The Highs and Lows of High Density Orchards

Reproduced from 2018 Growers Handbook: Nut Growers Society of Oregon, Washington & British Columbia – 103rd Annual Meeting, January 18 2018, pp85-89

A panel discussion with Jeff Newton, Lance Kirk and Rich Birkmeier. Moderated by Jeff Choate (OSU Extension)

Summary (HGA editor)

US orchardists have been experimenting with double density planting since the 1970s. Trees are planted more closely together than the intended final spacing, to increase per-hectare yields while the trees are still growing to mature size. The temporary trees are removed once the trees start to grow together.

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International Hazelnut Congress 2022

The International Hazelnut Congress is the industry’s leading event to share advances in research and industry. In September 2022, the Congress will be held in Corvallis, Oregon (USA).

Invitation from the conveners:

The International Congress on Hazelnut has been organized every 4 years in different countries for over 30 years. Academics, researchers, farmers, private companies and governmental organizations from many countries attend the congress.

Topics of sessions:

  • Breeding, genetics, and germplasm
  • Biology, physiology, rootstocks, and propagation
  • Orchard management
  • Pests and diseases
  • Post-harvest handling and quality
  • Marketing, economics and policies
  • Status of hazelnuts in different countries

Abstracts will be published in an abstract book. Full-text papers will be published in Acta Horticulturae.

For more information, please visit the congress website, available at

See you in Corvallis (Oregon, USA) in 2022! – Feel free to spread the news and invite friends and colleagues to submit.

Survey – how organisational factors affect horticulture industries

Julio Botero, a tutor and PhD candidate at Lincoln University, is conducting a research project into factors affecting horticultural industry growth and has asked whether HGA members might answer a survey to contribute to his research:

Growers are being asked to participate in a survey as part of research project to help unlock growth in the horticulture industry. The survey is part of Lincoln University PhD student, Julio Botero’s, research project on the business factors that enable or restrict growth of horticultural businesses.

The survey will take 15 minutes to complete and asks questions about your business structure and preferred ways of operating. Having a range of grower input is crucial for ensuring that the results reflect the breadth of the industry.

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NZ industry update: Uncle Joes and Hazelz NZ

In 2021, two of New Zealand’s larger hazelnut processors changed ownership. Uncle Joes, located just outside Blenheim, is now owned and managed by Debbie Whiteside and Alan Crawford.  Hazelz New Zealand, near Christchurch, is now run by Shane McKenzie.

Over the next few newsletters, we’ll be introducing the new owners to you.

Debbie Whiteside & Alan Crawford – Uncle Joes

Please tell us a bit about your personal background.

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Opportunities for expansion of the NZ hazelnut industry

By Murray Redpath

HGA newsletter, February 2009

The New Zealand hazelnut industry is steadily establishing itself as an economically viable horticultural industry. With over 400 hectares planted, the increase in hazelnut production over the coming years will enable the existing cracking plants to take advantage of the expanding market for nuts. This market expansion is being led by research that is showing the health benefits of including nuts as a daily part of one’s diet. Research is continuing to prove that the nut oils are heart friendly, rapidly lowering levels of bad cholesterol, and recent research is indicating that they may also be useful in preventing diabetes.

The expansion of hazel growing out of the main Canterbury area has indicated the potential for hazelnut production in many areas that are now dominated by livestock production. In recent years the dairy boom has made it difficult for other land uses to attract attention but there is potential for a significant hazelnut industry in the sheltered, moister areas of South Canterbury, the lower Waitaki, and coastal Otago. Examination of new plantings and old stands indicate that the best sites have growth rates as good as in the main hazelnut producing areas overseas. Compared to dairying or intensive livestock production, hazel growing has lower total water use, no effluent disposal costs, and lower energy input costs. Nuts are machine harvested so seasonal labour requirements are not an issue.

The majority of hazels planted in New Zealand are the Whiteheart variety, selected for its high quality kernel. Grower success with this variety has been mixed, with many experiencing poor yields and high losses of young plants in some soils. The Hazelnut Growers Association of NZ (HGANZ) and the NZ Tree Crops Association have been working to identify the causes of these problems, running field days on pruning, orchard management, and testing young trees for disease. Poor pollination has been identified as the probable cause of poor yields and assistance from the Sustainable Farming Fund is enabling us to provide accurate advice to growers through a series of workshops in June of this year.

The Oregon hazelnut industry is a highly profitable horticultural industry concentrated on the high quality soils of the Willamette Valley. With returns of about $US7000 per hectare over cash costs, hazelnut production competes well with other land uses. Production is concentrated in the northern part of the valley between Salem and Portland, an area with large areas of grass seed cropping, berry growing, ornamental tree nurseries and wine grapes, especially pinot noir. Having watched the changes in the Oregon industry over the last 15 years, I had the chance to examine it during a visit in August/September of 2008 and see if there were lessons for the NZ industry.

