Hi,
I just posted about my plum tree and I have a similar problem with our cherry tree (North Star). It's our second year here and both years, all of the fruit prematurely darkens and drops. You can see how tiny it is in the picture below.
It is a very young, small tree. So far this year, we had probably 20 cherries do the early death thing and about 3 remain, growing to normal size and looking on track to develop.
There are no signs of pests or disease that I've noted. The fruit just looks shriveled and is all pit inside.
Zone 5A, regularly fertilized and watered. Conditions last year were normal, this year hot and dry but watering more to compensate.
Thanks for any tips on identifying what's going on and how to remedy it.