Many activities in forestry, such as the total harvest, afforestation and regeneration of forests, have an impact on changing conditions of site. On that occasion, violate the edaphic and hydrological conditions and parameters of light and many plant species in the changed conditions are favourable conditions for its development. In these changed conditions, there is fouling the regeneration areas of herbaceous vegetation mainly nitrophil, ruderal and invasive plant species. The presence of invasive plants and their spread is a major danger to native flora. Analysis of ground vegetation in the reforestation of sessile oak registered 25 plant species were grouped into 14 families. Most species belong to the family Asteraceae. On the investigated locality more numerous were perennial herbaceous plants hemicryptophytes. Phytogeographical analysis revealed that the greatest number of plants (28%) belongs to the group adventive floral elements and have an invasive character.