New Zealand Treecrops Association

Archive - NZTCA Magazine

Volume 1 Number 1, July 1975

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This on-line document is dedicated to the memory of Mary Banks, whose efforts in helping set up this web site and sourcing archive material were pivotal to it eventuating.

GUEST EDITORIAL - Roland Clark

TREES AND AGRICULTURE

Last year nearly 90% of New Zealand's export income came off the land with no likely substitute in sight. By world standards our agriculture is efficient though obviously there is plenty of room for increased production if all available knowledge were used and if the nation had the long term sense to pour as much money into this productive sector as it does into politically desirable projects. We could produce much more grass which would be sold second in the form of wool, meat and dairy products than we do. Has the practical limit been reached by those farmers who run 19.8 ewes a hectare (8 ewes/acre) and those dairy men with better than 2.5 cows a hectare (1 cow/acre)? Where do we go from there?

TWO TIER AGRICULTURE

I think we should develop a two tier system of agriculture integrating trees and our grazing animals. Few would deny that most of our farms would be improved by planting trees to slow the abominable summer norwester and to give shelter from those screaming southerlies that we seem to strike in the middle of lambing. The conventional answer has been to plant shelter breaks but I think we should go further than this and space trees over our paddocks. There's been a lot of work on this recently using conifers under conditions of light stocking. This is a step in the right direction. However, I think we can carry the idea further, by growing trees on land already highly productive.

TERMINAL CROP

We can grow a terminal crop which will be milled at maturity. The obvious tree is the poplar. I have poplars growing in a paddock which easily carries eight sheep an acre. The trees are spaced at forty foot centres giving 24 stems an acre. I am thinking of planting ten acres a year which could give a very nice retirement income starting in twenty years time. Trees have to be protected from stock till their bark is thick enough to be unpalatable to hungry sheep. If the rust beats us, we should try other trees such as alder, or the cricket bat willow which is cropped in England after fifteen years.

FOOD FOR HUMANITY

We can grow food for humans in the form of nuts. This is nothing new. There are many good nut trees in this country but they are grown in a haphazard fashion. As far as I know, there are only a few small walnut orchards in this country and yet in California 67, 600 hectares (167,000 acres) are devoted to them. Pro rata on a population basis, this country would have 1000 hectares (2,500 acres). The Pecan industry in the United States has an annual turnover of $80 million. There are 6,900 hectares (17,000 acres) of Macadamias in Hawaii. Both these nuts grow well in parts of the North Island and already our DSIR is doing research into them. There are 265 hectares (650 acres) of hazels in England and they are a major export from Turkey.

In the Pink pages of the Sydney telephone directory, there are eight firms listed as nut importers. Sweet chestnuts, have been selling for $3.04 a kilogram ($1.38 a pound) in Sydney.

FODDER TREES FOR STOCK

The third possibility is to grow trees that will provide stock feed, dropping sugar rich beans and fruit, on a self service basis. Carobs, Honey Locust, Persimmon, Mulberry, Oaks and others will all supplement the grass and provide feed for nothing, year after year.

Trees can make more money than most conventional crops. At $0. 88/kg (0.40/lb), walnuts should gross $2175 a hectare ($880 an acre). In Australia, pistachios give a gross return of $2720 a hectare ($1100 an acre). In the Hunter Valley of NSW, olives are quoted as grossing $2470 ($1000 an acre). These may be specialist orchards but surely we can earn some part of this from two tier agriculture ?

The following trees fit in the two tier concept and we hope that someone will try some or all of them and become the experts.

These will all grow but obviously some will do better than others. To make money I think we should concentrate on Persian walnuts, Hazels, Chestnuts, in the South Island adding Pecans, Macadamias in the North, but don't let that stop anyone. Some of the other nuts may well be a winner and I have my money on Ziziphus jujuba, the Chinese date but then as far as I know, I have the only seed in New Zealand.

               

THE NATIONAL SECRETARY writes

from one small seed . . .

Following a visit to Mr. Roland Clark's property at "Glenshane" in May 1974 by Messrs Halliwell, Hyde, Neilson and Davies to discuss the immediate requirements for improving and expanding research with Tree Crops, discussions were held with Dr. H. C. Smith, Director of Crop Research Division, DSIR Lincoln.

FIRST MEETING

As a result of these explanatory talks a decision was taken to call a meeting of all known interested people from relevant Government Departments, Universities, Commerce, Nurserymen and Farmers.

This inaugural meeting was held on 31st July 1974 in the Botany Division Library at DSIR, Lincoln and was attended by 25 people.

