After feasting on bar-be-que ribs and chicken a few years ago in Austin, it comes as no surprise to me that Texans would find another, equally tasty use for mesquite trees. Right now they're best known as a fuel that imparts smokey flavor to food. But they're also an invasive species that can overtake farmland grazing grasses. Jim Ansley of the Texas Agricultural Experiment Station in College Station is leading a study to take waste mesquite trees and turn them into ethanol. Potentially, dealing with a pest plant could thus become a revenue-generator for farmers.

Ansley suspects that, of the 52 million acres of Texas infested with mesquite, perhaps 20 million are dense enough to harvest economically using such machines. Other countries with vast tracts of ranch lands, such as Australia, might also be able to collect and use mesquite or similar trees in the same way.

The next step, says Ansley, is to calculate more precisely how mesquite harvesting would work. He envisages a network of small refineries taking 10-year-old mesquite wood from surrounding ranch lands within a radius of 30 kilometres, and redistributing the resulting ethanol to mix with gasoline for greener fuel. "I've been amazed at the level of interest," he says. "Every counsellor of the small rural towns in west Texas has been in touch. A lot of them think we've got the refinery there already though."

Mesquite are apparently pretty difficult to remove, so a big part of the effort is finding a way to harvest the material most efficiently, while not damaging the grass or soil underneath. Link to news @ nature.com article