^^I would NEVER use a paper towel on a painted surface. That's a no no.
I would try a clay bar first, then maybe Tarminator or 3M's all purpose cleaner. Use a new micro fiber towel... then throw it away after you are done removing the tree sap.
I have even seen people(detailers) use kerosene fuel as a wheel cleaner, maybe that would work too. ??? But I would be afraid of damaging the paint with kerosene. I think if the clay or 3M cleaner(s) don't work... maybe seek the advice of a pro detailer in your area.