Gevuina avellana

INTRODUCTION:

Isolated Gevuina trees have been grown in New Zealand, milder areas of Great Britain, Ireland and other countries for several decades as an ornamental tree. In Chile, the nuts from natural forests are harvested and enjoyed by local people but few attempts have been made to date to encourage commercial cultivation and marketing of gevuina nuts.

Unimproved gevuina trees have been grown in New Zealand for many years and seeds of the species have been available since the 1950’s. In the late 1980’s Crop and Food Research in co-operation with the New Zealand Tree Crops Association (NZTCA) and set up a series of trials throughout New Zealand to test sixteen accessions of gevuina under a variety of conditions. Only two or three of these are presently being commercialised.

As with most new crops, there is still much to learn about the growing and management of gevuinas. This set of notes has been prepared to collect together the available advice on the commercial establishment of gevuinas. They are written in good faith as a help to gevuina growers. People deciding to grow gevuina do it under the understanding that there are risks, and that they have made up their minds based on their own understanding of the commercial prospects. These notes are reproduced and amended from Halloy, Greu and McKenzie 1996, in “Economic Botany” and Halloy 1997 in “Tree Cropper”. As more is learnt, these notes will be updated.

Plant description

Gevuina is a member of the Proteaceae family included in the subfamily Grevilleoideae and the tribe Macadamieae which includes several other nut bearing genera. Gevuina is restricted in its natural distribution to the southern Sub-Antarctic forests of South America (Argentina and Chile), from 35 to 44º S latitude, and from sea level to close to 700 m.

Figure 1 shows the distribution of gevuina natural stands compared with that of macadamia.

Figure 1: Natural distribution of Gevuina vs Macadamia

Gevuina is a medium sized tree which grows to a size of 10-12 m, (rarely 15 m), with a rather compact canopy of large bipinnate leaves divided into glossy, coriaceous dark green leaflets with serrated margins. Canopies are generally much more open under shady conditions. The branches are stout and pubescent, young shoots being covered in dense reddish hair. The tree is hermaphrodite but seems to require or at least benefit from outcrossing. Wild plants have showy sprays of creamy white flowers contrasting vividly with the dark green foliage. The flowers are similar to those of macadamia, borne on the outside of the canopy on racemes in pairs, the four tepals fused into a single structure with the stamens, curving back at full opening to reveal the simple style and ovary. Opening in late summer, the flowers attract a variety of insect pollinators, including honey bees, to feed on the abundant nectar. This timing ensures very little risk of frost damage, unlike macadamia which flower in late winter. Some trees show a second flowering flush in late spring.

Botanically, the fruit of gevuina is a globose woody drupe derived from a follicle which has become indehiscent. Nut sizes range from 1.2 to 2.3 cm in diameter. Weights are typically 1.7-1.9 g, but some populations have fruits weighing up to an average of 4.2 g. Nuts produced in Auckland have been recorded as weighing up to 4.4 g (fresh weight). Initially green, nuts mature to bright red and finally brown or black. The husk (pericarp) is about 3 mm thick and rather flexible. Unlike the stone-hard macadamia seed cover, this husk can be cut off with a knife or cracked with a handheld nutcracker. When fresh, the husk may weigh up to 3/4 of the total fruit weight. As nuts take almost a year to mature, they are borne simultaneously to the next years flowers, compounding the attractiveness of the whole tree. The nut tastes somewhat like Hazelnut and macadamia. As in other Proteaceae, gevuina develops proteoid roots

NATURAL ENVIRONMENT

Gevuina naturally occurs in the Valdivian forests of southern Chile. These diverse Subantarctic forests show many Gondwana affinities and Gevuina’s closest relatives grow in Australia and New Caledonia, and in the Andes further north.

Climate

The Southern Chile climate is temperate oceanic and wet (Table) with conditions comparable to a range of coastal areas of New Zealand, from Invercargill to Auckland. Gevuina ranges further south than Puerto Montt, so that temperatures will be cooler still and rainfall higher at the southern extreme of its distribution. Table 1 gives approximate values of physiological tolerances of gevuina compared to macadamia. The general range of values for cold tolerance have been confirmed by the plants growing in New Zealand.

