Wood fuel sustainability is becoming a concern as worldwide we’re using more biomass boilers and wood-burning stoves than ever before.
In the UK, domestic boilers and stoves are very popular. As Dispatches questions The True Cost of Green Energy, public concern about wood fuel sustainability is likely to rise. The Scottish Government recently put on hold a motion to ban wood-burning stoves in smokeless zones, which attracted no signatures but a lot of media coverage. The trend of wood-burning stoves as a luxurious addition to central heating is the main target of this movement. The fear is that those for whom stoves are necessary will suffer.
Luxury or necessity?
The UK has a large rural population and for these households, oil and mains gas central heating is often impossible or intermittant. As a rural-dweller, my power supply is frequently cut off and without my stove I would have no heat at all during these often prolonged periods. It’s also often a cheaper source of heat in many of our poorly-insulated homes. So a wood-burning or multi-fuel stove becomes a necessity in many rural homes, rather than a luxury. However, there are questions we need to ask about burning solid fuels generally, in order to ensure that as suppliers and consumers we’re making responsible decisions.
Wood or coal?
At the Wood Fuel Co-operative, as our name suggests, we prefer wood fuel over coal. Coal is a finite resource whereas responsibly sourced wood can be sustainable. Dried to the right level, wood produces far fewer pollutants when burned.
The source of the wood is vital, however, as felling trees, especially hardwoods, to make firewood vastly increases the environmental impact.
This is a huge part of the argument against biomass pellets. Dispatches argues that hardwood forests are being felled to power huge biomass power plants. Biomass sustainability is going to become an increasingly hot topic in coming months and years, so expect to hear more on this soon. In the meantime, knowing where the raw materials for our individual wood-burners come from is very important.
The best firewood logs are hardwoods, as they’re denser and have less sap. But hardwood comes from broad-leaved trees, which support greater biodiversity. Softwoods, from conifers, support much lower levels of biodiversity. Hardwoods grow slower (hence are denser), so they burn slower. This means they take longer to replace so are less sustainable. But softwood logs are not as good for your stove and burn very quickly.
On a local level, where trees are removed because of wind damage, end of life, or for safety reasons, this is a perfectly sustainable process. Well-managed woodlands are productive, healthy and bio-diverse. As log-burning stoves become increasingly popular though, our ability to produce enough firewood to meet demand is becoming problematic.
This is one of the main reasons that the UK has to import firewood from Europe. Imported firewood is excellent quality, usually consisting of singles species such as Birch, Ash or Oak. It’s clean, kiln-dried and stacked in wooden crates. We reluctantly import small quantities of logs each year, because the demand for logs outstrips the local supplies.
The trees are felled in vast tracts though and they have to travel a long way by both road and sea. This clearly increases their carbon footprint. Moreover, there are potential plant heath concerns with importing firewood. There are diseases and insects that can be inadvertently imported with the firewood which can cause serious problems for UK woodlands. For kiln-dried firewood this is less problematic as the kiln-drying process destroys the diseases and insects. Stringent checks need to take place by anyone importing firewood. We work with the Forestry Commission to ensure that the logs we import are not posing a risk to UK ecosystems. This invoves carefully checking every load we receive.
Waste not, want not
Traditional firewood logs are only about 5% of what we sell. We believe that wood briquettes offer a better long-term solution to wood fuel sustainability.
One of the many reasons we like briquettes is because they’re made using a waste product. As a family who have spent our lives working in conservation and planting many thousands of trees, the idea of felling trees to produce firewood seems wasteful.
The briquettes we stock are all made from wood waste, such as sawdust, wood flour, and wood chip. These are all by-products of a variety of timber-based industries. These include manufacturing hardwood flooring, timber-framed buildings, wooden staircases, furniture etc. Any industry that processes wood produces waste materials and usually these go to landfill. Briquetting this by-product means that it is saved from landfill, whilst also negating the need for trees to be felled for firewood.
Many manufacturers have now started investing in briquetting machines, which turn their waste wood into firewood briquettes. Although there’s no legal regulation, we will only stock briquettes made from wood waste that is unadulterated by additives, such as paint, glue, varnish etc.
That’s because burning these chemicals and additives are bad for you, your stove and the atmosphere.
There is no doubt that burning wood fuel produces particulates. The best way to minimise this is to make sure you’re burning dry firewood on an efficient appliance. Burning wet firewood in an old, inefficient stove produces pollutants on a par with that from coal fires.
Wood burning appliances should be well-maintained and as modern as possible. The efficiency of stoves has increased hugely in the last ten years or so, and that needs to be taken into account. Bowland Stoves have an excellent blog post that addresses this in more detail.
The fuel should be as dry as possible, and certainly under 20% moisture content. The amount of moisture in firewood affects the amount of pollutants released into the atmosphere.
To burn or not to burn?
Yes, we’re biased but we say burn. Stoves are a vital and valuable addition to many UK homes. Stoves keep many of us warm through cold winters and long power outages. Wood fuel sustainability is something we can all improve and benefit from with responsible choices.
Make sure your stove is running as efficiently as possible. Here are our suggestions:
- Have your appliance checked throroughly. Make sure it’s running as efficiently as possible. Consider replacing very old or inefficent stoves – take advantage of modern technology.
- Only burn wood-based products and avoid using coal.
- If you’re burning traditional logs, invest in a moisture meter. Only burn logs that are under 20%.
- Try briquettes. They’re drier, produce fewer particulates and made from pure wood waste.