Answer: It's difficult to diagnose a problem long-distance but it does sound as though your tree is showing signs of stress. When we don't know the primary cause of stress we can only offer the following:
1) Water as needed. Plants need an inch of water/rain per week during the growing season; if droughty conditions develop, make sure the plant gets at least this amount of water.
2) Fertilize as needed. Use a balanced fertilizer in amounts as recommended on the product label; ideally a soil nutrient analysis should be performed to determine specifically what, if any fertilizers, are needed.
3) Avoid soil compaction around the plant (no swing sets, picnic tables, etc. near by!), and avoid mechanically wounding the plants (weed whacker damage, lawn mower damage, swings or dog runs bolted to the tree, etc.). Aerate the soil if compaction is a problem.
4) Make sure other obvious insect and disease problems are taken care of (defoliators, leaf spot fungi, etc.).
You can visually inspect the branches of the tree for signs of insect or disease problems.
Hope this information is helpful!
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