Research conducted on biomass for Ulcos (“Ultra-Low CO2 Steelmaking” European Integrated Project)has progressively focused on charcoal supply fromtropical eucalyptus plantations. The sustainability of suchplantations is being investigated from the viewpoint oftheir carbon, water and nutrient budgets: they must allbe neutral or positive. Field research is producing resultsat the tree or stand level in several sites of Congo andBrazil, while a spatial model is developed to identifythe conditions of biomass neutrality at the scale of theforest ecosystem. The productivity of biomass has beenanalyzed through the description of practices along theAbstracts of technical articlesvarious supply-schemes that competitively feed the steelindustry in Brazil and the identification of bottlenecks forfurther expansion.