Hazelnuts

24.05.17

The hazelnut (Corylus avellana) is a member of the birch family of trees. Hazelnuts are shrub-like deciduous trees growing up to six metres, originating from the temperate regions of Europe including Turkey, Iran and Syria. The nuts form during summer and ripen in late summer to early autumn. In most varieties, the ripe nuts fall to the ground. The nuts are dried and can be kept in-shell for many months prior to cracking. The terms ‘filbert’ and ‘hazelnut’ are often used interchangeably to include all plants in the genus Corylus. In the United Kingdom, the term ‘cobnut’ is often used.

Overview

Hazelnuts are regarded as a health food, being high in monounsaturated fats, oleic acid, protein, vitamin E, calcium and potassium. Hazelnuts can be eaten whole, raw or roasted; or they may be crushed or ground and used as an ingredient in confectionery and baked goods.

Hazelnuts have been grown commercially, but not to a large extent, in Australia for over 100 years. Interest in hazelnut production reignited in the 1970s, with a new suite of varieties introduced and some level of industry coordination was achieved by the 1990s. However, hazelnut production in Australia has only averaged about 170 tonnes per year and there has been a market deficit between local production and estimated domestic market requirements. In late 2013, a large global confectioner announced a AU$70 million hazelnut project in Australia. The group, which makes chocolates and hazelnut spread, planted one million hazelnut trees on 2,600 hectares in the Riverina of New South Wales. This significantly dwarfs the previous total industry growth target of 200ha by 2015, as estimated by the Australian Nut Industry Council.

Hazelnut production is a small and developing industry in Australia, and its growers are represented by the Hazelnut Growers of Australia.

Facts and figures

Hazelnuts were introduced into Australia more than 150 years ago
Hazelnuts have traditionally been a crop for cool temperate regions of southern Australia, however a very large orchard was planted in 2014 in the warm temperate region of western New South Wales
Hazelnuts can be used whole as a table food, or processed in a range of confectionery and bakery products
Global production is approximately 800,000 tonnes, 54% of which was produced in Turkey

Production status

Nearly 800,000 tonnes of hazelnuts were produced globally. Turkey accounted for 54% of world production for that period. Other important production areas include Italy, Spain and Oregon in the United States of America.

Australia is estimated to produce 60 tonnes of hazelnut kernels, and imports about 2,000 tonnes of kernels.

As at 2012, there were about 130 hectares planted to hazelnuts in Australia. In 2013, an international company planted 2,000 hectares in the New South Wales Riverina for hazelnut production.

Hazelnut production in Australia occurs at several levels. There are commercial-scale growers with between 1,000,000 and 1,000 trees, as well as smaller producers with less than 1,000 trees. Hazelnut enterprises are often combined with other agricultural enterprises or pursued as a part-time enterprise or a hobby, rather than a main income source.

Map of current and potential growing regions

Uses

Hazelnuts are enjoyed as a whole nut, raw or roasted; or they can be used in a wide range of food products, such as muesli and salads. Ground or crushed, it is a key ingredient in confectionery such as gelato, bakery goods and chocolates. Praline is a paste made from hazelnut meal and has a wide range of uses. Oil obtained from cold pressed raw kernels is high in vitamin E and monounsaturated fatty acids and can be used in salad dressing and cooking. Flour from residual meal after oil extraction can be used as a flour substitute and is gluten free. Noisette (hazelnut) liqueur is made from green hazelnuts.

Hazelnuts are regarded as a health food, being high in monounsaturated fats, protein, vitamin E, calcium and potassium. Their high oleic acid content has been linked to lowering levels of blood cholesterol and the risk of death from coronary heart disease is reduced by 50% in people consuming hazelnuts at least once per day.

The health benefits of nuts have been strongly promoted to health professionals through the Nuts for Life program; and nut consumption in Australia has increased over the life of the campaign.

Another potential use for hazelnuts is as a sustainable and high-yielding feedstock for biodiesel; theoretical estimates indicate that hazelnut oil yield is potentially around twice that of soybeans. The high-quality protein meal remaining after oil extraction may add substantial value to the hazelnut crop in the form of animal feed or in other products such as baked goods or supplement bars. However, its use in this manner has not yet been fully evaluated.

