Yeah, that would be the drop-down box.
What I'm talking about is the commonplace linkbar that most forum softwares use by default, where the board hierarchy of whatever forum you're viewing is listed at the very top of the page. It's a very effective way of allowing users to jump to parent forums without having to scoll all the way down to the bottom of the page and use a drop-down box, which by the way adds an annoying extra click to the process since you first need to open it.
In addition, the drop-down list isn't meant to be used as a main form of navigation anyway. Its intended purpose is to allow jumping between completely unrelated forums.