We discuss the issues related to the formation of phytogenetic mounds on sand massifs in the eastern part of the Silesian Highland. These regions formed on originally deflated fossil soils. The formation processes of mounds are directly associated with the growth of Salix arenaria. The spread of Salix arenaria in deflation regions is not accidental but exhibits a direct linkage with underlying substrate, especially with the emergence of silt material in it. Species that colonize such regions form propagation cores of vegetation through the spread of secondary roots. Adventitious (daughter) branch roots of Salix arenaria that are responsible for the formation of phytogenetic mounds develop along the main mother roots.Keywords: Salix arenaria, phytogenetic mounds, vegetation successions, soil formation, soil-vegetation interaction.