The species most commonly used for the production of nuts in Australia and overseas is M. integrifolia. For commercial production, it has been crossed with or grafted onto other Macadamia species, particularly M. tetraphylla, to achieve varieties better suited to commercial production, which are often smaller than wild-growing species.
In the wild, M. integrifolia can grow to 20m in height and attain a similar dimension in foliage width — giving the tree a rounded shape. The leaves are thick and leathery, growing to 14cm and arranged in groups of three. The tree produces flowers from August to October, with sprays (racemes) about 30cm in length, each with 40–50 flowers that eventually produce about 15 nuts. The nuts are round with a green fibrous husk and about 2.5–3.5cm in size; each contains a smooth hard brown nut-shell containing a white edible kernel.
The first macadamia orchard was established in Australia during the 1880s but the industry did not develop on any scale until the 1970s. Australia is one of the world’s largest macadamia producers, however commercial-scale production was first achieved in Hawaii in the 1930s, and Hawaii remains a major world producer.
The macadamia industry is established yet still growing and has a strong representative body, the Australian Macadamia Society, which is driving development of the industry at commercial, environmental and political levels for its 600 or so members.
Facts and figures
- Macadamias evolved over 60 million years ago in Gondwana Land and there are four species endemic to the eastern seaboard of subtropical Australia
- Australia produces around 30% of the world’s macadamias and exports to more than 40 countries
- There are around 22,000ha planted to macadamia in Australia and the area is growing, as global demand outstrips supply
- Macadamia is a long-term investment, with orchards taking 7-10 years to reach full production
- It is an intensive horticultural enterprise that requires many regular operations throughout the year that have to be completed in a timely manner
- Macadamias can be marketed as in-shell, bulk raw, roasted and/or flavoured kernel, retail packs of kernel (raw or roasted) and value-added product
The Australian Nut Industry Council estimates that by 2020, 24,000ha will be planted to macadamias and production greater than 18,500t. Export value is set to exceed $280 million.
Macadamias are grown in subtropical and tropical climates, mainly along the seaboard of northern New South Wales and the eastern seaboard of Queensland. The majority of plantings are in the Northern Rivers region of New South Wales (47%) and around Bundaberg in Queensland (32%).