TABLE 1. PHYSIOLOGICAL TOLERANCES OF GEVUINA COMPARED WITH MACADAMIA.

Although Gevuina seems to grow quite often in dense forest, it also grows well in disturbed second growth areas. This pioneering habit leads it to tolerate situations exposed to sun, wind and frost. One prospering population of gevuina lives across the Andes in the drier areas around Lago Puelo (Argentina). There it seems to grow well in areas where forest has been destroyed by fire.

Soils

The soils are often highly organic and well drained in the Valdivian rainforest. Trees can also grow well in almost swampy forests with saturated soils and on secondary re-growth after slash and burn, where much topsoil has been destroyed. Most of these soils are acid and generally similar to areas of Westland in New Zealand. Gevuina also prospers on free draining volcanic ash soils in the Andes foothills. From present information it would seem that Gevuina is either not too particular, or it has several different genotypes adapted to different soils and climates. The latter would allow for careful selection of commercial types adapted to different regions.

USES

Edible Nut

Gevuina produces an edible nut somewhat similar to hazelnut or Macadamia in aspect and taste. The nuts are cream-white inside, with a crisp texture somewhat like coconut. Nuts can be eaten raw, or more frequently roasted. As other nuts, gevuina has a large potential for confectionery, either whole, split or ground into many different preparations. An important industrial advantage of gevuina over macadamia is the relatively thin easy-to-peel shell. This not only makes extracting the nuts easier, it should also reduce the level of waste produced by nuts being destroyed in the process of cracking.

Animal Feed

The high protein content of gevuina makes it an attractive option for stock feed. Such an option could make use of cracking residues, giving it added commercial value. Much of the Chilean production is presently used as stock feed. Cáceres and co workers (1982) studied the effects of incorporating gevuina nut in chicken rations. Incorporating 20% gevuina into their feed, they obtained a live weight from hatching to 30 days 37% higher than controls without gevuina.

The abundant nectar in gevuina flowers supplies excellent bee feed. Beehives would benefit from being in close proximity to a gevuina orchard, which in turn would benefit from the pollination.

Plant Extracts and Nut Composition

Gevuina nuts are rich in oils, which are similar in their chemistry with Macadamia, but show some important differences. Some of the oils in gevuina have been identified by Chilean researchers as having particularly high value for health-cosmetic purposes. In particular, palmitoleic acid is well absorbed by the skin, and is a good natural UV filter for sun lotions. Gevuina oil has a particularly high content of palmitoleic acid (up to 27.6%,)

The lipid content of gevuina is comparable to that of rapeseed, sunflower and peanuts. The protein content, after oil extraction, increases to 16%. The oil is of a high quality for a table oil, comparing favourably with olive oil although the high proportion of polyunsaturated fatty acids may require the addition of stabilisers. The whole nut can be processed into a “gevuina butter” paste of high nutritional value, which can be on a par with peanut butter.

Market And Export Potential

We could not find recent figures for gevuina consumption in Chile. However, it is reportedly slowly increasing in popularity, being sold all around the country at different outlets, ranging from side street vendors in the cities of southern Chile to supermarkets in the country’s capital Santiago.

In the international scene, nuts are a valuable commodity. World nut exports were above 700 000 metric tons/year during the period 1986-1990 (McGregor 1991), with Macadamia accounting for less than 1% of that total. This leaves considerable room for expansion of Macadamia type nuts (Martin 1992a, b), particularly in the USA, Japan, SE Asia and Europe.

As with other nuts, gevuina nuts have the advantage of low volume, high price, long lasting products; and thus a high benefit per unit transport cost. The same would be true of oils and cosmetic products which may be developed from gevuina, with the added benefit of establishing a local processing industry.

Table 2 Chemical composition of gevuina and macadamia nuts (g/100 g).

The essential amino acid composition of Gevuina flour makes it a well-balanced food, with all except lysine ranking above FAO /WHO (1981) standards. This, together with its lower fat and higher fibre content, gives it attractive prospects as a health food, complementary to legume based proteins which are low in cystine and methionine. Added to this are the high contents of polyunsaturated fatty acids such as linoleic, linolenic and ecosaenoic acids. The value of such essential fatty acids for a healthy diet, and their role in reducing the risk of serious illnesses is increasingly being recognised by the medical profession.

