Dear Pat,
       From your photos it appears that you have some sort of lichen on your tree.  Most of the lichens while unsightly do not cause hare to the tree.  We are including a link to more detail information below.
Non harmful tree conditions | UMN Extension
Lichen, Algae, and Moss on Trees | University of Maryland Extension (umd.edu)

Thank you so much for contacting us and if we can be of further assistance please contact us at the information below.
Thank you
Lynn 
Master Gardener Volunteer
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From the descriptions in the article you sent me I don’t think that’s what I have. Lechins aren’t hard and crusty like this. This one is about 1/2” thick and very, very hard and crusty. To break off pieces of it I have to actually get a hammer and screwdriver to pry it off near the bottom.

Dear Pat,
     That is a ponderance.  We are going to recommend that you send samples to the plant diagnostic clinic they should be able to id what is wrong with your tree. We are sending you information to the plant diagnostic clinic, which can exam tissue from your tree and evaluate. Send as much tissue as possible and time it so that it will arrive at the clinic on Tuesday, Wednesday or Thursday so the samples will be their freshest.
Texas Plant Disease Diagnostic Lab | Texas A&M AgriLife Extension Service (tamu.edu)
D1178 – General Diagnostic Form and Instructions | Texas Plant Disease Diagnostic Lab (tamu.edu)

If we can be of further assistance, please contact us at the information below.

Thank you
Lynn and Kathy
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Great! Thank you so much. I will do just that.

Howdy Pat! (and Howdy Lynn!)

Let me jump in here and add another thought if I may. Below I have attached a link to a resource for Ganoderma Root Rot. Judging from your images and description this is different from our earlier diagnosis of lichen. The shelf mushrooms of Ganoderma are hard, almost woody. Please cross reference images found for this online and see if it matches up. Note, there are several species of Ganoderma and each one affects different tree species differently, as in the coloration and shape of the mushroom bracts will differ. Ultimately if this is what's going on, the outcome is similar, typically not treatable. 



Ganoderma rot | Texas Plant Disease Diagnostic Lab (tamu.edu)

Upon researching if you find this is indeed our "beast", reach out to the Help Desk and Lynn or one of her fine team members can guide your next steps. 



Ask a Master Gardener - Fort Bend County Master Gardeners (fbmg.org)

Hope this helps. Have a great day and a fun and safe Independence Day holiday. Take care,

Boone

Thank you very much. I will definitely research this.
Pat Burnette