Trees, Shrubs and Conifers: My Japanese Red Maple is not happy, 3 by JoParrott

JoParrott wrote:
This tree is 6 years old and until recently has been beautiful. Earlier this summer the leaves began to curl and get crispy, falling off. There is no sign of any insect damage, either boring or sucking. The branches are totally flexible and alive- We had many many days of temps above 100-up to 109, and hot winds, which explains the color not being red like usual. The naked branches are mostly on one side, which doesn't make sense as that is not where the prevailing winds come from. It is watered with underground irrigation as it has always been. I am at a loss, and worried that I may lose it. I am OK waiting through the winter and see what next spring brings- Could it be a problem with some kind of fungus or mildew? I would appreciate any help.