Charcoal kilns as a source of data on the past iron industry (an example from the River Czarna valley, Central Poland)

Charcoal was the primary fuel used for iron smelting and processing until the end of the 19th century. It was produced through burning piles of wood called charcoal kilns. The aim of the study was to identify and record traces of charcoal kilns related to past ironworks in the valley of the River Czarna (Małopolska Upland, Central Poland). Detailed analysis was conducted in areas adjacent to historical centres of iron processing in Maleniec, Kołoniec and Machory. A quantitative analysis of the traces of charcoal kilns in the topography was done based on DEM from airborne LiDAR. Soil profiles were analysed at the sites where traces of charcoal kilns were identified from DEM. Radiocarbon dating and palaeobotanical analyses were performed for selected charcoal from kiln remnants. In the study area we identified over 11,500 charcoal kilns. The radiocarbon age of these charcoals indicate that the charcoal kilns under study were used in the 15th, 18th and 19th century. Thus the results suggest that the iron industry in the studied area is c 100 years older than the historical written sources indicate. Palaeobotanical analyses show that coniferous trees were used for charcoal production. The large number of traces of charcoal kilns and their wide spatial distribution indicate that past charcoal production has had a significant impact on the environment and landscape change in the River Czarna valley and adjacent areas.