Tis the season… to burn wood?
By Dan Lazarou-West
People sometimes ask me at parties, (yes, I still get invited to parties) which is the best type of wood to burn. And although, like many, I have a wood burning stove at home, I don’t always have a satisfactory answer to hand. At best people lose interest before I finish instilling them with the merits of one type of wood over another. However, the best piece of advice I can give is that the timber should be properly seasoned. For oak this could mean leaving it outside and covered for at least a year.
So why is burning seasoned wood so important? Well most of the moisture content in firewood will consist of wood resins and as the timber heats up the wood resins emit combustible gasses. When unseasoned “green” wood is burnt the leftover water content within the timber turns to steam and mixes with the wood gasses, preventing them from igniting and releasing the additional heat. This effectively uses up some of the energy that should be keeping your toes warm. Burning wood in this way is inefficient and can also cause problems with the flue.
I also get asked if burning firewood is good for the environment, and I guess that depends on what criteria you are basing it against. As we all know, as a tree grows it locks up carbon which is then released back into the atmosphere when burnt. You could argue that this carbon can then be recaptured through planting and growing new trees (yay forestry). The same is true of coal; however, the carbon locked up in coal has been captured and stored in the geosphere for millions of years and is not able to be recaptured (by the same process) in our lifetimes. Of course, it’s not that simple, as extraction of timber involves many processes which can release carbon, including the release of carbon that had been captured in the soil. Although, the same can be said of extracting coal.
So, is it ok to heat your home with a wood burning stove? I’m going to stick my neck out here and say that we clearly need to find more eco-friendly alternatives than burning stuff. You can still, however, get a warm glow from the fireplace knowing you’re emotionally better off burning timber than burning other fossil fuels.
Oh, and by the way – Oak/Sycamore and Cherry or Apple are my favourite types of wood to burn.