For starters, stop watering so often! It's much better to give your trees a thorough soaking less often than to water daily. You don't say how much water you're giving your trees. If it's a light sprinkle, you may be wetting only the surface. (It's common for water to begin puddling on the soil's surface when only the top inch or two of soil is wet. Sometimes the water can't soak in as fast as you're applying it.) In this case, the soil in the lower part of the root ball may be completely dry, and your trees are suffering from lack of moisture. The opposite may also be true. If you're watering enough to soak the entire root zone of the trees daily, you may be drowning your trees. The roots need oxygen just as much as they need water. If they're deprived of oxygen, the roots can't absorb water, and they die. So although there may be plenty of water in the soil, the top of the tree won't be getting any because the roots can't drink it up. The solution to both scenarios is to water the soil deeply once every 4-7 days. If it's warm and windy, water more frequently. Plants that were grown in pots require more frequent watering than those that were field-grown and balled and burlapped. Cover the root zone with mulch to help hold in moisture.