What is biochar?

That’s the easy part. It is just charcoal that ends up in the soil. Charcoal is made from carbohydrate-rich biomass such as wood, almond hulls or corn stalks. Heating carbohydrates without oxygen results in fairly pure carbon being produced — i.e., charcoal.

Why is it important to our region’s future?

Most people are aware that we have been dumping too much carbon into our atmosphere and that we need to stop. Making biochar is a way to keep carbon out of the atmosphere by putting it in the soil — “sequestered,” where it belongs. Until we came along, our planet seems to have evolved to take atmospheric carbon and bury it. Shellmounds, soil, limestone and the fossil fuels we have been burning are the result of this. It might be wise of us to start putting carbon back into the ground.

As plants grow they pull carbon dioxide (CO2) from the air and add water, making oxygen and carbohydrates. When they die or lose leaves, roots and branches, decomposition releases CO2 and methane (which is a far more potent greenhouse gas than CO2). Some carbon remains as humus, mainly from the plant’s lignin. A tree may live a thousand years, but most of a twig it drops will be turned to gasses within a few. Even a massive trunk has usually rotted within a century or two. Geologic time and favorable conditions (like bogs and swamps) will make lignite and coal beds.

Charcoal can last in soil for thousands of years. It is very “recalcitrant.” It doesn’t rot. It also increases the fertility of soil by aiding life in the recycling of nutrients, although it may take up some nitrogen at first. Naturally frequent low intensity wildfires put more carbon into the ground than litter accumulation alone. Charring trimmings sequesters more than scattering them. While a low-intensity fire adds carbon to the soil, high-intensity, stand-destroying fires can burn so hot even soil carbon will burn. We need to tend to our forests before it is too late.

When heated without enough oxygen to burn, carbohydrates turn into charcoal; gasses such as hydrogen, methane and carbon monoxide; and diesel or tar-like liquids. The details vary depending on the process and feedstock. For example, cooler (400-ish Celsius) temperatures promote charcoal formation, and turpentine was historically collected from buried pine log fires. The gasses are flammable and have been called “producer gas” and “town gas,” among other things. They have less available energy content than methane but have more than enough to heat the feedstock and drive the process. Excess can be used like natural gas for other uses, though it may need processing. Hot charcoal (like coal) can be gasified using steam to make syn (synthetic) gas which could augment town gas in a carbon negative economy.

Wood heat users can throw the charcoal that may be present after damping down a fire overnight into their gardens. A traditional way to produce more is by making a log cabin style pile of three-inch thick branches around and within which are piled smaller branches and twigs. The pile is set alight then doused when the little stuff has burned. The larger pieces will be charcoal. Note the word “doused.” That implies water being on hand. Do not not make more charcoal than you intended to make, especially not on your neighbor’s land! A safer technique is to place branches in a 55 gallon steel drum with several holes drilled in the middle of the lid. Invert it over a burner or small fire and as it starts reacting it’s gasses will exit through the holes, be ignited by the flames, and provide heat needed to finish the process. If we had the requisite industrial infrastructure, waste from lumber production and material thinned from forests could be chipped and turned into gas for town and charcoal for the ground. Worms and other critters distribute surface applications over time.

Our forests are overgrown tinderboxes. The sorts of stand-replacing fires our conditions promote are disastrous. We claim to be a “free market” economy, yet the economists’ sense of “free market” means markets are free from distortion, partly because all information about the full costs of a product or service is reflected in the price paid for that product or service by its consumer. The price consumers have historically paid for forest products has not included the costs of restoring forests to a safe, productive state. Our markets failed our forests.

Releasing fossil carbon into the atmosphere involves another market failure. If there were a price signal taking into account the costs of global climate change, consumers would have the information they need to make rational choices. I advocate a carbon fee-bate — more on that soon — although any tax that curbs net releases of carbon into the atmosphere would help. Don’t go trolling about taxing your breath unless you eat dirt and oil instead of food.

Were the markets for carbon releases and forest products truly “free” they would work. As it is now, biocharring is service done for the world. If unsustainable technologies had their full prices factored in, putting charcoal in the soil and harvesting town gas would be normal forestry practice and a valuable part of our diversified economy. Chopping down forests to make biochar is, of course, not what I am advocating. A significant amount of all types of carbon should be left undisturbed to live and decompose naturally. Healthy, mature, gently managed forests produce the most value for lumber, biochar and nature.

There is one current use that can pay for itself. Charcoal is great for your soil! Another whole article could be written about biochar in farming. For now I’ll just point out that if every bag of dirt sold around here was 30 percent biochar crumbs plants would be healthier and people could be funding lots of fuel load reduction for fire safety.

Disclaimer: While I am a board member of RCSD and RREDC, these views are my own.