as a kid I remember thinking the Swiss Family Robinson's treehouse was awesome..well here's the modern version - complete with running water, zip lines, bridges and gathering places. Check out the articles for the rest of the pictures - you have to see the rest of the pictures to get the full idea. http://www.businessinsider.com/finca-bellavista-2012-7?op=1#ixzz22CMNYTNL
I think that excess weight so high in the canopy could lead to unrest in the forest. And in the 1st picture, the 3rd elm tree from the right looks like it could have trouble.
They have a botanist inspect the trees and tell them which ones are good to build on. Most of the buildings are built with a mix of trees and stilts, so all the weight is not really on the trees.