Sediment accretion rates for natural levee and backswamp riparian forests in the Mobile-Tensaw Bottomlands, AlabamaThis article is part of a larger document. View the larger document here.
Several methods to quantify sediment deposition patterns in riparian forested wetlands have been used during recent decades. In this study, we used a dendrogeomorphic technique with green ash (Fraxinus pennsylvanica) to estimate sediment accretion rates for two time periods (1881 to 2012 and 1987 to 2012) along a natural levee (35 m from river) and water tupelo-baldcypress (Nyssa aquatica-Taxodium distichum) backswamp (75 m from river) adjacent to the Tensaw River in southwestern Alabama. Sediment accretion rates were significantly higher for the 1987 to 2012 time period along the natural levee (p = 0.009; 1.6 cm yr-1) and backswamp (p = 0.032; 1.2 cm yr-1) than for the 1881 to 2012 period (0.4 and 0.5 cm yr-1). We further compared dendrogeomorphic sediment accretion rate estimates along the natural levee and backswamp to rates previously obtained using sediment pin and elevation survey methods at increased distances from the river (160 to 330 m) for the 1987 to 2012 time period. Regardless of method used we identified a negative trend in sediment accretion rates as distance from river increased and elevation decreased. Overall, this study demonstrates effective use of dendrogeomorphic techniques while minimizing site visits, compared to the other methods, to estimate sediment accretion rates across temporal and spatial scales.