Hazelnuts

Introduction:

Although hazelnuts (Corylus avellana) were introduced into Australia over 100 years ago, to date they have only been grown on a relatively small scale. Current annual production is estimated to be approximately 50 t of in-shell nuts. However, there appears to be an opportunity for considerable expansion of the local industry, since more than 1600 t of nuts and kernels, valued at over $12 million, are imported into Australia annually.

Establishment of a local industry could complement overseas production through the provision of fresh, locally grown nuts that could be stored, in-shell, at a relatively low cost and cracked as required to supply fresh kernels for local processors and consumers. Major users of hazelnuts in Europe are also interested in obtaining product from Australia, provided the nuts or kernels are of appropriate quality and are available in sufficient quantities.

In addition to the freshness of the Australian product for local users, there is potential to capitalise on “clean and green”image, as few of the major pests and diseases of hazelnuts have been introduced into Australia. In order to capitalise on these market opportunities, there is a need for research to evaluate appropriate varieties and develop efficient production systems. To be competitive and gain labour efficiencies, growers need to mechanise harvesting, storage and processing of nuts. Although opportunities exist for growers to market their own produce, as production expands and smaller market niches are satisfied there will be a need for growers to develop strategic alliances with major buyers.

Markets and 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; these can be eaten fresh but the vast majority are blanched or roasted and then used in confectionery products, cakes and biscuits. Hazelnuts are highly nutritious and can be used for a wide range of purposes, such as in muesli and salads and as a complement to many food dishes. Other products include hazelnut spreads, nougat, hazelnut oil and liqueurs.

The major center of hazelnut production in the world is in northern Turkey, on the Black Sea coast. Other important production areas are in Italy, Spain and Oregon, in the United States. The nuts produced by Turkish growers are commonly stored on-farm and then sold during the year to operators of cracking plants. The cracked kernels are size-graded and placed in plastic vacuum packs, which are kept in cool storage to prevent rancidity. The volume and value of nuts and kernels imported into Australia in recent years are shown in Table 1. The quantity of imported kernels has generally risen in the last decade, as has the average price. The unit value is the landed price in Australia.

There are many variations of the market chain from production to processing and consumption (Figure 1). To date, one of the major constraints to the development of the local industry has been a lack of knowledge about the performance and management of introduced varieties that might be grown to complement imported nuts.

Production requirements:

Hazelnut production is suited to a climate with a cool winter and mild summer, as is found in the coastal and upland areas of southern Australia. Hazelnut trees have poor tolerance to heat, wind and moisture stress. The trees are deciduous and, when dormant, can tolerate temperatures as low as –15°C. At the time of pollination ( June–August) the pollen and stigmas can be harmed by temperatures below –8°C and above 20°C. In Australia, spring frosts at the time of leafing in September and October do not seem to be a problem.The main production areas in the Northern Hemisphere have a Mediterranean-type climate and are in the latitude range 37° to 47°. The climate of locations in Australia where hazelnut groves have been successfully established compares favorably with major Northern Hemisphere production areas (Table 2).

Hazelnut trees prefer well drained, fertile loam soils with a pH range of 6.5 to 7.5. Overseas, where annual rainfall exceeds 900 mm, the crop is generally grown without irrigation, particularly where soils are deep. In Australia it is considered highly desirable to irrigate orchards in the establishment phase. Where annual rainfall is less than 850–900 mm and soils are not deep, irrigation is recommended for mature orchards, particularly during the phase of nut development and kernel fill, which is from late November to early February. Water requirements are estimated to be about 1–1.5 ML for every 150 mm of rainfall less than 900 mm. Dry weather during the harvest period is advantageous. This is generally during March in Australia.

Hazelnut trees do not tolerate strong winds, so selection of sheltered sites, or the planting of windbreaks before establishing the grove, is very important. Flat or gently sloping sites are preferred to facilitate operations within the grove, particularly mechanical harvesting.

