Agriculture and Natural Resources Extension Agent, Adam Downing, explains what to look for when harvesting wood for charcoal or firewood. Hardwood is more dense and makes a better quality charcoal while pine is lighter and burns hotter, making it less desirable for cooking chicken, for instance. Leaving the dead trees on the forest floor is best because it provides habitat for forest dwellers. Live trees should be cut, which will open the canopy and allow the remaining trees to receive more light, thus improving forest health. Adam suggests marking desired trees during the summer while they are easier to identify and then returning during the cooler months to harvest the trees. Harvesting trees for charcoal can be done at any time of year, but allowing the cut timber adequate time to dry before burning in the kiln is critical. Allow trees to dry for a minimum of two months. For more information on charcoal production, please visit this website: http://web1.cnre.vt.edu/forestry/charcoal/
Forest Farming does not always entail growing medicinal herbs, wild edibles, or decorative plants. Sometimes it could mean removing trees from the forest to be made into firewood or charcoal. The removal of invasive species for charcoal is especially beneficial for the forest. Invasives such as Ailanthus tend to form a monoculture which provides poor habitat for forest dwellers and also takes valuable resources from native species. Adam Downing explains how to identify Ailanthus by its serrated leaves and its pith which smells of burnt peanut butter. When making charcoal with any tree, it is important to let the wood dry from 2 to 6 months. The wood runs the risk of rotting if it gets wet. For more information on charcoal production, please visit this website: http://web1.cnre.vt.edu/forestry/charcoal/
Removing invasive species is an important step in promoting and maintaining forest health. Tree of Heaven, also called Ailanthus, forms a monoculture and often outcompetes native plants. Invasive species often have no redeeming qualities and should be removed. Charcoal can be made out of ailanthus, and by cutting the trees down, forest health is improved. Woody invasives generally require the application of herbicide to properly eliminate regrowth. When mixing herbicide, gloves, long pants, closed-toed shoes, and goggles should be worn. For more information on charcoal production, please visit this website: http://web1.cnre.vt.edu/forestry/charcoal/
When producing charcoal in a kiln, it’s important to protect your hands with insulated leather gloves. Leather gloves without insulation will not provide enough protection against the heat of the kiln. It’s also important to wear closed-toed shoes., preferrabley leather work boots.
Preparing the Kiln
Kilns for charcoal production come in a variety of styles. A common feature of all kilns is the ability to control oxygen. The control of oxygen within the kiln is critical during the charcoal making process as is the ability to “close down the kiln”, i.e., shut off the flow of oxygen to finish the charring process. The kiln used in this demonstration requires a small fire at the base. A long stick placed in the center and protruding through a vent in the kiln allows access to the wood for initially lighting the fire after the kiln is fully loaded. The wood is packed/loaded as densely aspossible to maximize the charcoal yield. For more information on charcoal production, please visit this website: http://web1.cnre.vt.edu/forestry/charcoal/
Adam Downing, Agriculture and Natural Resources Extension Agent, demonstrates the process of loading the kiln to make charcoal out of ailanthus and walnut timber. Logs of the same size should be loaded to insure evenly charred pieces at the end of the burning process. Short pieces combined with longer pieces of wood will yield ash as the shorter pieces burn up and unfinished pieces as the larger pieces of timber do not burn completely. The kiln should be loaded as densely as possible. The more wood that can be fit into the kiln, the greater the charcoal yield will be. For more information on charcoal production, please visit this website: http://web1.cnre.vt.edu/forestry/charcoal/
When lighting a kiln, it’s important to consider the type of fuel used to start the flame. Diesel fuel and diesel oil combined is recommended over straight gasoline. Gasoline is too volatile and can explode. Adam Downing, Agriculture and Natural Resources Extension Agent, demonstrates the process of lighting, sealing and controlling the heat within the kiln. During charcoal production, control of the heat is critical to the outcome of the product. The fire should burn towards the bottom where the oxygen is allowed to enter the kiln through vents. By opening and closing various vents and using stacks, the oxygen and therefore the heat, can be controlled and dispersed evenly. This ensures that the wood is charred in a uniform manner.
For more information on charcoal production, please visit this website: http://web1.cnre.vt.edu/forestry/charcoal/
After allowing the kiln to cool completely, it is safe to unload. Logs that have been cooked all the way through will yield charcoal which should be carefully handled to avoid reduction into smaller pieces. Logs that have not been cooked thoroughly can be set aside for use in the batch. Use eye protection and wear a mask to avoid breathing in excessive dust while unloading the kiln. Gloves may also be worn, although charcoal smudge is easily washed off.
After the kiln has cooled completely, sorting and bagging the charcoal can commence. A typical sorting will divide the material into three different sizes: large (grade 1), small (grade2) and the fines. Fines are approiatley called “biochare” when added to soil, such as in garden which is often has a positive effect on the mechanical soil properties. Small and large charcoal lumps are good to use for the grill. The rotary sorter used here is turned by hand and separates the three grades as it spins. Large and small pieces of charcoal are bagged separately as grade one (larger) and grade two (smaller). The fine pieces, are left in larger containers (such as trash cans) to be added to a garden but could be bagged and sold as biochar (for more information on bio-char: http://www.ext.colostate.edu/pubs/crops/00509.html) . Once the charcoal is sorted and bagged according to size, a portable bag stitcher is used to close the bottom of the bag. This step is not necessary. A stapler or a mesh bag outfitted with twine will work just as well.
Adam Downing, Agriculture and Natural Resources Extension Agent, demonstrates the process of loading a barrel kiln to make charcoal out of ailanthus and walnut timber. While log length is not important except for ease of loading, logs/wood thickness is important. Pieces of similar diameter/thickness should be loaded to insure evenly charred pieces at the end of the burning process. Smaller diameter/thickness pieces combined with bigger pieces of wood will result in lower yields as as the smaller pieces burn up and leave ash and the larger pieces do not have time to completely char resulting in unfinished pieces , called “brands”.. The barrel kiln should be loaded as tighlty as possible. The more wood that can be fit into the kiln, the greater the charcoal yield will be. Once the wood has turned into charcoal, it’s necessary to close off the kiln. This involves starving the fire of oxygen. Sand is spread around the bottom barrel where the holes are located. The top barrel or afterburner is removed and the lid is secured on the bottom barrel which contains the charred wood. After everything has cooled the following day, the charcoal can be removed safely. It’s best not to handle the pieces too much as they are very fragile and fall apart easily. Large chunks are preferred by most grillers for the simple fact of staying ontop of the charcoal grate in their grill. For more information on charcoal production, please visit this website: http://web1.cnre.vt.edu/forestry/charcoal/
A barrel kiln is a good way to produce charcoal on a smaller scale in a back yard. Once the barrel has been closed off and has cooled completely, the charcoal can be put into a metal container. A metal container is recommended over a plastic one if the charcoal still has heat from the cooking process, however, plastic containers can be used once the product is completely cooled. It is important to keep the charcoal dry.