Assessment of carbon storage potential of forested wetland soils as affected by urbanization degree in two different physiographic provinces of Virginia, USA

Abstract

This study assessed carbon storage potential in terms of total carbon (TC) and total carbon stocks (TC stocks) in soils of four forested wetlands in Northern Virginia along with associated soil physicochemistry [e.g., soil pH, bulk density (Db), and gravimetric soil moisture (GSM)]. The study sites were selected across two vastly different degrees of urbanization (urban [U]; non-urban [N]) and the two main physiographic provinces of the region (Piedmont; Coastal Plain). Soils were sampled and analyzed at three depth intervals (0-10cm; 10-20cm; 20-30cm). No significant differences were found in TC (3.07 ± 0.31% [U]; 3.82 ± 0.40%; [N]) or TC stocks (2.81 ± 0.35 kg∙m− 2 [U]; 3.58 ± 0.28 kg∙m− 2 [N]) between urbanization degrees (p > 0.05). There was no significant difference in TC stocks by physiographic province (p > 0.05), however, Coastal Plain wetland soils had higher TC than the Piedmont wetlands (4.32 ± 0.41%; 2.57 ± 0.22%, p < 0.05). Db and GSM were significantly different along urbanization degree and physiography, and were highly correlated to TC, being able to estimate the total variability of TC to a significant degree (R2 = 0.39 and R2 = 0.47, all p < 0.05). The outcome shows that urban wetlands fairly mirror the carbon storage potential of non-urban wetlands and more likely so in the Coastal Plain than in the Piedmont, especially in their top 10 cm of soils. Further studies may be warranted across an urbanizing landscape to elucidate carbon storage potentials of urban wetlands that can combat urban carbon emissions.