What is a wild macadamia?

A wild macadamia is one of the following four types (species), either in pure form or a cross (hybrid) between two species:

Wild trees are not cultivars or varieties, such as you might find in the fruit tree section of your local nursery.

It can be difficult to tell a cultivar from a wild tree by its looks, so we’re using age as the key distinguisher.

Macadamia trees that are around 100 years old are likely to be wild trees.

These old trees may be found growing naturally in rainforest scrubs or areas that once were rainforest, or could also be trees planted many years ago – by indigenous people or early settlers – in your backyard, acreage block, pastoral property, old orchard or local park.

Why are wild Macadamias under threat?

Habitat destruction and fragmentation, weeds and fire have caused the loss of many wild populations of macadamia, with nearly 80% of all macadamia habitat lost since European settlement. These threats are ongoing and are likely to being exacerbated by climate change. Remnant wild macadamia trees and populations also struggle with:

  • poor recruitment due to lack of pollination and nut predation,
  • competition and smothering by weeds such as cats claw creeper (Dolichandra unguis-cati), and
  • weakened genetics due to cross-pollination with cultivated macadamias

The impact of these threats has led to the protection of wild macadamia trees under the Queensland Nature Conservation Act 1992 and Commonwealth Environment Protection and Biodiversity Conservation Act 1999. It is an offence to damage or interfere with wild macadamias unless permitted by the respective Acts. Compliance with the Queensland Code of Practice for the Harvest and Use of Protected Plants is also required before collecting any seeds, fruits, flowers or other propagating material; for more information on this, please click here.

Why are you only looking for old macadamia trees?

There is currently a mix of wild and cultivated macadamia trees scattered across South East Queensland, northern New South Wales and elsewhere in Australia.

The early 1900s was a growth time for the Australian macadamia industry, resulting in distribution of large numbers of macadamia seedlings. Though these seedlings had wild parents, the seeds (nuts) were collected from only a few trees, limiting their genetic diversity. Compounding this, from around 1960, imported trees (both cultivars and hybrids) from Hawaii started replacing Australian stock in local orchards. The imported trees have significantly less genetic diversity than wild trees or are mixed species.

So now, we are hunting for macadamia trees that are at least 100 years old. These trees are likely wild trees, either planted or naturally occurring; some may be the sole descendants of wild populations that no longer exist.

Which macadamia trees are you looking for?

We want to find macadamia trees that are at least 100 years old, and we’re interested in three species (or types) of macadamia:

  • Queensland Nut (Macadamia integrifolia)
  • Rough-shelled Bush Nut (Macadamia tetraphylla)
  • Gympie Nut (Macadamia ternifolia)

Our Macadamia Identification fact sheet will help you to work out which species you might have.

The Wild Macadamia Hunt is not looking for Bulberin Nut (Macadamia jansenii). This macadamia is endangered and only found in a small area of central Queensland. Visiting the area could lead to the species becoming more threatened than it already is.

Examples of all four species of macadamia can be seen at the following Botanic Gardens:

Why are young macadamia leaves preferred for genetic analysis?

Young leaf or shoots yield a higher quality and quantity of DNA than older leaves.

Young leaves are light green or reddish (depending on species) and softer than older leaves.

Whilst only a few young leaves are needed, these can be hard to find and may be difficult to reach. Here are  a couple of tips for finding young leaves:

  • Look for a flush of new leaves after good growing conditions, such as recent rainfall or exposure to sunlight, or before flowering – this may need patience.
  • Look for young leaves or shoots.
  • If the tree has no new growth, collect two or three small older leaves.

What happens once I have registered my tree/s?

If your tree/s is one we’d like to investigate, we will send you a leaf collection kit. The kit contains instructions on how to collect and supply leaves, storage materials and a prepaid envelope.

Project resources are limited, so priority will be given to Brisbane residents and collected leaves will be sent for storage and future genetic analysis. We hope to find funding to expand the Wild Macadamia Hunt and to undertake genetic analysis.

Why is genetic analysis important?

Recent research by Dr Craig Hardner (University of Queensland) and Dr Catherine Nock (Southern Cross University) on macadamia genetics can provide valuable information on the ancestry of trees.

The genetic composition of wild and cultivated trees varies. Through genetic analysis researchers can confirm species identification and determine whether a tree is a pure strain, a natural hybrid or a cultivar.

Genetic analysis may also help us to understand how closely related wild populations of macadamia are to each other, to discover unique genetic traits, and to find trees that are the progeny of macadamia populations that no longer exist. Understanding macadamia genetics will help inform conservation priorities and the commercial potential of wild macadamias.

For more information on macadamia genetic analysis refer to:

Hardner, C., Nock, C., Batley, J., Termizi, A.A.A., Peace, C., Hayashi, S., Montenegro, J.D. and Edwards, D. (2016).  Backyard macadamias in Brisbane as a reservoir of genetic diversity for breeding. Available online here.

How can I help conserve wild macadamia trees?

  • Learn about wild macadamias and share your knowledge with family, friends and colleagues
  • Take part in The Wild Macadamia Hunt
  • Protect wild macadamias from weeds, fire and livestock
  • Eat only Australian grown macadamias
  • Support the Macadamia Conservation Trust

Get in touch

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  • PO Box: 13204, George Street Brisbane QLD 4003
  • Phone: (07) 3177 9100
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