Hazelnuts – a delicious time capsule that speaks to the changing landscape

With the help of hazelnut shells found at archaeological sites, researchers have succeeded in finding out how the landscape of Scania has evolved over the past 10,000 years. Stable carbon isotopes in shell fragments attest, among other things, to the introduction of agriculture about 6,000 years ago.

Most people probably associate hazelnuts with Italian confectionery manufacturer Pietro Ferrero, which developed the chocolate substitute Nutella during rationing in the 1940s. But Europeans have been smearing their gizzards with hazelnuts for much longer than that. Since the ice sheet released its grip on northern Europe about 10,000 years ago, walnuts have provided our ancestors with an important source of protein and energy. Thanks to the popularity of the walnut, shell remains are often found at archaeological sites. With the help of these crusts, researchers have now been able to find out how the landscape of southern Sweden has changed since the glaciers melted and the pine, birch and hazel forests began to spread. A type of landscape that later changed when humans began cultivating the soil in southern Sweden about 6,000 years ago.

The results showed that hazelnuts, one of the most important resources for humans since the Stone Age, carry within them a signal from the environment in which they grew. Walnuts provide a piece of the puzzle of how our ancestors used their surroundings and how they changed naturally and through human influence, says Karl Leung, a geological researcher at Lund University.

In the new study, published in the scientific journal Frontiers in Environmental Archeology, the research team collected hazelnuts from trees growing in different light levels in three locations in southern Sweden. The variation in carbon isotope values ​​of the nuts was then analyzed based on the amount of light they were exposed to and divided into three categories: dark, semi-dark and light. In the next step, the values ​​corresponding to ancient nuts found at archaeological sites in southern Sweden were examined. The shell fragments came from 15 excavated settlements, ranging in age from 10,000 to 2,000 years.

– We discovered that the oldest nuts from the Mesolithic period were collected from more closed environments with denser tree canopies. When agriculture began in southern Sweden, there was a shift to more open areas with pastures. But hazelnuts have continued to be an important source of food for people even in these progressively more open landscapes, says Carl Leung.

The study opens new opportunities to directly link changes in the environment to people's livelihood activities. But also to reconstruct the exact environments used by our ancestors. The researchers will now go further by dating and measuring carbon isotopes of hazelnut shells from a wide range of archaeological sites and environments.

– It will provide more detailed knowledge about forests and landscapes in the past, which can help archaeologists better understand the impact of humans on their environment. Carl Leung says this study may make us think differently about forests and the changes we are witnessing today.

The study is a collaboration between Oxford University, Lund University and the Norwegian Museum of History.

The study was published in the journal Frontiers in Environmental Archeology: “Carbon isotope values ​​of hazelnut shells: a new proxy for canopy density.”

For more information please contact:

Carl Leung, researcher

Department of Geology, Lund University

0462223996

0761046069

[email protected]

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