The historic American elm in front of the Douglas County Courthouse got its annual trim this week to preserve the health of the tree. A deodar cedar at the west end of the courthouse and a red oak in the back courtyard were also pruned. The county’s building facilities director, Kevin Potter, said the elm has become an unofficial county symbol. Congressman Binger Hermann gave the tree to the county in 1898 when the courthouse was rebuilt after a fire. “It’s kind of been the county courthouse landmark, so we make sure we maintain it properly,” Potter said. It was …