Here is the trunk

Looks like you have cherry leafspot. Very common on tart cherries. Montmorency is especially prone to it. There is nothing you can do for it now until after your fruit is ripened and harvested.

Then spray with a fungicide product containing chlorothalonil. This will coat the remaining leaves and slow the spread of the disease. If left unchecked and conditions are right, you could have the whole tree partially or fully defoliate from this disease.

Be sure to clean up all fallen leaves this fall when the tree is dormant. Applying a fungicide spray at white bud stage next year and again after fruit harvest will help prevent or at least slow down the spread of cherry leaf spot.

Your fruit will no be affected by this fungi just the foliage. Severe outbreaks can weaken the tree if it totally defoliates too early in the season. I had one of my cherry trees once so severe with it it was totally defoliated by August 15th. The tree never re-leafed until the following spring.