The Las Osobowicki forest is remnant riparian woodland of the Odra valley. Floristic data were collected from circular 100m2 plots (with a radius of 5.64m) which were systematically chosen in forest communities. Four plant communities were determined within data set. They were represented Fagetalia order and Querco-Fagetea class. Flood prevention caused disappearance of riparian forest species, expansion of common hornbeam and Norway maple expansion and a decrease of species richness. However, spatial distribution of phytocoenoses proves the river influence on the vegetation.