Eucalyptus Leaves Can Reveal Buried Gold—But This Is Exploration, Not Mining

The famous finding of gold in eucalyptus leaves is often retold as if trees could be used to mine gold. The 2013 Nature Communications study actually demonstrated something more specific: biogeochemical exploration for concealed gold deposits.

At the Freddo Gold Prospect in Western Australia, the deposit was buried beneath roughly 30 m of barren sediment. Researchers analysed eucalyptus leaves, twigs, bark, litter and soil to test whether gold was genuinely absorbed into living tissue rather than simply deposited as dust.

Table of Contents

A deeply buried deposit and deep eucalyptus roots
Leaf gold was anomalous directly above the deposit
Gold particles were observed inside living leaf tissue
This is not phytomining
The 2018 correction did not change the science
References

A deeply buried deposit and deep eucalyptus roots

Diagram of the Freddo gold deposit and eucalyptus root system — The Freddo deposit lies beneath about 30 m of cover. Source: Lintern et al. 2013

Eucalyptus species can develop unusually deep root systems; sinker roots reaching about 40 m have been documented in Eucalyptus marginata. That does not prove that every tree sampled at Freddo had roots physically touching the orebody. The study instead supports a coupled system in which deep roots, groundwater and geochemical transport can move trace gold into vegetation.

Leaf gold was anomalous directly above the deposit

Gold concentrations across the Freddo deposit sampling traverse — Leaves, twigs and soil showed gold anomalies over the buried deposit. Source: Lintern et al. 2013

Dried leaves from large Freddo eucalyptus trees contained up to 80 ppb Au and twigs up to 44 ppb, while background plant material was around 0.1 ppb. The anomaly was strongest over the buried deposit.

Individual leaves were highly variable, however. This is not a one-leaf detector that pinpoints an orebody by itself; sampling design and local calibration matter.

Gold particles were observed inside living leaf tissue

Using synchrotron X-ray fluorescence microscopy, the researchers directly imaged naturally occurring gold particles up to about 8 µm within leaf tissue. This helped rule out the idea that all measured gold came from surface dust contamination.

Some particles were associated with calcium oxalate crystals. The authors proposed that moving gold to extremities such as leaves and compartmentalizing it could reduce toxicity, but this should not be treated as a fully proven, gold-specific detoxification pathway.

This is not phytomining

Natural gold concentrations in the foliage were in the ppb range. The work did not demonstrate commercially useful gold recovery from leaves. Its value is as an indirect exploration tool in terrains where mineralization is hidden beneath thick cover.

The 2018 correction did not change the science

A Publisher Correction in 2018 fixed an incorrect HTML article number. It did not alter the experiments or conclusions.

Eucalyptus is therefore better described as a potential biogeochemical sensor of buried mineralization than a literal “gold-producing tree.”

References

Lintern M et al. Natural gold particles in Eucalyptus leaves and their relevance to exploration for buried gold deposits. Nature Communications. 2013;4:2614. https://doi.org/10.1038/ncomms3614
Publisher Correction. Nature Communications. 2018. https://www.nature.com/articles/ncomms16199