How to Season and Store Firewood for Burning in the Home
Wood is a very good and sustainable choice of fuel for the home. It can be burned on many appliances with a variety of wood types available.
When burned in a responsible manner wood can actually be a good choice for the environment, unlike the burning of fossil fuels. However, smouldering or smoky fires that produce a blue smoke can actually contribute towards air pollution, wood smoke can also be harmful if it is inhaled. However, if the right wood is burned, in the right way, then there shouldn't be much smoke. A slow-burning wet fire can produce lots of thick smoke, this is undesirable. What is required is a quick, hot, dry burn with very little smoke. A smoky fire is inefficient because heat energy goes up the chimney in the form of unburned gases, steam, soot and ash. Carbon dioxide, the product of a quick, hot burn, is a colourless gas, so a hot fire is an efficient and less polluting one.
Seasoning is a process in which the water content of wood is reduced, this is absolutely essential in order to make it fit for burning.
This is achieved by leaving the wood in the right conditions. All wood contains water, especially freshly-cut wood which can be up to 45% water. Well seasoned wood should generally have a water content of between 20-25%. Well seasoned firewood is easier to light, produces more heat, burns cleaner and should not damage the stove or chimney.
If freshly cut wood or green wood is burned, the heat produced must first dry the wood, this leads to inefficient combustion. This results in less heat delivered by the appliance and acidic compounds like creosote being deposited on the walls of the flue. Overtime this can corrode the chimney lining causing significant damage.
The first step to seasoning and driving the water out of the wood is to cut it into lengths - usually 12 - 18 inches long or less depending on the dimensions of your appliance. Wood contains microscopic capillaries which transport water from the ground up. Cutting the wood to shorter lengths opens the capillaries and helps moisture content leave the wood.
The second step involves splitting any logs that are more than six inches in diameter. This increases the surface area and increases the rate of drying. The cutting and splitting of the logs should be done as soon as possible after the wood is felled and not just before it is required.
Trees being cut down for firewood should be felled in deep winter (Dec - Jan) as the tree is dormant and the sap has not yet risen. Once the sap starts rising with the onset of spring the tree's moisture content increases and seasoning takes longer.
When wood is being seasoned it should be protected from direct rainfall and should be on a dry base. The sides of the stack should be well ventilated to aid drying.