I'll blog this with a grain of salt, being suspicious that it may have been manipulated in some fashion. I'm familiar with epiphytes, but this looks to be a conventional fir tree, and there doesn't seem to be enough material at the base to support that degree of growth; it would also require more water than would settle on the branch. The only explanation I can offer is that the deciduous tree is hollow at the top, with enough dirt there to support the growth.
Unless it's a well-differentiated "witches broom." (?)
Found at Bits and Pieces, but the sublink goes to Reddit's homepage, and I haven't found the original.