When it comes to sourcing the best firewood to burn on a wood burning stove, your primary consideration needs to be whether it’s properly seasoned. Burning wet, unseasoned wood is completely ineffective for burning and should be avoided at all costs. A living tree or one that has been recently felled can contain over 60% moisture, and this means that it will require a lot of heat – and therefore energy – to boil off the water before it even starts to emit a proper heat output into the room. This inefficient burning practise then leads to excess smoke, which not only damages the flue and appliance but also contributes to air pollution.
Since this article was originally published in 2019 there has been a UK retail ban placed on the sale of smaller quantities - less than 2 cubic metres - of unseasoned wood.
According to DEFRA, the Department for Environment, Food and Rural Affairs, switching from wet wood to dry wood alone could cut particulate emissions from a stove by half. Dry wood that has been properly seasoned means that it produces far fewer of these harmful particulates, but in turn increases heat efficiency and lowers maintenance. Provided you follow the correct burning practices, wood can a sustainable, renewable and carbon-neutral fuel, and provide a great source of heat for your home.
You should never burn green wood. Also known as unseasoned or ‘wet’ wood, this timber, regardless of species, is counterproductive for burning, and will result in excess smoking and a build-up of creosote (damaging sticky tar deposits) inside of the appliance and flue. It will be hard to ignite and difficult to burn – if your wood smoulders in the stove with little heat emission then it’s green. Another tip for identifying unseasoned wood is the noise it makes – if you knock two pieces together and they make a dull thud, then the wood is most likely too wet to burn.
You should only ever burn seasoned wood with moisture content of below 20%. If you’re collecting and chopping your own timber, the drying process can take up to a year, so ensure that you factor this in when sourcing your fuel. The wood of some particularly dense hardwood tree species, such as Oak, can take in excess of two years to fully season. Visual signs of properly seasoned wood include radial cracks in the logs’ cross-section, loose bark and a dull colouring. The weight of seasoned wood is also noticeable lighter than green wood. If you’re buying your logs pre-cut then make sure you look out for the Ready to Burn logo. This will indicate that the timber is fully seasoned and ready to burn on your stove.
The answer is, yes. Timber that is too dry can ignite and burn quickly and aggressively, using large volumes of air, which in turn can increase particulate emissions. It’s about getting the balance right. A small percentage of water is actually beneficial for wood burning, between 12 – 20%. This helps to moderate the combustion process and gives out the right amount of heat into the room. You can use our handy Moisture Meter to measure your firewood’s moisture content.
Further reading: