We planted a nursery-grown 9-ft mountain ash last fall on our Lake Superior property. It seemed very healthy this spring and early summer and bloomed beautifully. A couple of days ago we noticed that most leaves had suddenly become brown, especially around the edges. We also found insect activity. Another smaller mountain ash about 15 feet away, transplanted last fall from another spot on our property, seems fine (although it did not bloom). We have been watering both regularly. These trees are planted in an area behind a sea wall we had replaced last summer. The planting area was disturbed, and a foot of gravel now helps drainage behind the wall, but we added much soil before replanting this area. Previously, several mountain ash had thrived in this spot. Let us know if you have any idea what may be wrong with this tree and if there is anything we can do to help it.