Production Requirements

Growing regions

In Australia, the main hazelnut production areas are the Central Tablelands of New South Wales and the alpine valleys of north east Victoria. However, hazelnuts are also grown in the Dandenongs and Gippsland in Victoria; the northern and southern districts of Tasmania; and the Southern Highlands and South Coast of New South Wales. Other potential areas identified for hazelnut production include the Mount Gambier district and parts of the Adelaide Hills in South Australia, and the Manjimup district of Western Australia.

Soil type

Soil characteristics are a key factor for successful hazelnut production in Australia. Clay loams and loamy clays that are well structured and have a loam texture to a depth of at least 500mm, are the most suitable soils. Hazelnuts will grow on heavy clay soils and shallow soils, but they will be less productive.

The ideal soil pH for hazelnuts is considered 6.5–7.5. High levels of soil manganese on some red volcanic soils with low soil pH may have an adverse effect on trees but both problems can be overcome with liming.

Climate

Generally, hazelnuts require a relatively cool temperate and typically Mediterranean climate, with winter and spring dominant rainfall, and a dry autumn.

Average annual rainfall should be greater than 850mm, but supplementary irrigation should be available to ensure consistent soil moisture during key growth stages.

There are varietal differences for ideal temperatures but generally, the mean maximum temperature for the hottest month should be less than 31°C. A mean maximum temperature in the coldest month of less than 10°C, and about 1,200 hours below 7°C, is sufficient chilling to initiate kernel production.

When dormant, hazelnuts can tolerate temperatures as low as –15°C. During the time of pollination, June–August, the pollen and stigmas can be harmed by temperatures below –10°C and above 20°C. While frost damage can occur in Australia, frosts are generally not a limiting factor for production.

Varieties

There are a number of characteristics to consider when selecting a hazelnut variety or varieties to grow, including high yield potential, high percentage kernel weight, shape, free-falling from tree, maturity, time to bear and resistance to pests and diseases. End use will also be an important consideration, as the nuts best suited to processing may come from different varieties to those best suited to the fresh table nut market.

Variety evaluations and grower experience have shown five varieties — Barcelona, TBC, Lewis, Ennis and Tonda di Giffoni — that consistently perform and yield well in the cooler temperate areas of New South Wales, Victoria and Tasmania. Australian growers have reported that varieties grown in one region may not be suited to another, suggesting an interaction between climate and/or soils and varietal performance. This observation is consistent with overseas experience. In Italy, for example, the cultivars grown in the central and southern parts of the country appear to have lower chilling requirements for flowering and bud burst, compared with some varieties grown in much colder climates, such as Oregon, in the United States of America.

Hazelnuts are not self-fertile and depend on wind pollination for fertilisation of the flowers. Therefore, the planting has to be a mixture of the main (target) variety along with a genetically compatible pollenising variety. The selection of appropriate pollinisers is a critical aspect of hazelnut production, and as well as being genetically compatible, the polliniser must shed pollen at a time when the female flowers of the main variety are receptive.

A ratio of one polliniser tree to nine main crop trees is generally recommended to ensure sufficient pollen is spread throughout the grove. The polliniser trees can be planted in rows of their own or within rows of the main variety. The Hazelnut Growers Handbook discusses planting options in more detail.

Useful information on varieties and nut characteristics for Australian growers was gained from a 12-year variety assessment for south-eastern Australia. Prospective growers are also advised to speak with industry advisors, specialist nurseries and potential buyers about suitable varieties for their location.

Planting and crop management

There are several key considerations for site selection for a hazelnut grove. Flat or gently sloping sites are preferable to facilitate operations within the grove, particularly mechanical harvesting.

Relatively sheltered sites are important, as hazelnut trees do not tolerate strong winds or hot dry winds. A windbreak may be required and should be established two or three years ahead of planting the grove.

If annual rainfall is less than 850–900mm, irrigation is recommended for mature orchards. Depending on the region and soil type, growers should have access to about 3–8ML/ha of irrigation water, to ensure a consistent supply of water to the trees during nut development and kernel fill (late November to early February).

If the soil at the site is prone to compaction, ripping the planting rows in the autumn of the planting year may be beneficial. Soil testing well before planting is recommended, to detect and correct soil acidity and nutritional problems. Liming may be required to achieve a soil pH of about 6.5–7.5. High levels of soil manganese, which may be a concern on some red volcanic soils, will be corrected with the pH increase brought about by liming.