Varieties:

Selecting the most appropriate hazelnut varieties for planting is a very important decision. The University of Sydney is researching this matter with funding provided by RIRDC. A report of research to date is available at http://www. rirdc.gov.au/reports/NPP/03- 141sum.html

Two main aspects have to be considered when selecting varieties—the productivity of the variety for the particular conditions of the site; and the marketability of the nuts. Ideally, the varieties planted should be both productive and of a type for which there is a market demand. Although a wide range of varieties can be sold in-shell, there is a customer preference for nuts that are large with a clean, shiny appearance and even size. Varieties that meet these requirements are Ennis from the United States and Wanliss Pride, an old Australian selection (Table 3). A large proportion of the imported in-shell nuts are of the variety Oregon Barcelona, which has relatively large, attractive nuts. However, imports of this variety are being superseded by the larger sized Ennis.

Growers who plan to sell into the kernel market need to talk to buyers or potential buyers to ascertain whether any particular variety or varietal characteristics (such as kernel size, shape, texture, taste, oil content and blanching or roasting characteristics) are sought. Some processors have very specific requirements for their products. Small round kernels (13–15 mm diameter) are generally preferred in confectionery products, such as from the variety Tonda di Giffoni. A few buyers have specific varietal preferences; for example, Bristowe Farm Hazels prefers the variety Tokolyi–Brownfield Cosford (TBC), see http://www.hazelnuts.net.au/

Wanliss Pride is a variety that was widely grown in the past. It has a large nut and produces a sweet- tasting kernel. However, it is prone to rancidity when insufficient care has been taken to thoroughly dry the nuts at harvest time. Hazelnut kernels are covered with a skin, or pellicle, which varies in thickness and appearance between varieties. The pellicle can be readily removed from most varieties by a process known as blanching, which involves heating the kernels for 10–15 minutes at 140°C, followed by brushing off the loose pellicle to leave a clean white kernel. Examples of varieties that blanch well are Tonda di Giffoni, and the Australian selections TBC and Wanliss Pride. Roasting, which involves heating for a longer period, increases the flavour and crunchiness of kernels. General descriptions of nut and kernel characteristics are given in Table 3.

Many of the early hazelnut introductions into Australia were in the form of nuts. Because the species is cross-pollinated, the seedlings grown from these nuts were not true to varietal type. Local selections have been made from these seedling types; some of these have been found to be useful, such as Wanliss Pride, Tokolyi– Brownfield Cosford and Tonollo. (The word “Cosford”as applied to Tokolyi Cosford is a misnomer: the selection is a round nut, rather than the typical elongated Cosford shape.)

During the last 10 years, many individual growers and propagators have imported varieties from the United States and Europe. These are currently being evaluated at sites in New South Wales, Victoria and Tasmania. The yield attributes under Australian conditions of the local selections and promising overseas varieties are given in Table 3.

Agronomy:

It is important to select a sheltered planting site: hazelnut trees are very sensitive to wind damage, particularly in the establishment years. It is advisable to plant shelter belts around a proposed site, two or three years ahead of planting the grove. It is generally advisable to apply lime to sites that are acid one year before planting, to bring the soil pH up to a reading of about 6.5. Ripping the planting rows in the autumn of the planting year can be beneficial on soils that are prone to compaction. Cultivating the planting row in autumn will loosen soil in preparation for planting in winter and provide an environment that favors root growth.

Groves are commonly planted at a density of 400–500 trees/ha, with a spacing of 5-6 m between the rows and 3–4 m between trees within the rows. The more vigorous varieties are planted at wider spacing. It is essential to keep new plantings free of weeds and highly advisable to mulch around the base of young trees to favor moisture retention and lower the soil temperatures in summer. It is very important that young trees receive adequate water. Supplementary irrigation will be required if rainfall is insufficient.

Hazelnut varieties produce suckers to varying degrees. These suckers grow vigorously and must be removed several times each year, in order to restrict growth to the main productive part of the tree. Suckers are removed either by hand or by chemical spraying. The removal of sucker buds before planting can reduce subsequent sucker production.

