Thrill-seekers aren't the only ones who ride zip lines in the Black Hills.
Logs ride them, too.
That was the case Thursday, as the high-pitched whine of a motorized pulley-and-cable system overtook the roar of heavy equipment on a rise 400 feet above Dalton Lake. Trees measuring as much as 15 inches in diameter and weighing about 2,500 pounds came zipping up the steep mountainside, attached to the cable.
Soon, the motion reversed and the cable's empty carriage zoomed back down the slope. A lone worker grabbed a smaller cable hanging from the carriage and hooked it around more felled trees. Over and over, the process repeated.
It’s called skyline logging, and it's a special technique for harvesting timber in steep areas. Among 28 logging subcontractors who work with Black Hills-area sawmill company Neiman Enterprises, only one, Jeff Gamet Logging, does skyline work.
It’s a more expensive way to harvest timber, but Derek Larsen, of Neiman Enterprises, said skyline logging is good for the long-term productivity of the forest. He said neglecting steeper slopes from logging can leave behind denser tree stands and undergrowth that mountain pine beetles and wildfires thrive on.
“With skyline logging, you’re not leaving pockets behind to breed those bug epidemics or large fires,” Larsen said.
The skyline logging above Dalton Lake — in the Nemo area about 25 miles northwest of Rapid City — began last month and will continue for at least a couple of weeks. Logging crews started by cutting down select trees on the slope, with a machine known as a Timbco and also by hand with chainsaws. A Timbco is a track-driven piece of equipment with a cutter arm.
To get the logs off the slope, a machine called an escaliner was taken to the top of the mountain. The machine looks like an excavator with a tower attached to the arm and a loop of heavy metal cable strung through the tower.
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The escaliner's cable is tethered to a large tree at the bottom of the slope, as far as 1,200 feet down. The escaliner powers the cable around pulleys, and a worker known as a choker-setter connects logs to the cable.
At the top of the slope, another machine strips the logs of branches and piles them to be hauled away by truck to Neiman Enterprises sawmills in Spearfish or Hulett, Wyo.
It takes only four or five people to run the operation. By the time it's finished, the loggers will have pulled perhaps 25 truckloads of timber up the slope, from an area spanning about 25 acres.
Rather than clear-cutting, the loggers take only those trees marked with blue paint by the Forest Service, leaving much of the mountainside forested. Jami Morrison, a timber sale administrator for the Black Hills National Forest, said many users of the Dalton Lake campground and picnic area probably will not notice that the slope above the north shore of the lake has been logged.
Morrison said skyline logging opportunities in the Black Hills are limited, partly because it's difficult to find areas where trucks can access the mountaintops and ridge lines where skyline logging is useful. In the Dalton Lake area, some decades-old logging trails and roads helped provide that access.
It's difficult to justify the building of new roads for skyline logging, Morrison said, because the relatively small amount of timber pulled from a skyline operation might not justify the expense of building the roads.
But the Forest Service still tries to accommodate a skyline operation every logging season. And even though it may look complex, it’s based on a simple concept.
“It’s like a zip line that you ride along,” Morrison said. “It’s the same principle.”