Using invasive trees to make jet fuel

July 21, 2013, Central Valley Business Times

U.S. Navy fighter jets may soon fly on tree-fuel. Researchers at the U.S. Department of Agriculture are exploring ways to convert invasive trees such as junipers and pinyon pine trees that are common in the West, into aviation fuel. It’s to be tested by the Navy.

Seen as invasive species, the two types of trees could supply enough biomass to produce millions of gallons of renewable jet fuel, according to preliminary estimates.

Agricultural Research Service scientists at several locations in the West are contributing to the biofuel project called “Accelerated Renewable Jet Fuel (RJF) Supplies from Invasive Woody Species.”

In addition, removing the trees is thought to help restore productive rangeland for livestock and protect critical sagebrush habitat for the western sage grouse and other animals.

“Juniper competes with grass and forbs for water and nutrients, and this leaves bare soil that is vulnerable to erosion,” says ARS scientist Mark Weltz, who works at the Great Basin Rangelands Research Unit in Reno, Nev. “We have also lost habitat for sage grouse and mule deer, and the amount of forage available for cattle has declined as well.”

In Burns, Ore., research leader Tony Svejcar and others will inventory trees available for harvest and biofuel production. This information can also be used to determine optimal locations for restoring wildlife habitat and locations where harvests could adversely impact existing wildlife.

“Our options for controlling juniper expansion are limited,” says Mr. Tony Svejcar, a rangeland scientist at the Eastern Oregon Agricultural Research Center in Burns. “There’s not much of a market for cut juniper, so we usually just cut the trees and leave them where they fall.”

The scientists will also focus on devising plans for harvesting the trees in a sustainable manner. ARS research leader Fred Pierson plans to conduct experimental juniper harvests on a variety of sites in Idaho to observe how the removal affects erosion, and will use the information to model the environmental impacts of large-scale tree harvests.

Much of the harvest planning will be conducted with computer models that have been developed by ARS scientists and their colleagues. David Goodrich, a hydraulic engineer at the ARS Southwest Watershed Research Center in Tucson, Ariz., will fine-tune modeling estimates of watershed-level rainfall runoff and erosion, which will help guide decisions on where to harvest trees.