Since the tree is surrounded by lawn, I'm interested in your lawn care practices and which products you use.

I use Scott's crabgrass preventer around Easter. After that I use Milorganite once in July and again in late September. No other chemicals.

Did you water well during your drought? If not, that could be your problem. If there is no or little rain, young, newly-planted trees need to be watered for at least the first year until they get established. I always water well when I first plant, Watering well would be about five gallons a week and out to the drip line, although maybe more since your tree looks to be a good size. Depending on where you live, you can stop watering once the ground freezes. Here in VA, I might water in winter if we have no precipitation and the temps are in the high 30s, 40s. If you don't get rain throughout the summer, just be sure to water. You can check the dryness by digging down to see if there has been enough rain to soak into the soil. We had what seemed like decent rain recently, but when I was planting, the ground was bone dry four inches down.

I would not touch the roots.

It's a cherry.......I'd honesty be surprised if there was nothing wrong with it!! Cherries - both ornamental and fruiting - are prone to more disease and insect issues than any other tree I can think of. Bacterial canker, gummosis, black knot, brown rot, shothole, leafspot, leaf scorch - all are common cherry ailments and all can cause leaves to brown, dry and die.

My best advice is to take samples to your county extension office for a diagnosis and treatment options, if any.

That is not a young or newly planted tree, so the advise about watering is unlikely to apply except for times of drought. I also wouldn't mess with the roots.