First Step, The Trees of Texas website can help identify your tree.  Or How to identify Ash

Symptoms of an infestation may include any or all the following: dead branches near the top of a tree, leafy shoots sprouting from the trunk, bark splits exposing larval galleries, extensive woodpecker activity, and D‐shaped exit holes.  

Trees infested with Emerald Ash Borer (EAB) may be saved if treated while still healthy. There are many insecticide options available. Contact a certified arborist to help determine which treatment options are available.

Illustration provided by Texas A&M Forest Service