Need more information. How old are these trees? What variety of cherry?
What
climate zone are you in? What rootstock are they on? Did the effected
tree ever
look healthy and/or give fruit, or was it like that from the beginning.
What kind of
soil are they growing in? What other trees and plants are growing nearby?

Do the fallen leaves look attacked? Any of these questions and possibly
more
can give clues as to the cause of the problem.
Just read you live in Minnesota. Cherry trees should be cold hearty
there, but there
are some varieties and/or rootstocks only good up to zone 5 (you must be
in zone 4)

Sherwin D.

wrote:

I have a pair of dwarf cherry trees. Both leaf out fine in the spring
but one looses it's leaves shortly thereafter. The other seems pretty
well but I have noticed a branch or 2 starting to do the same thing as
the other tree. Is there a cure for this? I don't see any other
problems on the surface.

Thanks,
Tim