Perhaps they grow underground more commonly then above?
Rollback Post to RevisionRollBack
~Please click these Eggs, you should try out MagiStream~ “When you cut pieces out of the truth to avoid looking like a fool you end up looking like a moron instead.”
― Robin Hobb, Assassin's Apprentice
I think the pillar is going to be just another different type of wood, and the "leaves" are going to have a chance of dropping saplings and/or mushrooms. You will only be able to grow theese type of "trees" in light levels lower than 7.
I suspect the existing mushrooms are going to *be* the 'saplings' for these. If so, it will definitely force a redesign of mushroom farms!
I really hope these grow primarily underground or in the Nether.