The paper analyse the substitution of hornbeam coppice stands andconversion into high forest stands, formed by species that better valorise the site conditions. An improved alternative for the method of substitution in corridors is presented. The main goal of this new substitution-conversion alternative is to gradually conduct the actual structure of the coppice stands towards the target structure imposed by the forest management objectives, without a total elimination of the species that will be substituted. Two plot areas were selected in order to put into practice the proposed method. Bands were created for reducing the effective costs of the substitution process. 450respectively 468, small seedlings (of beech, pedunculate oak and sessile oak)per hectare were planted in the created bands. The planting scheme took into account the shadow tolerance of the species from the target composition. Based on the field data and using the yield tables, the evolution of the stands in the two selected plots was simulated. In this respect, the forest treatments were parameterized according to the Romanian forest rules regarding theapplication of thinning and regeneration cuttings. The substitution-conversion process started from an almost pure hornbeam coppice and, simulating the application of the proposed method for 120 years, it was predicted that the method allows directing the actual stand structure to the target structure.The dynamics of species and structural diversity were assessed and the results of 120 years simulation indicate an important increase of both the species(the Shannon species index increases from 0.203 to 1.073) and structural diversity (the Gini structural index increases from 0.032 to 0.200).