From the viewpoint of the hierarchy of shoot systems crown architecture in virginal and young reproductive individuals of Quercus robur L. in meadow steppes and various insular pineries in the Northern Voronezh refion is studied. The number of studied individuals is over 700. While systematized diversity of shoot systems categories of architectural model, architectural unit and architectural type (AT) were used. It has been established that Q. robur in the zone of the southern forest-steppe forms the same AT as in the mixed and broadleaved forest biomes in the Oka River basin. The individuals of the AT I prevail both under full light and canopy. Under shading most individuals of the AT I demonstrate decrease of growth processes and simplification of shoot systems. All AT of Quercus robur in the southern forest-steppe form a wider range of forms than in the mixed and broadleaved forest biomes. This is caused by realization of reduction and increasing processes and by forming new shoot structures of different levels.