Spring is here and the woodstoves will be going into the summer mode. They will be shut down and cleaned out, semi-retired for the season. Wood ash will be shoveled out and put into ash buckets and dumped over the bank, along with the winter’s worth of cleanings, probably 5 to 10 buckets worth.
Whoa, let’s backtrack in time, and reevaluate what we have here. Wood ash is not a waste product. Wood ash is a valuable natural resource, from a renewable resource — trees! This so called waste product has many uses.
First let’s look at where it came from, and then we will figure out where it should go.
A tree starts out as a seedling, and then grows to a sapling, then to a small tree or pole timber, then to a saw log, and finally to old age, unless Mr. Stihl or Mr. Husqvarna decide to intervene, and turn the tree into a log for boards or for fire wood. Culling out damaged, diseased or inferior species of trees for firewood or other wood products are sound forestry and silvicultural practices and should be encouraged, not frowned upon. Try to leave a few dead trees per acre for cavity nesting birds.
As a tree grows, the nutrients and water in the soil are taken in by the root hairs and transported throughout the tree. Nutrients and minerals such as nitrogen, phosphorus, potassium, magnesium, calcium, iron, and other trace minerals are taken in through the roots, which also support the tree. Much of what is taken up depends on what is in the soil. Rich soils versus nutrient poor soils make a difference in the quality of the tree, type of tree and nutrients in the tree. Some trees like aspen (popple) are higher in calcium, while others have different ratios of minerals in them.
OK, we have looked at the roots. Now, what about the leaves? The leaves are involved in the greatest wonder of the ecological world; photosynthesis. This stuff is very cool. Without this process, there would be no vegetation on earth. We would not exist. The earth would be a dead rock floating around in space. (Some scientists will call me out on this and say there would be some slime mold or something weird like that that would grow, but hey, I’m trying to keep it simple). Photosynthesis is the process where solar energy is converted to chemical energy. Carbon dioxide, water, and sunlight are used to produce glucose, oxygen and water. The chemical reaction is 6CO two, 12H two O plus sunlight ---converts to C two H twelve O six and 6 O two and 6H two O. Which means carbon dioxide and water plus sunlight converts in the leaf to glucose (sugar) with oxygen and water given off. Solar energy is being converted to chemical energy.
The minerals and nutrients along with the glucose and water combined with the biological process of cell division and all the other wonders of growth make a tree, shrub, flower, alfalfa, green bean, corn plant and grass plant that feeds wildlife, dairy cows and grass-fed beef. This stuff is the real deal, not science fiction.
So, you had your dry firewood (clean wood, no paint or wood preservatives) stacked up. You’ve handled it 3, 4 or 5 times now and it’s finally made it to the stove. The final heating cycle you get from the wood is when you burn it. Now you ask, what is the burning process?
Living things are made of oxygen, carbon and hydrogen along with all the minerals that we got from the roots and the glucose from the leaves. When wood gets hot it, the chemical bonds of the cells and structure of the wood start breaking down and they releases gases; hydrogen is one of them. This process is called pyrolysis. The released gases, burn due to the addition of oxygen from the air. Parts of the wood like sap and resins have greater deposits of glucose which is a volatile compound, making it very flammable. The carbon and minerals are resistant to burning. That’s what your ash is composed of, the left over products of combustion that didn’t burn, carbon (charcoal) and minerals, which added together we call ASH. Depending upon the temperature in the woodstove, more or less of the carbon compounds get burned off. The high temperatures due to increased oxygen, burn off more carbon leaving only minerals. Now you know what ash is! So what do you do with it?
Ash is used as a soil amendment to increase the pH of the soil. You can add all of those minerals that the roots took in over the years and spread them around the yard for growing grass, trees, and in your garden. Check out gardening books and see what the pH should be for the plants you are growing. You don’t want to try growing acid loving plants like blueberries in neutral, alkaline soils. Most of the recommendations I’ve seen, say about 10 pounds of ash per 1,000 square feet to start with. Ash has potassium and potash in it, but no nitrogen, which is burned off.
Common sense says; make sure the fire in the coals and ash is completely out before you use it. Sadly, common sense doesn’t prevail anymore so I must resay it. Make sure the fire is completely out before you use it. As a firefighter I don’t really want to make another house call at 3 a.m. Been there, done it! Stay up wind when you spread the ash, you don’t want to breathe it in.
Wood ash is used instead of salt on the walkways and driveways to add traction during icy weather. You can use it for traction in the barn. Mix it in with manure when you spread to add minerals to the soil and it can be sprinkled on plants as an insect repellent. Mixed in with compost you get excellent nutrient rich fertilizer to spread around all those apple trees you released and pruned during the winter. Spread wood ash out on that new food plot seeding you did during the frost thaw period. Feed the plants, feed the wildlife! Over the years wood ash has also been used to make soap, and as a mild abrasive for polishing metals. And you thought it was just something to dump over the bank. This is simple recycling of nutrients. We are all part of nature’s circle of life. Our food comes from the earth.
I also have my thoughts about spreading it on stream-banks and ponds to slowly dissolve in the water to help in pH and add minerals for bugs, which feed fish of course. I can’t advise you to do this due to NYS DEC regulations. A permit may be required. Ash may be considered a waste product. So don’t do it without checking with DEC first. You are on your own on this one.
Rich Redman is a retired District Conservationist for the USDA Natural Resources Conservation Service and an avid outdoorsman. His column will appear regularly. He may be reached at firstname.lastname@example.org.