Our 1 year old Shumard Red Oak is having leaves brown out (die) near ends of top branches. Planted it late last Spring and watered every other day but when we left for a week in June, we came back to a nearly dead tree. It got no water that week. Our soil is very friable fine sandy and drains fast - you can run water in a post hole and it will never fill. This Spring it came back to life except for the two long vee-shaped at top. Watering about once per week - slow and long. Now the upper branches have leaves dying back. Checked and found only the central 18 inches were getting wet. The outer root zone (drip line) is dry from 1"-24" down. I'm watering much more and moving the hose all around root zone yesterday. Any other ideas looking at the pix?