It was resolved at this meeting to form a committee to be known as the National Tree Crop Advisory Committee whose scope and aims would be limited to studying the potential of Tree Crops with special reference to nut tree products. Mr. H. R. Clark was appointed Chairman and Mr. D.J. Davies, Secretary.

CANTERBURY BRANCH FORMED

On 26th August 1974 a steering committee was initiated to make arrangements for convening a meeting to form a local Canterbury Branch.

The inaugural meeting of the Canterbury Branch was formalised at a Field Day Meeting held at Glenshane on 30th November 1974. Over 50 persons attended this most interesting day and Mr. H. R. Clark was elected President of the Branch and Mr. G. Halliwell, Secretary. Committee members were elected to represent the four regional territories within the Canterbury province.

On 19th March 1975 the second Field Day and meeting of the Canterbury Branch was held on the Deans properties at Coalgate-Darfield and a visit was made to the arboretum at Adams estate Greendale. The current membership of this branch is now 40 members and is expanding rapidly. Many members have been enrolled outside Canterbury demonstrating that interest in the new Tree Crops organisation is universal throughout the country.

FIRST NATIONAL CONFERENCE

On 16th April 1975 the first A.G.M. of the Tree Crops Committee was held at the Cawthron Institute in the province of Nelson. It was resolved at this meeting to become an Incorporated Society and to be known as the New Zealand Tree Crops Association. The membership fee would be three dollars with one dollar per member being returnable to branches as they were formed.

The next meeting of the N. Z. T. C. Association would be held in Hamilton in the autumn of 1976 and would be a two day Conference including a field trip to inspect trees in the Waikato and Bay of Plenty region.

CROP RESEARCH DIVISION, DSIR

EXPERIMENTAL TREE CROPS PROGRAMME AT LINCOLN

The Director of C. R. D. , Dr. Harvey Smith, has requested three scientists on his staff to include work on different aspects of tree crops in their programmes.

Dr. Ivor Lewis would concentrate on the immediate problems of propagation techniques with the basic objective of developing methods which could eventually be used by commercial nurserymen for large scale propagation of certified plant material.

Mr. Laurie Hurndell has already started a nursery where selected material from various parts of the country can be evaluated and where a range of grafted and named imported cultivars can be raised for eventual testing in various parts of New Zealand. Priority in the meantime is being given to different species and strains of walnuts, sweet chestnuts, hazelnuts or filberts, almonds and pecans. It is also proposed to establish a nut seed collection for identification purposes. In addition a small miscellaneous collection of interesting tree crops of commercial potential will be maintained if space and time allows.

IRRIGATED TREES

Mr. Doug Davies has been allocated approximately 1 hectare of land which has recently been prepared for border dyke irrigation and this will be used for study of management systems and the yield performance of local cultivars as compared with imported named material.

The objectives of this site will embrace the following aspects:

(a) Two tier agriculture - Where the combined and reciprocal effects of trees and grazing under both lucerne and pasture will be assessed. The kind of trees used will be walnuts and sweet chestnuts.

(b) Irrigated hedgerow shelter - Where the shelter influence of close planted trees will be studied on process crop yields. Hedgerow trained almonds and hazels will be used in this single and double crop study.

(c) This small scale tree crop field experiment will ultimately provide opportunities for looking at mechanical harvesting, fertilisation and disease control, as well as stock protection and numerous other possibilities.

Members of the N. Z. T. C. A. will be welcome to call and discuss ideas and problems with the staff of the several DSIR Divisions located on the Lincoln Campus.

REPORT FROM REGISTRATION, CLASSIFICATION AND IDENTIFICATION SUBCOMMITTEE - Miss P. M. Bates

One of the important activities of this Association is the location of superior clones of nut trees. Obviously it is impractical for the Register Sub-Committee to comb the country so we need the help and publicity that members can provide. Scionwood from quality trees is being imported from overseas but it will be some years before evaluation under our conditions is possible. It is likely that there are good nut trees here and certain clones adapted to particular regions in N.Z. These are the trees we should like to hear about. I have seen two magnificent old pecans in Auckland and Coramandel but bearing only small nuts. However, the growth of these trees indicates that soil and climate are favourable to pecan production in those regions.

It is essential that superior trees are conserved for valuable propagating material and as well as listing their locations we hope to come up with a suitable permanent label which, hopefully, will keep the chainsaw at bay. Roland Clark is looking at the possibility of a modified plastic ear-tag. The Royal N. Z. Institute of Horticulture has a scheme for registering notable and historic trees on Town and County plans and legislation now exists for the protection of such trees in the event of sub-division or road works. Superior nut trees should be registered in a similar manner.

