I find it kind of odd that a USFS campground has a host! I've never seen any hosts at the USFS "campgrounds" up here.
With that being said at about every USFS spot that I've been to I've seen left over firewood that wasn't used by the previous campers. I always make it a point to at least leave one or two good logs if I have some left for the next campers just in case they forgot to bring some. Kind of a pay-it-forward deal. It really helped me out once when I forgot the bin of wood in the garage and didn't even realize it until that night when we wanted to cook dinner!