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The 'Common Hazel' (''Corylus avellana'') is a species of hazel native to Europe and Asia. It is typically a shrub reaching 3-8 m tall, but can reach 15 m. The leaves are deciduous, 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 male pale yellow and 5-12 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, produced in clusters of one to five together, each nut held in a short leafy involucre ('husk') which encloses about three quarters of the nut. The nut is roughly spherical to oval, 15-25 mm long and 12-20 mm broad, yellow-brown with a pale scar at the base. The nut falls out of the involucre when ripe, about 7-8 months after pollination. It is readily distinguished from the closely related Filbert (''Corylus maxima'') by the short involucre; in the Filbert the nut is fully enclosed by a beak-like involucre longer than the nut.
Common Hazel is used by a number of species of Lepidoptera as a food plant. See List of Lepidoptera which feed on Hazels.
The name of the species, ''avellana'' is derived from Avellino, a place in Italy.

Contents

Cultivation and uses

Harvesting

Diseases

References

External links

Cultivation and uses

The Common Hazel is an important component of the hedgerows that were the traditional field boundaries in lowland England. The wood was traditionally grown as coppice, the poles cut being used for wattle-and-daub building and agricultural fencing.

Common Hazel is cultivated for its nuts in commercial orchards in Turkey, Italy, Iran and Caucasus. The name "hazelnut" applies to the nuts of any of the species of the genus ''Corylus''. This hazelnut or cobnut, the kernel of the seed, is edible and used raw or roasted, or ground into a paste. The seed has a thin, dark brown skin which has a bitter flavor and is sometimes removed before cooking. The top producer of hazelnuts, by a large margin, is Turkey, specifically the Ordu Province. Turkish hazelnut production of 625,000 tonnes accounts for approximately 75% of worldwide production.^[1]

In the United States, hazelnut production is concentrated in two states, Oregon and Washington; however, they are also grown extensively just to the north, in the Fraser Valley of British Columbia, Canada. In 1996 the production in Oregon was about 38,800 tons (in shell) compared to 200 tons in Washington^[2]. Recent orchard plantings in California are likely to increase production in the USA. The hazelnut is also growing in popularity in the USA with a Hazelnut Council set up to promote its use. The harvesting of hazelnuts is either by hand in rural communities, or by manual or mechanical raking of fallen nuts.
Hazelnuts are extensively used in confectionery to make praline and also used in combination with chocolate for chocolate truffles and products such as Nutella. In the USA, hazelnut butter is being promoted as a more nutritious spread than its peanut butter counterpart, though it has a higher fat content. In Austria and especially in Vienna hazelnut paste is an important ingredient in the world famous ''torts'' (such as Viennese hazelnut tort) which are made there. Vodka-based Hazelnut liqueurs, such as Frangelico, are also increasing in popularity, especially in the U.S. and eastern Europe.

Hazelnut is popular as a coffee flavoring, especially in the form of Hazelnut latte. Hazelnut-flavored coffee seems (to many users) to be slightly sweetened and less acidic, even though the nut is low in natural saccharides. The reason for such perception is not yet understood, but might be due to synergistic interaction with components of coffee.

In Australia over 2000 tonnes are imported annually^[3] mostly to supply the demand from the Cadbury company for inclusion in its eponymous milk chocolate bar which is the third most popular brand in Australia. Hazelnut oil, pressed from hazelnuts, is strongly flavored and used as a cooking oil. Hazelnuts are also grown extensively in Australia in orchards growing varieties mostly imported from Europe.
Hazelnuts are rich in protein and unsaturated fat. Moreover, they contain significant amounts of thiamine and vitamin B6, as well as smaller amounts of other B vitamins. Additionally, for those persons who need to restrict carbohydrates, 1 cup (237 ml) of hazelnut flour has 20 g of carbohydrates, 12 g fibre, for less than 10 net carbohydrates.^[4]
There are many cultivars of the Hazel, including 'Barcelona', 'Butler', 'Casina', 'Clark' 'Cosford', 'Daviana', 'Delle Langhe', 'England', 'Ennis', Fillbert, 'Halls Giant', 'Jemtegaard',Kent Cob, 'Lewis', 'Tokolyi', 'Tonda Gentile', 'Tonda di Giffoni', 'Tonda Romana', 'Wanliss Pride', and 'Willamette'. Some of these are grown for specific qualities of the nut including early and late fruiting cultivars, whereas other are gown as pollinators. The majority of commercial Hazelnuts are grown as grafts onto stock of the Turkish Hazel (''Corylus colurna''), because of its non suckering habit.
Primitive archers have also used the wood of the hazelnut in the making of arrows. The fine grain and tendency to grow with fairly straight shoots makes them suitable shaft material.

Harvesting

Hazelnuts are harvested annually between the months of September and October. As fall comes to a close, the trees drop their nuts and leaves. Most commercial growers wait for the nuts to drop on their own, rather than use equipment to shake them from the tree.
There are three primary pieces of equipment used in commercial harvesting; the sweeper, the harvester, and the forklift. The sweeper centralizes the material into rows, the harvester lifts and separates the nuts from the debris, and the forklift hauls the nuts away for processing.

The sweeper is a low-to-the-ground tractor that makes multiple passes up and down the rows with a 6 foot belt attached to the front that sweeps leaves, nuts, and small twigs from left to right, depositing the material in a row as it drives forward. On the rear of the tractor is a powerful blower that pushes material left into the adjacent row with wind speeds up to 200 mph. Careful grooming during the year and patient blowing at harvest can eliminate the need for hand raking around the trunk of the tree where nuts can accumulate. The sweeper will prepare two rows at a time as it goes up and down the rows. After its final pass, all the material on the ground has been deposited in two foot wide rows for the harvester to process. It is best to only sweep a few rows ahead of the harvesters at any given time, as the rows are susceptible to moisture and parasites over time.

The harvester is a slow moving machine that lifts the material off the ground and separates the nuts from the leaves, empty husks, and small twigs. As the harvester drives over the rows, a fast spinning cylinder with hundreds of tines rakes the material onto a belt. The belt takes the material over a blower and under a powerful vacuum that sucks the light weight dirt and leaves off the nuts and discharges it into the orchard. The remaining nuts are conveyed into a tote box.
Once a box fills with nuts, a third tractor will haul away full boxes and bring empties to the harvester to minimize time spent not collecting nuts.
There are two different timing strategies for collecting the fallen nuts. The first option is to harvest early when only half of the nuts have fallen. With less material on the ground, the machines can work much faster and are less subject to breakdown. The other option is to wait for all the nuts to fall and go over the crop once. The first option is easier, but takes longer to perform with two passes.
Ideally, the orchard should not be so dry that an abundance of dust can reduce vision and equipment efficiency. Conversely if it is too wet, mud cakes in the machinery and moisture weighs down the material, making it more difficult to lift and separate.

Diseases

References

1. ''World Hazelnut Situation and Outlook'', USDA 2004
2. Hazelnut Production (8/26/96), USDA NSS report
3. http://www.agric.nsw.gov.au/reader/deciduous-fruits/h3149-hazelnut-production.htm
4. Nutrition Facts, Bob's Red Mill All-Natural Hazelnut Meal/Flour (Amazon.com)

External links

★ Hazelnut Council

★ Hazel species profile on the Scottish Trees for Life website