When burning solid fuels the efficiency of extracting useful energy and the pollution that is produced varies depending on the fuel used and the appliance in which the fuel is burned. There is particular concern regarding the health impacts of PM2.5 emissions. These are very small particles (less than 2.5 microns in diameter) that can penetrate the lungs. Relative production from different methods of wood burning in comparison with other fuels is illustrated below.
When burning logs the least polluting option is a “DEFRA exempt Ecodesign Stove” or boiler. These are designs approved for use in smokeless areas where they are the only legal option but they are the best choice anywhere. The DEFRA link leads to a list of the approved appliances. See also the case studies below for some examples.
It is also important to use dry wood as it produces more heat per unit mass or volume, as well as being less polluting. Burning wet wood uses energy to drive off the water. Another reason for avoiding the use of wet wood is it causes the build up of tar inside chimneys, increasing the risk of chimney fires. There were 3,130 chimney fires in houses in England in 2019-20 caused by flammable tar; infrequent sweeping was the main cause but wet wood would be a contributory factor.
In February 2020 the Government published a response to a consultation on Air quality: using cleaner fuels for domestic burning, with regulations being made later in the same year and guidance for sellers being published in 2021. The regulations came into force on 1st May 2021 and are enforced by local authorities. It is now possible to buy wood in small volumes of less than 2 m3 only if it certified as ‘Ready to Burn’, confirming it has a moisture content of 20% or less. Suppliers may achieve that by kiln drying or natural seasoning. There is an exception to this rule that will be in place until 30 April 2022. Small scale wood producers who sold less than 600 cubic metres of wood between 1 May 2020 and 30 April 2021 will have an extra year to comply with the ‘Ready to Burn’ certification scheme.
Consumers now have 3 options when buying logs:-
- Buying logs in small quantities in nets or bags from garden centres, petrol stations or other retail outlets. These must be labelled with the ‘Ready to Burn’ logo, the supplier’s company name and unique certification number, guaranteeing the moisture content is less than 20%. The ‘Ready to Burn’ logo shows the logs are ready for immediate use.
- A bulk delivery of logs in loose volumes of less than 2 m3. These must be certified as ‘Ready to Burn’ unless sold before 1st May 2021 by a small producer. The logo can be expected to appear on company websites or other advertising.
- A bulk delivery of 2 m3, or more. The logs do not have to be certified as ready to burn but if they are not the supplier must provide you with a copy of this notice with seasoning instructions
Consumers can find out about suppliers offering deliveries in their area that are certified as Ready to Burn by entering their post code here. As well as logs information is available on suppliers of wood briquettes, pellets and chip.
When logs are certified by Woodsure suppliers have to show they are sourced in line with government sustainability criteria. That requirement is most likely to be met by woodlands being assessed against the UK Woodland Assurance Standard (UKWAS), so that woodlands will continue to benefit future generations, not just providing timber and other products, but also maintaining biodiversity and natural ecological processes as well as giving social and economic benefits. The standard covers many aspects of woodland management. When trees are felled they will almost always be replaced with new tree planting that will absorb he carbon dioxide released by burning logs.
In the year 2021 many small scale log suppliers will not have the Woodsure certification but that is not a reason for ignoring them when making decisions on where to buy your logs. Small scale log suppliers are likely to source logs from a variety of local sources. They may produce logs from operations such as woodland thinning that encourages the growth of the remaining trees and from widening forest rides that will bring benefits to woodland wildlife such as butterflies, so will be contributing to sustainable management in its widest sense. When logs are sourced locally there will be lower carbon emissions from transport. It may be easier for customers of small scale producers to ask about precisely how the logs they are buying are produced.
More information for consumers can be found by following the link below to the Woodsure leaflet.
DEFRA has published two leaflets that are available via the links below.
For more information about wood fuel in Yorkshire follow the link to the Yorwoods website
Moor Sustainable Case studies using logs
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