Groves are commonly planted at a density of 400–500 trees per hectare, with a spacing of 3–4m between trees within the rows, and 5–6m between the rows. Planting density will vary with variety and age of trees being planted. It is considered that density will have little effect on tree growth and yields before the seventh year of leaf but thereafter, it is very likely that inter-tree competition from the closer planted trees may be experienced.

The trees are generally planted as bare rooted plants which are clonally or vegetatively propagated in stool beds. Some newer plantings are established from potted plants which can assist versatility and extend the planting window. Generally, a new grower would engage a specialist nursery to provide planting stock. It is critical that material is planted out in winter, to ensure good root development before warm weather occurs.

Nitrogen fertiliser is recommended for developing hazelnut trees and then, as the trees come into production, a nitrogen–phosphorus–potassium fertiliser is required to maintain soil levels of major nutrients that have been removed in harvested nuts. Leaf samples can be taken from trees as a basis for determining nutritional status and required fertiliser applications.

Hazelnut trees require minimal pruning, compared with other deciduous trees, however some varieties produce suckers, which may grow vigorously and must be removed several times each year by hand removal or chemical spraying. The removal of sucker buds before planting can reduce subsequent sucker production.

Weeds, pests and diseases

It is essential to keep new plantings free of weeds and highly advisable to mulch around the base of young trees to assist moisture retention and lower soil temperatures in summer.

As a result of strict quarantine regulations, Australia is relatively free of major insect pests and diseases, compared with international hazelnut groves. In Australia, recorded pests include:

painted apple moth
cerambycid borer, a longicorn beetle
fruit tree borer
green peach aphid
hazelnut aphid.

The key disease for hazelnuts in Australia is bacterial blight. This is controlled via regular copper sprays through leaf fall, pruning at appropriate times to reduce infection, and the use of clean planting material. A number of chemicals are now registered for use on hazelnut in Australia to control a range of pests and diseases, the full list is available from the Hazelnut Growers of Australia website.

More detailed descriptions of these common pests and diseases are found in the New Crop Industries Handbook or Pest and disease analysis in hazelnuts published by Horticulture Australia.

Big bud mite, a serious pest of hazelnuts in Europe and North America, is present in Tasmania but not known on the Australian mainland. Potential mainland growers need to be aware of this when sourcing plants from Tasmania, to minimise the risk of introducing this pest.

Sulphur crested cockatoos can be a major pest at the later stages of nut development and during nut fall, particularly in small orchards where landholders are absent. The birds can consume the entire crop if left uncontrolled. The selection of compact varieties planted at relatively high density and netting during nut development are potential control options for new orchards in vulnerable areas.

Foxes can also be a pest at harvest time, as they eat the fallen, ripe nuts. They have also been known to destroy irrigation lines if these are left exposed. Other vertebrate pests include hares, deer and wallabies that may damage young plants. Mice and rats can be a problem in processing and storage sheds, contaminating and causing loss of product.

Infrastructure Requirements

Standard equipment and machinery used on horticultural farms for maintenance and weed control will also be required for hazelnut production. Netting of orchards may be necessary to protect from bird predation.

An irrigation system is important to supplement rainfall deficiencies at key stages of tree and nut development. Micro-sprinklers and drip irrigation have been used successfully in commercial orchards. Tensiometers should be used to monitor soil moisture levels and determine irrigation requirements. A secure source of water is also required.

In small groves, nuts may be collected from the ground by hand but generally, mechanised or partly-mechanised systems that vacuum or sweep up the fallen nuts into a field bin are used. Most harvesters use air/wind to separate the nuts from the leaves, and have dehuskers and rotary screens for cleaning the nuts. Owning a harvester will depend on the size of the orchard. Medium-sized growers may engage a contractor or several growers, working together, may be able to justify a collective investment in a machine.

Once harvested, facilities are required to clean, dry, grade and store the nuts. Drying equipment such as prune driers or small dehydrators can be adapted for drying hazelnuts. Small growers use drying racks set up outdoors, for drying.

Harvesting & Processing

Hazelnuts will bear fruit about three or four years after planting and by six years should be yielding about 2.0–2.5kg/tree. Annual yields of 2.5–3.5t/ha would be considered an acceptable level of production.

