Comparison of revegetation of a gas pipeline right-of-way in two forested wetland crossings involving conventional methods of pipeline installation and horizontal drilling, Nassau County, Florida

摘要

One year after pipeline installation, vegetation in the right-of-way (ROW) was inventoried at two stream floodplain crossings in Nassau County, Florida. Both sites were forested wetlands composed of Acer rubrum, Fraxinus caroliniana, Liquidamber styraciflua, Nyssa ogecho, Quercus laurifolia, and Taxodium distichum, together with other wetland trees. Pipeline installation across the Brandy Branch floodplain was by conventional ditching and backfill methods. Installation across the Deep Creek floodplain was by horizontal drilling after clearcutting the ROW. The latter method left tree stumps, understory vegetation, and soil layers intact, except for disruptions caused by logging. According to the inventory, vegetation at the drilled site was more diverse (nearly twice as many species occurring in the ROW as at the trenched site) and more robust (no unvegetated exposed soil compared to 15% at the trenched site). Differences between the ROW vegetation at the two sites can be attributed to both site differences and installation technologies used.