Table 3 Composition of gevuina flour after fat extraction. Percent of dry weight, from Voullieme (1982).

Ornamental, Wood And Other Uses

Gevuina sells easily as an attractive garden and park specimen tree. Present sales in New Zealand and the UK are based on this value, which led Britton to call gevuina “one of the most beautiful of all trees”. Gevuina is known as a valuable durable wood with beautiful grain, particularly apt for turnery. It is valued for tiles, musical instruments, furniture and oar making on a local scale. Its small volume and widely dispersed wild stands has precluded its development as an important timber species. Experimental forestry plots of gevuina were initiated in Chile in the 1970’s.

In addition to its use as a live plant, gevuina’s cut foliage is so durable that cut branchlets are sold in Chilean flower shops at a very good price. The hardy leaves can be used in wreaths and floral arrangements and to garnish food and tables in restaurants.

The husks of Gevuina are rich in tannin. As the husks are left over after processing the nuts, tannin extraction might be used as a secondary source of income

Cultivation and Productivity in Chile and New Zealand

Gevuina is reported to be “intensely cultivated” around Pucón and other areas of southern Chile. Several experimental orchards have been planted in Chile, some on a reasonably large scale. However, most Chilean production still originates from wild trees, with an estimated 300 000 tons being produced (but not harvested) in the wild. However, this estimate must be regarded with caution, and it may be over an order of magnitude in error. Such estimates are based on assumed plant distribution, production and density in native stands. Karmelic (1982) estimated the total area covered by wild gevuina is around 24000 ha, but estimates of the density of such populations are highly uncertain and using them to calculate actual production is risky.

The officially recorded harvest of gevuina in Chile in 1982 was 180 tons, which were processed into 50 tons of nuts for roasting and grinding into flour (Karmelic 1982). All was for the domestic market. More recent estimates have not been published.

Table 4 compares the productivity expected of gevuina with that for macadamia. This data must be read with caution. The peak production noted for macadamia is the result of decades of selection, improvement and research on management techniques. Gevuina data is based on very few initial trials.

TABLE 4. PRODUCTIVITY OF GEVUINA AND MACADAMIA. NIS = NUT IN SHELL.

The low average production per tree obtained in the Chilean data may be the result of several factors. Trees monitored were still relatively young and planting density was very high (see below). Karmelic (1982) says that productivity can vary widely from year to year, an aspect that needs to be researched. However, it seems possible to conclude from present knowledge that seedlings would take some seven years to first production, and given minimal management techniques, estimated productions of 3-9 t/ha of nut in shell could be achieved.

Accessions

Trials of different provenances have not yet shown major differences from a commercial point of view. Accessions do vary in leaf shape hairiness and colour, and also vary in nut quality and size, productivity, hardiness and other factors.

At this stage the Gevuina Action Group are still in the process of trialing a number of accessions but it will be several years before the group can determine the important differences and select best cultivars.

Crop and Food Research and Tree Crops Association have identified two accessions, (557 and 63) which appear to have good vigour, good nut size, flower productivity and hardiness. Accession 557 has larger nuts with a pointed tip, while 63 nuts are spherical and smaller. All stocks of cutting grown material available through commercial outlets through the Action Group are presently being propagated from these accessions

Graph X shows the distinct differences in harvest times between the two accessions selected for further commercial development. This data was gathered from a small number of fruit producing trees at Invermay Research Centre. The Genetic control of flowering time and fruiting will be of value to growers in selecting the most appropriate variety to suit the microclimate of their site as well as the timing of supply to the markets.

Although there is not proof, it may benefit production to have cross pollination between two different accessions. People purely interested in marketing nuts will benefit from presenting an agreed standard quality, the reason behind concentrating on only two accessions. They will be the first to produce a uniform quality nut even if it may not be the very best. Simultaneously research must continue on genetic diversity (accession and seedling trials) to provide future superior standard varieties. People interested in this process need to keep detailed records of performances and may not have a high value crop due to heterogeneity.

