Rough macadamia - Macadamia tetraphylla

Description and Uses

Macadamia tetraphylla (Rough macadamia) is a tropical tree from Northern Australia. It is mainly grown for its nut crops (long shelflife), but also Other uses include; nut, oil, ornamental and timber can be produced. The crop is harvested by ground gathering. It starts flowering after 8 - 12 years. The first yield will be 1kg/tree but in its top season there will be a yield of 20kg/tree. The seed/nut is edible. Medical uses include; there are no known medical uses. The seed/nut contains oleic acid (60%/oil - 67%/oil). There is Rough macadamia oil extracted by expeller pressing from the tree`s seed/nut yielding 60 - 70% oil. The tree`s wood is called Rough macadamia wood and has a density of 550 - 800 kg/m³. Regarding firewood production the tree`s growing speed is slow, its energetic value is 3200 ckal/kg and the wood`s drying speed is medium; for firewood production it is not ideal. After 70 years the tree can be totally removed as it reached its commercial and ecological goal. Macadamia tetraphylla has a lifespan of 200 years.

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Environmental limitations

The tree is 18 meters tall. It is slow growing and tolerates not less light than full sun. Macadamia tetraphylla has a shallow root-system and forms symbiotic relations it has symbiotic associations with the Glomus intraradices fungus. (endo-mycorrhiza). It is not able to fix nitrogen. The tree`s flower-morphology is hermaphroditic and is pollinated by bees. Macadamia tetraphylla is evergreen and not allelopathic and has no thorns.

Macadamia tetraphylla thrives in an altitude of 5 to 2000 meters above sea-level (tropical). The minimum temperature is -2°C and optimally between 15 - 29°C. The optimal rainfall is 2000 mm/year. Without irrigation the annual rainfall should be between 700 - 2600 mm (L/m²). The optimal soil-pH is between 5.0 - 6.0 in a soil texture of loam. To salt it is intolerant to wind intolerant and to fire intolerant.

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Pests and Diseases

Amblypelta lutescens,Amblypelta nitida,Cryptophlebia ombrode,Eriococcus ironsidei,Homoeosoma vagella and Blossom end rot,Soybean mosaic virus diseases.

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Seed Propagation

Seeds are orthodox and can be stored for 6 months. There are approximative 325 seeds/kg. The seeds can be propagated as followed: (1) Store harvested seeds in water or in the fruit at room temperature, (2) Soak the seeds overnight in warm water before sowing., (3) press the seeds twice its size in the soil soil.

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