Two wooden logs joined by a precisely carved groove are the oldest known wooden structure ever discovered. It was found near Kalambo Falls in Zambia and was dated to 476,000 ± 23,000 years by luminescence analysis of the sediments surrounding the find.
One log is placed crosswise on top of the other and is secured in a large groove shaped like an inverted U. Marks on the surface indicate that the wood was cut, chiseled and scraped with stone tools. The builders thus changed the shape of the wood to obtain a stable joint.
Platform, path or base for shelter
The exact function of the structure is not established. The team, led by archaeologist Larry Barham of the University of Liverpool, suggests that it may have been part of a path or a raised platform above the seasonally wet terrain. It may have been used to store wood, food or tools, or as a base for a light shelter.
“When I first saw it, I thought this couldn't be real,“ Barham told the “Guardian“. He said that working with large pieces of wood required skill, proper tools, and advance planning.
The wooden structure survived for so long thanks to the waterlogged soil, which was almost devoid of oxygen. It was these conditions that limited the decomposition of the material. Wood is generally much more difficult to preserve than stone, which is why information about its early use is scarce.
Who built the structure
The question of the builders remains unanswered. The find is older than the earliest known remains of Homo sapiens, and no human bones have been found near the structure itself. Researchers suggest that it may have been the work of Homo heidelbergensis - an ancient human species that lived in Africa and Eurasia between approximately 700,000 and 200,000 years ago. However, this is a hypothesis, not a proven identification.
During the 2019 excavations, other processed wooden objects were also found. Among them are a digging stick, a wedge, a split branch with a groove, and a log processed at both ends. These finds are younger - some are about 390,000 years old.
The results of the study were published in Nature in 2023. They show that ancient human relatives did not use the tree only for sticks and weapons, but were able to join large parts of it into more complex structures. Who exactly stood by the Kalambo River and made the first known wooden structure, however, remains unknown.
Sources: theguardian.com, amp.dw.com, apnews.com