The following qualities make a superior tree:
1. Disease resistance and reasonable vigour.
2. Heavy and regular bearing.
3. Fair size nuts. Chestnuts are tiresome to peel so large nuts are sought which fall free of the husk for easy harvesting. Sweetness is preferred over a starchy flavour. Walnuts should be well filled.
4. Easy cracking. A good walnut should crack out 100%. halves.

If you know of an outstanding tree send the details to Miss P.M. Bates, Ruakura Agricultural Research Centre, Private Bag, HAMILTON.

As far as we are aware the following cannot be grown in New Zealand

Mango, Litchi, Cashew, Tropical paw paw, Brazil nut, Date Palm & Oil Palm & Coconut Palm, Mangosteen, Cocoa, Coffee, Nutmeg (mace)

ANY CORRECTIONS OR ADDITIONS WELCOMED.

CANTERBURY BRANCH FIELD DAYS

First Branch Holds Two Successful Field Days

FIRST FIELD DAY

The Canterbury branch held its first field day on Mr. H. R. Clark's property, "Glenshane", Springburn on Saturday 30th November 1974.

Dr. H. C. Smith, Director of the Crop Research Division DSIR presided over the meeting. Farm Forestry Association members were among the 49 people present at the field day. Several speakers felt there was a need for the forma-tion of a specialist tree crops group to help promote greater inter-change of ideas on the subject. The meeting was addressed by Mr. Clark, President of the National Tree Crop Advisory Committee, Mr. D. J. G. Davies, its Secretary, and Mr. H. G. Halliwell, a member of the Committee. The meeting then formed the Canterbury branch of the N. Z. Tree Crops Association. President Mr. Clark; Secretary/Treasurer, Mr. Halliwell;

Assistant Secretary/Treasurer, Mr. D. H. Ryde; Committee Dr. I. Lewis, Messrs. Davies, H. H. Deans, G. H. Goldsbrough, A.N. Hope, A.C. Meyer and R.J. Thomson.

Mr. R. Clark showed the visitors his extensive plantings of nut and other trees. Dr. I. Lewis demonstrated the relatively new propagation technique of grafting directly into the germinated nut itself with scion or grafting wood from older trees, an approach which has already been found very successful with Macadamias and Chestnuts.

Mr. Davies mentioned that the Crop Research Division at Lincoln had, the previous week, started a small nursery to produce initially sufficient stocks of walnuts, sweet chestnuts, hazels, almonds and pecans for field trials on selected sites throughout the South Island.

TREE SELECTION AND RECORDING

The Tree Crops Committee was particularly interested in hearing from anyone who had good types of nut trees such as walnuts, sweet chestnuts, hazels and almonds and who would be prepared to make available fruit or scion wood for propagation purposes. They should contact Mr. Davies or Mr. L. C. Hurndell at the Crop Research Division, DSIR, Private Bag, Christchurch or alternatively a member of the Association's Committee. It was hoped to undertake a survey of suitable trees in the coming autumn.

Overseas material is to be checked out for disease by the Plant Diseases Division at Lincoln and Auckland, and by the Ministry of Agriculture and Fisheries at Ruakura and Levin.

SECOND FIELD DAY

The second field day of the Canterbury Branch of the New Zealand Tree Crops Association was held under the chairmanship of Mr. Roland Clark on Mr. H. H. Deans' property, Auchenflower, Darfield on 19th March 1975. Fifty people attended the day.

The reason for the field day was to meet and exchange ideas on tree crops generally, and to demonstrate the different types of nut trees growing in the Darfield area. Emphasis was placed on high yields and freedom from disease.

POINTS OF INTEREST

Mr. Clark in the course of his address demonstrated the Czechoslovakian "hot box" (26º - 27ºC) technique of walnut grafting which has recently come into use in New Zealand, and nurse nut grafting. Other points raised by Mr. Clark included (1) the recent acquisition of walnut scion wood, valued at over $100, from the U. S. A.

(2) A Californian expert could not understand why Canterbury was making no effort to produce "out-of-season" walnuts for the overseas market. More so as the Canterbury walnuts presented certain desirable features e.g. low rancidity.

(3) An Auckland importer had recently imported improved walnut tree varieties by air from California. The time taken from the site in California to the time of replanting in this country was 26 hours. On a cost study the importer considered 30 acres to be the requirement for a hulling plant.

