Pine-beetle mitigation means finding a solution to piles of slash

While wood smoke probably remains an unwelcome smell in Larimer County, many forest managers are hoping for a wet winter that will allow for more burning.

Across the state there are more than 170,000 slash piles from forestry operations, and last winter was too warm and dry to burn most of them, said Mike Eckhoff, a PhD candidate in Forest and Rangeland Stewardship at Colorado State University.

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“We need a cold and wet winter,” said Eckhoff, whose specialty is in forest utilization. “Some of these slash piles are just huge.”

Slash is the cut limbs and tops of trees — usually everything but the log and the stump — resulting from forestry operations. With most of western Larimer County now in the midst of pine beetle infestation, there is a great deal of logging going on for pine beetle mitigation and home wildfire defense, and a lot of slash piling up on both public and private lands.

There is also a glut of logs available, which may be causing some of the slash piles to grow even larger, containing logs that in times past would have been used for firewood, wood chips or post and pole material, Eckhoff said. So while slash management is always a difficult part of forest operations, on both public and private lands, it is becoming much bigger issue in Colorado today.

“Some of these slash piles have 8-inch diameter logs,” Eckhoff said.

In Larimer County, there won’t be any shortage of material either.

Last winter about 25,000 piles were burned in Larimer County alone, which translated to about 1,300 acres of slash material, said Arapahoe and Roosevelt National Forests spokeswoman Reghan Cloudman.

“These piles can vary, from 6-foot by 6-foot hand piles to much larger piles from mechanized operations,” Cloudman said. “We don’t pile slash in all operations, usually only when they are close to public access areas.”

On public lands, forest treatments range from very selective hand cutting operations that might take place next to roads and trails, to heavily mechanical operations. One fairly heavy-handed operation – which is much more cost effective than hand cutting – is called machination, in which a machine pretty much just grinds up most of the trees in a selected area.

Machination leaves much of the forest floor covered in the chewed up material, which is larger than wood chips and sometimes piles up a few feet thick. There is considerable debate on how healthy that heavy floor covering is for forest regeneration.

Deep in the forest, loggers often just throw the slash around so that it is distributed across the forest floor, which is called lop and scatter. Another option is chipping the material, which is fairly expensive and also can leave a large amount of material on the forest floor.

So burning is a preferred option, Cloudman said. She said it’s difficult to say from year to year whether all slash piles are getting burned, because they are left to dry for a year or two, possibly longer in wetter climates.

However, there probably is not going to be any shortage of slash on federal lands in Larimer County.

Over the last three years there have been about 14,000 acres of forest logged, primarily to thin out the most dangerous trees left dead and dying by beetle infestation, Cloudman said. Over the next three years, there should be an additional 11,000 acres of forest management.

On private lands slash removal becomes an even a bigger problem, and one few counties have been able to come to solve.

In Larimer County, there is one private slash collection operation for Rist Canyon and Buckhorn residents, a Boulder County operation on the county line near Meeker Park, and Slash Solutions, a for-profit operation started by forest landowners.

Slash Solutions disposes of slash in an air-curtain burner, an expensive piece of machinery that reduces smoke and other emissions. The business, which is pretty much for profit in name only, has been operation for about a year and in the beginning, also burned logs.

This year, most of the logs have been taken and used by Shreiner and Sons in LaPorte for animal bedding, but the slash burning has come under criticism from nearby residents because of the smoke.

Slash Solutions continues to operate under an old license, as the Colorado Department of Public Health and Environment is rewriting regulations that might affect the business. Slash Solutions administrative manager Shirley Pfankuch said she is confident the company is operating in compliance with both the existing regulations and any that might be proffered in the future.

Many private forest owners will seek to burn slash over the winter, said Larimer County Forester Dave Lentz. County permits are required to burn slash piles, but besides countywide bans on open burning, the timing of those burns is largely not controlled.

Lentz said the forest service was able to burn because it was largely logging in higher elevations, where the snow pack was deeper. Private landowners – most of their properties being in lower elevations — had a much harder time finding suitable conditions for burning slash last year.

Lentz said that forest operations taken on a subdivision level appear to have better options for dealing with slash, as the larger scope of operations makes hauling and chipping more financially feasible.

Those larger operations also make beetle control a much better proposition, he said, noting the work that occurred in Cherokee Park over the last two years has resulted in a dramatic decline of infested trees.

“Those people worked (hard) and they’ve pretty much cleared that area of beetles,” he said. “In subdivisions, if they work together, they really can make a difference.”