Ivy can damage a tree when it gets thick enough; however, one year of growth probably isn’t enough to hurt the tree yet.  The ivy should be carefully removed from the tree, but don’t rip it off.  The roots have attached to the bark and this may cause you may remove the bark if pulled to hard. Cut the base of the ivy climbing the tree and cut off as much as possible from the trunk.  The winter may kill the rest of the ivy on the trunk, but if it doesn’t carefully use weed killer.