Further analysis confirmed that the pieces of wood were about 476,000 years old. Photo: Geoff Duller.

The discovery of pieces of ancient wood on the banks of a river in Zambia has changed archaeologists' understanding of early human life.

Researchers have found evidence that wood was used to build structures 500,000 years ago.

The discovery, published in the journal Nature, suggests that people in the Stone Age would have built places to shelter.

"This discovery changes what I thought about our early ancestors," says Professor Larry Barham.

Barham, a scientist at the University of Liverpool in England, leads the Deep Roots of Humanity research project. It was his team that excavated and analyzed the wood.

Professor Larry Barham discovers the wooden structure on the slopes of the river. Photo: Geoff Duller.

The discovery could transform the current idea that ancient humans lived simple, nomadic lives.

"They made something out of wood, new and big," Professor Barham said.

"They used their intelligence, imagination and skills to create something they hadn't seen before, something that didn't exist before."

The researchers also discovered ancient wooden tools, including digging sticks. But the most exciting were the two pieces of wood that were found carved and arranged at right angles.

"One is on top of the other and both pieces have been notched into notches," said archaeologist and Aberystwyth University professor Geoff Duller.

"You can clearly see that the notches that were carved with stone tools, cause both logs to hunt and become a structural object."

Making fire

The discovery, published in the journal Nature, suggests that people in the Stone Age would have built places to shelter. Photo: Larry Barham.

Further analysis confirmed that the pieces of wood were about 476,000 years old.

Team member Perrice Nkombwe, from the Livingstone Museum in Zambia, said: "I am surprised to learn that woodworking is such a deep-rooted tradition."

"I thought we had discovered something extraordinary."

Until now, what was known about the use of wood in early humans was related to fire, and to making tools such as digging sticks and spears.

Looking for dates with luminescence

One of the oldest wooden discoveries ever made was a 400,000-year-old spear at Clacton-on-Sea, Essex, England, in 1911.

Unless the wood is preserved under very specific conditions, it simply rots.

But on the slopes of the river, above the Kalambo waterfalls, located on the border between Zambia and Tanzania, the wood was waterlogged, practically being pickled for millennia.

The team measured the age of the layers of the earth in which it was buried, using a method that uses luminescence.

Rock grains absorb natural radioactivity from the environment over time, basically charging themselves as if they were small batteries, Professor Duller explained.

And that radioactivity can be released and measured when the grains are heated and the light they emit is analyzed.

The size of the two logs, of which the smaller is one and a half meters, suggests that whoever put them together was building something substantial.

As it was unlikely to have been a cabin or a permanent place of residence, it could have been part of a platform or a den, the team says.

"It could have been some kind of structure to sit next to the river to fish," Professor Duller said.

"But it's hard to know what kind of structure it might have been when it was standing."

It's also unclear what species of ancient human or hominid built it.

No fossils have been found at the site so far.

And the wood is much older than fossils of early humans, or Homo sapiens, which are about 315,000 years old.

Tradition with wood

The ancient wood was preserved in the sediments of the river. Photo: Larry Barham.

"It may have been Homo sapiens, but we just haven't discovered fossils from that era yet," Duller said.

"But it could be a totally different species — Homo erectus or Homo naledi — because there were different hominin species in that area of southern Africa."

The wooden artifacts were moved to the UK for preservation in water tanks that copy the waterlogging that kept them intact for the last half million years. But they will soon return to Zambia to be exposed.

"With this discovery, we hope to enrich our collection and use it to give more information about wood carving in Zambia," said Nkombwe of Zambia's Livingstone Museum.

Continuing work at the Kalambo waterfalls site, he added, "has the potential to deepen our knowledge of ancient carving techniques, crafts and human interactions with the environment."

(Taken from BBC News World)