Three conservation groups are defending plans to log, thin or control burn more than 20,000 fire-prone acres of federal forest in north-central Washington, urging a judge to dismiss a lawsuit by the Alliance for the Wild Rockies that seeks to stop the project.

The alliance, based in Missoula, Mont., alleges the work will harm wildlife and fish and make the Okanogan-Wenatchee National Forest a tree farm. The claims are bogus, say conservationists who helped shape the plan.

“A lot of good work went into this, and we stand behind it,” Conservation Northwest spokesman Chase Gunnell said.

“We feel it’s a model outcome for collaboration,” he said. “Then you have a group from 300 miles away who objects and takes it to court.”

The alliance is seeking an order from U.S. District Judge Salvador Mendoza Jr. in Spokane to stop the project. A hearing is set for November.

The group’s executive director, Michael Garrity, called the conservation organizations supporting the project “pseudo environmental groups.” He said the project’s real goal was to turn the national forest into a tree farm for timber companies.

He disputed the idea that the project will make fires less severe. “The only way to stop fires in a forest is to pave it over,” he said in an interview.

Garrity said the Forest Service should have consulted with U.S. Fish and Wildlife Service about whether project will disturb grizzly bear habitat.

In court documents, the Forest Service notes that grizzly bears have not been seen in the national forest for decades. The agency says it assessed the consequences of the project and found no significant environmental harm.

The Okanogan-Wenatchee National Forest covers 4 million acres. The region has been hard hit by wildfires. The Cold Springs Fire in September burned almost 190,000 acres near Omak in Okanogan County.

In response to wildfires, insects, diseases and floods, the Central Washington Forest Health Collaborative was formed in 2013. Its membership includes public officials, conservationists, tribal leaders and community members.

The collaborative helped shape the plan to commercially log about 1,800 acres, non-commercially thin 8,300 acres and control burn 10,200 acres in Okanogan County.

Wildfires have become unnaturally severe after years of fire suppression, and opening the forest canopy will reduce their intensity, according to project supporters.

Other elements of the plan include removing 23 culverts and 34 miles of roads, and improving beaver and fish habitat. In all, the project will include 50,000 acres of forest.

In court documents, the alliance calls the extent of the proposed logging “massive” and that opening up the forest will cause sediment to run into streams, clouding the water, raising temperatures and harming fish.

The Wilderness Society and the Methow Valley Citizens Council joined Conservation Northwest in submitting a brief defending the plan, saying the region will need more science-based collaborations to adapt to climate change.

The groups said it’s wrong to call it a “logging project,” since only a fraction of the land will be logged. Timber sales will finance some of the work, they note.

Other briefs asking Mendoza to dismiss the suit have come from Chelan County, the Yakama Nation and members of the forest health collaborative.

The Yakama Nation says work in the forest’s watersheds affects its fishing treaty rights. The project, according to the tribe, “equals the Yakama Nation’s most ambitious restoration projects in streams of this size.”