Hikers climbing above the tree line in Wyoming’s Medicine Bow National Forest nowadays encounter a startling landscape: the gray skeletons of millions of dead lodgepole pine.

It’s on these slopes of the Rocky Mountains that the U.S. Forest Service would pioneer a novel approach to rid forests of the detritus from “epidemic levels” of beetle infestations that wiped out 38,000 square miles of trees — an area larger than the state of Maine.

What’s left fuels historic wildfires, prevents wildlife and cattle from finding forage, threatens to topple onto campsites and slows regeneration of trees needed to sustain the beleaguered timber industry.

The plan would allow construction of up to 600 miles of temporary roads to log, thin and set prescribed burns across 850,000 rugged acres from the Colorado-Wyoming border north across the Snowy and Sierra Madre ranges.

The controversial 15-year project, a marked departure from the agency’s historical approach to restoration, is moving forward as President Donald Trump blames the deadliest wildfire in California’s history on “gross mismanagement of the forests” — a widely disputed allegation.

“This is a new way of doing business — it’s unique for us not only in terms of size but the amount of collaboration,” said Melissa Martin, planning and information program manager for Medicine Bow. “This is about providing resiliency for the future, so we don’t wind up in a situation 100 years from now (like) we find ourselves in today.”

That situation is bleak. A generations-old policy of fire suppression and reduced timber harvests caused stressed, overstocked forests that were unable to fend off mountain pine beetles and spruce bark beetles. Both insects bore through bark to lay their eggs, and the larvae that hatch spend the winter in place, emerging only when fully grown to begin the cycle anew the next summer. Their activity severely disrupts a tree’s nutrient system.

Unleashed by drought and warm winters — both tied to climate change — the rice-size insects have attacked huge swaths of the Rockies, Tetons, Cascades and Sierra Nevada since the 1990s.

Nearly half of the lands managed by the U.S. Forest Service, or 81.3 million acres, need attention. Their poor condition, in combination with a succession of wildfire seasons unprecedented in their deadliness and destruction, is forcing a reckoning among federal agencies, environmentalists, timber companies, ranchers, outdoor enthusiasts and local communities.

“Expansive work is needed to reduce fuels and threats from insects and diseases,” wrote Forest Service Chief Vicki Christiansen after Agriculture Secretary Sonny Perdue announced a new management strategy in August.

“Poor conditions demand treatments at a scale that match the immensity of the problem,” she said. “But we can’t do it alone.”

Environmentalists, who have often battled the government on the issue, agree Washington must speed efforts to cull beetle kill in forests up to five times denser than a century ago. Tinder-dry dead trees jeopardize the purity of water supplies for parched cities and the lives and property of millions of people who live in what’s known as the wildland-urban interface — areas prone to wildfires.

“If we are going to have a chance at combating climate change, forests are one of our best tools for mitigation because they sequester carbon,” said Chris Topik, director of the Nature Conservancy’s Restoring America’s Forests initiative. “So it’s vital that we help them to adapt.”

The Trump administration’s shift to decades-long management plans encompassing vast stretches is in stark contrast to the Forest Service’s historical practice of grooming 3,000- to 10,000-acre parcels over a period of months.

In New Mexico, the agency is preparing an environmental report for the 185,586-acre Luna Restoration Project in the Gila National Forest. Work on the 179,054-acre La Garita Hills Restoration Project in Colorado’s Rio Grande National Forest is underway.

The Medicine Bow project would authorize clear-cutting on up to 95,000 acres, selective logging on up to 165,000 acres, and other treatments such as prescribed fire and hand thinning on up to another 100,000 acres. Martin said funding could come from the federal government and other sources.

Not everyone considers the plan a good idea. Some biologists say science doesn’t back up the efficacy of the treatments proposed, particularly logging and the prescribed burns that the Forest Service calls necessary for lodgepole pine to reproduce and more diverse species to take root.

“They say they are going to reduce fuel loads to limit wildfires, and the literature doesn’t support that,” said Daniel Tinker, an associate professor at the University of Wyoming, who has studied the region for 23 years. “We’ve had fires this summer that burned through areas that were clear-cut 15 years ago. Those stands weren’t supposed to burn for 100 years.”

Conservation groups also say the Forest Service truncated scientific review in a rush to meet congressional demands for increased timber production on public lands. For now, the proposal does not specify which parcels would be targeted and where those hundreds of miles of road would be built.

“They are trying to fast-track this,” said Marla Fox, an attorney for WildEarth Guardians. “This is in line with the agency’s shift and approach under the Trump administration to ‘get out the cut,’ which means ‘let’s do some logging in the name of restoration.’?”

Indeed, the national harvest in fiscal 2018 was expected to be the biggest in 20 years, the Forest Service’s Christiansen told the Senate Committee on Energy and Natural Resources in June. Supporting the timber industry is among the Medicine Bow plan’s goals, Martin said, but she added, “I wouldn’t say that timber interest takes precedent over any other interest.”

As many as 180 cattle and sheep ranches use the forest for grazing, according to Jim Magagna, executive vice president of the Wyoming Stock Growers Association, which supports the project. Dead trees cost ranchers money and time when they fall and knock down fences.

Some pushback is internal. A group of Forest Service employees is skeptical the agency can pull off an undertaking of this size, citing the funding and infrastructure challenges that have slowed a massive restoration initiative in Arizona.

That 2.4 million-acre partnership is harvesting ponderosa pine across four national forests. Only about 106,000 acres were treated between fiscal 2010 and fiscal 2017.