Activists who oppose a U.S. Forest Service plan to thin 1,800 acres near Santa Fe have asked a federal judge to delay work scheduled to begin in October in the Hyde Memorial State Park and Pacheco Canyon areas until their legal challenge has been decided.

Wild Watershed and the Multiple Chemical Sensitivities Task Force — groups that have a pending lawsuit challenging the legality of the Forest Service’s plans — filed an application for preliminary injunction Tuesday in the U.S. District Court in Albuquerque, which, if granted, could delay the work for 60 days or longer.

“That will stop any activity this fall,” said Wild Watershed Director Sam Hitt. “Any burning or tree cutting or road construction.”

The groups, along with two individuals, filed a lawsuit in May challenging plans to thin thousands of acres in the Sangre de Cristo Mountains in coming years on the basis that the planned thinning violates federal law because the Forest Service did not complete an environmental impact statement to examine the projects’ effects.

Hitt said the work poised to start in October is among the most destructive of the proposed projects and would include cutting trees on about 300 acres adjacent to the Black Canyon Campground and more in the Pacheco Canyon area about five miles north.

“They will stage all this activity from the campground, and it would be closed,” Hitt said. “And there would be bulldozers and masticators [machines that chew up trees], and lots of [all-terrain vehicles] and of course chain saws. So this is a large operation, probably the largest in the Santa Fe area in many years.”

Santa Fe National Forest spokesman Bruce Hill said Tuesday he hadn’t read the lawsuit yet and couldn’t comment specifically on the pending litigation even if he had. “But our plan is to continue to do work in the Pacheco Canyon and Hyde Park areas that we had planned,” he said.

“We are not allowed to speak about specific projects if they are in litigation,” Hill said, adding that the benefits of prescribed burning and thinning are “well grounded in science.”

Such projects are generally aimed at protecting watersheds and other “values at risk,” such as homes, he said.

Hitt says he and his co-plaintiffs disagree that the proposed burning and thinning efforts are the best way to prevent fires in the target areas, which he said are largely “roadless, wilderness quality” forests.

“Our plan is … reduce the fuel around people’s homes instead of going into roadless areas and and doing significant harm,” Hitt said.