Modeling below-ground biomass to improve sustainable management of Actaea racemosa, a globally important medicinal forest product

► Thousands of kilograms of black cohosh rhizomes are sold world-wide for medicinal use. ► Natural populations are harvested with no efforts to manage this natural resource. ► We developed a model to inventory below-ground biomass based on above-ground metrics. ► The validated model effectively predicts rhizome biomass at the stand level. ► This management tool supports sustainable use of commercially harvested rhizomes.