Forst- und Köhlerhof Wiethagen, Open-air forestry and charcoal museum in Rostock, Germany.

The Forst- und Köhlerhof Wiethagen is an open-air museum in Rostock displaying traditional forestry and charcoal production. The grounds contain original buildings and work areas where visitors can observe how these trades were carried out in the past.

The site was established in 1837 as an active working facility for forest labor and charcoal production. It received official protection as a technical monument in 1984 and has since preserved the story of this important regional industry.

The name Köhler comes from the charcoal burners who worked here; the exhibition notes that their trade in remote forests, with pyrolysis and wood sulphur, was long surrounded by prejudice and myths, since pitch and sulphur were linked to the devil in Christian belief and in the Grimms' Frau Holle. Wood tar and pitch served to grease wooden axles, preserve ropes and seal ships.

The grounds are entered on foot and include the former cattle shed, rebuilt in 1988–1989, which now holds the permanent exhibition. The smaller tar oven of 1905, holding 13 m³, is fired up to four times a year, producing about six tonnes of charcoal and 150 litres of wood tar. The upper floor, redesigned in 2024, shows a small special exhibition on the wood sculptor Harald Wroost, who died in 2023.

The smaller tar oven, built in 1905 with a capacity of 13 m³, is the last working example of its kind in Europe. It is fired up to four times a year, producing around six tonnes of charcoal and 150 litres of wood tar each time.