I thought the same things as you, but then, im Seoul, I've seen plenty of rooftop gardens (which include trees as well, obviously), so maybe they found a way for it to actually work... But I bet the maintaince must be costly...

Not just from the standpoint of what trees can do to a building but the effect on the growing trees, this can be problematic. How much sunlight would the trees receive on the north facing side for healthy photosynthesis, soil compaction in potted plants leads to poor root systems, trees would end up leaning out toward the light as their tops got near the next floor up, exposure to wind (unprotected as plants close to the ground and/or surrounded by other trees) can weaken and stress the trees and all trees have a limited lifespan - who's going to remove dead or dying trees and replace them. I'm writing as someone very knowledgeable about botany and these are only a few of the more obvious problems. Such a building might look good for a few years but it wouldn't last long.

I'm sure they have considered all of this before giving it the go ahead. Not much different than most roof top penthouses that hold large enough trees. In which case, will not grow more than the soil allows. As they appear to be imbedded in a concrete enclosed section. I personally love it! Though wonder how much the maintenance fees are? In fact, I wonder how much these units actually cost?

Since two 112m towers already exist...yes it's realistic to go 5m further

At first I was thinking: "I want to live in such a place". Then I looked at the pictures and like you I started to ask myself questions. Now I think: "I would never live in such a place". I prefer to go live in the forest, this building brings too much questions even if I'm sure he thought about all this.

I'm sure there is some kind of barrier to prevent that. Maybe research it.

Yeah. Jakub, you're right. I was talking with a contractor once who said far too many architects lack the concept of what makes a design not just interesting but practical. I've read too about some big name famous architects whose buildings have a lot of problems.

Why not both? :) Designer = Engineer or close co-op