One Year Old Dwarf Cherry Tree has Little Black Bugs
It appears that your dwarf cherry tree has aphids and ants under the leaves. We can't see them clearly enough to be absolutely certain, but the insects are not any of the other common pests that get on cherry trees. And, ants and aphids are a combination that works because ants actually "raise" aphids like livestock. They harvest the honeydew (sugary excrement) of the aphids.
Aphids are easy to control with a horticultural oil. Be sure to use a summer weight dilution rate or product. The ants will leave when the aphids are gone, though ants are beneficial insects and are not a problem anyway.