Don't trees need like, light, in order to stimulate needle production? I don't have trouble believing that you could get something to sprout in your lungs, (nice moist place after all,) but to get a tree to start to put on needles and stuff, it would have had to break the surface of the ground, notice the light, and then it would put on needles to get the photosynthesis going. No light = no needles, it will still think it is underground and it would grow stem instead.
And since it is pretty dang dark in the lungs, I'm going have to call this fake.
I worked for the Navy for a summer and one of their propaganda/safety brochures detailed what would happen if you didn't wear safety goggles... a fucking tree seedling would embed itself in your EYE and would grow into a little tree. It came with a ghastly picture. Stupid Navy.
And since it is pretty dang dark in the lungs, I'm going have to call this fake.