scrooloose/nerdtree — comment on commit 49b88757b019143ec6604b35c399de8f9bd2d954
File:  line 0
By scrooloose:

@ggustafsson - hey, i havent updated the docs yet.

The option you want to set is `let g:NERDTreeDirArrows = 0`. Look at the diff above for why. Some time soon I'm gonna start smashing through all the issues etc on nerdtree, so that option name may end up changing.