Last month, Alaska Airlines completed a historic cross-country flight from its hub in Seattle (SEA) to Washington, D.C. (DCA), with a 20 percent sustainable biofuel blend.

The fuel was produced with the help of the Northwest Advanced Renewables Alliance (NARA), which crafted the alternative jet fuel with leftover limbs and branches from the harvesting of managed forests. The industry-first fuel is chemically indistinguishable from regular jet fuel.

Alaska Airlines says if it can replace one-fifth of its entire supply with biofuel, it could reduce greenhouse gas emissions by as much as 142,000 metric tons of carbon dioxide — the equivalent of taking around 30,000 cars off the road for a year.

“This latest milestone in Alaska’s efforts to promote sustainable biofuels is especially exciting since it is uniquely sourced from the forest residuals in the Pacific Northwest,” said Joe Sprague, senior vice president of communications and external relations, Alaska Airlines, in a statement. “NARA’s accomplishments and the investment of the U.S. Department of Agriculture provide another key in helping Alaska Airlines and the aviation industry reduce its carbon footprint and dependency on fossil fuels.”

The flight comes after a pair of Alaska Airlines flights in June fueled with a blend of biofuel from non-edible, sustainable corn.