Bishop’s Wood at Strathkinness is a wood of our own that provides Recreation, Woodfuel and Education, whilst Supporting Wildlife and Biodiversity. It is predominantly a self seeded birch wood with some beech, sycamore, goat willow, and conifers. Our Woodland Manager, Tony Wilson, brings students from Elmwood College to the woods for training which includes woodland maintenance.
We run woodfuel sessions that are very popular with Trust members and includes children. Wind blown and diseased trees are harvested and processed into stove and fire sized logs. Volunteers can take wood home in return for helping. Some wood is transferred to our large village drying/ seasoning store that was kindly made available by a villager. This wood is in netted bags and is available to buy once it has dried. We test the seasoned wood with a moisture meter making sure it is less than 20% moisture.
The photo below shows one of my own open fronted wood stores; it’s not as visually pleasing as those you find in Austria but it does the job. Freshly cut and split wood is approximately 50% moisture but stacked storage reduces this and after 12 months the wood is ready to burn. At point of sale our wood is typically 15% moisture. It is worth bringing cold seasoned wood indoors for 24 hours before burning it. This allows the wood to burn more efficiently and keep the amount of particulates released to the atmosphere to a minimum.
Our Trust is a member of Community Woodlands Association Scotland who have an advisory service and run excellent courses including a recent one on Woodfuel the recording of which I can forward to you. Also please let me or Iain Duncan know if you wish to have notice of future events. The woodfuel workshop had a lot of technical information on drying/ seasoning and the calorific values of different hard and soft woods.
Operating and maintaining a stove
Most stoves have two air vents, a Primary and a Secondary (airwash). It is important to use these to the manufacturer’s manual both on initial lighting of the stove and controlling it to get the highest efficiency and lowest pollution. Once the fire is going it can be controlled with the secondary vent and wood added in small amounts to keep it glowing as in the photograph above.
The photograph below shows a flue thermometer that is attached magnetically. This can be a useful way of controlling the burner’s efficiency by keeping the temperature within the white zone which for my stove is between 180 and 240 degrees C.
Stove maintenance is very important and stoves should be inspected for cracks in the metalwork and firebricks, door seal ropes replaced when frayed, interiors cleaned regularly, and flues cleaned regularly by a competent chimney sweep who will also report on the state of the flue. Burning unseasoned wood can lead to a build up of tar in the flue.
Current legislation and the development of wood burning
DEFRA have identified that burning wood and non smokeless house coal is the largest single contributor to small particle pollution that can be released into the home and outside. The WHO has classified these particulates ( PM 2.5) to be the most damaging air pollutant of all, and can lead to respiratory and cardiovascular diseases. In January 2019 DEFRA published a Clean Air Strategy which is now enforced in England but not yet in Scotland. However it includes useful guidelines that we can apply now. The Strategy requires that all wood sold for domestic combustion in volumes less than 2 cubic metres should be less than 20% moisture, a condition that we will continue to meet in our supply to the village.
In addition there are a new generation of wood burning stoves that are claimed to reduce particulates by 80% compared to older designs. These are designated ECOdesign Ready and will be the only stoves available in the near future. See hetos.co.uk for more information.
Is burning woodfuel good or bad for the environment?
The carbon balance for woodfuel is almost neutral I.e. the carbon dioxide given off in burning wood equates to that taken from the atmosphere as the tree grows. There is a very small deficit attributed to the processing e.g. chainsaw fuel/ transport nets and the transport itself to the home although in our case this again is minimal. Compared to heating our homes with fossil fuelled energy sources many would say this is a good choice; it’s up to each household to access the data and make their own choice. This would also apply to those with open fires that use woodfuel which are known to be less efficient than wood burners.
In Summary if you are thinking of going down the woodfuel route the following may be useful:
- Buy your woodfuel locally. Ask where it came from.
- Make sure it is dry with less than 20% moisture unless you intend on drying it yourself.
- Let your wood reach room temperature before you burn it.
- Get the most efficient stove you can afford and have it installed by a competent professional.
- Operate your stove to the handbook, maintain it regularly.
If you have any questions please contact me at firstname.lastname@example.org.