> I've been seeing a lot of trees shedding bark this year.

I don't know if this is what you're seeing, but inconsistent cold can cause the bark on trees to crack and pop off. During the warmth of the day (or if a tree gets a lot of direct sun) the sap can begin to flow but then night falls and the sap freezes and expands, pushing the bark off the wood. This is why you'll often see trees that get direct sun be wrapped in white tape/fabric or painted white from ground level up a foot or two.