Your stove is designed to burn well seasoned firewood; and with proper wood it will burn cleaner and more efficiently. Green, wet or unseasoned wood will cause more smoke, a bigger creosote buildup, potentially odours in the house and even potentially dangerous chimney fires.
Seasoned Wood
So what is seasoned wood? Well all trees contain water, the amount will vary dramitaclly by species of tree. A freshly cut tree may contain up to perhaps as much as 45% water and properly seasoned firewood will be 20% to 25% maximum and preferbly slightly under 20%. Wood-stoves are designed to burn in the 15-20% range most efficiently.
Properly seasoned firewood is not only easier to start but you will get more heat out of it into the home and it burns cleaner. While all wood produces the same number of btu’s, green wood uses that energy to evaporate water and is not able to deliver it to your home as heat value. Generally if your wood is cut minimum 6 months to a year in advance and properly stored the sun and wind will do work of seasoning for you free of charge. However, if you use the wood green the wood will do the job for you, and cost you in use of more wood and in more chimney cleanings – as gallons of creosote laden water is condensing on your chimney walls. Note that while I said 6 months to a year, that varies by wood species and some may even take closer to two years to be well seasoned.
When trees grow the cells are in the shape of microscopic tubes or straws that were used to transport water from the roots of the tree to the leaves, and sugar energy produced by photosynthesis back down the trunk. These tubes/straws will be full of water when cut and will naturally remain full of water for years when the tree dies. These cells are designed to NOT LEAK, and why it is important to cut the firewood into shorter lengths, allowing the water to reach the ends faster. Wood does not dry or absorb water through the sides, but through the ends. Cutting it into shorter lengths allows the water to evaporate out the ends as the water has to migrate only a foot or two to escape. Many who supply wood do not realize this, and likely I would not if I were not previously a Certified Arborist. There are a few things you can look for when purchasing wood to see if the wood is seasoned or not. Well seasoned firewood generally has darkened ends with cracks or splits visible, it is relatively lightweight, and makes a clear “clunk” when two pieces are beat together. Green wood on the other hand will be fairly heavy, the ends will look fresher, and when two pieces are struck together it tends to make a dull “thud”. These however are not perfect indicators and you can be fooled.
Storing Firewood
So how do you store firewood properly? Realistically even well seasoned firewood can be ruined by poor storage.
Leaving it exposed to constant rain or covered in snow, wood will cause it to decay more rapidly and it will begin to rot and become unusable faster. The first thing to ALWAYS remember is to STORE IT OFF THE GROUND – even a cement floor – DO NOT LEAVE ON THE FLOOR. Put skids or some other space between it and the floor or ground.
The ideal situation is really a wood shed with a roof but realitively open sides with lots of room for ventalition. If you don’t have that, then storing outside would be next. But pile in an open and sunny location and do not trap it tight – keeping air out. Instead it is best to either have a cover with an air space between it and the wood or if you don’t have that then cover when snowy and rainy and take the cover off on sunny days. With the right storage you can turn pretty much any green wood into well seasoned wood in six months to a year and you can keep it 3 to 4 years if needed.
Buying Firewood
Firewood is generally sold by volume, the most common and in Canada only legal measures are cord or cubic metre.
Other terms used may be bush cord, face cord, rick, or maybe just a truckload. These are actually all illegal terms in Canada. See brochure on left.\
A cord of firewood is 128 cubic feet of wood, generally measured as a pile 8 feet long by 4 feet tall by 4 feet deep. Legally you should be sold either a full cord, a 1/4 cord, 1/2 cord or 1/3 cord. Many will use the term face cord, however that could be actually 16″ lengths (1/3 cord), 12″ lengths (1/4 cord) or 24″ lengths (1/2 cord) so beware and check the lengths of firewood.
Another thing to remeber is that while firewood is sold by volume, heat production is dependant upon weight. That is true; virtually every species produces the same amount of heat or btu’s by weight (kg or lb). However some wood will weight twice as much as another species, meaning twice as much potential heat. Yet if you buy buy the cord you pay the same for each of them – ensure you know the spieces of wood you are buying. If the wood is not all hardwood then you should be paying less. In fact some hardwood like birch, poplar, soft maple (Norway, Manitoba) are actually much lighter than sugar maple.
Some Firewood Tips
- It is far more important that the wood is dry rather than the actual species.
- Do not burn any construction scraps as they are too dry – which is a problem with overheating and potentially increase production of creosote. Do not burn painted wood or pressure treated wood or old railway ties or telephone poles.
- If the “seasoned wood” you bought is really quite green and you have not choice but to burn it, have your chimney checked more frequently – call us to help (we also have moisture meters of high professional quality).
- If the wood you have is mixed – birch, elm, ash, maple, oak, etc.. then learn to manage and mix the wood. Burn harder wood in the colder season, mix the wood during warmer parts and the softer wood species in the shoulder seasons (fall and spring).
Softer wood which is dry can be burned, but you will need to carry more logs to the firebox to get same amout of heat. - If you burn commercial logs sold in stores, they are fine, but be careful and burn only one at a time. Do not put second one in until first is pretty much burned and be careful to not poke at the log when burning as it may break up and get a much larger fire than you had bargained for.