Answer: Unfortunately, based on your description I am not certain what is affecting your trees. Both of these kinds of tree are potentially subject to a wide variety of pest and disease problems that can cause defoliation as a symptom. I would strongly suggest you work with your local Cornell cooperative extension to obtain a specific diagnosis of the problem(s) with each tree. Based on knowing that, you can decide how to treat them. If a chemical control is needed, they will have the most up to date information on what to use and how/when is best to apply it for maximum results. I'm sorry I can't be more specific for you long distance.
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