The Oregon hazelnut industry has always been based on providing high quality nuts for the world inshell nut market. Fifteen years ago the traditional in-shell markets (Europe and domestic US consumption) were declining and the focus for hazelnut production was turning to the dominant kernel market. The situation has changed with the rise of China as a dominant economic force and about 50% of the total US in-shell hazel production now goes to China and Vietnam, often with prices negotiated and contracted prior to harvest. Processing plants in Oregon are keen to promote extra hazelnut production.

Both of the preferred in-shell hazel varieties, Barcelona and Ennis, are susceptible to Eastern Filbert Blight, a disease that has been spreading through the Willamette Valley since the 1980’s. This has restrained new plantings as growers wait for EFB-resistant varieties to emerge from the Oregon State University breeding programme. Recent years have seen resistant varieties emerge for the kernel trade but the first EFB resistant in-shell variety was not released until January this year. Oregon growers have a huge replanting task. Larger growers that we visited are replanting 10,000 trees per year.

The markets that the Oregon industry is supplying would be open to New Zealand growers if they had the right varieties. Good quality Barcelona and Ennis nuts are already being grown in Marlborough but quantities are not yet sufficient to fill local market requirements. The opportunity exists to expand our hazelnut plantings to take advantage of profitable markets for healthy food and growth in Asian economies.

Soil and nutrients for hazels

By Sjef Lamers of Sustainable Nutrition
B. For. Sc., Dip. H.L.S. Dordrecht, MNZSSS

HGA newsletter, February 2009


There are 16 essential nutrients required for plant growth: carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), and chlorine (Cl). Of these 16 nutrients most are derived from the soil except carbon, hydrogen and oxygen.

Nature has provided the soil with a form of nutrient storage (a nutrient cupboard): very small clay and organic particles called colloids. These colloids have electrical charges: they are positively or negatively charged. The amount of these colloids in a soil determines the total amount of charges in a soil. Nutrients are electrically charged ions in the soil. A positively charged ion (called cations e.g. potassium or calcium) will attach itself to a negatively charged colloid. A soil with a small amount of negatively charged colloids will have a very limited capacity to store elements like potassium and calcium. A soil with a high amount of negatively charged colloids is able to store a large amount of cations. The amount of fertilizer to use depends on the storage capacity of the soil. There is no general fertilizer application which will be valid for all soils. Every property will require its own fertilizer program.

Important aspects to monitor in the soil are:

  • pH and Buffer pH: soil acidity determines the growth and health of roots
  • organic matter: plays an important role in soil structure, water and nutrient holding capacity, reservoir of organic nitrogen and other nutrients
  • the major elements phosphorus, sulfur, calcium, magnesium, potassium
  • the trace (or micro) elements boron, zinc, copper, manganese, aluminium and iron.

Soil analysis takes the guesswork out of making fertiliser recommendations and leads to more efficient nutrient management.

Nutrient content and pH vary with soil depth. We suggest to take soil samples from the main soil horizons. Sub soil samples tend to be taken while investigating the suitability of land for hazelnut growing. The analyses results of the sub soil will give information about any chemical imbalances.

Soil analyses of New Zealand top soils (0­150 mm depth) frequently indicate low levels of potassium, boron, magnesium, zinc, relatively low pH levels and high aluminium levels.

Soil pH

Excessive soil acidity can reduce growth and yield of hazelnut trees. A large amount of New Zealand soils are naturally acidic with a pH generally in the range of 5 to 6. Soil pH can decline over time due to the acidifying effects of rain, plant growth, fertilization (nitrogen and phosphate fertilizers). Lime (or dolomite if magnesium is required) can be used to improve the pH of the topsoil. Some laboratories conduct a buffer pH or lime requirement test. This test determines how much lime should be applied to adjust the pH to a target level.


Young hazels require potassium (K) for shoot and root growth. Mature hazels have a need for potassium for nut production. Soils with a low K level or a high Mg level require extra potassium. The amounts of available potassium, magnesium and calcium in the soil are interrelated; an excess of any one of them can cause deficiencies of the others.


Phosphorus (P) deficiency has not been a problem in general in hazelnuts despite the low content of P in some soils. Several factors contribute to this: hazelnuts have a good ability to extract P from the soil, P is mobile in the hazel and crop removal of P is relatively small. Generally P fertilisation is not necessary, but if soil analyses indicate very low P levels you may consider a P application before planting. If the pH is very low or very high then the phosphate fertiliser should be applied close to the plant rather than broad spread. Lock up of phosphate can occur within 48 hours in these soils.

Nutrient functions

The functions different nutrients perform in the hazel are:

  • phosphorus: root growth and flowering
  • sulfur: quality aspects like aromatic properties
  • calcium: soil structure, cell division
  • magnesium: chlorophyll
  • potassium: root, shoot and nut growth
  • boron: bud development and nut quality
  • zinc: leaf size, height growth
  • copper: enzyme systems; please monitor build-up in the soil from fungicide sprays
  • aluminium: toxic element for roots, interferes with phosphorus and magnesium uptake, antagonistic to calcium
  • manganese: chlorophyll, flowering.

Sustainable Nutrition gives independent advice on soil and plant nutrition. We endeavour to help hazelnut growers to achieve optimal production of hazelnuts.

Sustainable Nutrition: PO Box 54, Wakefield 7052.