Master of Science Thesis submitted 1993

Assessment of Sediment Accumulation in Restored Bottomland Hardwood Stands Using Cesium137 as a Soil Tracer

Kevin Nunnery


Abstract

Floodplain sediment accumulation on bottomland hardwood sites restored from agriculture in southwestern Kentucky was assessed using Cs-137 as a soil tracer. The depth of Cs-137 within the soil profile was used to determine sediment accumulation since 1954, when the Cs-137 was introduced to these systems through radioactive fallout.

Three study sites were located on three different watersheds on Kentucky Lake in southwestern Kentucky. Planted and naturally regenerated restored stands were compared to old growth bottomland stands and to an undisturbed upland stand. Old growth stands were located on two of the watersheds. Cs-137 data from soil of an undisturbed upland site in North Carolina were used as a baseline for comparison to the data collected in the bottomland hardwood stands in Kentucky.

All bottomland hardwood stands had Cs-137 at lower depths in the soil profile than the undisturbed upland stand, indicating that sedimentation had occurred. The naturally regenerated stands accumulated more sediment than the planted stands. The old growth stand on Jonathan Creek accumulated much more sediment than the naturally regenerated and planted stands there, but site disturbance adjacent to it could have caused the larger accumulation.