Staring at the forests of Faerûn and trying to find The Greenwood… or is there some cheeky answer like “It’s all Greenwood,” You've got it. It's ALL Greenwood. ;}
Seriously, Professor Tolkien got there first: Mirkwood's real name is "Greenwood The Great." Ahem.

— Ed Greenwood (@TheEdVerse) June 23, 2017