Fab Tree Hab low-impact house takes the term 'treehouse' literally

Money doesn't grow on trees, but this house does. It's not really built, it's grown over five years, with its supporting trees trained to grow in the right direction with scaffolding holding it in place. Its creators, architects Mitchell Joachim and Javier Arbona, teamed up with environmental engineer Lara Greden to figure out how to grow vines, roots and trees to create a framework for a house that's perfectly normal inside.

After the shell of the house is grown in the right shape, the walls are filled in with mud and plaster, and then the insides of the house are constructed using conventional building materials. The only sticking point so far is the windows, and the designers are now experimenting with transparent plastic materials made of soy they hope will expand as the house's supporting trees grow. Take a video walk-through of the house on the next page.

This modernized grass hut is bristling with green tech, run by solar power, and using a septic system that collects rainwater and then treats and recycles it. Still in the concept phase, the design has no takers so far, but the architects say they're close to their first sale.