why do hogs rub trees?

Been seeing a lot of mud rubs on trees and I was just wondering what's the reason for them is it territorial or just to get the mud off?

Some of it is probably marking territory. Most is simply scratching!

Most is scratching but when you find one that also has cuts up and down from tusks that is a territory marking.

I am just going off what I have seen in the woods without any information to back it. Lol

If it is a pine or cedar they are trying to get the sap on their hide for bugs. They love to get creosote off telephone poles.

What they said. They'll cake mud on real good to help with parasites, and they rub trees cause it feels good and also helps with scent marking.