Smooth macadamia - Macadamia integrifolia

Description and Uses

Macadamia integrifolia (Smooth macadamia) is a tropical tree from Northern Australia. It is mainly grown for its nut crops (long shelflife), but also Other uses include; apiculture, 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 10kg/tree but in its top season there will be a yield of 30kg/tree. The seed/nut is edible. Medical uses include; there are no known medical uses. The seed/nut contains oleic acid (53% - 67%). There is Smooth macadamia oil extracted by expeller pressing from the tree`s seed/nut yielding 60 - 70% oil. The tree`s wood is called 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 30 years the tree can be totally removed as it reached its commercial and ecological goal. Macadamia integrifolia 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 integrifolia has a shallow root-system and forms symbiotic relations Glomus intraradices,Glomus mosseae (endo-mycorrhiza). It is not able to fix nitrogen. The tree`s flower-morphology is hermaphroditic and is pollinated by bees. Macadamia integrifolia is evergreen and not allelopathic and has no thorns.

Macadamia integrifolia thrives in an altitude of 5 to 1600 meters above sea-level (tropical). The minimum temperature is 1°C and optimally between 15 - 25°C. The optimal rainfall is 2200 mm/year. Without irrigation the annual rainfall should be between 700 - 3000 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

Xylotrechus smei,Xystrocera alcyonea,Xystrocera festiva,Xystrocera globosa,Zeuzera coffeae and Bacterial blights,Bacterial spot,Downey mildew (blue mould) diseases.

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Seed Propagation

Seeds are recalcitrant and can be stored for 4 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, (3) Remove the seeds from cold to a permanent warm temperature., (3) Seeds germinate above ground (epigeous)

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