Three conservation groups filed a lawsuit Friday against the U.S. Forest Service in another attempt to stop the controversial Big Thorne timber sale.

The Big Thorne sale was approved by the USFS last year and promptly appealed by concerned groups and individuals, triggering a year of additional investigation on the part of the service. But the USFS announced last week it is upholding its original decision, allowing for harvest from more than 6,000 acres of old-growth and 2,000 acres of young-growth timber near Thorne Bay and Coffman Cove on Prince of Wales Island. Supporters of the sale hope it will reinvigorate the region’s timber industry.

It’s the old growth acreage the conservation groups are aiming to protect. The Southeast Alaska Conservation Council, the Sierra Club and the Alaska Wilderness League are the three plaintiffs listed on a complaint filed in U.S. district court for Alaska by nonprofit environmental law organization Earthjustice against the USFS, the U.S. Department of Agriculture, Regional Forester Beth Pendleton and Tongass National Forest supervisor Forrest Cole.

SEACC said the Big Thorne sale is at odds with its work to promote a “local wood economy” and support local fishing and tourism industries. The organization, and others, said the sale will also diminish the area’s deer habitat.

“At issue with the Big Thorne sale is the inflated volume of old growth logging, up to 50 percent of which the Forest Service allows to be shipped overseas as round log exports,” a release from SEACC stated.

“Big Thorne will export long-term jobs for short-term profits, and do so at a completely unsustainable rate,” SEACC Executive Director Malena Marvin said in the release. “That’s not progress.”

The organization has been asking the USFS to look to smaller sales and “micro sales” that “spread logging out over decades while making wood accessible for local manufacturers that can’t afford mega sales like Big Thorne,” the release stated.

“We want to increase the number of local jobs per log cut on the Tongass, and are working to keep forestry dollars in our communities,” Marvin said.

Earthjustice attorney Tom Waldo said in a news release that large projects like Big Thorne “compromises the environmental and economic viability of the Tongass.”

The sale would produce 116 million board feet of timber.

The three conservation groups, along with the Natural Resources Defense Council, are plaintiffs in a second lawsuit brought by Earthjustice against the USFS over the forest-wide Tongass Land Management Plan. The service is attempting to adapt the plan with the help of a new Tongass Advisory Committee, and plans to transition timber harvest from old growth to new growth over the next decade. But Earthjustice said in a release the existing plan “fails to preserve the old growth trees that provide crucial habitat to numerous species including the Sitka black-tailed deer and the Alexander Archipelago wolf, which is currently being considered for Endangered Species Act listing due in large part to the Forest Service’s failure to prevent unsustainable logging of old growth forests.”

“The U.S. Department of Agriculture has announced plans to transition out of old growth logging in the Tongass, but massive old growth sales like Big Thorne… are contrary to achieving this goal,” the release stated.

U.S. Sen. Lisa Murkowski voiced “guarded optimism” about the “already-overdue” sale and chided conservation groups “determined to stop all responsible timber harvests” in a Friday statement.

“I am disappointed that the Forest Service has reduced the first sale from the Big Thorne project in the face of opposition from the environmental community,” she said in the release. “The Big Thorne project is key to returning the Tongass to a working and healthy forest, and to ensuring that the timber mills in Southeast survive.”

The “use of the Endangered Species Act as a cudgel to threaten legal action against every management decision” slows progress and is harmful to the forest and the economy, she said.

“I expect the Forest Service to stand up and defend its decisions and not be cowed by threats to tie up the sale in the Ninth Circuit Court,” Murkowski said.

She said the first sale of the project is scheduled to be awarded at the end of next month.

“It is vital that the Forest Service move heaven and earth to award the sale this September,” she said. “The economic future of our timber mills and good paying timber jobs in Southeast Alaska are dependent on it.”