Parent trees of Accessions 63 (right foreground) and 557 (rear background) at Invermay Research Centre, Mosgiel

North Otago mixed Orchard site with Gevuinas in foreground

TABLE 5. CLIMATE DATA FROM GEVUINA NATIVE AREAS (FROM MEDEL AND ORUETA 1986), COMPARED TO GROWING SITES IN NEW ZEALAND (FROM NZ METEOROLOGICAL SERVICE 1983).

Selecting a good site to grow gevuinas

Plants are best sited in their final positions, 3-4 mm apart in well drained soils. Exposure depends on areas, but sunny slopes exposed to drying winds (eg. N and NW slopes) are clearly a high risk at establishment time. Cool south-facing slopes ensure best establishment but may not be best for fruiting. Flat areas, east and north facing slopes may be best for fruiting, but may require individual shelter on establishment for best survival (e.g. shadecloth, Tagasaste). A shelterbelt around the whole area is recommended. Depending on conditions, plants could be protected from heavy frosts and from full sunlight with shadecloth or by other plants during the first summer. Once established, plants will thrive and fruit more heavily in full sunlight.

In Chile, Gevuina seem to produce better on sunny slopes, a situation which coincides with macadamia preferences in New Zealand.

Tree Spacings

Donoso and Soto (1979) used spacings of 2 X 4 and 4 X 4 m in 1/4 ha experimental plantings in Chile. However, previous Chilean data on production was obtained from smaller plots with higher densities of 2200 to 3200 trees per hectare. Such densities were thought to restrict overall productivity since up to 25% of trees with this level of crowding were not productive. Donoso and Soto also noted a correlation between stem diameter and fruit production for individual trees. Trees below 6 cm diameter at breast height (DBH) produced less than one kilo of fruit. Above 12 cm DBH trees produced over 4 kg and above 18 cm production surpassed 8 kg per tree. Although diameter is obviously related to age, the exact relationship is not known in this case.

Donoso (1978) noted that coppiced gevuina grew much faster than seedling and produced heavier crops. However this is still to be demonstrated fully as Donoso’s data are ambiguous in this respect due to samples taken from different density plantings. Limited New Zealand experience is that trees in full light and heavily pruned, produce heavy crops of nuts at an early age.

NUMBER OF TREES PER HECTARE

Pollination Needs

Gevuina is insect pollinated. Single trees have few or no fruit, suggesting a need for cross-pollination. Initial observations seem to indicate the need for out-crossing to produce fruit. Of the adult plants found around New Zealand, solitary trees flowered but generally did not fruit. Cross-pollination improves initial fruit set in macadamia, where self-incompatibility and protandry have been reported. In consequence, interplanting rows of different cultivars is recommended practice in Macadamias and Gevuina may have similar needs.

Vegetation Control

Where the trial is to be established in pasture the whole area should initially be mown and the trial area marked out. Plants could be placed in rows 4m apart with spacing of 4m within the rows, although experimenting at different densities will be worthwhile.

Clear an area of one square metre for each planting site by removing all vegetation. This may be done either mechanically or chemically. The chemical Roundup has been used for this purpose without any known problems. The remaining area should be kept mown or sprayed.

Soil Preparation

Each site should be dug over to a depth of 50mm. This is essential to provide the adequate drainage required. Poor structure can be improved by the addition of a mixture of well-composted pine bark, peat and sand in the ratio of 6:3:1.

Irrigation

Provision must be made for individual watering of plants by installation of a watering system to each plant. Moisture sensors may be available to automatically control the system. Susceptibility to drying requires irrigation to moisten the top 20 cm of soil, at least during the first year or two (depending on soils and temperatures).

Gevuina can suffer from drought even if subsoil is wet, and can suffer from transplanting through lack of water supply to leaves,

Soils must remain moist but not be waterlogged. The Gevuina has shiny hard waxy (coriaceous) leaves, meaning some delay in showing symptoms of wilting or stress. With its coriaceous leaves, gevuina does not show signs of wilting until root destruction is practically complete. The plant has an inability to physiologically “shut down” in conditions of heat and water stress. In such conditions other plants wilt or shut down, thus conserving water and enabling them to survive. Gevuina seems to keep on transpiring, literally killing itself in the process if there is no water available within its root zone. For recent transplants, such deaths can occur quite suddenly, even when the soil seems moist all around, if the heat leads to the depletion of water within the root zone. This is quite frequent in potted plants as well, particularly in warm conditions or in glasshouses. Plants surviving such conditions may take years to recuperate, or end up dying after a long decline possibly mediated by fungal diseases,

Shelter

Shelter needs to be provided for the trial site as a whole. Shelter trees appropriate for the area should be used around the trial site. Placing of trees should take into consideration factors such as shading and air movement for frost control.

