Knowing how trees grow leads you to the conclusion that this is immediately a fake story.

Trees grow from root and shoot tips, and they also increase in girth. This explains why your childhood swing doesn't get higher as the years go by, and why the rope sometimes gets engulfed by the increasing diameter of the branch.

That bike was deliberately tied up or thrown up a tree. Maybe to hide it idk. But it definitely wasn't left leaning against the tree at ground hight by a child. It's just not how trees grow.