Giant, climate-controlled tents that simulate the carbon dioxide-heavy conditions expected in the second half of the 21st century have been erected over gum trees by University of Western Sydney researchers.

Air inside the tents is carefully regulated to raise the carbon dioxide content to over 600 parts per million - above the predicted "tipping point" for highly damaging climate change.

The results suggest the hardy eucalypts will survive and maybe even prosper, even as surrounding ecosystems collapse.

"The trees are basically taking up more carbon and using up to 25pc less water," said Professor David Tissue, a lead researcher.

"Hopefully this could have important implications for the use of plantation timber, and the way carbon sequestration is accounted."

Professor Tissue and his colleagues decided to use Sydney blue gum saplings for the trial near Richmond because the trees are commonly used in plantation forests and as carbon offsets.

Some blue gums are being raised in carbon-rich atmospheres beneath their transparent plastic tents, while others are being starved of water to simulate drought conditions.

Those given extra carbon have been shown to create more wood and lose less water by closing pores on their leaves.

But Australian native trees are not the solution to climate change, said Dr Bert Drake of the Smithsonian Institute, who has maintained the world's longest-running carbon sequestration experiment in the US since 1987.

"The largest factor determining the uptake of carbon dioxide is still the availability of water, and that is a major issue from Australia," said Dr Drake, who is in Sydney to discuss carbon sinks at a Whitlam Institute forum tonight.

"None of the data suggests that plants can absorb enough of the carbon dioxide to compensate for the amount we are putting into the atmosphere by burning fossil fuels."

If the amount of carbon dioxide being put in the atmosphere by human activity does not decline sharply over the next four decades, by the second half of the century the global average is expected to reach the levels being simulated in the UWS experiment.

A senior CSIRO plant industry scientist, Dr Roger Gifford, said some regions would receive higher rainfall as others dried out.

But any advantages for plants were likely to be short-term.