Restoration of Impounded Forests of Coastal Louisiana Using Spoil Bank Gapping

Impoundment and increased flood duration are some of the most common stressors to declining forested wetlands in coastal Louisiana, USA. One type of restoration that has shown itself to be cost-effective is spoil bank gapping. This type of hydrologic restoration has occurred within the Lac des Allemands swamp of Barataria Basin. After 60 years of impoundment, the hydrogeomorphic processes in the study area were improved. The study area included eight paired 625 m2 sites. Basal area growth over the 7-year period varied between 5.93% and 14.39%, with an average of 8.31%, or just over 1% wood growth per year. Post-restoration basal areas indicate that all our study areas are improving. Pooled together, the 2018–2023 years had significantly higher net production than the pre-project 2017 growing season. The distribution between leaf and wood production was remarkably similar within species types across years, with leaf production consistently exceeding wood production, particularly due to Taxodium distichum. Canopy cover has increased by 20 percent since project construction, and as a result, herbaceous cover tends to decrease over time.