Shelter for individual plants can be provided (depending on site conditions) by shade cloth attached to posts around each plant.

Timing of planting

Planting in autumn to early winter ensures a minimum of water stress. Investing in foliage pruning, frequent watering and shading can extend the range of suitable times. For sites prone to heavy frosts, hardening off of plants before planting and frost protection in the first two winters may be required.

Planting tips

Several days prior to planting, ensure that the soil in each planting site and plants in containers are thoroughly moist. Follow good planting practices taking care not to damage roots but gently teasing out any badly congested root systems. Ensure that plants are adequately watered in after planting.

Selecting the right plants

Plants should be well hardened and have been growing either in pots or have been root-pruned previously (2 months before) if in soil. Large plants in pots tend to have a high leaf to root ratio, making them very susceptible to drying out at transplant. Techniques that could help get around this problem include, pruning part of the foliage (particularly older leaves) and branches, watering plants frequently during the first 1-2 years of establishment, and reducing evaporation by shading and sheltering the plant. Small plants may be tender, and suffer from frosts or from drying winds. Again, this can be allayed by shelter and watering.

Older plants, which have been maintained small by being partly root bound in small pots, seem to fare quite well on transplanting. This may relate to the better hardening of these plants, coupled with the fact that foliage has not increased disproportionately to the roots. The pattern with respect to age and size at planting is not yet clear. Results from a trial at Timaru show a peak of survival for 40 month old plants when planting seedlings and cuttings 25 to 45 months of age. Size classes with best survival were from 45 to 75cm (sample ranged from 20 to 90). However, plants younger than 25 months were not compared in this trial and Chilean practice is to plant seedlings at around 12 months.

Cuttings planted at less than 12 months old have suffered badly from frost, drought and exposure around Dunedin, unless carefully sheltered and watered. Nursery plants which show signs of suffering from drought or disease will tend to perform poorly or die.

Mulching

Appropriate mulch should be applied around plants to conserve moisture during dry periods. This should be spread over the root zone area to a depth of 25mm taking care to keep it clear of the plant stem. The mix used above for soil conditioning would be appropriate.

Frost protection

Mature gevuina plants tolerate hard frost (-8 to -12°C or somewhat less), but young unhardened plants can suffer badly or die from hard frosts (greater than -6°C). Frost protection and selection of larger plants is necessary in the first one or two years if the selected site is expected to have harder frosts than this. The frost protection is only necessary until the plants get above 0.75 metres in height to main leaves.

Gevuina also does not tolerate heat well. This is probably related to the water supply and root development. However, under optimal water and root conditions, heat thresholds may be higher. For the same reasons given above, drying winds are also not well tolerated.

Gevuina grows well under shade, but does not flower and fruit abundantly in these conditions. Optimum fruiting is obtained under full sunlight.

Examples of frost damage caused by –9degree C frost on unprotected unhardened very young gevuina plants.

Record Keeping

Given the nature of a new crop, it is important to maintain good records that will allow for reconstruction of events leading to a success or failure, thus helping Gevuina agronomy to mature. It is good practice to have a record of soil analysis and modifications performed on the soil. Weather observations are also important, particularly of stressful events such as strong winds, very high or cold temperatures, drought, and excess rainfall. Maintain a written record of management and plant performance (height, flower and fruiting date, weight and size of nuts produced each year).

Draw a map specifying the position and accession number of each individual tree for future reference. Update this when necessary if trees are replaced.

Pruning

Some accessions tend to produce a single leader. For timber production this is ideal and has been encouraged in some trials in Chile. For abundant fruiting it is best to encourage branching, and pruning the tips of the leader and most vigorously growing branches can do this. Retarding growth by branch pruning, root pruning or possibly other retardant techniques may produce dwarfed but heavy cropping trees. A variety of such management techniques need to be trialed. In the meantime, this suggests that speed of growth is not always a good indicator of best performance from a commercial production point of view.

