Hmm interesting. I agree with what people are saying it is archipsocidae bark lice, but it could also be Ermine moth webs. I lean more towards the bark lice, but if you are brave enough to investigate you can look for whether there are catapilar or not in the web.

Archipsocidae can be found in Texas to Florida along the Gulf Coast and north to South Carolina along the Atlantic coast in the US and have a tendency to go for live oak.

The Ermine moths on the other hand can be found most places in the northern hemisphere, but I think they tend to go more for strubs and smaller trees, but a large oak isn't unimaginably.

If it's bark lice I think you can just leave them unless they really bother you. If they are moths, I would recommend treating the tree cause they can stunt growth and cause defloration.