Building straight into the sky is easy. You'd be amazed at how earthquake-proof skyscrapers are with modern technology. You want a challenge? Build in a city where you're required to post notice any time you cut down a tree on your own property.
That's because you're talking about one of the most beautiful cities in the world (despite the attempts of some people to decry otherwise) and, as expressed through the will of its electorate, intends to stay that way. It's also a city that's keenly aware of ecosystem dynamics and environmental issues generally, and the effect of removing that removing certain kinds of trees (for example, trees of significant age, size, and/or foliage) -- particularly if they're close to the street -- can have on the neighborhood well beyond the tiny confines of your own property.
If you want to live in a city that couldn't begin to give a flying F* about trees, or anything else green, for most of its history -- and has the corresponding development footprint and visual character to show for it -- try moving to San Jose.