Woodkerne Nurseries

THE FRUIT AND NUT CASE

Growing fruit and nut trees for food crops

 

Imagine a forest, canopy trees interspersed with lower growing shrubs. It looks like any other, yet this forest grows not only timber, it grows food. This could be part of the future landscape of Ireland. In these times when more of us are facing up to the reality of climate change and seeking solutions to life after peak oil, the role of trees and their crops in providing for our diet in a post fossil fuel society has yet to be recognised.

Tree crops are good for our health and good for the health of the Earth. Fruit and nuts contain proteins, carbohydrates, vitamins, minerals and sugars – in fact, most of the necessary components of a balanced diet. Together with meat and/or fish, fruit and nuts form the basis of the ‘hunter-gatherer’ diet to which the human body has evolved.  It is now thought we may be less well adapted to the grain/flour based diet -a diet that stems from a 10,000 year experiment with grain agriculture.

Modern intensive agricultural practices are oil dependant and produce greenhouse gases through fertiliser use, oxidation of soil carbon during ploughing, habitat destruction etc. Food forests as a agricultural land-use have multiple advantages over annual agricultural crops. A perennial food supply, that sequesters carbon and requires less labour and energy inputs can help to reduce the negative impact of both climate change and oil depletion. The role of trees in sequestering carbon is often underestimated because the carbon sink in forest soils is overlooked. Consider soil build-up by trees, (via leaf mould and fallen branches), the root masses, and the fungal hyphoid web, all of which are carbon-based and can be stable for centuries. This carbon sink is relatively permanent in contrast to industrial forest plantations which the forestry industry claims sequester carbon but which is in fact release most of their carbon during clear felling.

For the past ten years we have been producing and growing a range of fruit and nut tree species at our tree nursery and woodland farm on the banks of the River Ilen in West Cork. We are engaged in a long term, small scale research project trialling a variety of species, and collating information to determine what fruit and nut tree species are productive in our conditions -a mild climate with a mixture of soil types and aspect. We believe the results are applicable to much of the country and further afield.

The main species we are trialling are;

Fruits – Apples, Pears, Plums, Hawthorns

Nuts-   Hazel /Cobnut, Sweet Chestnut, Walnut Species, Pine nut , Monkey Puzzle

APPLES

Apples prefer a fertile, well drained soil but will grow under most conditions. When grown in poorer soil apples can fail to thrive. The method we use to compensate for poor soils is to grow trees on their own roots by planting the tree deeper than usual so that the graft is buried thus allowing scion roots to form. This contrasts to the general practice and gardening advice of leaving the graft above the soil. (Apples shoots are joined to a rootstock by a process called grafting to propagate a particular variety). This method can produce trees that are larger than usual but given poor soils and difficult growing conditions extra tree vigour is not usually a problem. Vigour is easy to control for most varieties by tying down new shoots to the horizontal and by summer pruning.

The main diseases of apples are canker and scab, which can be controlled by selecting less susceptible varieties and cutting out the diseased branches.

The only significant problem we have encountered with apple growing is the loss of flower buds to bullfinches resulting in limited cropping some years. The most successful solution we have found is to hang old CDs in the branches before and during the flowering period to deter our feathered friends, remembering to remove after fruit set to avoid familiarisation.

Most apple varieties are not self-fertile and require pollination by a different variety of the same flowering group or one group either side, i.e.

an ‘Early’ flowering apple can be pollinated by an Early or Mid-season, a Mid flowering by early, Mid or Late, and a Late flowering by Mid or Late.

 

Most successful apple varieties

Allen’s Everlasting: Latest keeping eater, ripening off the tree, some canker

Annie Elizabeth: Latest keeping cooker

Ardcairn Russet: A sweet apple

Chiloe Apple/ Fillingham pippin: A South American variety, a small tree with sweet apples, and very hardy

Cornish Aromatic: A late eater, sweet and sharp

Golden delicious: Surprisingly this commercial variety grows well, ripening well off the tree late in the season

Grenadier: An early cooker, juicy, no disease noted

Irish Peach: Early eater, some scab, still worth growing

Irish Russet/ Sam Young: Our favourite, a small, flavoursome apple, no diseases

Katy: Early eater, probably the most disease-resistant variety

Apple varieties difficult to grow

Egremont Russet: Very susceptible to canker.

