XVI International Botanical Congess
At present, the invasive tree Sapium sebiferum is spreading throughout the coastal prairie ecoregion of Louisiana and Texas, but is currently restricted from westernmost locations. This study examined the potential roles of site, soil type, and soil moisture on the growth and survival of S. sebiferum along an east-west gradient across the coastal prairie. In a field experiment it was found that plant survival and growth was very poor on the western soil. Greenhouse results further showed that growth was poor on the western soil and that this effect was not related to watering frequency. Soil analyses revealed higher sand, sodium, phosphorus, and electrical conductivity levels in the western soil. It is concluded that the western soil is unfavorable for S. sebiferum growth. Available evidence suggests that elevated soil salinity may be the primary cause of poor S. sebiferum growth on the western soil.