Dynamics of Diversity of Woody Species Taxa under Human Impact in the Upper Volga Region (NW Russia) According to Pedoanthracological Data

We studied charcoal from several types of natural soil archives, including cultural layers of archaeological sites (hillforts), surrounding forest and arable soils, and sediments in lower parts of the slopes associated with hillforts and moraine hills. The stratigraphy of the charcoals was described, and 41 samples were radiocarbon-dated. Analysis of 2277 charcoals showed the presence of 13 taxa of woody species; Pinus and Picea charcoals dominated. Charcoals older than 300 BC were found only in sediment and in several pits formed after treefalls with uprooting. The greatest diversity of woody species was found in the hillforts' cultural layers composed of Anthropogenic Dark Earth soils formed between 300 BC and 300 cal. AD (Early Iron Age). All charcoals from ancient arable soils were younger than charcoals from the hillforts. Charcoals indicated that burning for arable farming started in the study region in the 6th century AD. Woody taxa exhibited a decrease in number of species and a decrease in the proportion of nemoral (broadleaved) species from the Early Iron Age to the Middle Ages and to the present. Quercus, Tilia, and Corylus have become relatively rare, although they still occur in the study region. Ulmus and Acer are now rare in the Upper Volga region and were not found in the vicinity of the study sites.