From a climate change perspective, one of the most important ecosystem services that wetlands provide is carbon sequestration, a regulating service that helps moderate the impact of increased anthropogenic and natural emissions of greenhouse gases like CO2 and CH4. Carbon dynamics in wetlands are influenced by processes that promote the accumulation of carbon in sinks and those that govern the release of carbon (e.g. act as carbon sources). The research described here evaluates the role of vegetation in carbon source/sink dynamics in a restored coastal freshwater forested wetland. Taxodium distichum (L.) Rich (bad cypress) represent a foundational species in coastal freshwater wetlands. These long-lived canopy dominants are well-adapted to flooded freshwater conditions, but particularly sensitive to changes in water chemistry associated with salinity incursion, an increasingly common situation in coastal regions of the southeastern United States. Chapters II and III investigate the impact of salinity incursion events on the ability of bald cypress to sequester carbon. I apply traditional techniques within the discipline of physiological plant ecology to a restoration setting to develop a baseline data set for the long-term evaluation and monitoring of restoration efforts at the Timberlake Observatory for Wetland Restoration. These data indicate that salinity incursion represents a long-term threat to the species ecophysiology, hence the success of the restoration effort currently underway. In addition to functioning as an important carbon sink, wetlands also represent the largest source of the annual flux of methane to the atmosphere. Vegetated wetland ecosystems in particular are hot spots of methane emissions. In Chapter IV, I provide the first comprehensive assessment of the importance of vegetation to the annual flux of methane to the atmosphere. In Chapters V and VI, I work towards identifying standing dead trees as a novel pathway in the annual flux of methane to the atmosphere from wetland ecosystems. Because of the substantial role that carbon gases play in greenhouse effects on global climate change, a greater resolution of the anthropogenic and biologic forces that control the source/sink dynamics of carbon in wetlands is important as society works towards mitigating current and future global warming.