Practical considerations aside, it intuitively seems like making green covered skyscrapers like this can actually increase the primary productivity of a given g

Practical considerations aside, it intuitively seems like making green covered skyscrapers like this can actually increase the primary productivity of a given ground area. In a typical dense forest, plants at the top of the canopy are probably not efficiently using all of the light they absorb, and much is lost to branches. Given how many plants can thrive without any direct sunlight, just having sunlight for half the day from an angle (a plant on one of the balconies) is probably forcing more efficiency and growth out of the plant relative to the amount of light energy it receives. I suppose if the ground was covered in skyscrapers of comparable height, the effect would be more or less neutralized by the shade from neighboring buildings.