(4) An important fact was that the export potential of tree nuts has not been considered in New Zealand studies. In addition 90% of New Zealand's walnut needs are imported.

(5) Walnut shells are used in chip-board manufacture, sandblasting machines, tyres, and non-skid surfaces, and other industrial purposes.

Mr. D. J. Davies, secretary of the New Zealand Tree Crops Association mentioned that it was proposed to set up a series of sub-committee's covering the various aspects of the growing and utilization of tree crops.

The secretary, Mr. G. Halliwell, read out points of particular interest from a letter by Mr. J. N. Harris, Waikanae. Mr. Harris wrote on the subject of spaced trees and multitiered agriculture. He referred to the use of fodder trees for feeding farm animals and useful insects e. g. bees, and to the climate tempering effects of trees.

Following an inspection of trees on Mr. Hamish Deans' property Auchenflower, visits were made of plantings at Mr. Douglas Deans, Rowallen, and Mr. Russell Deans Sandown. The meeting concluded with a visit to the Adams' Estate and inspection of the old arboretum plantings (1890 to 1925) including Pinus sabiniana (Digger Pine) Hickory and walnut varieties.

FIRST NATIONAL CONFERENCE

The Annual Meeting of the New Zealand Tree Crops Association was held on April 16th at the Cawthron Institute, Nelson. Over 50 attended. Our thanks go to Dr. Thornton, Director of the Institute, for the welcome extended and the use of the excellent facilities.

It was decided at the meeting that the tree crops group should become an Incorporated Society. The annual subscription was set at $3. 00 per member with $1.00 dollar being returned to branches. A draft constitution was presented at the meeting and will be resubmitted at the next annual meeting following approval by the registrar of incorporated societies.

Officers elected were Patron - Dr. Harvey Smith; President - Roland Clark; Vice President - Stuart Dawes; Secretary - Doug Davies; Treasurer - David Jackson. Sub-committees were also elected.

David Ryde was appointed Editor of the N. Z. T. C. A. Journal and it is intended that 2 publications per annum will be produced. Our sincere thanks go to Mervyn Burbery of Burbery Finance Limited for assisting with the production of our firs: few issues. In addition Crop Research Division have offered to produce technical bulletins under the auspices of DSIR. Additional articles are required for both publications. Members are urged to write about their own particular interests in tree crops and forward to the Editor of the Journal, D. H. Ryde, c 'o Winchmore Irrigation Research Station, Private Bag, Ashburton.

OBJECTIVES

The objectives of the association were to promote interest in tree crops generally with particular reference to nut-bearing plants; to encourage scientific research in their selection and culture; the standardisation of varietal names; the dissemination of information through meetings, publications and conferences; to foster establishment of provincial branches throughout New Zealand, and to support other organisations with similar aims and objectives.

REGIONAL AND RESEARCH REPORTS

Although the organisation of the association took the greater part of the day 7 regional reports were presented at the meeting and one report was received by mail. In addition 6 research and advisory reports were presented. The main report was presented by Mr. L. G. Morrison of the Plant Health Division, Ministry of Agriculture and Fisheries. He outlined the requirements of his division and said they were now operating the search light rather than the bucket approach, to their inspectorial role. He recommended that the NZTCA should maintain its own quarantine area and keep a register of all imported cultivars.

In the evening a social was held. Some interesting slides were shown and a prominent Nelson member gave a graphic demonstration of how to prepare planting sites with gelignite.

FIELD TRIP

The annual meeting was followed by a field-day which consisted of visits to 3 properties. The first call was to the Plant Diseases Division DSIR's research orchard at Appleby. Here, 12 well established hazel trees were inspected. The yields were not outstanding but this in part may have been due to the limitations of the soil and the site. These trees were on an exposed ridge with a northerly aspect, and in a rather close proximity to a tall eucalypt plantation. Questions raised by the meeting were:

(1) compatibility of hazels with eucalypts
(2) suitability of soil type and shortage of humus and nutrient elements
(3) relationships of the cultivars to the soil type and aspects.

It was pointed out by members that hazels tend to thrive in a cool, damp situation that there are many high-yielding cultivars world-wide, some of which could no doubt be utilized in the Nelson district. This would require extensive and methodical trial work.

The next stop at a private property on the Waimea Plains emphasised the importance of pre-planted shelter and the need for high yielding cultivars and suitable pollinators for almonds. The almond is one of the most sensitive of all tree crops to poor drainage.