Disease and soils

Evidence of disease or soil problems is not yet conclusive. Soil limitations do exist, but mainly in relation to water availability, temperature and drainage. Plants have been reported doing well on a range of soils from poor well-drained stony soils to rich organic soils to clayey soils. However, plants have also been subject to sudden death in all of these conditions. Fungal problems occur, but mainly on plants already weakened by other factors such as drought or waterlogging. Plants are palatable and highly appreciated by some caterpillars and rabbits.

Phytophthora cinnamomi Rands was identified as a cause of root rot in Gevuina at Mt Albert in 1978. The disease caused severe root rot and death of container grown nursery stock. The fact that many Proteaceae are particularly susceptible to Phytophthora cinnamomi dieback and the success obtained with the fosetyl-aluminium (Alliet) treatment suggests that Phytophthora may be one cause of nursery problems. The same organism may be associated to the difficulties reported in transplanting and handling and the weak root system mentioned by Rosengarten (1984) and growers in New Zealand.

Propagation trials at the Invermay Agricultural Research Centre by McKenzie suggest that cuttings fare remarkably better than seedlings, regardless of treatment. After two years without treatment, seedling survival was 13% in his trials, while cutting survival was 69%. D. Endt reported a similar observation, with cutting grown trees also being more dwarfed and cropping more heavily.

Some other diseases reported in Chile include the fungus Pestalotia truncata Lev. Mature gevuina trees have also been known to abruptly wilt and die in New Zealand. It has been difficult to identify the cause of these deaths. With its coriaceous leaves, gevuina does not show signs of wilting until root destruction is practically complete. By that time, the disease agent is often impossible to identify. Bruce Taylor of DSIR Plant Diseases Division, Mt Albert, identified white crown canker as the frequent cause of gevuina deaths in the Bay of Plenty some twenty years ago, but no record of this seems to have been published. It is plausible that this common name was applied to the symptoms of a Phytophthora cinnamomi infection.

Gevuina’s susceptibility to fungal diseases suggests that in areas where these are prevalent (as in many areas of New Zealand), commercial success will depend on developing ways to avoid the diseases. This may include selection of resistant genotypes, careful selection of soil types for good drainage, and soil management practices to favour a rich soil microflora.

“Sudden death” occurring in gevuina has been attributed to a variety of reasons (eg Horst 1996, Cairens 1997, Halloy 1997). At this time it seems unlikely to be caused by a single factor, but rather a single symptom resulting from a variety of factors which affect the plants physiological water balance.

Pests

In New Zealand Gevuina has not suffered from common glasshouse pests such as aphids and white fly. Its densely pubescent apices may act as a deterrent. Jenifer Johannsen identified Broad mite [Polyphagotarsoyiemus latus (Banks), Tarsonemidae] on seedlings of gevuina grown by DSIR in 1975 (S. Dawes, pers. com. 1993). Outdoors, leaf roller caterpillars (Tortricidae) have occasionally produced some damage to young leaves. The small number and incidence of pests identified may partly be due to the small numbers of plants in New Zealand and should not be taken as yet as a strong indication of a relatively pest free species.

Rabbits can destroy trees by ring-barking. An insect, suspected to be black vine weevil, produces partial defoliation in young trees and the larvae damages the root system, which could also lead to sudden death.

References

Cairns, E. 1997. Comments on Gevuina avellana. Tree Cropper 12: 41.

Halloy, S. 1993, Gevuina, a cool climate macadamia. NZ Institute for Crop & Food Research Ltd., Broadsheet 42: 2 p.

Halloy, S. 1997. Investigating the potential of Gevuina for New Zealand. Overseas Travel Report 182, NZ Institute for Crop & Food Research Ltd, Lincoln, NZ 11p

Halloy, S.; Grau, A., McKenzie, B. 1996. Gevuina nut (Gevuina avellana, Proteaceae), a cool climate alternative to macadamia. Economic Botany 50(2): 224-235.

Hart, R. 1996. “Sudden death” in Gevuina. Tree Cropper 9: 9- 1 0.

McKenzie, B. 1993. Vegetative propagation of three plants with commercial potential, Averrhoa carambola L., Gevuina avellana Mol., and Hillia valerii Standl. Combined Proceedings International Plant Propagators Society 43: 389-392.

