Medieval vegetation dynamics and montane-industrial history of the central Ore Mountains, Czech Republic, as reflected by alluvial geoarchives

• Research on alluviual geoarchives with a high density of sampling sites. • Past mining, metallurgical and agricultural activities were detected. • Alluviums have been formed in the last 1000 years as a result of human impact. • The natural floodplain vegetation mainly consisted of spruce. The methodically complex analysis of alluvial sediments from stream valleys makes it possible to reconstruct the medieval and early modern history of vegetation and land use in low mountain ranges. For this purpose, eight alluvial sections were documented and analysed in the central part of the Ore Mountains at an altitude interval of 700–800 m a.s.l. An interdisciplinary approach was applied using methods from archaeology, micro-artefact analysis, geomorphology, radiocarbon dating, pedology, sedimentology, geochemistry, and archaeobotany. Our results show that the alluvial valley fills are about 1–2 m thick and consist of various sediment types including coarse wood remains. According to radiocarbon dating, these fills represent the last millennium. Before local medieval clearing in the second half of the 13th century CE, the wet valley floors were covered by spruce, supplemented by alder and other woody taxa. The adjacent dry slopes and plateaus were predominantly overgrown by beech and fir. Silver mining of hydrothermal vein deposits, iron smelting, agriculture, and rural settlements were recognised as specific types of medieval and early modern land use in the study area. These different land-use forms occurred contemporarily, but sometimes spatially separated. Over the course of time strong human impact in the area becomes evident, which has led to deforestation, changes in vegetation and relief, soil erosion, siltation of stream valleys, and local geochemical contamination. A special feature, in comparison with other Central European low mountain ranges, is the existence of a mixed mining-agricultural colonisation in the Ore Mountains, as opposed to a mode in which mining and metallurgy clearly precede permanent rural settlement.