First off I believe the tree is an oak. Have noticed a couple areas where the bark has appeared to turn milkish white and is quite crumbly and fairly easy to break off. Have had two branches fall during the course of a month. One was wider around than myself the other was maybe 5 inches around. I don't see any of the white around the large break and I'm not sure where the smaller one broke from. I do however see some substance on part of the smaller branch (pic 1).
As far as the location of the areas one is about 5 feet from base and covers an area of about 10 square inches. The other is maybe 15-20 feet up and is a longer strip of 3 feet approximately. I do not see any kind of mushrooms around the base or main trunk though I maybe see one or two small ones growing about a foot or two from base every year or two (Don't remember any this year). Nothing widespread though I know mushrooms are more expansive in the soil than what you see above.
What else might help.. I didn't notice any bark had broken off to expose the tree. There are a few dead limbs but nothing that is directly connected to the trunk, just branches that are off other branches. I will note that what is on the trunk and what is on the branch don't look alike. I would say that what is on the branch appears to be fuzzy like a mold. It also came out of the socket from the main part of the branch easily and there were a few little worms inside. Should note that rainfall is not heavy.
I would try to contact an arborist but there is none in my area. Best I can get are trimmers for limbs. And I'm going to take a guess and say that our Home Depot will just try to sell me something with no real knowledge of whether it would help or not.
Apologize for the image quality. Only have an old ipod touch.
If I can provide anything else please let me know. Can try to take some clearer pictures when sun is out again.
Some context as well. The piece that is on the grass (pic 3) is from the trunk and the strip (pic 2) is so high up I'm not sure if it is the same thing or not but figured to include it anyway.
I'm really hoping that this is treatable and not deadly as I would hate to lose what is my only real source of shade. Not to mention something that has been there before I lived in the house and I hope to still be there after I'm gone.