The sweet gum,Liquidambar styraciflua (sp?) is a tree native to the eastern United States charactarized by its tall, thin form, its maple-like leaves, and its extremely vivid fall color. (This tree is not to be confused with the gums and eucalyptus trees from Australia; they arent at all related.) *I just spilled beer on my keyboard!* anyway, sweet gums also bear seed in little balls that look like spiny maces. Some say that crushed leaves of this tree smell like turpentine. Sweet gums are popular as landscape trees, and for good reason. They are hardy, pretty fast growing, nice in the summer, fairly compact in wideness, and vivid in the fall even if it doesnt get cold (they turn bright red in LA even though fall is usually the season of 90 degree santa ana winds) If you want really good fall color there is a variety called liquidamber which is really nice. The only thing i can really say about sweet gums is don't plant them if you're planning on running around barefoot, the little 'fruits' are brutal. Oh yeah, and never 'top' a tree of any type. it looks ridiculously stupid. If you dont want a tree to get tall, dont plant a tree which will get tall.