Using the 3rd half of my brain

 

It doesn’t take much effort for the sun to stretch a tree’s shadow to twice its length, or longer.  Therefore, it would make sense to use tree shadows to build houses.  Each tree would yield at least double the amount of building material.  We would no longer be depleting our forests simply to construct subdivisions.

We just need to think back to the time we would create dogs, rabbits and crocodiles on the wall for our children.  We’ve always had the technology.