'Shocking' die-off of Africa's oldest baobabs: study

June 11, 2018 by Mariëtte Le Roux
The iconic tree can live to be 3,000 years old and one in Zimbabwe is so large that up to 40 people can shelter inside its trunk

Some of Africa's oldest and biggest baobab trees—a few dating all the way back to the ancient Greeks—have abruptly died, wholly or in part, in the past decade, researchers said Monday.

The , aged between 1,100 and 2,500 years and some as wide as a bus is long, may have fallen victim to climate change, the team speculated.

"We report that nine of the 13 oldest... individuals have died, or at least their oldest parts/stems have collapsed and died, over the past 12 years," they wrote in the scientific journal Nature Plants, describing "an event of an unprecedented magnitude."

"It is definitely shocking and dramatic to experience during our lifetime the demise of so many trees with millennial ages," said the study's co-author Adrian Patrut of the Babes-Bolyai University in Romania.

Among the nine were four of the largest African baobabs.

While the cause of the die-off remains unclear, the researchers "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."

Further research is needed, said the team from Romania, South Africa and the United States, "to support or refute this supposition."

Between 2005 and 2017, the researchers probed and dated "practically all known very large and potentially old" African baobabs—more than 60 individuals in all.

Collating data on girth, height, wood volume, and age, they noted the "unexpected and intriguing fact" that most of the very oldest and biggest trees died during the study period.

All were in southern Africa—Zimbabwe, Namibia, South Africa, Botswana, and Zambia.

The is the biggest and longest-living flowering tree, according to the research team. It is found naturally in Africa's savannah region, and outside the continent in tropical areas to which it was introduced.

It is a strange-looking plant, with branches resembling gnarled roots reaching for the sky, giving it an upside-down look.

The iconic tree can live to be 3,000 years old, according to the website of the Kruger National Park in South Africa, a natural baobab habitat.

'Difficult to kill'

"One ancient hollow baobab tree in Zimbabwe is so large that up to 40 people can shelter inside its trunk," says the park.

"Various baobabs have been used as a shop, a prison, a house, a storage barn, and a bus shelter."

The tree serves as a massive store of water, and bears fruit that feeds animals and humans.

Its leaves are boiled and eaten as an accompaniment similar to spinach, or used to make traditional medicines, while the bark is pounded and woven into rope, baskets, cloth, and waterproof hats.

The purpose of the study was to learn how the trees get so enormous.

The researchers used radiocarbon dating to analyse samples taken from different parts of each tree's trunk.

They found that the trunk of the baobab grows from not one but multiple core stems.

According to the Kruger Park, baobabs are "very difficult to kill".

"They can be burnt, or stripped of their bark, and they will just form new bark and carry on growing," it states.

"When they do die, they simply rot from the inside and suddenly collapse, leaving a heap of fibres."

Of the ten trees listed by the study authors, four died completely, meaning all their multiple stems toppled and died together.

The others saw the death of one or several parts.

The oldest tree by far, of which all the stems collapsed in 2010/11, was the Panke tree in Zimbabwe, estimated to have existed for 2,500 years.

The biggest, dubbed Holboom, was from Namibia. It stood 30.2 metres (99 feet) tall and had a girth of 35.1 m.

Arguably the most famous baobab, called Chapman, was a declared a national monument in central Botswana, bearing the carved initials of explorer David Livingstone.

The tree named after South African hunter James Chapman, who visited it in 1852, saw all six its stems topple simultaneously on January 7, 2016 where it had stood for some 1,400 years.

Other than the oldest and biggest, the research team observed that many other mature baobabs had died.

The deaths were not caused by an epidemic, they wrote, with Patrut adding: "there were no signs of disease".

Explore further: Characterizing baobab, the nutritious African 'Tree of Life'

More information: Adrian Patrut et al. The demise of the largest and oldest African baobabs, Nature Plants (2018). DOI: 10.1038/s41477-018-0170-5

Related Stories

Characterizing baobab, the nutritious African 'Tree of Life'

January 8, 2015

A new publication, 'Descriptors for Baobab,' opens the way for accelerated and better-standardized research into this iconic tree. This highly nutritious African food tree is called the 'Tree of Life' because of its importance ...

Recommended for you

How quinoa plants shed excess salt and thrive in saline soils

September 21, 2018

Barely heard of a couple of years ago, quinoa today is common on European supermarket shelves. The hardy plant thrives even in saline soils. Researchers from the University of Würzburg have now determined how the plant gets ...

Basking sharks can jump as high and as fast as great whites

September 20, 2018

A collaborative team of marine biologists has discovered that basking sharks, hundreds of which are found off the shores of Ireland, Cornwall, the Isle of Man and Scotland, can jump as fast and as high out of the water as ...

Decoding the structure of an RNA-based CRISPR system

September 20, 2018

Over the past several years, CRISPR-Cas9 has moved beyond the lab bench and into the public zeitgeist. This gene-editing tool CRISPR-Cas9 holds promise for correcting defects inside individual cells and potentially healing ...

7 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

RealScience
3.3 / 5 (7) Jun 12, 2018
Between 2005 and 2017, the researchers probed and dated "practically all known very large and potentially old" African baobabs—more than 60 individuals in all.


So these trees lived for thousands of years, and suddenly died just after being "probed".

Maybe they don't like being probed!
JRi
4 / 5 (4) Jun 12, 2018
Between 2005 and 2017, the researchers probed and dated "practically all known very large and potentially old" African baobabs—more than 60 individuals in all.


So these trees lived for thousands of years, and suddenly died just after being "probed".

Maybe they don't like being probed!


I was thinking the same. When they drilled the trees for samples, they may have infected them somehow.
Shakescene21
5 / 5 (2) Jun 12, 2018
Were the drills sterilized before each probe? This should be an easy thing to investigate.
SURFIN85
5 / 5 (1) Jun 12, 2018
Drilling trees is a boring job
Tyrant
1 / 5 (1) Jun 13, 2018
Hmmmm, maybe not climate change this time.......

"Various baobabs have been used as a shop, a prison, a house, a storage barn, and a bus shelter."

Its leaves are boiled and eaten as an accompaniment similar to spinach, or used to make traditional medicines, while the bark is pounded and woven into rope, baskets, cloth, and waterproof hats.

Ojorf
2 / 5 (8) Jun 14, 2018
Do I sense a distrust of science and scientists here, or not?
Blame the scientists, they probably infected the trees.
Have you ever even seen a baobab? As the article says, they are VERY difficult to kill. These trees have been damaged for 1000's of years and survived, someone taking a sample will hardly kill it.
Google for images of "baobab elephant damage" to see the type of damage these trees can survive, they are incredible.
I will not at all be surprised if climate change has something to do with this. The trees might just be under some stress that opens the way to attack from some pathogen or other, but who knows.
RealScience
1 / 5 (1) Jul 08, 2018
No distrust of scientists in general (after all, I am one).

As the article says, they are VERY difficult to kill. These trees have been damaged for 1000's of years and survived.
...
I will not at all be surprised if climate change has something to do with this.
The trees might just be under some stress that opens the way to attack from some pathogen...
.

@Ojorf - that's exactly why the suspicion.
These trees have survived for thousands of years, and then they die within a decade of each other? A factor like climate change might make conditions worse, but it would not affect widely distributed sites so equally.

What is the one thing that recently happened to ALL of them? Someone team visited all of them and took samples!

Remember when researchers went to find ponds not yet affected by amphibian die-off, and then a year later those ponds were fungus-infected as well?
It turned out that researchers were tracking in the spores on their boots!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.