Hurricane damage to old-growth forest in Congaree Swamp National Monument, South Carolina, U.S.A.

Abstract

Hurricane Hugo caused much damage to the old-growth forests of the Congaree Swamp National Monument, but most of the damage to trees >20 cm dbh consisted of crown breakage and defoliation. Serious damage (>25% of crown lost, snapped trunk, or uprooted) was more common in mixed bottomland forest (49% of trees seriously damaged) than in adjacent sloughs dominated by Taxodiumdistichum (L.) L.C. Rich, and Nyssaaquatica L. (19% of trees seriously damaged). Of the trees >20 cm dbh, about 12% were uprooted in the bottomland forest, whereas only 2% were uprooted in sloughs. The storm reduced diversity in sloughs because most trees of species characteristic of better drained sites, and especially those rooted on nurse logs and other unstable elevated microsites, were uprooted. Dynamics of the entire forest were greatly influenced by the capacity of most tree species to recover vegetatively after suffering even severe crown and stem damage. Trees with resprouted crowns, however, were particularly likely to be broken, presumably owing to the presence of stem rots and architecturally unsound branching patterns.