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Hazelnut shells offer a glimpse of ancient landscapes

In the quest to visualize the landscapes of our Mesolithic ancestors, scientists have turned to an unlikely source: hazelnut shells. Preserved through the ages, these shells offer a window into the past, unveiling whether ancient microhabitats surrounding archaeological sites were dense forests or open pastures.

Consequently, this innovative approach not only paints a picture of past environments but also sheds light on the impacts that humans have had on these habitats over millennia.

Hazelnut shells at archaeological sites

Dr. Amy Styring from the University of Oxford and her team have pioneered this research, focusing on hazelnuts found at archaeological sites across southern Sweden. The sites span from Mesolithic hunter-gatherer camps to major Iron Age settlements, providing a broad timeline for their study.

“By analyzing the carbon in hazelnuts from these varied periods, we’ve discovered a shift towards harvesting in increasingly open environments,” said Dr. Styring. This finding is crucial for understanding the interaction between early humans and their surroundings.

Significance of hazelnuts shells

Hazelnuts have been a staple for northern Europeans for thousands of years, valued for their nutritional benefits and versatility. “The nuts were a significant source of energy and protein, easily stored and consumed in various forms,” noted study senior author Dr. Karl Ljung of Lund University.

Beyond their nutritional value, hazelnut shells served as a practical fuel source, highlighting the multifaceted role of hazel trees in early human societies.

Insights from hazelnut shells

Focusing on the science, the study revolves around carbon isotopes found in hazel trees. These isotopes vary according to the tree’s exposure to sunlight and water, influenced by the density of surrounding vegetation.

Specifically, in sun-rich, water-abundant Sweden, sunlight plays a pivotal role, making hazelnuts from open areas richer in certain carbon isotopes. “A hazelnut shell from an archaeological site thus acts as a record of the openness of the environment from which it was collected,” said Ljung.

To confirm their method, the researchers collected hazelnuts from current hazeltrees in southern Sweden, exposed to different light levels, analyzing the carbon isotope values and their correlation with sunlight exposure.

The experts applied these findings to hazelnut shells excavated from various archaeological sites, categorizing them into closed, open, or semi-open environments based on their carbon isotope composition.

Evolving landscapes and human influence

The study reveals a compelling narrative about how the environment around human settlements evolved over millennia. Initially, in the Mesolithic era, the research indicates that people primarily collected hazelnut shells from dense, forested areas. This suggests a landscape dominated by thick woodlands.

However, by the Iron Age, the findings depict a shift to predominantly gathering hazelnuts from open areas, indicating significant environmental changes. This is possibly due to human activities like agriculture or natural climate fluctuations.

Several factors could have contributed to the transformation. Human activities like clearing forests for agriculture likely played a role, creating open fields. Alternatively, natural changes in climate may have influenced forest density.

This evolution shows humans increasingly affecting the environment. Also, the move to collect hazelnuts from open areas in the Iron Age suggests humans had already changed the landscape.

Future directions and impact

“Our study unveils new avenues for connecting environmental changes directly to human activities,” said Dr. Styring. Eagerly, the team plans to broaden their research by examining hazelnut shells from more sites. This expansion aims to deepen our understanding of ancient landscapes and human impacts.

Ultimately, the research urges us to reconsider our current relationship with forests, offering a new perspective on the value of conserving natural habitats.

 The study is published in the journal Frontiers in Environmental Archaeology.


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