## 2 Methods  
### Site Description  
The natural forested wetland was located at Alligator River National Wildlife Refuge (ARNWR) in Dare County, North Carolina (35\({}^{\circ}\)47\({}^{\prime}\) N, 75\({}^{\circ}\)54\({}^{\prime}\) W), with the Alligator River to the west, Albemarle Sound to the north, and the Croatian Sound to the east (Supplementary Figure S1). The refuge was established in 1984 and is characterized by a diverse assemblage of pocosin (wetland fed by rainwater or groundwater, acidic peat and mineral soils, oligotrophic, woody vegetation) wetland types and swamp forests [40]. ARNWR has a network of roads and canals, but in general contains vast expanses of minimally disturbed forested- and shrub-wetlands. Thirteen plots were established in a 4 km\({}^{2}\) area in the middle of a bottomland hardwood forest surrounding a 35-m eddy covariance flux tower (US-NC4 in the AmeriFlux database) [41]. Of the 13 plots (7 m radius), the five central plots were utilized for this study. Over-story plant species composition was predominantly composed of black gum (_Nyssa sylatica_), swamp tupelo (_Nyssa biflora_), bald cypress (_Taxodium distichum_), with occasional red maple (_Acer rubrum_), sweet gum (_Liquidambar styraciflua_), white cedar (_Chamacyparis thyoides_), and loblolly pine (_Pinus taeda_). The understory was predominantly fetterbush (_Lyonia lucida_), bitter gallberry (_Ilex glabra_), red bay (_Persea borbonia_), and sweet bay (_Magnolia virginiana_). The mean annual temperature and precipitation from an adjacent meteorological station (Manteo AP, NC, 35\({}^{\circ}\)55\({}^{\prime}\) N, 75\({}^{\circ}\)42\({}^{\prime}\) W, National Climatic Data Center) for the period 1981-2010 were 16.9 \({}^{\circ}\)C and 1270 mm, respectively. These wetlands are characterized by a hydroperiod that operates over short time scales and is driven primarily by variation in precipitation. Soils are classified as Pungo series histosols (very poorly drained cystic thermic typic Haplosaprist) with a deep, highly decomposed muck layer overlain by a shallow, less decomposed peat layer and underlain by highly reduced mineral sediments of Pleistocene origin [42]. Ground elevation is <1 m above sea level. The drained wetland was an intensively managed loblolly pine plantation located in Washington County, NC (35 deg48' N, 76 deg40' W) within the lower coastal plain mixed forest province (Supplementary Figure S1). In the late 1800's/early 1900's, the area was clearcut and ditched for agriculture. Since the mid-1960's, this site has been owned and operated by Weyerhaeuser NR Company for commercial timber production and is currently in its fourth rotation of loblolly pine. The pine plantation watersheds are managed with a network of parallel ditches (0.9-1.3 m deep; 90 m spacing) and more widely spaced roadside canals. Drainage lowers the height of the water table and improves site access and tree productivity by reducing stresses caused by excessive soil water, especially during winter months. The current loblolly pine stand is also part of the AmeriFlux core sites (US-NC2 in the AmeriFlux database) and was planted in 1992, on bedded rows, with 2-year-old half sibling seedlings after clear-cutting the previous mature pine plantation. Planting spacing was 1.5 m by 4.5 m. Bedding is common best management practice along the southeastern lower coastal plain [31] in order to increase growth and survival of seedlings. Bedding creates unique micro-topography in managed pine forests, resulting in high (bed) and low (interbed; space between beds) micro-topographic locations, which influence SOC stabilization [28] and N cycling [43]. Thirteen plots were established in a mature loblolly pine stand surrounding a 28-m eddy flux tower [41]. Of these 13 plots (7 m radius), five central plots were utilized for this study. The understory was primarily composed of young red maple (_A.