Sustainability is a research priority for clonal eucalypt plantations planted on very sandy and poor soils in the Congo. Results from a study using cloned Eucalyptus hybrids conducted since 1997 show: (1) a marked depressive effect on tree growth of rernoving slash and tree biomass after harvest; (2) a high risk of nutrient leaching in the first year after harvesting linked to, the high rate of litter decomposition; (3) a temporary starter effect of litter burning but a depressive effect in the medium term; and (4) a slow but lasting impact of burying litter. It is concluded that site management must conserve a maximum amount of organic matter to ensure a sustainable production system. Debarking and retention on site of the upper stem and other harvesting slash without burning is recommended.