Teese, D. Gevuina avellana. Quandong 22(3), cited by Cairns 1997.

Alberdi, M., and D. Rios. 1983. Frost resistance of Embothrium coccineum Forst. and Gevuina avellana Mol. during development and aging. Acta Occologica/Oecologia Plantarum 4(18) n° 1:3-9.

Baines, J. A. 1981. Australian plant genera. The Society for Growing Australian Plants, Surrey Beatty & Sons. Chippin. Norton, NSW.

Bell, H. 1993. The macadamia industry and genetic diversity. Australia Macadamia Society News Bulletin. Nov 1993:35-36.

Brownwell, B. 1991. A guide for New Zealand Macadamia nut growers. The Te Kauwhata Tattler, Thames.

Caceres J., 0., R. Anrique G., A. Voullieme S., and C. Méndez S. 1982. Utilización del fruto del Avellano (Gevuina avellana Mol.) en alimentación de pollas Cornish de 0 a 30 dias de edad. Simiente 52(3-4):161.

Cairns,E. 1997 Comments on Gevuina avellana. Tree Croppers 12:41

CIDERE. 1972. “Mantequilla” de avellanas chilenas. CIDERE, Bio Bio. 3 pp.

Cull, B. W. 1984. Proteaceae. Pages 150-160 in P.E.Page, Tropical tree fruits for Australia. Queensland Department of Primary Industries, Brisbane.

Davies, D. J. G., and R. P. MacFarlane. 1986. Avellano or Chilean Macadamias. Growing Today, April 1986:62.

Dimitri, M. J. 1982. La Región de los Bosques Andino-Patagónicos. 11. Flora Dendrológica. Colección Cientifica del INTA. Buenos Aires.

Donoso Z., C. 1978. Avance de investigación: antecedentes sobre producción de avellanas. Bosque 2(2):105-108.

-, and L. Soto 0. 1979. Antecedentes sobre producción de avellanas (Se-,unda información de avance). Bosque 3(l):69-70.

Duke, J. A. 1989. Handbook of nuts. CRC Press, Boca Raton, Florida.

Endt, D. 1982. The Chilean wild nut or Avellano, a further report. California Macadamia Society Yearbook 27:133-136.

-. 1990. Frustrating hazels and fast growing walnuts. Growing Today, June 1990:42-43

FAO/WHO. 1981. Energy and protein requirements. Final Draft, Rome.

Gordon, 1. 199 1. Nuts about Macs. Macadamia trees management and research. Growing Today, July 1991:22-24.

Grinbergs M., j., E. Valenzuela F., and C. Ramirez G. 1987. Forrnación y desarrollo de raíces proteiformes en plantulas de Gevuina avellana Mol. Agro Sur 15:1-9.

Hackett, C. 1991. PLANTGRO-A software package for coarse prediction of plant growth. CSIRO Publications, Australia.

Halloy, S. 1990. Large scale collection of South American germplasm for development and conservation in New Zealand. MAF Technology report, Mosgiel.

-. 1993. Gevuina, a cool climate macadamia. Crop & Food Research, Broadsheet 42:1-2.

- 1997 Suggestions for successfully establishing Gevuina Trees. Tree Cropper 14:27-30

-, and B. Brown. 1993. The detective story of Gevuina nuts in New Zealand. Lesser Known Plants Newsletter 2:2-5.

Halloy, S. Greu, A. McKenzie, B. 1996 Gevuina nut (Gevunia avellana, Proteacase), a cool climate alternative to Macadamia. Economic Botoany 50 (2): 224-235

Hart, R. 1996 “Sudden Death” in Gevuina. Tree Cropper 9:9-10

Hoffmann, A. 1982. Flora Silvestre de Chile Austral. Ediciones Fundación Claudio Gay, Santiago de Chile.

Hue, N. V., and E. T. Nakamura. 1988. Iron chlorosis in macadamia as affected by phosphate-iron interactions. Journal of Plant Nutrition 11:16351648.

Islam, N. 1990. Horticultural exports of developing countries: Past performance, future prospects, and policy issues. Research Report No. 80 International Food Policy Research Institute. Washington, D.C.

