The fall has not deterred this cub's love of climbing. His/her mother is a young sow who occupies the territory of a longtime Yellowstone favorite: Rosie. Rosie has not been seen this year and is presumed dead. The park rangers believe that this sow is Rosie's daughter, because she occupies the same territory, and "acts like Rosie". Having never seen Rosie, I would not presume to disagree. They are also certain that this cub is her first.
What I have observed beyond any question is that that this sow absolutely adores her cub. She constantly interrupts her feeding to nuzzle him. Since he has no siblings, she fills the role of playmate as well. Here, she has climbed up the dead snag apparently to rub noses, and for no other reason that I can see.