Holz köhlern burn charcoal

http://www.dict.cc/blaettern/298.php

The name "Köhler" (Koehler) is derived from an old occupation, that meanwhile almost died out in Germany. For many chemical processes, like iron smelting or glass production high temperatures are necessary. Also to forge iron or process noble metals heat is needed. In areas without natural deposits of coal, but richness of forest, the Köhler (i.e. charcoal burner) made the necessary coal by charring the regenerating raw material wood. Today's humans think of barbecue parties when thinking of charcoal. Technical heat is generated by electricity or oil today. But in former times charcoal in gigantic quantities was needed for the early industry. This led to the extermination of whole forests. The Augsburg local recreation area "Stauden" (i.e. shrubs) owes its emergence to the immense need of wood for the city of Augsburg in earlier years.
To anyone interested in old, died out jobs, Rudi Pallas' book "Das Lexikon der untergegangenen Berufe" (= The encyclopedia of the gone down occupations) may be recommended. To the topic "charcoal burners" the following lines are found there:

http://franzx.koehler.bei.t-online.de/e_koehler.html