/s).

Careful grooming during the year and patient blowing at harvest may eliminate the need for hand raking around the tree trunk, where nuts may accumulate.

[16] The harvester is a slow-moving machine pushed by a tractor, which lifts the material off the ground and separates the nuts from the leaves, empty husks, and twigs.

The belt takes the material over a blower and under a powerful vacuum that sucks any lightweight soil, leaves from the nuts, and discharges them into the orchard.

In 2023, world production of hazelnuts (in shells) was 1.13 million tonnes led by Turkey with 58% of the total, and Italy and the United States as other major producers (table).

In a 100-gram (3+1⁄2-ounce) reference amount, raw hazelnuts supply 2,630 kilojoules (628 kilocalories) of food energy and are a rich source (20% or more of the Daily Value, DV) of numerous essential nutrients (see table).

Hazelnuts contain particularly high amounts of protein, dietary fiber, vitamin E, iron, thiamin, phosphorus, manganese, and magnesium, all exceeding 30% DV (table).

In lesser but still significant amounts (moderate content, 10–19% DV) are vitamin K, calcium, zinc, and potassium (table).

The hazelnut is used as a literary device by Julian of Norwich (c. 1343 – after 1416) within her mystical Christian treatise Revelations of Divine Love.

[23] The hazelnut shell is imagined as a chariot for the fairy Queen Mab within English playwright and poet William Shakespeare's play Romeo and Juliet.

The hazel fruit is also used as a metaphorical device in the poem To Autumn by the English Romantic poet John Keats.