Hazelnut trees are cross-pollinated. The male catkins, formed during late summer and autumn, elongate in winter and shed pollen, which is carried on the wind to the small female flowers. When receptive, these female flowers appear as small buds with reddish filaments (stigmas) at their tips. Although catkins and female flowers are borne on the same plant hazelnuts are not self-fertile. Pollination occurs in the winter, but fertilization does not take place until early summer, when the seed (kernel) develops within the shell. The mature nuts ripen in late summer, with most varieties falling free from their husks to the ground during March.

For pollination to be effective, the two varieties involved need to be genetically compatible and their period of pollen shed and stigma receptivity must be synchronous. The genetic compatibility of overseas varieties is known and can be used by growers to select appropriate varieties for effective pollination. The variety Barcelona, for example, which is grown for its high nut yield, is pollinated by the varieties TBC and Hall’s Giant. TBC sheds its pollen earlier than Hall’s Giant. These two varieties cover the main period when the female flowers of Barcelona are receptive. Both TBC and Hall’s Giant produce many catkins and copious quantities of pollen.

Selection of appropriate pollinisers is a critical aspect of hazelnut production. A ratio of one polliniser tree to nine main crop trees is generally recommended to ensure sufficient pollen is spread through the grove. Some main crop varieties such as Barcelona and TBC are cross compatible, with TBC giving good pollination of Barcelona. Unfortunately, Barcelona only pollinates the early flowers of TBC, so additional pollinisers are required for TBC.

Pests and diseases:

Hazelnut producers overseas have to contend with many pests and diseases but, as a result of strict quarantine regulations, most of these have so far been excluded from Australia. Hazelnut blight (Xanthomonas corylina), an important bacterial disease of hazelnuts worldwide, does occur in Australia. It was first detected in Victoria in 1980. Blight mainly affects young trees, causing dieback of new shoots and reddish brown lesions (1–3mm diameter) on the leaves. The husks of infected nuts also have reddishbrown lesions on them and some staining or discolouration of the actual nuts can occur. The disease is favoured by wet weather in spring and seems to be more prevalent at sites where trees are exposed to strong winds. The rubbing of leaves under windy conditions causes damage to the leaf surface, which allows bacteria to enter and blight to develop.

The principal method of blight control is through the application of protective copper-based sprays. Cupric hydroxide is the most commonly used chemical. Aphids are often found on the underside of hazelnut leaves. These small, greenish insects suck out the sap of the plant and can affect development when aphid populations are high. Sooty mould develops on the honeydew excreted by the aphids, causing an unsightly black discoloration of the leaves, nuts and wood. Flocks of sulphur-crested cockatoos have caused losses of mature nuts in some Australian groves. This pest is a major threat in some areas. Foxes can also be a pest at harvest time, as they eat the fallen, ripe nuts.

Harvest and post-harvest:

In most commercial varieties, nuts fall freely to the ground, falling free from their husks. In small groves, nuts are often picked up by hand, but because this is a relatively slow process mechanized or partly mechanized systems are usually employed. There are three types of mechanical harvesters— sweep and pick-up; vacuum; and finger wheel. The sweep and pickup method is fast and best suited to larger orchards. Flory Industries in the United States manufacture a range of sweeping and pickup machines for hazelnuts, see ‘Products’on their website http:// www.floryindustries.com/

Vacuum harvesters are of intermediate price. They have hand-held hoses that operators use to suck up the fallen nuts. Most of these harvesters use wind to separate the nuts from the leaves and have dehuskers and rotary screens for cleaning nuts. A tractor driver and two operators on the suction hoses can pick up 5 kg of nuts per minute in productive orchards. Leading Australian growers Brian and Glenice Horner, of Glenbri Farm near Eden, use a small suction harvester for their crop. This can be seen on the RIRDC 30 Australian Champions website: http:// www.rirdc.gov.au/champions/ GlenbriFarmHazelnuts.html

It is essential to have a level, smooth, firm soil surface in the grove at harvest. Nuts that are dirty should be washed. All nuts should be dried to a moisture content of 5% as soon as possible after harvest. Nuts at this moisture content will keep satisfactorily for 12 months.

