Effects of Habitat, Burial, Age and Passage through Birds on Germination and Establishment of Chinese Tallow Tree in Coastal South Carolina

Abstract

RENNE, I. J., T P. SPiRA (Department of Biological Sciences, Clemson University, Clemson, South Carolina 29634) AND W. C. BRIDGES, JR. (Department of Experimental Statistics, Clemson University, Clemson, South Carolina 29634). Effects of habitat, burial, age and passage through birds on germination and establishment of Chinese tallow tree in coastal South Carolina. J. Torrey Bot. Soc. 128:000-000. 2001.-Factors affecting germination and seedling establishment of the nonindigenous, invasive Chinese tallow tree (Sapium sebiferum (L.) Roxb.) were investigated under greenhouse and field conditions. In greenhouse experiments, buried seeds had higher germination rates and percentages than surface seeds, and simulated and actual seed passage through the avian gut enhanced germination. One year of aging reduced germination and seed viability, particularly for seeds unhandled by birds. In the field, seedling emergence and survival were greater in mixed pine-hardwood forest than in pine-turkey oak forest or spoil areas. Planting date did not affect overall seedling emergence or survival. Seeds sown in March 1998 and 1999 in five coastal forests that contained established tallow trees emerged throughout the growing season. While seedling emergence rates varied, final seedling numbers were similar across habitats in 1998, but were lower and differed across habitats in 1999. Recruitment was thus spatially and temporally variable. Viability of seeds buried for one and two years ranged from 16 to 69% in the five habitats, but did not differ among habitats or length of burial time. Because habitat type did not affect seed dormancy (both years) and final seedling number (1998 only), we conclude that other factors influence the differential success of tallow trees among coastal forests in South Carolina. Management strategies (e.g., fire) should consider the seedling phenology and seed bank capability of tallow tree.