Science solves mystery of the hollow baobabs

Hollow baobabs are home to pubs and venues for weddings, but how these massive cavities formed in the trees has come as a surprise.

It was always thought that the hollowed-out trunks of baobabs were caused by the actions of animals, insects or fungi.

But this changed when scientists radiocarbon dated a large baobab on the Lebombo Eco Trail in Mozambique, close to the South African border.

"When the results came out, there was a lot of head-scratching," said Dr Stephan Woodborne of the National Research Foundation's iThemba laboratories, who was one of the researchers on the project.

"We did a lot of baobab-gazing after that to try to work out this strange result."

This tree had a circumference of just more than 21m and is large enough to hold several people within its girth.

But what the scientists found was that the samples taken from separate sections of the tree's trunk revealed different dates. The oldest part of the baobab is 1355 years old and the youngest is 900 years old.

The team realised that the baobab was made up of entwined stems.

"With a young tree that has two or three stems, as they grow they move closer together and eventually fuse," explained Woodborne.

The scientists believe that the often massive cavities are empty spaces between fused stems.

Their research was published in the PLOS One journal. The mechanism of how this happens still needs to be investigated and is just another mystery pertaining to this iconic tree.

Another mystery that Woodborne is attempting to solve is why some baobabs stop growing for hundreds of years then suddenly come back to life.

The Lebombo Baobab is believed to be made up of five stems and, after nearly a millennium and a half of growth, is still alive. Woodborne believes it will probably live for at least 200 years.