Nuts for the in-shell market should be size-graded. The five size grades used in the United States are recommended for Australian-grown nuts, ranging from Small, (less than 13 mm) to Giant or Jumbo (over 22 mm). The maximum moisture tolerance is 5%, as is the maximum tolerance for blanks.

For the kernel market, nuts are cracked and size-graded. Kernels produced by the major exporting countries are subject to stringent quality specifications. There is a zero tolerance of foreign material and uncracked nuts, as well as kernels that are rancid and moldy. Those planning to crack nuts and sell kernels must develop quality control systems to similar standards.

Financial information:

The economics of production are strongly influenced by crop yield, the price obtained for the kernels or nuts, and the scale of operations. The cost of land will have a major influence on establishment costs. Assuming that an intending grower already has the land and a water supply, the main costs incurred in establishing a hazelnut grove are land preparation, purchase of young plants (whips) and the installation of an irrigation system. Typical establishment costs are:

Little production occurs before the fifth year, with nut yields rising steadily over the next five years. Assuming a yield of 2 t of nuts/ha/yr by the tenth year from planting, the following annual gross margin could then be achieved:

The overall economic viability of the enterprise can be improved through value-adding, such as cracking nuts, roasting the kernels or using them to make some special products such as biscuits, or hazelnut chocolate. At Glenbri Farm, Brian and Glenice Horner have equipment to crack nuts and value-add to their kernels, which are all sold locally. Brian and Glenice have no difficulty in selling locally all they produce, indicating the potential for Australian-grown fresh hazelnuts.

Key references:

Allen, A. (1986) Growing Nuts in Australia. Night Owl Publishers, Shepparton, Victoria.

Baldwin, B., Gilchrist, K. & Snare, L. (2003) Hazelnut Variety Assessment for South-eastern Australia. Pub. no. 03/141, RIRDC, Canberra.

Flory Industries (2002) http:// www.floryindustries.com/floryproducts.htm

Hyde, K. (ed.) (2000) Glenbri Farm Hazelnuts. In: 30 Australian Champions. RIRDC, Canberra.

Snare, L.N. (2002) Hazelnut Production. Agfact H3.1.49. NSW Agriculture, Sydney.

Sources of planting materials:

Bristowe Farm Hazelnuts (Nursery), Mudgee, NSW. http://www.hazelnuts.net

Hazelnut Nursery Propagators, Megalong Valley, NSW. http://www.hazelnuts.com.au/ default.htm

Milan Paskas, 24 Olsen Road, Nar Nar Goon North, VIC. Tel: (03) 5942 8381

Mountain Greenery Nurseries Richard Salt, Daylesford, VIC Tel: (03) 5348 7818 rsalt@bigpond.com

About the author:

Basil Baldwin B.Sc.(Hons), Grad Dip Ed, M.Ag.Sci. is a Senior Lecturer at the Faculty of Rural Management, University of Sydney. His experience in agronomy includes developmental work with new crops to Australia, including oil-seed poppies and faba beans. Current research includes an evaluation of hazelnut varieties and factors influencing the growth and production of hazelnuts.

Key contacts:

Expert advisers Basil Baldwin Senior Lecturer Faculty of Rural Management University of Sydney PO Box 883 Orange NSW 2800 Tel: (02) 6360 5562 Fax: (02) 6360 5590 Email: bbaldwin@oac.usyd.edu.au

Lester Snare Technical Officer Orange Agricultural Institute NSW Agriculture Forest Road Orange NSW 2800 Tel: (02) 6391 3879 Fax: (02) 6391 3899

Industry association Hazelnut Growers of Australia Ltd http://www.hazelnuts.org.au/