Maritime forest habitat dynamics on Bulls Island, Cape Romain National Wildlife Refuge, SC, following Hurricane Hugo

Bulls Island is a 2180 ha barrier island located within the Cape Romain National Wildlife Refuge near Awendaw, SC. Maritime forest covers 777 ha, much of which was considered as old-growth prior to Hurricane Hugo in 1989. Vegetation surveys done in 1991 revealed that Pinus taeda was almost eliminated by the hurricane (reduced to 1.7 stems/ha and <0.1 m2/ha basal area), while live oak density and basal area declined only 33.3 and 28.6%, respectively, after the hurricane. Sabal palmetto was the most resistant species in the maritime forest, declining by only 26.3 and 21.8% in density and basal area, respectively. By 1998, P. taeda trees (≥1.4 m tall) were 10 times greater in density and 77.3% of pre-storm basal area, indicative of its resilience in these coastal forests. S. palmetto density and basal area in 1998 were almost double pre-storm stocking values. Quercus virginiana density and basal area were similar to 1991 levels, but 38% of the tree crowns suffered from moderate to complete dieback by 1998. Q. virginiana decline appeared to be due to increases in exposure to ocean-strength salt spray and raised levels of the ground water table. Sapium sebiferum accounted for 9.8, 4.1 and 22.6% of the tree density-frequency-dominance index in the pre-storm, 1991 and 1998 forest, respectively. Increased sunlight to the forest floor and the raised water table that increased moist mesic sites conducive to reproduction and growth of this species were probably responsible for its rapid spread. The nature of the maritime forest on Bulls Island appears to be on the verge of rapid change during the next several decades due to water drainage problems that appear to be adversely affecting live oak health in the interior of the island and S. sebiferum expansion.