Employees at Plum Creek Timber Co.’s Columbia Falls sawmill learned last week that their hours will be cut from 40 to 36 hours per week starting Oct. 6.

Tom Ray, Plum Creek’s vice president of northwest resources and manufacturing, blamed the cutback on a shortage of raw logs after a federal court ruling blocked several timber sales on state forest lands.

Ray said Plum Creek had planned to buy logs from several contractors who had agreed to purchase logs from timber sales on the Stillwater State Forest, north of Whitefish.

About 36,000 tons of logs now won’t be coming to the mill this fall, Ray said. The cutback will impact two shifts at the sawmill, which employs 103 workers.

Plum Creek had been purchasing logs from four different sales, Ray said. The company is optimistic the logs can be harvested this winter because the court ruling doesn’t stop winter logging.

The cutback comes on the heels of F.H. Stoltze Land and Lumber Co.’s announcement last month that it would cut hours at its Half Moon sawmill, and that nine to 10 workers would be laid off.

The timber sales were stopped after an Aug. 21 ruling by U.S. District Court Judge Donald Molloy blocked plans to build new logging roads in the Stillwater State Forest.

The ruling came in a case filed in March 2013 by Earthjustice on behalf of the Friends of the Wild Swan, Montana Environmental Information Center and Natural Resources Defense Council.

The conservation groups challenged the U.S. Fish and Wildlife Service’s approval of a 50-year “take” permit and an associated habitat conservation plan that authorized increased road building and logging across 550,000 acres of state lands.

The state’s conservation plan included elimination of the only unroaded grizzly bear habitat area remaining on state lands — a 39,600-acre “core” area composed of several blocks within the Stillwater State Forest. The largest contiguous block is more than 14,000 acres in the center of the forest.

To minimize impacts to grizzly bears, state land managers had proposed imposing seasonal restrictions on road use and logging, particularly in the spring — to create what it called “seasonally secure” conditions.

Molloy, however, concluded that the Fish and Wildlife Service violated the Endangered Species Act because the agency didn’t provide a rational scientific basis for allowing new road-building in the Stillwater Core based on the state’s plan.

“The Service has not rationally justified its finding that the approach under the plan constitutes a complete offset — much less a net benefit — such that additional mitigation measures did not even need to be considered,” Molloy said in his ruling. “Absent independent investigation into the impracticability of greater mitigation measures, the Service’s finding that the plan mitigates take of grizzly bears to the maximum extent practicable is arbitrary and capricious.”

Ray said he recently spoke with state land officials, and the company plans to assist them with possible solutions and advice. Plum Creek owns millions of acres in Montana, much of it grizzly bear habitat.

State land officials meanwhile might take more information back to court to seek a remedy. One misnomer is that the area isn’t roaded — it is, said Sonya Germann, forest management bureau chief for the Department of Natural Resources and Conservation. Those roads are bermed, however. The state’s original plan would have built 19 miles of new road, however, some of which would have been in the grizzly core regions.

The conservation groups also challenged the state’s plan to protect streams for threatened bull trout, but Molloy ruled the state’s bull trout plan was adequate.