The nuts ripen in late summer with most varieties falling free from their husks to the ground during March. Nuts should be harvested promptly, by hand or mechanically, when ripe—nuts left on damp ground for over a week will gradually darken, become less attractive and be prone to fungal attack. Rain at harvest time can cause discolouration of the shell.

After harvest, the nuts are cleaned (brushed) and dried to approximately 8% moisture, depending on the end use of the nut and storage time. Some confectionery companies may require a maximum moisture level of 6%. Nuts are dried on open-air racks or in fan-forced ovens, where the amount of heat required is relatively small and the speed of drying is not critical. Once dried, the nuts may be stored under dry, vermin-proof conditions for up to 12 months.

Prior to sale, the nuts should be graded for the in-shell market, or cracked and graded for the kernel market. The kernel market is subject to stringent quality specifications, and those planning to supply that market must develop quality control systems to meet domestic and international standards.

Hazelnut kernels are covered with a skin or pellicle, which varies in thickness and appearance between varieties, and can be readily removed from most varieties by a process known as blanching. Varieties that blanch well are highly prized in the confectionery trade.

Hazelnut kernels are often roasted to bring out their flavour. The duration and temperature of roasting differs with variety, kernel size and the desired flavour. Flavouring or coatings may also be applied to hazelnuts to be sold as snack food.

Markets & Marketing

Hazelnuts are marketed as two products, nuts in-shell and kernels. Nuts in-shell, marketed mainly for home or table consumption, account for less than 10% of the total market. Most hazelnuts are cracked and sold as kernels, which can be eaten fresh, but the vast majority are either blanched or roasted and then used in confectionery products, cakes and biscuits.

Market research is important when establishing a hazelnut grove, as with any agricultural enterprise. Growers planning to sell to the kernel market should talk to buyers (processors) to determine if a particular variety or varietal characteristics are sought, such as kernel size, shape, texture, taste, oil content and blanching or roasting characteristics. Some processors have very specific requirements for their products.

In Australia, about 96% of available hazelnuts (domestically produced and imported) are used in the confectionery and baking industries. Of domestically produced hazelnuts, about 56% goes to retail outlets including farmers markets, 36% to export and 8% to food service. Hazelnuts represent less than 1% of fresh nut retail sales in Australia, where the leading products are almonds and cashews. A good explanation of the hazelnut market is provided in the document Hazelnut Market Profile prepared by Tasmanian government agencies.

While Australian-produced product faces price competition from imported product, the ability to place freshly cracked hazelnuts kernels on the Australian market is a potentially competitive advantage over imported product that invariably lacks freshness. An alternative market that is yet to be explored is providing northern hemisphere markets with fresh hazelnuts in their off-season.

Risks & Regulations

Risks/challenges

A newly planted hazelnut orchard takes many years to come into full production and provide a return on invested capital. Developers of hazelnut groves will need to carefully assess their ability to finance inputs throughout the establishment phase, as well as their ability to service debt if development capital was sourced through borrowing. Hazelnuts can have biennial bearing patterns, i.e. trees bear a heavy crop one year, followed by a light crop in the subsequent year. The income stream from this production pattern may impact on cash flow and budgeting.

A challenge for the industry is to achieve greater expansion and coordination so that networks or cooperatives of smaller growers could collectively supply Australian confectionery processors with their hazelnut requirements.

Individual growers take some risk when selecting varieties for new locations. While considerable variety assessment work has been done, there needs to be continued research to fine-tune the interactions between region, variety and end product. There also needs to be more R&D on irrigation methods, especially to achieve better results during kernel fill.

Regulatory considerations

There are no specific regulations or laws related to the growing or production of hazelnuts but growers should consider consulting the relevant food authority if considering value adding.

Awareness and adherence of biosecurity is critical when obtaining planting material. Hazelnuts are almost free of all the significant pests and diseases that affect hazelnut production overseas. The only major problem encountered is big bud mite in Tasmania. In New South Wales this pest is a notifiable pest and if growers identify or suspect presence of this mite they should contact the Exotic Plant Pest Hotline.

To maintain this relative freedom from pest and disease, planting material should only be imported according to the Australian Government’s biosecurity requirements, and interstate transfer (especially from Tasmania) should only involve clean planting material.