 A significant part of Operation Cedar Falls was also characterized by large-scale combat engineering and chemical operations.Tankdozers, bulldozers, and Rome plows were used in so-called jungle-clearing operations in which enemy held terrain was cleared of its vegetation in order to conduct search-and-destroy operations and to destroy enemy installments.Chemicals were used to defoliate parts of the area and to contaminate enemy rice supplies which American forces were unable to remove.