Slash-Burning in the North Cowichan Forest

January 20, 2019

Definition of slash-burning: the burning of logging debris that occurs every fall and winter to reduce the risk of wildfires

Why is slash-burning a problem?: Opposition to slash-burning is growing within the forest sector. The fires are a major contributor to B.C.'s greenhouse gas emissions.  In 2012, slash burning accounted for 13 per cent of the province's total greenhouse gas emissions, or  eight megatons of carbon dioxide into the atmosphere, according to B.C.'s 2016 greenhouse gas inventory. B.C. Forests Minister Doug Donaldson said the government would look at applying carbon tax on slash burning "in the next couple of years."

Quotes from the CVRD Open Burning Brochure:

"Smoke particulates from burning are considered the greatest air pollution problem in British Columbia."

"Wood smoke contains highly toxic gases such as carbon monoxide, nitrogen oxides, dioxins and furans."

"Wood smoke worsens pre-existing heart and respiratory diseases, especially in pre-school aged children and the elderly."

"Dioxins and furans released during burning eventually settle on crops and in lakes and streams. These chemicals will enter the food chain and end up in our food!"

Locally, this is a going to be a hot topic - given the large scale slash-burning that is about to start in Maple Bay.

The picture above shows one of the 14+ slash piles getting ready for burning at the new Genoa Reach Estate development in Maple Bay.  The developers have clear-cut approx. 70 acres of forest. They chopped some of the debris into fire logs and some was chipped into large piles. What remains now needs to be burned.

The North Cowichan Open Fire Regulations state that: Category 3 burns (fires larger than 2m high by 3m wide or where multiple piles are being burned concurrently, typically to burn debris from land clearing or development) are allowed outside the urban containment boundary only in conjunction with an air curtain burner.

Open Burning of Landclearing Debris: Information and Alternatives (CVRD) states:
Landclearing debris should be chipped, ground and reused. If no suitable alternatives are available, landclearing debris may be burned ONLY with the use of an air curtain or trench burner.

What is an Air Curtain Burner?

The red containers above are Air Curtain Burners

Air Curtain Burners, also called Air Curtain Incinerators or FireBoxes were designed principally as a pollution control device for open burning. The primary objective of an air curtain machine is to reduce the particulate matter (PM), or smoke, which results from burning clean wood waste. Using a technology  called "air curtain," the smoke particles are trapped and reburned, reducing them to an acceptable limit per U.S. EPA guidelines.

Clean wood waste is loaded into the FireBox, and an accelerant such as diesel fuel is used to ignite the wood waste, just as you would start a campfire or open burn pile. The air curtain is not engaged until the fire has grown in strength, or the air curtain may blow the fire out. Once the fire has reached suitable strength, usually in 15 to 20 minutes, the air curtain is engaged. The air curtain then runs at a steady state throughout the burn operation, and the waste wood is loaded at a rate consistent with the rate of burn.

The air particles are trapped and reburned

looking into the Air Curtain Burner

In North Cowichan the Municipal Logging Operations burn approx. 83 slash piles per year (average of 2012 -17 based on NC Forestry Reports)

Questions for Council:

Is it economically feasible to use Air Curtain Burners to burn logging slash?

If slash-burning accounts for 7 to 13% of the total BC Carbon Emissions - how much does our Municipal slash-burning affect the total North Cowichan carbon emissions?

Why does the Municipality mandate this technology for the commercial sector on burns outside of the urban containment boundary - but not for the Municipal Forestry operations? With the expansion of logging on Mt. Tzouhalem and Stoney Hill - the slash-burning will be much closer to our communities.

Could the Municipality buy a portable Air Curtain Burner and rent it out to logging companies and commercial developers in the region to offset the initial investment and the increased burning costs?

This article is designed to pose questions and spark debate, not to provide answers. This article is based on online research, talking with experts and visual observation. Please use the online form below if you believe there is more to this story than we are aware of.

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District of North Cowichan, Vancouver Island BC