How to Choose the Right Firewood
Which firewood should you choose?
Different types of wood have different heat capacities and do not burn in the same way. Generally speaking, you should choose hard wood such as oak, beech, ash, hornbeam or fruit trees. They produce lovely flames and lots of embers, which glow for a long time.
Modern stoves will not tolerate damp wood or wood from species with a low calorific content – older stoves will often burn damp wood as their lower efficiency allows more oxygen into the burn chamber. This laos menas the older stove is burning your wood faster !
Some Sure signs of damp or low quality wood (fuel)
- Black glass after burning stove for around an hour – moisture and fly ash mixing to produce creosote
- Lack of heat from stove – moisture in wood is turning heat into steam
- Acrid smell – creosote and shiny black tar being produced from wet or bad quality wood.
- smoke back into room – can be caused by wet or bad quality wood not producing hot gases that are hot enough to over come coldness of flue.
Whatever wood you choose, it should be a dry as possible, ideally below 10% moisture content.- this is measurable with a wood moisture meter
Damp wood provides a great deal less heat and a large amount of the energy is used just to evaporate the water it contains. Moist wood also releases a lot of smoke, produces few flames and causes the stove, its glass door and the chimney to get dirty and soot up. Wood should be covered or sheltered from the rain but well ventilated. You should allow two years for the wood to dry properly. You will soon learn to estimate the dryness of the logs by holding them in your hand. The drier they are, the lighter they will feel and they will produce a clearer sound when you knock them together.
Wood that has been treated with chemicals, railway sleepers or chipboard quickly dirties the appliance, soots up the chimney and produces toxic fumes.
Beech and Ash
Firewood to be recommended: they dry quickly and are readily available. They should be stored under shelter as soon as they have been cut or split; otherwise they rot very quickly and lose their heat capacity. They are easy to ignite, provide good fires and bright flames.
An excellent fuel, but as opposed to other wood, must remain unsheltered for two years so that the rain can wash away the tannins it contains. Then it should be stored under shelter for another year or two before being suitable for burning. There is a significant proportion of sapwood (which burns too quickly) in small branches. Oak burns slowly, provides a steady fire and gives lovely embers. It is ideal for a barbecue and for slow burning.
Hornbeam and cherry wood, fruit trees
Excellent fuels but scarce. These are hard woods providing lovely steady flames, and give good embers. They are ideal for a barbecue and for slow burning.
Birch, lime, chestnut, poplar, robinia, acacia
These are broad-leaved trees producing soft wood. They provide nice, lively flames and few embers. This wood burns fast and can be used to light or rekindle the fire. Warning: poplar produces abundant and volatile embers. Robinia and acacia can cause embers to spit.
They produce a lot of heat but burn quickly; they spit embers and the resins they contain dirty the chimney. They should be avoided.
There are several traditional poems about firewood, giving advice on which are the best logs to burn. Here is just one example:
Beechwood fires are bright and clear
If the logs are kept a year,
Chestnut’s only good they say,
If for logs ’tis laid away.
Make a fire of Elder tree,
Death within your house will be;
But ash new or ash old,
Is fit for a queen with crown of gold.
Birch and fir logs burn too fast
Blaze up bright and do not last,
it is by the Irish said
Hawthorn bakes the sweetest bread.
Elm wood burns like churchyard mould,
E’en the very flames are cold
But Ash green or Ash brown
Is fit for a queen with golden crown.
Poplar gives a bitter smoke,
Fills your eyes and makes you choke,
Apple wood will scent your room
Pear wood smells like flowers in bloom
Oaken logs, if dry and old
keep away the winter’s cold
But Ash wet or Ash dry
a king shall warm his slippers by.