Answer: Brown buds can be caused by a light frost (unlikely in your situation) or by a fungus; possibly brown rot or Botrytis. Without seeing the tree, it's difficult to diagnose. I suggest you clip one of the branches with the dead buds and take it to your local cooperative extension office for microscopic examination. They are located in the Rockingham County Complex at 113 North Road in Brentwood. Office hours are 8:30 AM - 4:30 PM , Monday-Friday. Phone (603) 679-5616 or 1-800-248-6672 (NH only).
Best wishes with your cherry trees.
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