The last stop was at the hillside property in Todds Valley of Mr. G. R. Roberts who kindly provided an excellent lunch. This was greatly appreciated by all present. Mr. Roberts is devoting a small property to the planting of a wide range of tree crops. Some types were just starting to come into bearing in a tree park development. Nut trees, citrus, tropical trees, and trees that provide fodder for stock have been established.

It was an enjoyable bus tour under the very able and entertaining guidance of Alec Hastwell, from Richmond. The Association was deeply appreciative of the hospitality extended by the Nelson group.

TREE CROPS: LIST

Botanically speaking, every tree is a fruit tree unless it reproduces vegetatively only.

"Nut" Trees Walnut, Chestnut, Pecan, Oak, Hazelnut, Macadamia (Queensland Nut), Almond, Carob, Castanea sativa (Sweet or Spanish Chestnut), Castanea pumila (Chinquapin), Juglans cinerea (butternut).
Climbers Black passionfruit, banana passionfruit, Chinese gooseberry, Choko, Grape vine.
Fruit trees - temperate Persimmon, fig, olive, medlar, elderberry, mulberry, apple, pear, cherry, plum, peach, nectarine, quince.
Fruit trees - sub-tropical (sensitive to light frost) All citrus, tamarillo (tree tomato) feijoa (pineapple guava), sub-tropical mountain paw paw, pomegranate, anona sativa (custard apple or cherimoya), catley or cherry guava, Casimiroa (white sapote), avocado, loquat, Japanese banana.
Fodder trees Oak, Mulberry, Honey locust (Gleditsia), Some acacias, Carob, Chestnut.
Trees for Honey
Natives: Rewa-rewa, lacebark.
Others: Tree lucerne, Lime (Tilia), Eucalyptus species, Nyssa Sylvatica (Tupelo)
and many of the above.

REGIONAL REPORT

NORTHLAND - AUCKLAND

S. N. Dawes
Plant Diseases Div. , DSIR, Auckland.

(This report was not received in time for circulation to members at the Nelson conference).

In speaking about Northland and Auckland I am mainly considering the coastal areas from Gisborne and New Plymouth north. These are the areas where subtropical fruits such as citrus are grown commercially.

Macadamia

By far the most promising tree nut for this region is the macadamia. In general other nuts such as almonds and walnuts are climatically unsuited due to lack of winter chilling, droughty soils and the prevalance of disease.

The macadamia, however, an evergreen nut tree from eastern coastal districts of Australia, seems well adapted. The first planting of macadamia seedlings took place at Kerikeri in about 1932 and both of the species that produce edible nuts, the smooth shelled Macadamia integrifolia and the rough-shelled M. tetraphylla grow well and are capable of producing good crops.

Trees are common throughout the region as specimens and occasionally as wind breaks on orchards.

In recent years the success of the Hawaiian macadamia industry has created a lot of local interest. The Hawaiians have been able to obtain high yields of nuts from their commercially selected cultivars and the processed nuts are of very good quality and command a high price.

Now although the macadamia has been grown in New Zealand for many years, we still know very little about its potential here. Until very recently almost all trees were seedlings and macadamias are very variable from seed, most seedlings being quite useless for commercial production of nuts.

Only by vegetative propagation of good quality material can we discover if the macadamia has a commercial future in New Zealand. This means looking for local chance seedlings that produce good crops of quality nuts and introducing cultivars that have been selected overseas. A few macadamia selections from Hawaii and Australia have been established at the D. S. I. R. Research Orchard at. Te Puke and on Ministry of Agriculture land at Gisborne and Kerikeri and further material is being introduced as rapidly as possible.

This introduction of macadamia varieties has been seriously hampered in the past and to some extent still is, by a lack of expertise in propagation. Considerably greater effort has to be put into propagation of macadamias so that promising material can be more widely disseminated and evaluated.

Once clonal macadamias are carefully established in a few representative localities we will start to get some useful information on their performance.

At this point it is timely to emphasize that the only thorough selection of macadamias for processing has been done in Hawaii with Macadamia integrifolia for the Hawaiian environment. This took 30 or 40 years and meant an initial selection of about 800 seedlings from a population of approximately 100,000 from which have come 5 named commercial cultivars.

All the commercial plantings of macadamias for processing whether in Hawaii, Australia or South Africa are principally of Hawaiian cultivars. '

As I said previously we know this species grows and can crop well here, but we do not know if good quality nuts can be produced. If we find the quality and yield of nuts from the Hawaiian cultivars is satisfactory it will be very fortunate, for if we have to rely on tetraphylla, the selection of commercially important clones will take much longer.