Cox’s Orange  Pippin: Shy to crop in our climate, suffers from scab and canker.

James Grieve: Susceptible to canker

 

PEAR and PLUM

 

It is early days for our plum and pear selections. So far it seems that shelter to the North is a priority to improve the micro-climate. In poor Spring weather attracting bees to the flowers, which blossom earlier in Spring than apples, seems to be the primary limitation to cropping.

Our selections of pear and plum varieties are based on reviews of the available literature e.g. Pomona, Agroforestry News and communication with growers.

 

 

 

HAWTHORN SPECIES

 

We have had success with exotic edible hawthorn species. The haws of all hawthorns are edible but some are not very palatable. The most successful species for us so far have been Crataegus mollis and Crataegus schraderiana, both of which have large, tasty fruits and produce abundantly. Good specimens of many species can be seen at the John F. Kennedy arboretum, New Ross, Co. Wexford. Reports indicate that lots of hawthorn species have similar potential.

Hawthorns are tough trees withstanding wind and poor soils, but of course cropping is better in more favourable conditions.

 

NUTS

The fact that nut producing trees grow, thrive and crop in Ireland comes as a surprise to many people. To date we have collected crops of Cobnuts (large hazelnuts), Sweet Chestnuts, Common Walnuts, American Black Walnuts, Japanese Walnuts, and Monkey Puzzle nuts in County Cork, and Pine nuts in County Wexford.

Most of these are cropping by pure chance having being planted for reasons other than food production.This shows the potential for production if locally-proven varieties are selected.

It is important when growing nut trees to be aware of the difference between seedlings and varieties of trees propagated clonally. Cloned trees are produced by either grafting, layering or stooling techniques and are genetically identical to the mother tree. This means that their characteristics and production potential are more predictable. Because they are more difficult to propagate than seedlings they are more expensive to buy. Seedlings are trees grown from nuts and are more variable in size, vigour, cropping, etc. and results can depend on the provenance of the seed used (Provenance refers to the source of seed which can effect the characteristics of the tree e.g. Sweet chestnut seed from Brittany has a greater chance of success than seed from Corsica or Italy as the climate of Brittany is more similar to our climate than that of southern Europe.) Carefully selected seedlings have the potential to crop well however it is generally more advisable to seedlings for larger scale plantings where poor performers can be thinned out.

 

COBNUTS

Cobnuts are a cultivated form of hazel. They are medium-sized, short stemmed shrubs which grow up to 25ft in height. Cobnuts prefer some shelter and a neutral soil but can grow in almost all conditions other than peat bog.

Cropping begins within 4-5 years and production increases rapidly.

They are not self-fertile and require two trees or wild hazels nearby. We have  plenty of wild hazel around so pollination is not a problem for us.

Our trials to date show all 12 Cobnut varieties are producing nuts. The most productive varieties are Webbs Prize, Pearsons Prolific and Longue d’Espagne, whilst the largest nuts come from a variety called Ennis.        Cobnuts contain approximately 14% protein, 12% carbohydrate and 60% fat, and are also a good source of calcium and iron.

SWEET CHESTNUTS

Sweet Chestnut varieties have also been successful for us. The 10 varieties we have selected are mainly from France and have adapted well to our climate. Fruiting began at 7 years and three are now cropping well, namely Bouche de Betizac, Bournette and Marron de Lyon. We have recorded growth rates of up to 5 foot per year and in some instances flowering has occurred the year after grafting.

We also have seedlings grown from sweet chestnuts collected from local trees and some from hybrids grown in Western USA. All are thriving. Trees growing locally are of unknown provenance and do well but few crop well and the nuts are usually very small.

The Sweet Chestnut is a large tree, growing up to 100ft. It requires a well-drained, acid soil and cannot tolerate water logging. They are reasonably wind resistant but cropping is reduced by too much exposure. Pollination is mainly by wind but insects love the flowers and can help in pollination. A minimum of two trees is required because they are not self-fertile. The best pollinating varieties are Belle Epine, Marigoule and Verdale. The nuts of the Sweet Chestnut are high in carbohydrate (42%) suitable for flour, with 6% protein and 6% fat.

