The main species of Brazilian forestry is Eucalyptus, this specie is adapted to our soil and climatic conditions, also we have hybrids and clones ideally suited for different timber uses and the silvicultural treatments are well know. The experiment was set up with nursery substrate (NS) and mixtures of NS with biochar (BC) at 20, 40, 60, 80 and 100% to evaluate the seedling production of Eucaliptussp. clones VM01 and I144. Stem diameter, height, number of sheets, fresh and dry weight of roots and shoots and Dickson index were evaluated.The BC did not improve seedling growth compared to NS, but ratios below to 10% should be considered for this purpose