Martin Straßburger/Willy Tegel:
Use of timber in mining in the Black Forest during the Middle Ages and the Modern Age
Timber is among the most frequent finds made underground. One focus of the investigations into mining archaeology and dendrochronology to date has been the Schauinsland mine near Freiburg. Further samples have been taken from the mines, Caroline near Sexau, Segen Gottes near Haslach-Schnellingen in Kinzigtal and Teufelsgrund in Münstertal. As a rule, the timber examined with dendrochronological techniques is part of the mine structures. Timber was employed in many different ways in mines. The material was used underground mainly for carpentry, fireplaces, water works, transportation equipment, mining tool handles and also for wedges.
The frequently very good condition of preservation results from the mining waters or the airtight enclosure in clay sediments. Various minerals from lead and zinc lodes have dissolved in the mine waters. Especially zinc is fairly soluble and serves to preserve wood. Protective salts and chemical mixtures for conserving wood in mining operations in the 20th century contained mainly fluoride and zinc salts. The conditions for preservation can change underground over small distances. If there is no ventilation and under wet conditions, the substance of the wood is decomposed by fungi. In a permanently damp environment, however, embedded in sediment with a fairly efficient encapsulation against oxygen, wood can survive millennia. Finds of wood contain a lot of potential information because behind the sequence of annual rings of various thicknesses, not only absolute chronological data can be discovered, but also a veritable climate archive. Traces of being worked upon detected on the wood's surface relate a history of technology.