Attempting to simultaneously address my favorite subject of basketball and keep the thread vaguely related to words...

The Cardinal is the nickname for the Stanford team, which is likely to be the #1 seed in the west regional, and has as good a chance as any of winning the NCAA tournament. I believe that the Cardinal is a fairly recent nickname, changed from some term that offended some PC group or other. What I want to know is, why is the Stanford logo a tree? Why not call yourselves the trees, then? Explanations of the Stanford nickname and symbol histories would be appreciated.