All the named tetraphylla cultivars have only been observed for a very limited period and many will show faults.

Macadamia tetraphylla is considerably different to Macadamia integrifolia and is probably equally as important, but someone has yet to do the same work on this species as was done in Hawaii on integrifolia.

There are tetraphylla selections with much thinner shells and sweeter kernels than integrifolia and it may prove possible to select for nuts suitable for the fresh nut trade and not only for processing.

Pecan

The other tree nut that warrants evaluation in the north is the pecan. One of the prime factors to consider with this crop is the availability of suitable soil types. I think the most likely area for them to succeed in the northern coastal districts, is Gisborne. The deep fertile, moist, alluvial soils there should provide the conditions they prefer.

The vigorous breeding programme conducted by the US Department of Agriculture at the Pecan Field Station, Brownwood, Texas, is producing pecans that will greatly improve the profitability of pecan nut growing. Recently released cultivars are precocious, heavy bearing and allow much more intensive planting.

These are the varieties that we must introduce and evaluate as rapidly as possible.

Several of these new cultivars were among 9 varieties introduced from the U. S. A. last summer and planted at the Te Puke and Havelock North Research Orchards. I hope to be able to follow this up with further varieties next summer.

Other Subtropical Nuts

One further comment on nuts in the north is that we should be on the look out for other tree nuts from the subtropics. The successful development of the macadamia from a virtually unknown tree to a major crop in 40 years is an outstanding achievement and is an example of what can be achieved. There are other evergreen nut trees which warrant similar attention.

Fodder Trees

Finally I will just briefly mention fodder trees.

Both the Honey Locust and Carob, which bear edible pods, are worthy of trial in northern New Zealand. They could be ideal dual purpose trees on farms; providing shelter, shade and a valuable crop of pods. If we can find cultivars that crop heavily they could be a great boon in droughty areas of the north.

The pods are very nutritious being relatively high in protein and hence providing a good balanced feed. The honey locust is already being grown by one Bay of Plenty farmer who seems well pleased with the results. The carob however is still virtually unknown and we must introduce the high yielding varieties that are available.

HOW TO GET STARTED WITH NUT TREES

from H. R. Clark

This is no trouble at all. The best way to build a house is to build a house and the best way to grow nut trees is to grow nut trees.

Chestnuts and oaks quickly lose their viability so they should be planted as soon as possible or at least kept damp.

Persian walnuts are different. They can be kept dry till spring. Come August soak them in water for 48 hours, and place them in a container of damp sawdust and cover well. Scratch them over once a week and take out any that have sprouted. These should be planted in a potting mix in a container with some fertiliser and grown on for a year, when they should be 18 inches high. Next season they can go out into the paddock protected by a 44 gallon drum with the top and bottom cut out. Thanks to not having their root system wrecked and by taking advantage of the micro climate in the drum they will go ahead very quickly.

Another method is to plant them out in rows in the garden and run a row of carrots with them as a marker. Where you get a miss, at least you get some carrots. Where there is a seedling, pull up the carrots around it. With this method, the preliminary soaking is important.

Some seeds need stratifying i.e. a spell of cold weather to break their dormancy and this is easy enough using the home refrigerator. Wrap them in a plastic bag with a little damp newspaper. Hickories and Black walnuts need this treatment. Six weeks seems to be long enough. Then go ahead and plant in the garden or in a container.

Grafting nut trees is not difficult but requires specialist knowledge and you will notice that few, if any, nurseries in N. Z. sell grafted trees. The only one that I know of is Vernon Harrison's one in Palmerston North.

Many nut trees do not grow true from seed any more than children exactly resemble either of their parents. Their genes are mixed and the offspring will be a mixture of both.

The autumn grafting technique seems to work judging from my efforts last winter but I ran into trouble with the after care and lost most of my successes.

EFFECT OF SEED POSITION IN THE SOIL

A pamphlet by M. M. Tymko*, translated from Russian, describes the results of tests in which Persian walnuts were planted in different positions to determine the effect on stem and root growth.

The kernel of the Persian walnut and also those of hickory, black walnuts, butter- nut, pecan, Japanese walnut, heartnut and even the almond and filbert, consists of 2 halves (or cotyledons).

It seems, therefore, that the results of the tests made with Persian walnuts should also apply to the other kinds of nuts mentioned.

The embryo, from which the stem and root develop, is located between the cotyledons where the 2 are joined, under the tip of the shell. In the embryo are the elements of the stem, which grows upward, and the tap root which grows downward. The portion of the embryo which is to become the root is directed toward the tip of the shell while the part to become the stem is located opposite and pointed away from the tip.

