Species selection trials and silvicultural techniques for the restoration of bottomland hardwood forests

Since 1990, a series of experiments has examined the appropriateness of 24 tree species for restoring a bottomland and swamp forest in the delta of Fo urmile Branch in the coastal plain of South Carolina, USA. In addition, var ious silvicultural techniques used to maximize the survival of tree plantin gs, have been appraised for effectiveness. While the topographic relief on the delta is small (dm differences between most sites), it is sufficient to utilize woody species with different flood tolerances. Hence, a diverse fo rest community can be established, using these elevation differences. In th e wettest sites where water persists virtually continuously and may be one to two meters deep during large flood events, only the most flood-tolerant species, such as Taxodium distichum and Nyssa aquatica, can survive. These species will also survive very well at higher elevations, because the perma nent water table never fell below one meter deep. In sites that are not flo oded, unless the entire swamp is flooded, several additional species can be used. These include Fraxinus pennsylvanica, Carya aquatica, and Quercus ly rata. Finally, in slightly higher areas, Q. michauxii, Q. nuttallii and Q. phellos would have adequate survival. To minimize herbivory and maximize su rvival, tree shelters should be used if herbivore pressure is high. The pri me herbivore of concern is beaver. Thus, any plantings that are frequently flooded may require protection. Other silvicultural techniques, including f ertilization and control of herbaceous and willow competition, were not ess ential to ensure growth and survival. Finally, survival of the least expens ive planting stock, bare root saplings, was nearly as good as balled and bu rlapped stock. Thus, unless absolute maximal survival is required, bare roo t stock will produce good survival at a fraction of the cost. One critical characteristic of the bare root stock is height, which must exceed the hood depth during the growing season. In the case of the Fourmile Branch delta, this was at least 45-60 cm tall. Published by Elsevier Science B.V.