An archaeologist takes samples of pollen found in soil to comprehend the changing plants of a website: a buddy technique to the authors analysis of hazelnut shells. Credit: Nils ForshedArchaeologists study the carbon isotope values in hazelnuts from ancient websites to understand the qualities of the regional woods.If we could stand in a landscape that our Mesolithic forefathers called home, what would we see around us? Researchers have actually developed a technique to examine ancient hazelnut shells, protected over millennia, to identify if the surrounding microhabitats at historical areas were thick forests or more open, grassy landscapes. This method can shed light on the appearance of local environments thousands of years in the past, as well as reveal the level of human influence on these natural settings over the ages.”By analyzing the carbon in hazelnuts recovered from historical sites in southern Sweden, from Mesolithic hunter-gatherer campgrounds through to one of the biggest and wealthiest Iron Age settlements in northern Europe, we reveal that hazelnuts were gathered from progressively more open environments,” said Dr. Amy Styring of the University of Oxford, lead author of the short article in Frontiers in Environmental Archaeology.Neolithic NutellaHumans in northern Europe have actually been using hazel trees as a source of products and food for thousands of years. For individuals who collected numerous hazelnuts discovered at Mesolithic and Neolithic sites, they were a valuable resource.”The nuts are an exceptional source of energy and protein, and they can be stored for extended periods, taken in entire or ground,” said Dr Karl Ljung of Lund University, Sweden, senior author of the article. “The shells could likewise have actually been used as a fuel.”Like all plants, hazel trees contain carbon, which exists in different types called isotopes. The proportions of the various carbon isotopes are changed by the ratio of co2 concentrations between leaf cells and in the surrounding environment. In plants like hazel, this ratio is strongly affected by sunlight and water accessibility; where water is not limited, as in Sweden, sunlight influences the ratio a lot more. Where there are fewer other trees to compete for the sunlight and rates of photosynthesis are greater, the hazels will have higher carbon isotope worths.”This means that a hazelnut shell recovered on an archaeological site provides a record of how open the environment was in which it was collected,” described Ljung. “This in turn informs us more about the habitats in which individuals were foraging.”Gleaning informationTo test whether this impact can be seen in historical samples, the researchers collected hazelnuts from trees growing in varying light levels at 3 places in southern Sweden, and evaluated the variation in their carbon isotope worths and the relationship in between these worths and the light levels the trees were exposed to. They then examined the carbon isotope values of hazelnut shells from historical sites likewise found in southern Sweden. They picked shell pieces from 4 Mesolithic sites and eleven sites varying from the Neolithic to the Iron Age, a few of which had been occupied in more than one period.Using the recommendation values and the archaeological results, the archaeologists ran a model to assign their hazelnut samples to one of 3 categories: closed, open, and semi-open. Due to the fact that the carbon isotopes of a specific hazelnut will naturally vary a little from those of other hazelnuts growing in similar environments, the scientists utilized several samples from each website and assessed the percentage of hazelnuts which had grown in open or closed environments.Growing changesThe researchers discovered that nuts from the Mesolithic had actually been gathered from more closed environments, while nuts from more current periods had actually been collected in more open environments. By the Iron Age, the majority of individuals who gathered the hazelnuts tested for this research study had actually gathered the nuts from open areas, not woodlands. Their microhabitats had completely altered. This follows ecological reconstructions from pollen analyses, however isotope analysis can be utilized to imagine a regional environment where pollen records are limited.”Our research study has opened new potential for directly tying environmental modifications to individualss foraging activities and rebuilding the microhabitats that they made use of,” stated Styring. “We would like to straight radiocarbon date and measure the carbon isotopes of hazelnut shells from a broader variety of historical websites and settings. This will offer far more in-depth insight into woodlands and landscapes in the past, which will help archaeologists to much better understand the impact of people on their environment, and maybe help us to believe in a different way about forest usage and change today.”Reference: “Carbon isotope values of hazelnut shells: a new proxy for canopy density” by Amy K. Styring, Elin Jirdén, Per Lagerås, Mikael Larsson, Arne Sjöström and Karl Ljung, 9 January 2024, Frontiers in Environmental Archaeology.DOI: 10.3389/ fearc.2024.1351411 The study was moneyed by the Ebbe Kocks Stiftelse.
“By analyzing the carbon in hazelnuts recuperated from archaeological sites in southern Sweden, from Mesolithic hunter-gatherer campgrounds through to one of the biggest and richest Iron Age settlements in northern Europe, we show that hazelnuts were gathered from gradually more open environments,” said Dr. Amy Styring of the University of Oxford, lead author of the short article in Frontiers in Environmental Archaeology.Neolithic NutellaHumans in northern Europe have been using hazel trees as a source of materials and food for thousands of years. They then investigated the carbon isotope values of hazelnut shells from historical websites likewise discovered in southern Sweden. Because the carbon isotopes of a private hazelnut will naturally differ a little from those of other hazelnuts growing in comparable environments, the scientists used numerous samples from each site and examined the proportion of hazelnuts which had grown in open or closed environments.Growing changesThe researchers discovered that nuts from the Mesolithic had been collected from more closed environments, while nuts from more recent periods had actually been collected in more open environments. “We would like to straight radiocarbon date and measure the carbon isotopes of hazelnut shells from a wider variety of archaeological websites and settings.