While an all-biofuel economy is a nice notion, we often overlook the fact that biofuel sources, while renewable, are limited in their supplies just like fossil fuels. When you get down to the economics of it, there are still limited biofuel stocks to go around at any given time, and that can create economic pressures that are decidedly undesirable. So a group of Manchester, UK, researchers have identified the specific genes that make plants grow thicker in hopes of juicing trees and other plants species to produce more biomass.