TREE POPULATION-DYNAMICS IN 7 SOUTH-CAROLINA MIXED-SPECIES FORESTS

Seven 1-ha plots were established in second-growth, mixed-species fore sts across a soil moisture gradient in the Coastal Plain of South Caro lina. All trees in the plots were tagged in 1979 and measured in 1979 and 1989 to determine 10-yr recruitment of trees greater than or equal to 4.5 cm DBH (ingrowth) and mortality. Ingrowth to mortality ratios and sums of ingrowth plus mortality were used to quantify shade tolera nce and successional status of individual species. In all plots, small stem density decreased and large stem density increased, an indicatio n that the forests were in mid-successional phases where competition i s expected to be intense. Shade tolerant species, especially small tre e life forms, had the greatest ratios of ingrowth to mortality. Large differences in population flux, even among shade tolerant species, ind icated that different mechanisms can account for increases in populati ons of late-succesional species. Within some species, ratios of ingrow th to mortality varied significantly across the gradient reflecting fl ooding or soil moisture effects on succession.