I noticed little brown acorn like things growing on my emerald green arbovitae trees. What are they? and are they harmful? Should they be removed? In addition I had 12-14 foot trees planted in my backyard which lasted 2 seasons and now they are turning brown and the brown seems to be spreading. At least half of my 30 trees have died and there is no consistent pattern. There could be one healthy, two dead, two healthy three dead. What can I do to prevent the rest of them from dying? I live in New York.