Adrian Patrut, who organised the survey, added: "It's a odd feeling, because these are trees which may live for 2,000 years or more, and we see that they're dying one after another during our lifetime". While using radio carbon dating to investigate the age and structure of trees in Zimbabwe, Namibia, South Africa, Botswana, and Zambia, the team discovered that many baobabs had stems that had died completely, or had partially collapsed.
Some of Africa's oldest trees, which have existed for thousands of years, have suddenly started to die off for mysterious reasons, but an answer may be in sight. And it's no fluke, he adds.
"It's a odd feeling, because these are trees which may live for 2,000 years or more, and we see that they're dying one after another during our lifetime". The stories note baobobs' iconic place in African history. It was estimated to be about 2,500 years old.
Some of the largest are more than 20m wide - one specimen in South Africa known as the Platland housed a bar until it began to rot and split apart in 2016.
"Pretty much every baobab tree in Southern Africa is covered in the healed scars of past elephant attacks, which speaks to the trees' incredible fix ability", said David Baum, a University of Wisconsin botanist who is familiar with the new study and contributed to a recent Biodiversity International publication cataloguing the trees' attributes, in an email. Again, it's hard to determine exactly what caused their demise, but the researchers strongly suspect the deaths are associated at least partly "with significant modifications of climate conditions that affect southern Africa in particular".
A recent study suggests climate change is contributing to the death's of Africa's massive baobab trees.
Man-made climate change is a likely suspect, scientists said.
The study in the journal Nature Plants is the result of a survey conducted by co-author Adrian Patrut of Romania's Babes-Bolyai University.
Of those nine, four were believed to be the largest African baobab trees in existence.
The eldest tree - the Panke in Zimbabwe - was found dead in 2010. The increased temperature and drought are the major threats, says Patrut.
The baobab tree, sometimes called the "Tree of Life", has an unforgettable appearance. The common theory, Baum said, is that as the tree slowly grows around these scars, they can become large hollows. But on a baobab, new wood grows both on the outside and into the hollows, meaning that a straight line from the center of the tree can pass both forward and backward in time - or even skip decades altogether if they rotted out or were eaten.
"It is very surprising to visit monumental baobabs, with ages greater than 1,000 to 2,000 years, which seem to be in a good state of health, and to find them after several years fallen to the ground and dead", Patrut told National Geographic.