Apparently, the regions mountains were once very heavily covered in dark pine trees making for dark, very dense forests. Therefore, called the "black forest" logging and storms have taken away the...
The romians called it silva negra (black forest) cause it was really close and tight and the people lived just surround it, but not in it. The first time people settled in it was in the medieval age.
[1] Geologically, Germany's Black Forest, aka Schwarzwald, is part of the continental divide between the Atlantic Ocean and Black Sea drainage basins. The former's drained by the Rhine, the latter by...