Friday, April 6, 2012

The hills are alive with the sound of crackling slash piles

It's spring, and time to get rid of last year's slash piles by fire. In early March we made our way up to the property and ignited piles.





The best time to do this work is when there's still snow on the ground to control their spread. That means snow on the road. So step 1 is to plow the road, which this year still had plenty of snow on it.

We used two dozers to clear the last mile of access road and transport the propane flame thrower to the stand.
Once we reached the stand where the piles were, things went more smoothly. Most of the first 8 piles lit easily, but a couple still had too much moisture and wouldn't keep burning. Between plowing and burning, the day was done but at least 10 piles remained.

Curt adds ground fuel to a burn pile.
I returned a week later to finish the job. This time, thanks to a warm spell with little new snowfall, I was able to drive to the property without using snow chains. 

Of the piles we lit the previous week, almost all had burned down to ash with small rings of "bones" around them.

I lit 10 more piles. Since I had just come from the ski area and had my skis in the truck, I took one short ski run on a hold-out patch of snow in a shaded draw.

A few small piles remain, since they were still covered with snow. I doubt we'll burn them -- it's already getting too dry -- so those will be wildlife piles until they rot and return their nutrients to the soil.

2 comments:

  1. Firstly...I think your intention to manage your small forest is great. We need more people taking responsibility for the active management and stewardship of their land.

    There is a better way to "burn" your burn piles than the traditional open burn. The usual method for burning piles creates a huge amount of smoke containing long chain hydrocarbons (tars), particulates, carbon monoxide...all kinds of stuff that don't vibe well with what should be a healthy activity for the forest.

    If you make your brush piles by hand and then run a chain saw through the piles, you can reduce the height and increase the density of the pile. Arrange the material so that the pile is tall and narrow rather than short and wide. Light the pile on the top rather than the bottom. Most people think that heat rises, but in fact heat radiates in all directions, it is the hot gases from the fire that rise. If you light the fire on the top, the fire will spread downwards into the pile. The gases released will have to pass through the flame front to escape into the atmosphere. When all of those tars and carbon monoxide pass through the flame front they are fully combusted making a brush pile that barely smokes at all. Now if you are close to a water source you have another option. There will be a point when the fire burns down to coals meaning the volatile chemicals have burned off and whats left is essentially charcoal. You'll know when this happens because the fire will turn from yellow to blue. If you have enough water available you can put the fire out and spread the charcoal in your forest. The charcoal is an excellent soil amendment that retains moisture and has properties that support soil life. You've also just taken an action that reduces atmospheric carbon. The carbon in the charcoal (those in the know are calling it Biochar) will stay in the forest soils for a thousand years or more instead of being released into the atmosphere. Kind Regards, Matt

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  2. I appreciate that suggestion. I'm familiar with the "biochar" movement and I've seen clever techniques for reducing biomass to charcoal for various purposes.

    We could have accomplished this by papering our piles. Our crews hand pile according to USFS standards, so each pile is about 4' x 8' and 6' tall. Over the winter they settle down to 50-60% that height. By spring we have a compact pile, but the fuel is wet. It takes sometimes 15 minutes of intense heat from a propane torch to get it to light from the bottom. If we paid extra to paper the piles we could light them at the top.

    "Papering" involves laying a large sheet of waterproof paper (like waxed shopping bag paper) over the top of each pile and weighting it down with more slash. It keeps the fuel dry but only directly under the paper, so you also need to make sure there's a large amount of kindling-sized debris there.

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