The use of tree shelters in restoring forest species to a floodplain delta: 5-year results

Without herbivory control, natural seed sources, and seasonal flood events, recovery of the Pen branch delta in South Carolina to former conditions (prior to thermal discharge) may take many years. To assess the recovery process, seedlings of baldcypress (Taxodium distichum), water tupelo (Nyssa nr/lraticn), swamp blackgum (Nyssa sylvatica var. biflora), and green ash (Fraxinus pennsylvanica) were planted in four areas of the delta in 1994. One-half of the seedlings were protected using tree shelters 1.5 m tall. Heights of seedlings were taken after planting and at the end of each growing season from 1994 to 1998. Survival at the end of 5 years ranged from 67 to 100% for seedlings in tree shelters and 2-90% for those not in tree shelters. Survival of seedlings without tree shelters was generally low, and mortality was attributed mainly to beaver damage. Although water tupelo, swamp blackgum, and green ash seedlings tended to die once clipped by beaver, 85% of the clipped baldcypress resprouted after clipping, and new sprouts grew vigorously. During year 1, height growth of tree shelter seedlings was significantly greater than non-tree shelter seedlings for all species, but once the seedling emerged from the top of the shelter, growth differences declined dramatically. Differences in height growth among areas was highly variable from year to year, and no one species tended to grow better in one area over another throughout the period. Restoration of the Pen branch delta to a baldcypress-water tupelo forest similar to the surrounding forest is possible. Baldcypress and water tupelo seem ideally suited to growing in all areas of the delta equally well, but it may take 10-20 years before the seedlings are of sufficient size to not be affected by herbivory and old enough to produce sufficient quantities of seed to maintain the forest. (C) 2000 Elsevier Science B.V. All rights reserved.