Red oak tree problem
Can anyone help? Three weeks ago I planted a 5-gallon size red oak tree. The tree stands about 8 ft tall and had wonderful new-season leaves. I dug a wide-enough hole and added mulch to the hole before I planted the root ball into the hole. I water it regularly. Then about 4 or 5 days after it was planted, we had an early-season heat wave of 90+ temps, accompanied by a late-season high wind event (I live in SoCal, where we get those Santa Ana winds). After the wind event was over and after the heat wave ended, the leaves of the red oak went limp and are now turning brown. I did the "thumbnail test" by scratching the bark of a branch with my thumb, and it is still green inside. What has happened to the tree? Did it go into shock because of the extreme heat and/or high winds? What needs to be done to resore its beauty?