How to disable NERDTree buffer when opening certain file types

Currently the NERDTree buffer opens for every file that you open. If I'm writing to *.scala, *.py, etc. But I don't want this to happen for certain files that I'm writing (such as Haskell). For example, when I'm opening a Haskell file, I don't want the NERDTree buffer to open as soon as I type in vim file.hs in the terminal. Does anyone know how to get this to work?