Money doesn't grow on trees, but gold does.
A CSIRO team led by Dr Melvyn Lintern has found trees searching for moisture during droughts can tap into gold deposits up to 35 metres underground.
When the trees strike gold their roots can suck up minute amounts of the precious metal.
Dr Lintern says when the roots tap into underground water the gold is diluted and then transported through the vascular system of the tree.
Tiny charged, or ionic, gold particles tend to become concentrated in the extremities of the tree where a chemical reaction can cause them to grow into larger crystals.
"Gold occurs throughout the trees but the highest concentrations are found in the foliage," he wrote.
"Gold crystals may grow as a result of the propensity of ionic Au (gold) to reduce and autocatalytically precipitate."
The team used an X-ray to look for gold particles in the leaves, twigs and bark of eucalypts.
Dr Lintern says until now it's been very hard to tell if trace amounts of gold found in the soil beneath the trees was blown there or indicated a large gold deposit was underground.
He says his team's research will help prospectors find gold without having to dig to great depths and could also spur the development of new technologies for mineral exploration.
The results are due to be published in the UK journal Nature Communications on Wednesday.
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