Sapium sebiferum (L.) Roxb., a fast growing tree in the Euphorbiaceae, has rapidly spread and changed many aspects of plant community structure in the southeastern United States (Harcombe et al. 1993, Bruce et al. 1995). It is a major pest of natural coastal tallgrass prairie in Louisiana and Texas and is one of the first and most persistent invaders of abandoned agricultural land (Ewel 1986, Bruce 1993, Jubinsky 1995) and bottomland hardwood forest.