These are the sites of former piles, so-called pile plates. Coal was produced from wood in the piles. To minimize the transport distance of the wood to the pile, the piles were built in the middle of the forest. For this purpose, the charcoal burner piled up logs and covered them with plaggen and earth. Since the charring process took about 14 days, the charcoal burner lived in a hut near the piles in the forest.
The charcoal was mainly needed as a source of energy for the ironworks and hammer mills. To produce one wagon of pig iron, four and a half wagons of charcoal were needed, which in turn required 36 wagons of wood. For this purpose, a beech forest of about 1.5 hectares in size and 18 years old had to be felled. Even the extensive Brilon forests could not cover this immense demand for wood in the long run, so that at the end of the 18th century there was a real shortage of wood.