This looks like normal bark development for Sweetgum; they can develop quite prominent corky bark ridges as they mature, though young trees seem to have more abundant bark ridges than older trees (or older wood, at least). Examples can be viewed in the linked photo gallery. Most of this is likely genetic and particular to the individual tree, and some might have environmental triggers, though we are not certain about the nuances of bark development in this case. The growths on the bark do not look like insect eggs or scale insects, especially if they do not easily scrape off with a fingernail.

Miri

You're welcome.