Karmelic V., J. 1982. Recolección e Industrialización de Avellana Chilena. Instituto de Investigaciones Tecnológicas, Santiago, Chile.

Martin, N. B. 1992a. Viabilidade económica da produção da noz macadâmia no estado de São Paulo. Informaçôes Econômicas (Sâo Paulo) 22(10):9-53. -. 1992b. Andlise do potencial de competigao da produqao da noz macaddmia em Sdo Paulo e no Havai. Informagdes Econ6micas (Sdo Paulo) 22(1l):35-41.

McGregor, A. 1991. A review of the world production and market environment for macadamia nuts. Proceedings of the 31st Annual Meeting. Hawaii Macadamia Nut Association. Hawaii. p 62-95.

McKenzie, B. 1993. Vegetative propagation of three plants with commercial potential, Averrhoa carambola L., Gevuina avellana Mol., and Hillia valerii Standl. Combined Proceedings International Plant Propagators’ Society 43:389-392. 1994.

McKenzie, B. 1994 Vegetative propagation of Gevuina avellana Mol. Combined Proceedings International Plant Propagator’s Society.

Medel S., F., and J. A. Orueta B. 1986. Estados fenológicos y adaptabilidad climática de las especies frutales arbóreas en el sur de Chile. Agro Sur 14(2):89-94.

Menninger, E. A. 1977. Edible nuts of the world. Horticultural Books Inc., Stuart, Florida.

Monckeberg, F., and J. Garrido. 1975. Agroindustry and development. Part 1. University of Chile, Chile.

Morley, B. D., and H. R. Toelken, eds. 1983. Flowering plants of Australia. Rigby Publishers, Willoughby, Australia.

Nagao, M. A., and H. H. Hirae. 1992. Macadamia: cultivation and physiology. Critical Reviews in Plant Science 10:441-470.

New Zealand Meteorological Service. 1983. Summaries of climatological observations to 1980. New Zealand Meteorological Service Miscellaneous Publication 177:1-172.

O’Hare, P., and N. Vock. 1990. Growing macadamias in Queensland. Queensland Department of Primary Industries, Nambour, Australia.

Peredo, H., and A. Aguilar. 1983. Pestalotia truncata en hojas de Avellano (Gevuina avellana). Agricultura Técnica (Chile) 43(l):67-68.

Phillips, S. 1989. Macs. Horticulture News, Oct 1989: 16-18.

Richardson, A., and T. Dawson. 199 1. New Zealand macadamias: the industry and its research needs. The Orchardist of New Zealand 64(6):30-33.

Robertson, G. 1. 1982. New plant disease records in New Zealand: additional host records of fungal pathogens. New Zealand Journal of Agricultural Research 25:109-1 1 1.

Rosengarten, F. Jr. 1984. The book of edible nuts. Walter & Co., New York.

Sánchez, L., and W. B. Storey. 1970. The Chilean wild nut or Avellano. California Macadamia Society Yearbook 16:67-70.

Schmidt, H. H., and F. Pennachioti. 1985. Chemical composition of Chilean foods. University of Chile, Chile.

Schmidt, M. A. 1990. Childhood ear infections. North Atlantic Books, Berkeley. 312 pp.

Sedgley, M., M. A. Blesing, and H. I. M. Vithanage. 1985. A developmental study of the structure and pollen receptivity of the macadamia pistil in relation to protandry and self incompatibility. Botanical Gazette 146:6-14.

Villaroel, M., E. Biolley, R. Schneeberger, D. Ballester, and S. Ramirez. 1987. Amino acid composition of Chilean hazel nuts. Food Chemistry 25:155-158.

Voullieme, A. B. 1982. Posibilidades industriales del fruto del Avellano chileno. Simiente 52(3-4):161.

Weinberger, P. 1974. Verbreitung und Wasserhaushalt araukano-patagonischer Proteaceen in Beziehung zu mikroklimatische Faktoren. Flora 163: 251-264.

-, M. Romero, and M. Oliva. 1973. Untersuchungen über die Dürreresistenz patagonischer irnmergrüner Gehölze. Vegetatio 28(1-2):75-98.

Willett, W. C. 1994. Diet and health: what should we eat? Science 246:532-537.