After four years of battling pine beetles by cutting down infested trees, Custer State Park is trying a new tactic: relocating the beetles via helicopter.

A private contractor hired by Custer State Park on Tuesday began using a helicopter to haul out infested trees that are being cut down.

The idea is to salvage the timber from the newly infested trees and to move the beetles occupying the trees completely out of the park.

For the past four years, crews have cut down bug-infested trees and done other thinning to try to slow the spread of mountain pine beetles in the Little Devils Tower and Cathedral Spires area east of Sylvan Lake. That area, in the northwest corner of Custer State Park, lies just below the Black Elk Wilderness, which has been heavily infested with pine beetles.

The main beetle infestation in the park keeps happening in that Little Devils Tower to Cathedral Spires region, Custer State Park senior forester Adam Gahagan said.

Gahagan said he assumes many of the beetles attacking that part of the park are coming from the Black Elk, because that’s where the infestation started. The Black Elk is managed by the U.S. Forest Service.

“We, of course, have our own interior population of beetles. It’s not just their fault,” Gahagan said.

Until this year, crews have cut down infested trees, then into 2-foot chunks lying on the ground.

That technique kills about 85 percent of the beetles, according to John Ball, a professor of forestry at South Dakota State University and a forest health specialist for the South Dakota Department of Agriculture.

The felling and chunking helped slow the spread of beetles, Gahagan said. As proof, he pointed to the lack of red tree tops in the big bowl stretching out from the Cathedral Spires parking lot.

However, he said, that lack of red is due mainly to crews cutting down infested trees in that part of the park: 3,500 trees in 2006, 12,000 in 2007 and 21,000 in 2008.

This year, crews marked 18,000 infected trees in the 2,250-acre area.

Ground crews have already cut one-quarter to one-third of the 18,000 trees to be hauled out by helicopter.

The helicopter operated by Timberline Helicopters of Laclede, Idaho, hovers over the steep terrain and drops 100 to 200 feet of cable, which is hooked around downed trees below. The helicopter then is hauling the downed trees to a couple of landings nearby. From there, they will be trucked out to sawmills.

That accomplishes more than just thinning and chunking, Ball explained. Taking a tree out also takes out every beetle burrowed into its bark.

“Any time you can get in there and remove the tree from the site, then you can eliminate 100 percent of the beetles,” Ball said.

The beetles that flew into the trees last summer will die after the tree gets to the sawmill, and the bark is stripped off.

Gahagan cautioned that the trees remaining are still at high risk for beetle infestations.

“It’s buying us time,” he said.

Gahagan said the park will pay the contractor up to $520,000 for its work cutting and removing the infested trees. The company also is getting the value of the wood, estimated at $150,000.

Gahagan said the ground crews and the helicopter could finish the project in six to eight weeks.

Because of crews working in the area, the park has closed two trails to Harney Peak, the trail from Sylvan Lake and the Little Devils Tower Trail.

Gahagan said success of the park’s efforts will be difficult to determine. “Is success not doubling every year?”

“I can’t stand here and say, ‘It’s over, we’ve won,’” he said. “But I would say that it appears that we’re reaching a leveling point.”

But he said many factors are at play, including weather, the park’s thinning and logging efforts, and the reduction in the number of trees available to the beetles.

Soon, there won’t be any more beetles coming from the Black Elk Wilderness because all the trees there will be dead, Gahagan said.

Even though success won’t be total (it’s virtually impossible to wipe out all the beetles), park officials should be able to save some of the forest, Gahagan said.

“I think we are going to be able to say that we maintained and improved the aesthetics up here, and we maintained as much forest cover as we could.”

 

Contact Steve Miller at 394-8415 or steve.miller@rapidcityjournal.com.