A workshop before our species
At Kalambo Falls, on the border of Zambia and Tanzania, waterlogged sediments have preserved an unexpected record of early hominin tools. Among the finds are several wooden tools dated to between 390,000 and 324,000 years ago. These artifacts, which include a digging stick, a wedge, a cut log, and a notched branch, were crafted long before the appearance of Homo sapiens. The likely artisans were Homo heidelbergensis, an extinct human relative known from other sites in Zambia.
The preservation of the wood is exceptional. The permanently high water levels at the site created an oxygen-poor environment, preventing the organic material from decaying over the millennia. Analysis of the artifacts reveals clear cut marks made by stone tools, showing that these objects were intentionally shaped. These finds challenge the traditional view of the "Stone Age," suggesting that early hominins had a sophisticated understanding of wood as a raw material for tool production. The tools imply a settled, rather than nomadic, existence, as the creators had a consistent source of water and food from the surrounding forest.
The oldest wooden structure
The collection of wooden tools is not the remarkable find at Kalambo Falls. In 2019, archaeologists from the 'Deep Roots of Humanity' project uncovered the world's oldest known wooden structure. It consists of two interlocking logs, the smaller of which is 141.3 cm long, joined by an intentionally cut U-shaped notch. Using luminescence dating on the surrounding sand, which measures the last time the minerals were exposed to sunlight, the structure was dated to at least 476,000 years old.
This simple but effective construction predates the evolution of our own species by more than 100,000 years. Its purpose is thought to have been part of a raised platform, a walkway, or a foundation for a dwelling in the periodically wet floodplain. The logs, identified as a species of large-fruited bushwillow (Combretum zeyheri), show clear evidence of being chopped, scraped, and shaped with stone tools. The discovery demonstrates that early hominins were using wood for simple tools or fire, but were actively modifying their environment on a larger scale.