SERIES 30 | Episode 42





The land around Brisbane, like much of coastal Australia, has been heavily cleared and developed over the past few hundred years – and one of the casualties is the trees that produce our best-know food export, the macadamia nut.

Now grown all over the world, the nuts are native to Queensland and northern NSW, but more than 80% of bush macadamia trees have been lost and they are now threatened in the wild.

Jerry goes hunting with scientist Liz Gould, from Healthy Land and Water, to see what specimens they can find. Some still exist in remnant bushland around suburban Brisbane but others are limited to botanic gardens.

Macadamias are a member of the Proteaceae family, so are related to grevilleas and banksias. The nuts were traded up and down the east coast by the first nations peoples of Australia.

Early macadamia plantations by settlers were plagued by pests, diseases and fires. However, a few macadamia specimens were taken to Hawaii and soon a commercial macadamia industry flourished there instead. Ironically it is the cultivars developed in Hawaii that are now being grown commercially around the world, including here in Australia.





Featured plants

Queensland nut (Macadamia integrifolia) – a resilient species that grows in dry rainforest in southern Queensland, as well as more lush sub-tropical rainforests. “In this part of the world there’s a lot less of those rainforests, which is why their habitat is threatened,” Liz says. It can grow up to 25m tall and is the main commercial species.

Bulburin nut (Macadamia jansenii) – listed as endangered in the wild, it is only known from a small, isolated population that could be wiped out in a single fire. Grows to 8m tall and produces smaller nuts than other species.

Gympie nut (Macadamia ternifolia) – probably one of the first nuts tasted by early settlers, who decided the bitter nuts were poisonous and so took a while to discover the tastier M. integrifolia species and others. Listed as vulnerable in the wild. Grows to 18m tall.

Healthy Land and Water has started a register of trees and is keen to hear from anyone who has, or sees, a mature macadamia tree (eg around 100 years of age). You’ll be asked to supply a leaf sample to check the tree’s DNA. For more information and to register, go to the Wild Macadamia Hunt Website.



