Researchers from Tokyo Metropolitan University have made an important contribution to the study of prehistoric woodworking technology by using replica stone age tools for various tasks and examining the traces left on the edges. They found that a combination of macroscopic and microscopic traces can reveal how the tools were used, especially for wood-felling. Their findings have implications for understanding when and how early humans started to use wood for more complex purposes.
The Importance of Woodworking Technology
Woodworking technology was a key factor in the development of human civilization. Wood is a versatile and renewable material that can be used for many purposes, from simple tools to complex structures. However, working with wood requires specialized tools and skills that evolved over time.
While simple wooden tools such as spears or throwing sticks are known from the Paleolithic (early Stone Age) period, more sophisticated uses of wood such as building houses, canoes, bows, and wells emerged in the Mesolithic and Neolithic periods of the Holocene, starting about 10,000 years ago. This advancement was accompanied by the availability of better tools for crafting wood, particularly polished stone axes.
However, polished stone axes have also been found from much earlier periods, dating back to about 60,000–30,000 years ago, in sites around Australia and Japan. These tools are known as ground edge artifacts, and they raise the question of what they were used for at such an early stage. Were they used for wood-felling or for other purposes?
The Experiment with Stone Age Tools
To answer this question, a team led by Assistant Professor Akira Iwase from Tokyo Metropolitan University decided to investigate what kinds of traces might be left on ground stone edges when they are used for different activities. They took a hands-on approach and crafted their own replicas of tools that might have been used in the Early Upper Paleolithic period (about 38,000–30,000 years ago) in Japan.
The team used knapping and grinding techniques that would have been available at the time to create sharp edges on stones. They also attached handles to the stones using methods from Irian Jaya, since no hafts have been recovered from Japanese sites of that period. They then used these tools as adzes, axes, and chisels for 15 different tasks, including tree-felling, hide-processing, and butchering, as well as “non-use” events such as carrying them around and trampling them.
After each activity, they examined the edges of the tools for both macroscopic and microscopic traces of wear and damage. Macroscopic traces are visible to the naked eye or with a magnifying glass, while microscopic traces require a microscope or a scanning electron microscope (SEM) to observe. They also measured the length and width of the edges before and after use to calculate the degree of edge reduction.
The Traces of Wood-Felling on Stone Age Tools
The team found that impacts such as those required for cutting down trees leave distinctive macroscopic fractures on the stone edge, such as step fractures or hinge fractures. These fractures are caused by the high stress applied to the edge when it hits hard materials like wood or bone. They also found that friction between the stone and the wood creates microscopic traces that can also be used for identification, such as striations or polish. These traces are caused by the abrasion of the edge when it slides along the surface of the wood.
By combining these two types of traces, they developed criteria to distinguish tools used for wood-felling from other activities. For example, they found that tools used for wood-felling tend to have more macroscopic fractures than tools used for hide-processing or butchering, and that these fractures are more concentrated on one side of the edge than on both sides. They also found that tools used for wood-felling tend to have more striations than polish on their edges, while tools used for hide-processing or butchering tend to have more polish than striations.
The Implications for Stone Age Tools Research
The team hopes that their criteria can be applied to real ground edge artifacts from prehistoric sites to determine if they were used for woodworking or not. This could help shed light on when early humans started to use wood for more complex purposes than simple tools, and how this affected their way of life and their spread of technology across different regions.
For example, if ground edge artifacts from Marine Isotope Stage 3 (about 60,000–30,000 years ago) in Japan show traces of wood-felling, it would suggest that humans were already capable of advanced woodworking at that time. This would challenge the conventional view that woodworking technology emerged in the Neolithic era of the Holocene. It would also imply that humans had adapted to different environmental conditions and exploited different resources in different regions.
The team’s research demonstrates the potential of experimental archaeology to reveal how prehistoric tools were used and what they tell us about human behavior and culture. By using replica stone age tools for various tasks and examining the traces left on the edges, they found that a combination of macroscopic and microscopic traces can reveal how the tools were used, especially for wood-felling. Their findings have implications for understanding when and how early humans started to use wood for more complex purposes.
Recent Blog : High-Density Hydrogen Storage: A Future Energy Systems