Increased levels of forestry best management practices reduce sediment delivery from Piedmont and Upper Coastal Plain clearcut harvests and access features, southeastern states, USA

•Current BMPs reduce potential sedimentation in the Piedmont/Upper Coastal Plain.•Forest access features delivered a disproportionate amount of sediment (42–69%).•The effects of high BMP levels were most profound at skid trails and harvest areas.•Overall, the BMP + level reduced potential sediment delivery by 74 % compared to BMP–. A land use history of intensive agricultural practices, combined with highly erodible soils, have made erosion control and water quality protection essential for forest management in the Piedmont and Upper Coastal Plain of the southeastern U.S. Forestry Best Management Practices (BMPs), which include sustainable harvesting guidelines approved by state forestry agencies, are utilized in these regions to mitigate potential impacts to water quality. In this study, the relationship between three levels of BMP implementation ranging from 90% (BMP+ ), estimated erosion (Mg ha-1 yr-1) based on the USLE-Forest empirical model, and sediment delivery ratios was explored to better understand impacts to forest water quality. Erosion and sediment delivery estimates by BMP level were multiplied by estimates of area occupied by each operational feature (e.g., decks, harvest areas only, haul roads, skid trails, stream crossings) and annual clearcut timberland (ha-1 yr-1) provided by the U.S. Forest Service FIA Program. The overall goal was to estimate total annual masses of erosion and sediment (Mg yr-1) by BMP level for twelve states with timberland located in either the Piedmont or Upper Coastal Plain. Forty-four clearcut harvest sites were assessed in the region. Over 431,000 ha yr−1 are clearcut in the Piedmont and Upper Coastal Plain, which represents approximately 2% of total forestland area in the regions. The BMP+ (0.5 Mg ha−1 yr−1) and BMP-standard (0.9 Mg ha−1 yr−1) levels of implementation provide considerably more water quality protection than BMP– (2.0 Mg ha−1 yr−1) based on average sedimentation rates for the overall harvest. Overall sediment removal efficiencies at the BMP-standard (54%) and BMP+ (74%) levels indicate that current BMPs are highly effective at mitigating potential sediment delivery from clearcut operations in the regions. The BMP+ level most efficiently limited potential sediment from skid trails (80%), harvest areas (75%), and haul roads (61%), which were also the primary contributors of sediment. Over 93% of clearcut harvests sampled were classified as either BMP-standar