Here's what it says in the library article on driftwood.
"Quite often after driftwood is added to an aquarium, a white almost transparent fuzz will grow on it. This fuzz can appear several weeks to several months after the driftwood is added to the aquarium. Popular thinking is this fuzz is either a fungus or a mold. Either way it's harmless, unfortunately it's not pleasing to look at. Some people have had luck just brushing it off. Others have had luck by introducing algae eating fish, as they will actually eat it. Neither technique will guarantee preventing this fuzz from recurring. The important thing is to have faith, as it will eventually disappear."