Coastal Forest Seawater Exposure Increases Stem Methane Concentration Manuscript Data

Measurements of soil and tree stem O2, CO2, and CH4 concentrations were made at five sites representing two coastal eco-regions: the Mediterranean Pacific Northwest and the temperate Atlantic Eastern shore (Fig. 2). In total, 107 trees were sampled, pairing stem and soil gas measurements for CO2, CH4, and O2, and average stem wood density. We identified seawater exposure (exposed or unexposed), tree survival (living or dying), and tree species at each of the five sites. The five sites are Beaver Creek (BC), Goodwin Island (GI), Phillips Creek (PC), Monie Bay (MB), and Moneystump Swamp (MS). Seawater exposure was assigned qualitatively (visual identification of tree in flooded zone) and quantitatively (saline porewaters). The R packages used for data interpretation are freely available in R package version 0.8.3 and R 3.5.2 (RStudio Team, 2017).