The main problem that cherry tree do not bear fruit after the flowering stage – the flower buds are slightly freezed during frosts.
You can take a magnifying glass and move closer to the cherry tree and look closely at the flowers, its much more difficult with the naked eye to see at the top of the blackening pestle – stigma. If you can see a dark stigma, it means that the pestle is died, which needs for fertilization and further pollination. We will not get the harvest, unfortunately.
In winter the pestle is often frozen in a closed flower buds, at low temperatures.
Another reason for the lack of harvest, may be, the lack of pollinator another variety of tree that blooms at the same time with it. The territory of collective garden usually contains an extensive collection of different varieties, and the bees pollinate the trees within a radius 2-2,5km such situation is extremely seldom. Other insects also do this.