The shell also consists of two halves joined at a "suture" line. When the nut germinates the shell opens along the suture line, widest at the tip, the end opposite the base where the nut was attached to the branch.

In the test, 338 Persian walnuts, all from the same tree were planted in 4 different positions to determine the effect on stem and root growth.

Near the end of the first growing season the seed- lings were gently dug up and washed and the stem and root developments compared. The length and diameter of each stem and tap root was measured and the number of leaves counted.

These observations resulted in the following conclusions:

(1) When the nut is planted with the tip upward the upwardly pointing root element, emerging from between the shell halves, must do a half turn to grow downward. The stem element pointing downward likewise must do a half turn and may not find a way out of the shell, in which case the plant dies. Both the root and the stem are badly deformed and growth is retarded.
(2) When the nut is planted with the tip downward the root exits easily but the stem, growing upward as it is pointed, may become trapped within the shell and unable to escape. To emerge it must bend sharply and thus hampered it does not develop normally.
(3) When the nut is positioned horizontally with the plane of the suture line level, the tap root emerges easily and grows downward but the stem, under one of the cotyledons and under the dome - like upper half of the shell, has much difficulty in emerging for its upward growth. Again the stem is deformed and its development delayed.
(4) The best planting position is horizontal with the plane of the suture line, perpendicular to the soil surface. From this position, when the nut germinates and the tip of the shell opens, both the root and the stem, emerge readily and produce the strongest, most rapidly growing seedling.

The poorest results were obtained from nuts planted tip upward and the best from nuts planted on the suture.

Only 55% of those in section (1) sprouted, 62% in section (2) 70% in section (3), and 93% in section (4).

Nuts planted on the suture section (4), showed sprouts above ground 5 weeks earlier than those planted with the tip upward section (1).

*Reference

"Effect of seed position in the soil on the formation of the root system and stem in Persian walnut seedlings" by M. M. Tymko translated from Russian.

Compiled: H. G. Halliwell

AUTUMN GRAFTING OF WALNUTS

Poland lies at the northern border of the walnut growing region and has a total walnut population of about a million trees. Among these are many valuable, old, winter-hardy specimens, most of them in south-eastern Poland near the Carpathian mountains. They are frost-resistant, late-blooming types that give high yields of large and desirable nuts.

In Poland, until recently, these desirable specimens could not be reproduced vegetatively. All walnut trees had to be started from seedlings, and walnuts of course, do not breed true. The factor ruling out vegetative propagation was that spring grafting is impossible in the Polish climate. Graft union takes place very slowly, while the buds of the scion develop quickly. The buds then die, because they are not supplied with water and nutrients from the root stock.

However, Dr. Cerny, in Czechoslovakia, worked out a method of grafting walnuts that gives very good results in northern climates. The method has been tested in Poland over a period of years and gives excellent results.

Mr. Roland Clark who farms at Springburn near the foothills of Mid-Canterbury has found the method an excellent one.

The technique is simple.

Seedlings of black or English walnut, 1 or 2 years old, are dug at the beginning of October (April (?) in N. Z. ) and the scions from selected trees are grafted on them. The whip and tongue method of grafting gives the best results.

The grafts are then packed very closely in a box in which the temperature is thermostatically maintained at 20 to 21 degrees centigrade. The grafts stay in the box for about 3 weeks.

It is a known fact that the cambium has no winter rest. That is why the graft union takes place when the grafts are kept at such a favourable temperature. The buds of the scions do not break however because they are in deep winter rest. After 3 weeks, grafted trees are taken out and planted in the field or stored in peat moss in a cool cellar and planted in the spring.

In research trials, graft takes of up to 90 per cent were obtained. This percentage depends on proper humidity in the heated box.

Moulds develop if the humidity is too high. The scions for grafting should be taken from vigorous annual shoots that are at least 50 centimetres long.

Short, thin scions cannot be used. The method is inexpensive.

Many plants can be placed in the heated box since roots can be trimmed so that the plants are packed tightly. Two or three sets of grafts can be passed through one box during the autumn and winter.

It is hoped that this method will allow valuable cultivars of walnuts to be selected from the best-established trees.

Reference: Dr. S.A. Pieniazek, Instytut Sadownictwa, Poland.

Compiled: H. G. Halliwell.

