No, you will never have skyscrapers with trees on them - http://io9.com/no-you-...
"There are plenty of scientific reasons why skyscrapers don’t—and probably won’t—have trees, at least not to the heights which many architects propose. Life sucks up there. For you, for me, for trees, and just about everything else except peregrine falcons. It’s hot, cold, windy, the rain lashes at you, and the snow and sleet pelt you at high velocity. Life for city trees is hard enough on the ground. I can’t imagine what it’s like at 500 feet, where nearly every climate variable is more extreme than at street level." - Kamilah Reed (K. Gill)
They've been pushing this idea for a decade. It makes no sense. - Akiva