A 900-acre logging project in Southern Oregon must be enjoined because its impact on great gray owls wasn’t properly evaluated, according to a federal judge.

U.S. District Judge Ann Aiken has ruled the U.S. Bureau of Land Management’s approval of the Griffin Half Moon project was “arbitrary and capricious,” which means logging cannot proceed until the plan is revised.

Aiken has adopted a federal magistrate judge’s recommendation to block the project for violating the National Environmental Policy Act, dismissing the BLM’s objections that the case was analyzed under the wrong legal standards.

In 2018, the federal government authorized the vegetation management project, which is east of Ashland, Ore., to generate timber while creating young forest stands and reducing the forest’s vulnerability to wildfire, disease and insects.

The Klamath-Siskiyou Wildlands Center, Oregon Wild, Cascadia Wildlands and the Soda Mountain Wilderness Council filed a lawsuit the following year, claiming the project would harm the Pacific fisher, which requires dense canopy closure, and the great gray owl, which relies on older forest stands.

Earlier this year, U.S. Magistrate Judge Mark Clarke in Medford, Ore., agreed with the environmental plaintiffs regarding the great gray owl but rejected their arguments about the Pacific fisher, a carnivore in the same family as the weasel.

A broader “resource management plan” for 1.2 million acres of BLM property in the region dedicates “a large network of reserve lands for great gray owls” and expects their habitat to improve, but the agency didn’t analyze the project’s particular effects on the species, Clarke said.

The agency’s decision record “contains no meeting notes, memos, reports or other documentation” that it specifically considered site-specific impacts on the owls, he said.

“Because the BLM failed to consider an important aspect of the problem of threats to great gray owls, its approval of the project was arbitrary and capricious,” the judge said.

As for the Pacific fisher, the magistrate judge determined that BLM’s “consideration of impacts” to the species was “clearly and separately identified” in the agency’s environmental assessment of the project, the judge said.

The BLM’s analysis of the project’s impacts on the Northern spotted owl, a threatened species, also “properly functions as a proxy” for the effects on the Pacific fisher, he said.

Under the plan approved by BLM, the project was expected to generate 9 million board-feet of timber. The Murphy Co., a timber company that intervened in the case, said those logs were critical for three of its mills that employ 600 people.

During oral arguments last year, an attorney for the BLM argued that neither the great gray owl nor the Pacific fisher are protected under the Endangered Species Act.

Nonetheless, the effects of logging on their populations were still considered under the region’s 2016 resource management plan, said Sean Martin, the agency’s attorney.

“NEPA does not require every single effect on every single species to be analyzed on every single acre,” he said.

Susan Jane Brown, an attorney for the environmental nonprofits, argued that BLM was required to conduct an updated examination instead of relying on the resource management plan.

“We can’t know if there were changed circumstances since 2016 because the BLM never actually looked,” she said.