NURSE-SEED GRAFTING

by DR. I. LEWIS

CROP RESEARCH DIVISION, DSIR LINCOLN

Nurse-seed grafting is a method of propagation theoretically suitable for any woody plant that is hard to strike from cuttings and which has a large fleshy seed. Basically, a dormant scion is inserted into a germinating seed. The cut-surfaces join to give a graft union. It has been used with camellias and assorted nuts, and it may have extensions to stone fruits.

Where the procedure is applicable it has many advantages over conventional scion/ stock combinations. It is economical on time and space because stock plants do not have to be grown up to size. Generally it is done inside so the timing can be made to suit the operator. Scion wood of small diameter can not only be used but is preferable and short scions of one or two buds are quite sufficient. The process is therefore about as economical as budding.

The scion can be held so firmly by the seed tissues, depending on the species, that tying is not necessary and this is time saving. The graft union will eventually be below ground level and the scion is therefore then in a position to take root, which is advantageous in cases of delayed incompatibility. With at least one variant of the process, suckers cannot possibly arise from the stock unless adventitious buds form. The technique is not difficult as conventional grafting so even a novice can do it rapidly. Because of the smaller outlay in time and materials a percentage of graft failures is less important and there is also a strong possibility that losses can be made up the same season.

A germinating seed is necessary since only in this state is it obviously active.

Pushing a dormant scion into a dormant seed might sometimes work but in the time it takes for the seed to begin germination, infection or drying can occur. The seeds can be germinated in any convenient medium; peat, vermiculite and pumice would all be suitable. The fleshy part of a germinating seed mainly consists of the cotyledons. In favourable cases it is probable that simply pushing a wedge ended scion anywhere into the cotyledons will work, despite the curious situation of grafting onto what is basically a leaf.

Where it is known that adventitious roots will develop from severed cotyledons, it may be best to delay the graft until plumule and radicle are fully out and only attached to the remainder of the seed by the petioles. If the petioles are then severed and the scion wedged between them, no suckering from the stock is possible. If petiolar rooting is not satisfactory, then the root of the stock seed can be utilised by inserting the scion between the cotyledons. The plumule will have to be cut to prevent its competing with the scion, and there may be a tendency for axillary buds at the bases of the cotyledons to develop and cause more competition. Since callus tissues will only arise from cut (or at least bruised) surfaces, it would seem better to push the scion into a definite cut, rather than to try sliding it between the cotyledon surfaces. Another variant is the insertion of the scion into the hypocotyl and then the graft becomes a seedling form of the wedge graft. Since it has to be tied it is less convenient.

Dipping the new grafts into a fungicide solution would be advisable and sealing the top end of the scion and around the wound with vaseline might also be a worthwhile refinement. Otherwise the units are placed straight into something like peat, with the graft covered, and kept humid until the scion buds show signs of growth. Callus formation may be visible at the top end of a scion that is taking. The plants can then be carefully transferred and potted up. Some experimentation with temperatures may be necessary. For example, walnut grafts generally benefit from high temperatures, but these will also force buds into excessive growth and then there may be difficulties in hardening the grafts off.

Minor experimentation at Lincoln last season indicated that the technique works very well for Castanea sativa. Roots do arise from severed petioles of this species so this variant would currently be recommended since suckers from other variants were rather a nuisance. It takes more time, however, for an adventitious root system to establish. The grafts were kept at high humidity and high temperatures and this combination appeared detrimental since the soft leaves that developed collapsed readily when exposed to normal glasshouse conditions.

Walnuts were also tried but the method seems much less satisfactory with these, although the scion wood used had been stored sometime and could have been at fault.

Callusing was noted on the cut petiolar surfaces and some success has been reported overseas so it could be a matter of discovering the optimum conditions.

References:

1. Hartman, H. T. and D. E. Kester. 1968. Plant Propagation Principles and Practice 2nd Edition. Prentice Hall, Inc. , Englewood Cliffs, New Jersey.

2. Beck, A.R. Ann. Rpt. N. Nut. Grs. Assn. 1973 = 84-90.

Nurse-seed grafting (diagrammatic)

Introduction of New Nut Varieties

The committee responsible for importation, quarantine and standards would be greatly assisted if all members would supply a list of any named varieties of hazel nuts, walnuts or chestnuts that they retain, or have access to, for purposes of propagation. When all lists have been collected it will be possible to avoid future importation of material already in New Zealand. We hope that members will fill in the prepared sheet and send it to the convenor of the committee - Dr. Ivor K. Lewis, Crop Research Division, Private Bag, Christchurch.

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Created: Monday, 4 August 2003 - Modified: 2007 August 11