Slash to cash?

PRINCETON — Research scientists from the U.S. Forest Service and a private company have teamed up to create equipment that could result in cleaner burning of logging slash piles while producing a soil amendment product.

Forest managers got a glimpse of the CharBoss, a machine built by Air Burner Inc., at the University of Idaho’s Experimental Forest last week. The equipment, which looks something like a high-tech shipping container, works like a giant backyard fire pit. Slash from logging is piled into the CharBoss and ignited.

“As the smoke particles are rising, they encounter an air curtain and they stall under that air curtain for fractions of a second and they reburn,” said company President and CEO Brian O’Connor. “So the air curtain creates basically a secondary burn chamber and that’s why it tends to be very, very clean. Now, if we shut it off right now, it would blow smoke just like any open burning would, right? But you look at it now and it’s crystal clear.”

Most of the company’s products are designed to efficiently burn wood waste while producing less smoke. The CharBoss goes a step further. Working with Forest Service researchers, the company designed it to produce biochar out of what would normally be ashes. Biochar is charcoal used to amend soil.

Debbie Page-Dumroese, a soil scientist at the Forest Service Rocky Mountain Research Station in Moscow, said biochar can help rehabilitate soil at logging sites while sequestering some of the carbon from the wood waste.

“It’s highly porous, so it holds a lot of water. It also has a high exchange capacity, so it holds nutrients and you don’t get as much leaching. Nutrients are bound to this charcoal. It’s kind of like a slow-release fertilizer.”

She said the biochar could be used to loosen compacted soil at log deck sites and on skid roads. O’Connor said there could be a niche market for biochar.

“Right now, it’s selling for $125 a cubic yard. And this will make about 40 gallons of biochar per hour.”

The CharBoss eliminates about 1 ton of wood waste per hour. Some of the company’s bigger machines can go through 16 tons per hour.

There are three CharBoss prototype machines, all owned by the Forest Service. O’Connor hopes to go into production with a series of them at different sizes. He thinks he can sell hundreds.

The Forest Service and Air Burners held a demonstration of the equipment last week that was attended by dozens of people, ranging from private timber land managers, loggers and managers of public forests.

“It has potential to maybe have some applications in areas where we need to dispose of slash near neighbors. It sounds like it does have lower emissions than just traditional burning,” said Trevor Stone, Idaho unit timberlands unit for PotlatchDeltic.

Logging operations create tons of waste wood known as slash. Typically, the slash is pushed into piles, allowed to dry and then burned in the winter or spring when fire danger is low.

“This kind of broadens our opportunities for being able to treat slash at different times of the year, and potentially without creating as much smoke as we would normally with pile burning,” said Robert Keefe, manager of the UI Experimental Forest.

“This is exactly the kind of demonstration that we’d like to do on the experimental forest. The University of Idaho Experimental Forest is really managed for research, teaching and demonstration. And anytime we have a new piece of equipment that’s of interest to our industry — state, private and federal landowners — we try to do an event like this just to show it off and let people see it.”

O’Connor said his company now is working on a burn box with a turbine that creates electricity and can be used to charge battery-operated equipment.

“At night, you bring all your battery-powered vehicles around, plug them in and charge them up. So you’ve taken the waste and you’ve turned it into electricity and stored it in a battery.”

More information about the company and its products is available at airburners.com.

Barker may be contacted at ebarker@lmtribune.com or at (208) 848-2273. Follow him on Twitter @ezebarker.