Here is a Holly growing in the fork of a Cedrus libani. About 15' from the ground. I wonder if it has tapped the tree or is just surviving on collected mulch.

Trees can grow in unusual places. Here's one at my neighbor's.
It's a Tsuga heterophylla that was growing from a decayed Pseudotsuga menziesii stump. The stump as all but decayed away, leaving the Hemlock standing on 'legs'.

Awesome. We get a lot of that up in the woods with yellow birch. Seems that species cannot just grow from soil. It has to start on a rotting stump or log, with the same end results. That one's up there though!

+oM

I saw a stack of ash logs that were sprouting. Guess they'd have to be placed on the ground to survive but it shows the nurse log pricipal.

Hemlocks located inside stands of trees often come up on logs, stumps or other trees, the forest floor being less favorable for the seedlings much of the time.

Hollies, Cotoneaster species, tall Oregon grape and other bird-dispersed trees and shrubs are frequent on and beneath other trees in cultivated settings. However, these are not parasites, will always be living off of whatever decayed debris or soil they can get into among the branches or roots of the tree the bird was sitting in when it pooped out the seed.