is there an emacs tool to show a directory structure as a tree?

So I wanted to just print a tree quickly and all Emacs based solutions seemed either rather old or massive like (ECB/CEDET) which I don't know enough about, so for quick fix I did

sudo apt-get install tree

then from dired buffer

M-! tree --dirsfirst RET

voilà! directory tree without any specific libs, as an added bonus using tree -f outputs tree with full paths, making it obvious to jump to file with C-x C-f directly from the tree output buffer.

There is a tree extension for emacs mode Sunrise Commander. Sunrise Commander is like Midnight Commander.

There's the Emacs Code Browser. Last I heard using it with a current emacs may be tricky or difficult because it makes use of some tools that were recently integrated into Emacs via CEDET.