There is growing awareness of biochar but it has yet to take off in a big way. The Get Real Alliance is a strong advocate of biochar with its carbon sequestration program funding significant biochar creation and application. Biochar has multiple positive aspects. In the massive carbon cycle if we are to stabilize or reduce carbon dioxide levels without purely focusing on very unrealistic reductions in carbon emissions then we need to sequester carbon from the air into the soil and plant life.
Carbon is sequestered in a variety of ways that are either short term or long term or nearly permanent. To stabilize CO2 levels or lower them we need to do all ways but long term and nearly permanent are desirable. Plant growth sequestration is either short term or long term depending on whether it is growthof an annual plant or added growth of a long lived plant like a tree. Making biochar from plants at the end of their life cycle permanently sequesters a good part of the sequestered carbon in the biomass. That alone is a big benefit to making biochar but the agronomic benefits are much greater in increased water and nutrient retention by the treated soil.
Biochar granules serve as sinks for water soluble nutrients preventing them from leaching out of the soil and making them available for soil life and plant use. Water is a solvent that will wash nutrients that are not tied up out of the soil profile. Biochar is uniquely able to keep nutrients in the soil in a plant available form.
Plants can put up to 50% of the carbon compounds they create by photosynthesis down into the soil by their root system. What happens to these compounds which serve as food for soil life depends on mineral levels and how friendly the soil is to soil life. Biochar serves as a home with its porous microstructure for microscopic soil life. Ideally a lot of the exuded carbohydrates from the roots are converted to long lasting compounds such as humus. Biochar by itself has no nutrients. It has to be charged with nutrients before it is applied or it will scavenge nutrients away from the plants in a farming situation. It is ideal to mix biochar with compost perhaps even in the compost making process for maximum benefit.
Biochar which is plant material that has been partially burned to leave behind only a pure carbon material that represents near permanent sequestration of some of the carbon extracted from the air by the plant with photosynthesis. Ideally this plant material is already dead so that no living tree is cut down to make biochar but only dead trees are used which are in the process of decaying which releases some of the carbon that has been removed from the air back into the atmosphere. Currently most efforts to make biochar harvest dead wood and burn it in oxygen limiting kilns at a temperature below the level that carbon will burn. Trees and plants are composed of a variety of carbon compounds along with water. Anyone who has been in the woods or forest knows that there is a lot of dead wood with much standing still.
Many north America forests have been ravaged by disease and parasitic insects leaving much of the timber dead or dying. A healthy forest is a carbon sink that each year removes more carbon dioxide from the air on a long term basis. Green trees don’t burn easily even if struck by lightning but due to all the dead and dying trees in many forests along with underbrush that is easily desiccated during dry times, forest fires are a major problem and release large amounts of carbon dioxide into the air. We need a large scale program to remove dead trees and underbrush from the forest.
One of the challenges to convert America’s dead trees into biochar is getting the trees to the biochar machine. The solution maybe a new type of airship designed to lift up dead trees and use onboard equipment to chip the wood and burn it in an oxygen limiting way for power and biochar. You can visit www.allpowerlabs.com for more information on such systems although they aren’t thinking about airborne systems yet!! There is so much rugged land covered with dense forest where a large number of the trees are dead or dying that are far from a road. Practically it is nearly impossible to remove dead timber from a dense forest even very near a road as travel thru the forest with wood would be a manual job of great expense.
America has hundreds of millions of acres of forest full of dead trees that need to be removed often at very high tree density. One of the reasons why forests are dying is that the soil is demineralized so a tree removal effort also needs to include adding biochar, nutrients and rock dust to seedling trees and the soil to produce fast growing healthy trees that resist disease and insects. Currently America’s forest especially federally owned ones are just being left to either decompose or burn with no effort to replant badly damaged forests with trees that are resistant to disease and insect attack. A trip by car or air in the west often finds devastated forests where most of the trees are dead.
When most of the trees are dead or dying an acre of forest goes from sequestering substantial carbon in tree growth to actually being a net emitter of carbon dioxide just by decomposition. In the upcoming book, a carbon sequestration fund is proposed with funding coming from a tax on carbon emissions. It is very likely that harvesting dead trees with an aerial system to make biochar will cost a lot more per ton of sequestered carbon that some other processes but there are long term benefits to restoring a section of forest to health and preventing the release of a huge amount of carbon dioxide either by decomposition or worse fire.
In the case of making biochar from dead trees in a forest there are multiple benefits. Much of the carbon in the dead tree is converted to a permanent store of carbon and removed from the carbon cycle. If some of the biochar is added to the forest soil it increases tree growth and soil life. As there is so much dead wood most of the biochar can be used on other land such as desert and other lands to enrich it and increase carbon sequestration there.
There are a lot of good books on biochar available at www.acresusa.com that are recommended for those who want more detail and stay tuned to this blog for a lot more information on biochar, making it and its benefits. One of the things that the Get Real Alliance does is research on subjects such as biochar and we need money to fund research and advocate for change. Please go to the donate page and help us further the cause.