Greetings Tina:
Thank you for your question; however, I need a lot more information to make an educated guess regarding the demise of this tree (species, age of tree, site, history, vigor, construction, soils, pH, fertility, weather, insects, disease, soil moisture, etc.).
With that said, I strongly suggest you contact your local TX Extension office or your local Texas Forest Service office for on-site assistance with this question.
Best of luck!