The webbing on your oak tree is most likely due to the presence of fall webworms - Hyphantria cunea (Drury).

Fall webworms are found in late summer and fall, creating silken nests around leaves at the ends of branches. All feeding occurs within the silken nests. They will feed on almost all shade, fruit, and ornamental trees, but true damage is minimal. Eggs are laid on the undersides of leaves in early to midsummer and hatch in about a week. The caterpillars feed for six weeks before dropping to the ground to pupate. There may be as many as four generations in the South.

Tents may be removed by hand, or an insecticide with residual activity may be applied to foliage and twigs. Chemical treatments work best on the youngest larvae and will not penetrate the nest. Webworms have natural enemies such as birds, stinkbugs, wasps, and flies. Use of Bt is also effective against young larvae. Contact your local Extension office for a list of recommended pesticides; read and follow label instructions. http://entweb.clemson.edu/cuentres/eiis/pdfs/to11.pdf

There is another possible answer. Your description brings to mind a harmless event from the Gulf Coast. Psocids invade in late summer and inhabit the bark of trees. Do not confuse them with webworms. See picture and read detailed article about psochids here:
http://msucares.com/lawn/garden/coast/01/010922.html.