Looks like a sour cherry...but I can't tell you if it's the wallnut doing it, I've heard they can be a problem...this far away??

Walnuts have no negative impact on anything in the Prunus genus.....and that includes the cherry. And is there was a negative impact on the maple, it would have been apparent decades ago on a tree of that age, so it is relatively safe to assume that whatever is bothering your trees, it is NOT the walnut.

btw, you can easily look up what plants are sensitive to the walnut's presence. Just Google 'juglone toxicity' to find listings of plants both resistant or susceptible.

Where do you live?

Does it rain there in the summer? If so, how much and how often?

If no rain, do you irrigate once/month? If not why not?

P.S.: watering the lawn is NOT adequate for trees.

It looks like sour cherries, and may very likely be Montmorency.

Make yourself a cherry pie.

There are some people who actually prefer sour cherries for fresh eating, it's considered an uncommon treat.

Right now it's summer central MN coon rapids...there have been a few thunderstorm and rain fall I hear is about average for the area...and its right between 2 garden that get watered at least a couple time a week when dry..

Could those branches leaves died to lack of sunlight? The black walnut on the hill (+house)blocks all evening sun to that part of the tree..