Thanks for reaching out to AgriLife Extension.

May I ask if you have done any supplemental watering during the heat and drought?

Good morning!

Unfortunately, with the heat and drought, we are seeing a lot of issues with trees in the area. The increased stress is causing complications that would not normally appear. 

There are a few items to discuss.

First, picture 5 shows what may be Tubakia leaf spot. It is a cosmetic fungal disease that affects oaks. Our plant pathologist is interested in taking a look at it and is interested in a diagnosing a sample (at no fee.) Is it possible that I can visit for a sample or you can drop off at Extension?

Picture 4 indicates spider mites. 

Both of these issues are increased due to drought stress. The watering you mentioned for the lawn is not enough water for a tree. Supplemental watering for trees will require a hose on low flow. The water should be low enough it is not running off, but not long enough that it floods the area. Not only is the tree likely suffering from drought stress, but the high overnight temperatures are not enabling the leaves to transpire. It is a plant's equivalent of our sweating to heal cool. 

If you'd like to drop off a sample, our Extension office is at 13105 Northwest Freeway, Suite 1000 (on the 10th floor). We are off 290 between the Sam Houston and 610. Otherwise, if you'd like someone to come out for a sample, let me know it's ok to email you and I'll do so to connect.