New research has found Australia's iconic river red gum is under serious threat with urgent action on curbing carbon emissions needed to ensure its future.
The Australian National University study revealed that the river red gum produced and stored a lower amount of essential oils in its leaves under twice the levels of ambient carbon dioxide.
![A red gum.](http://web.archive.org./web/20170623232613im_/https://www.fairfaxstatic.com.au/content/dam/images/1/2/r/p/a/9/image.related.articleLeadwide.620x349.gwwnbi.png/1498120332247.jpg)
Study co-author Dr Carsten Kulheim said these essential oils were vital to defend the trees from insect and mammal herbivores - including koalas.
"Since this affects how the trees are able to defend themselves against leaf eating animals, we wanted to find out how future increases in CO2 would affect river red gums defence chemicals," he said.
"This is just one of many examples of how greenhouse gas emissions affect our environment, providing further evidence that action is needed now."
The river red gum is Australia's most widespread tree.
The study, a joint effort between ANU and CSIRO, was published in the Australian Journal of Botany.