Might be physiological leaf burn. Or a leaf blight caused by a pathogen.

I'm not sure of the type of Oak. The builders planted these along the roadway before the houses were built. It's probably a 5 year old tree. The damaged area of the trunk spans about 18-24 inches vertically, and maybe the bottom 4-5 inches was covered with mulch until i removed it. And the damaged area is restricted to less than half of the circumference (maybe 120-140 degrees). When i removed the mulch originally, i removed as much as i could before i started hitting 1/2" diameter roots that had started growing into the mulch pile, so i stopped. Would spraying any part of it with pruning spray be beneficial? or just continue to leave it alone as Ken suggested above. I did notice some green beetles crawling up and down the damaged area last summer.

We have the same thing around my house. We received over a foot and a half of rain in a week and a half. Now redbuds, dogwoods, white and red oaks (I've observed around 10 species around here), yellowood, maples (silver, red, and sugar), sycamore and finally cottonwood all have black and/or yellow/brown on the leaves killing some leaves outright. Now that the rain has stopped and it has been near 90 the last two days, the damage seems to have come to a stop. Perfect conditions for fungus to attack wet and cool but not cold or hot when the spotting began. Trees are used to this especially if it is isolated and short in duration. If your trees are otherwise healthy, they should re leaf. Of course pics will help the experts ID the pest and it might be worse that I mentioned. Have you noticed any other trees doing this in your neighborhood.

veinnalewis, Just wondering how your tree is doing. I was searching on trunk disease of a red oak and found your post and pictures. I have had a very similar thing happen, in short I live in N. TX moved into our house in 2003 and planted trees both live and red oaks. In 2009 all three red oaks had the same thing happen very similar to your pictures and got much worse where we lost one of the three trees. The other two are still here but show a lot of damage. We were told the same thing, paint the area and peel bark off, that Japanese boar beetle was to blame taking advantage of a weak tree. Sad to say I think that was the worst advice, the paint actually suffocated the damaged area making things worse. I'm not an expert but trying my best over the last 10+years to save my red oaks from this and what I have learned was the in the very hard way. Final decision is that that year along with prior years was a very hot and dry summer and the soft young bark was burnt from the late evening setting sun damaging it (very quickly) to the point where the core was showing and there were small holes from a beetle attack. The paint was prolonging the trees natural ability to try and help itself heal, the past four years I have had a board shading the injured side of the trees from the sun setting, don't peel any of the bark off until it falls off naturally, because peeling it off too soon exposes the soft bark to insects and beetles again causing further damage. I have fertilized in the spring, made sure they get plenty of water especially in the summer, and monitored them in the evening to make sure no direct sun was on the injured area and so far this has worked. I hope you get my message and I would like an update as to how your tree is doing. I wanted to try and help someone else with this terrible problem for the red oak trees, by far my favorite kind of tree.