WALNUTS

 

COMMON WALNUT

There are at least four species of walnut suitable for our climate. The most well-known is the Common Walnut Juglans regia. Our trials of various Common Walnut varieties are still in the early stages but we have already gathered some interesting information. Some varieties have been eliminated from our trials because of disease problems whilst the remainder have all produced only female flowers. Research has shown that the application of farmyard manure (FYM) or other nutrients can help male flowering and growth rates so we intend to try this in 2007.

We have located young Common Walnut trees cropping locally and our aim is to propagate from these trees by grafting and from seed.

Common Walnut prefers a neutral soil of good fertility but will grow well in most soils if fertility is enhanced. They can grow to 100 feet in height and are reasonably wind hardy. Frost damage can damage new growth and flowers so avoid frost pockets when planting.

 

BLACK WALNUT

The Black Walnut Juglans nigra is a magnificent tree from North America, growing to 120ft and highly valued for its timber. We have only started growing this species but have identified a mature specimen in a public park in Cork city that produced a crop of its strong, oil rich, tasty nuts in 2006. The ‘heat island’ effect of the city may have contributed to successful fruiting but the species is still worthwhile planting given predictions for temperature increases due to climate change.

 

BUTTERNUT

Another American species is the Butternut Juglans cinerea, which has grown well for us during the past five years. It shows good potential, especially as it seems to cope with wetter soils better than the other walnut species.

 

HEARTNUT

We believe the most promising walnut species is the Heartnut Juglans ailantifolia ‘cordiformis’, a ‘seed sport’ of the Japanese Walnut Juglans ailantifolia. We have recorded exceptional growth rates and the species has cropped at 7 years old in South West England – a similar climate to ours. We have a trial plot of 30 Heartnut seedlings which we will thin out to the most productive in the next few years.

The Heartnut is renowned for cropping  early  and produces the most beautiful heart-shaped seed. It also has the most spectacular foliage of any walnut. We have  gathered Japanese Walnuts on Fota Island in Cork, therefore we are confident our trees will crop well.

All walnuts are high in protein, 15% -25% and fat 55% -65% (again high in Omega 3). Carbohydrate content is low at 9% -14%.

 

PINE NUTS

Pine nuts are definitely worth planting if you have the time and space. The Stone Pine Pinus pinea should grow well in a coastal location as it seems to withstand some salt and sandy soils.

Two other pines worth growing, if you can obtain them, are the Korean pine Pinus koraiensis and the Siberian Pine Pinus sibirica. The latter tree seems very adaptable and grows on peat bogs in its native habitat. All three species produce the  familiar Pine nuts containing 53%- 68% fat (again high in Omega 3) and 14%- 35% protein.  All pines are self-fertile.

Another “pine” tree that definitely grows well here is the Monkey Puzzle tree otherwise known as Chile Pine Araucaria araucana. It is not actually a true pine but comes from a much more ancient lineage, being familiar to the dinosaurs. The huge pineapple shaped cones break up on the tree releasing the large oily almond shaped seeds. Individual trees are either male or female and the only way to determine the sex of a Monkey Puzzle tree is to wait until it flowers and this takes 30-40years. However when both male and female trees are together the trees pollinate well and fruit profusely.

There are many other tree and shrub species we aim to trial in the near future -Hickories, Pecans, Edible Oaks, Persimmons, Mulberries, Asian Pear and others. There is untapped potential worth utilising in all these species

 

If you have land, think about growing some fruit and nut trees. If not, talk to someone who has, be it a friendly farmer, or your local council, who should be lobbied to plant food-producing trees in parks, residential areas, hedgerows and roadside plantings.

We need to establish breeding programs now throughout the country to identify fruit and nut trees suitable for a secure local food supply into the future, Ireland has the best tree growing climate in Western Europe and we should take advantage of this to grow forests of food, fuel, and timber,-the truly multifunctional forest.