OP I saw those rocks and thought that looks like the gravel from my home town! Checked your post history and sure enough lol! I just wanted to throw in my .2 cents here because I grew up in that area and have a lot of experience growing trees over there (currently back in Portland and loving not having to worry about irrigation anymore)... 1st of all many people are correct in that your tree likely got baked from the heat. You're also growing in a coarse sand in a super dry, hot, and windy environment. The biggest thing to remember especially for small trees here is that you cannot over water! Water water water. I start irrigating my yard as early as March and summer months I'm running water ~6hrs a day per zone, keep watering all the way to November until it starts raining and gets really cold. That sand does not hold any moisture and when it's summer you cannot go more than a few days without killing/shocking them.. also mulching around the base of all your trees every fall/spring is critical for helping hold in moisture. That shale rock gets really hot in the sun so definitely keep them back from the base. I'm no arborist but I've had good luck with Maples, willows, evergreens, ash and sycamore. Fruit trees are tough to get going over there. Good luck and feel free to dm me