Hugelkultur is intended primarily to act as a long-term (5-20 year) fertilization and water absorption mechanism, so that other plants planted on top of the mou

Hugelkultur is intended primarily to act as a long-term (5-20 year) fertilization and water absorption mechanism, so that other plants planted on top of the mound grow better. In that context, you will have a net-positive CO2 absorption (or, a net-negative CO2 release into the atmosphere).