The biology of reproduction of some tree species of at introduction in Perm krai

Biological features of flowering and pollination, seed productivity of Tilia cordata; Padus maakii; Padus avium, Sorbus aucuparia used in landscaping of streets, parks and squares of the city of Perm are described. Observations and collection of material were carried out in the summer of 2016-2017 with 10 model trees of each species. The average dates of occurrence of phenological phases of seasonal development are established. The pollen fertility of all studied tree species was high and sufficient for successful pollination. But the productivity index was low and amounted to the Tilia cordata 11.3-15.3%, Padus avium - 12.9%, Padus maackii - 21.6%. Low rates of seed productivity are associated with abnormal weather conditions in 2016-2017. The coefficient of productivity of Sorbus aucuparia in 2018 ranged widely from 43.0 to 61.0.