If you'd like to put forth your opinion in selecting what tree you think best represents America, here's your chance.
Personally, I think this is rather cool. Although, admittedly I'm an outdoors person, and I love trees. Also, I suppose I should mention that the Arbor Day Foundation headquarters is only an hour or so from where I live(d) (when I was in Omaha), so I hear a lot about them. ;-)