Hazelnuts (Corylus avellana)

How well established is this crop?

This is a very new crop to the Otago region. The plants should grow but information on markets, commercial returns, current growers, and any form of regional research may be difficult to find.

Background

The Hazelnut (commonly known as Filberts) is a deciduous tree that is found in most of Europe, Asia and Northern Africa. It typically makes a broad mass of stems about 4-6m high. The main areas of production include Turkey, Italy and the USA. New Zealand currently imports around 200 tonnes of hazelnuts into the country every year for us in the baking and confectionary trade. Very little is consumed fresh.

It is estimated that approximately 175,000 trees are currently in the ground in this country. The majority are in Canterbury where they were planted as a way of showing income to allow people to subdivide blocks of land. Many of these blacks are no longer being looked after or harvested.

Hazelnuts are now being seen by many as a health food. They are rich in unsaturated fats (about 80% of the oil) and low in saturated and polyunsaturated fats. As domestic production increases more and more sales and marketing opportunities are being discovered.

Climate

A suitable climate and reliable rainfall or irrigation is important for good tree growth and the production of high quality nuts. The preferred climate is characterised by a mild summer and cool winter and exposed sites subject to the drying effects of summer wind should be avoided.

Hazelnut catkins, when dormant, can be killed at temperatures of about 21C and higher summer temperatures can cause leaves to scorch and burn and can prevent satisfactory fruiting. Hazelnuts do not tolerate windy conditions combined with high summer temperatures and low humidity.

Winter Chilling and Frosts

Long periods of chilling are required to ensure fruitfulness and reliable hazelnut yields. Chilling requirements vary for male catkins, female flowers and leaf buds. Australian research shows about 1200 hours between 5C and 7C is suitable.

For female flowers severe frost areas should be avoided and temperatures below5C should be avoided when the female flowers are opening. This may cause problems in some years in Central Otago; however frosts of this severity generally do not last too long. Low temperatures followed by warmer weather near the end of winter generally cause more damage to catkins than do low temperatures earlier in the season. Warmer temperatures can also be a problem.

Rainfall and Irrigation

Rainfall will not adversely affect growth of a hazelnut tree at any stage of its annual growth. In fact the recommendation is for more than 750 mm annual rainfall for good production. In places such as Central Otago supplementary irrigation will be essential to grow this crop.

Wind

Even though they are a tree, Hazelnuts are very like cut flowers when it comes to shelter requirements. A good rule of thumb when designing shelter is to multiply the final height of the shelter by 10. Use that measurement as the distance you position your shelters apart. For example, when using a 6m high tree species for shelter, you will need shelters every 60m.

Make sure the shelters running east-west are deciduous. This will allow sunlight into the blocks in the winter. Position all shelters at right angles to the prevailing winds. Talk to your local nursery when deciding on the right tree type for your property. They may also be able to help with design.

Soil

Hazelnuts have a fibrous root system and the deeper the soil the heavier the cropping. In Australia it has been noted that growing Hazels in areas of shallow soils, trees have initially grown but then declined. Heavy clays and very sandy soils should be avoided and a deep loam is preferred.

Fertility

Fertile soils are considered essential for profitable commercial production. A neutral to slightly acid soil (pH of about 6) is suitable. Lime should be applied below pH5.6. Simple fertilisers such as Nitrophoska Blue applied 1-2 times a year seems to be sufficient for most Hazelnut blocks.

Weed Control

Weed control under trees is essential to allow nut pickup. Grass in the rows is usually mowed. Be very careful if you are thinking of grazing between the trees. Sheep will and do eat the bark from around a hazelnut tree. They kill the tree by ring-barking it.

Varieties

The main crop variety in New Zealand is Whiteheart. Some other varieties such as Butler are also showing promise.

Hazelnuts are an unusual plant as they have separate male (catkins) and female parts (flowers) on the same tree. Most varieties are not self fertile as the pollen is released from the catkins at a time when the female flowers are unable to accept it. This means a pollinator tree is needed. The usual ratio of pollinator/crop trees is 10/1. That is 1 pollinator tree to every 10 cropping trees.

The majority of the crop trees are Whiteheart and the current thinking for suitable pollinators include; Alexander, Butler and Merville de Bowillier.

Pests and Diseases

Aphids do like living on Hazelnut trees and number can rapidly build-up. However ladybirds offer effective control.

Big Bud Mite (Phytoptus avellanae) is the most serious potential pest however it is not known to be widespread in Otago. Symptoms of damage include infested terminal buds becoming enlarged and swelling to several times their normal size. These buds are prone to desiccation and can fall from the tree prematurely.

A common disease in Australia is hazelnut blight (Xanthomonas corylina). This bacterial disease is at its most debilitating in young trees, as succulent tissue can be badly affected by lesions which girdle the shoot. In older trees, leaves show light-green lesions which darken with age. We have not seen this in New Zealand yet but it may be a problem in the future.

Layout

Block layout is an entirely personal choice. Most growers are using a distance of 4.5m between rows and 3m between trees within the row. This gives approximately 600 trees per hectare when an allowance is made for headlands and shelterbelts.

General Management

Bare-rooted trees approximately 1m tall should be planted into a well sheltered paddock in either autumn or spring. Shelter at this stage is essential and too many growers are getting this wrong in there rush to get things in the ground. In the first 3-4 years suckers will need to be pruned from around the tree to ensure it grows into the correct shape. Branches should start coming out from the main trunk approximately 1m from the ground. This distance allows machinery under the tree to spray herbicide and later to gather the nuts. Spray guards are useful in the first few years to allow herbicide spraying and to prevent rabbits from eating the bark. Once the bark has matured on the trees, herbicides can be used to kill off these suckers.

Keeping the ground under the trees clean of foliage is essential near harvest. If you do not do this you cannot pick up the nuts from the gound.

Harvest

Nuts fall form the trees onto the ground about Easter. They will sit on the ground without deteriorating for up to 3 months. To pick the nuts up a modified vacuum system behind a tractor is used. A few of these units are already in the country and it is expected that they will be hired out to growers on a contract type rate, rather than everyone having to own a nut harvester. In the first few seasons a rake and bag can be used to collect the small amount of nuts that are produced.

Equipment

Because of the area taken up with a Hazelnut plantation most growers have a tractor for weed-spraying and cutting the grass. As the trees do not seem to need any form of insecticide or fungicide, this is enough machinery. Pruners and loppers are needed when shaping trees and a set of knee-pads is useful for bending down and cutting off root suckers.

Returns

Because this is a very new industry it is hard to give good financial information. One grower estimates it costs approximately $25,000 to set up a 4.5ha block. This includes the price of trees, shelter, tractor etc.

Returns depend on what you do to the nut. In-shell prices are approximately $4.00kg but by adding value (roasting, packaging etc) this may increase up to as much as $20.00. When mature it is expected that most trees will be capable of producing up to 5kg of in-shell nuts.

Contacts

If you are thinking of growing Hazelnuts, contact your local branch of the New Zealand Tree Croppers for the addresses of growers in your area.

Trees can be sourced from
Linda Gardener, Quality Tree Company Phone 03 344 1977:
Mark and Caroline Eastmond PO Box 24 Waiau, 03 315 6173,
Allenton Nurseries Ltd, Number 6RD, Ashburton, 03 308 5875

Good Websites for further information on hazelnuts
www.agric.nsw.gov.au/reader/11246
www.thehazelnutnursery.co.nz