Carbon sequestration of a forested wetland receiving nutrient inputs - soil, tree and greenhouse gas data

Here we describe a pilot wetland carbon project located 30 km west of New
Orleans where measurements were taken in 2013 and 2018, and applied to the
carbon offset methodology, “Restoration of Degraded Deltaic Wetlands of
the Mississippi Delta” (“the ACR Methodology”) published by the American
Carbon Registry (ACR). Baseline emissions were modeled using values
derived from scientific literature. Results indicate net sequestration
rate of 619,727 tons carbon dioxide equivalent (CO2e)
over the 40 year project duration, which equates
to 16,527 t CO2-e/yr, if wetland greenhouse gases (GHGs)
are included, and 200,143 t CO2e over 40 years, or 5,003
t CO2-e/yr, if wetland greenhouse gasses were conservatively omitted. A
kriging exercise was carried out that modeled the tree and soil pools,
which resulted in net sequestration of 723,375 t CO2-e over 40
years (annual mean 18,084 t CO2-e/yr) with greenhouse gases,
and 262,472 t CO2-e over 40 years (annual mean rate 6,560 t
CO2-e/yr) if greenhouse gases were
omitted. Unfortunately, the project was withdrawn, prohibiting
the issuance and eventual transaction of carbon credits, due to very large
uncertainty estimates mostly associated with GHG emissions and the kriging
approach as in situ sampling could not be conducted as required by the
methodology.