A tree regarded as the icon of the African savannah is dying in mysterious circumstances. International scientists have discovered that most of the oldest and largest African baobab trees have died over the past 12 years.

They suspect the demise may be linked to climate change, although they have no direct evidence of this. The tree can grow to an enormous size, and may live hundreds if not thousands of years.

The researchers, from universities in South Africa, Romania and the US, say the loss of the trees is “an event of an unprecedented magnitude”.

Revealing the findings in the journal Nature Plants, they say the deaths were not caused by an epidemic.

“We suspect that the demise of monumental baobabs may be associated at least in part with significant modifications of climate conditions that affect southern Africa in particular,” said the team, led by Dr Adrian Patrut of Babes-Bolyai University in Romania. “However, further research is necessary to support or refute this supposition.”