Harvesting the Yule log, from Chambers Book of Days (via Wikimedia)
The Yule log was traditionally a large branch, trunk or whole tree brought indoors to burn slowly over the Christmas period and in to the New Year. Currently Yule concides with the 12 days of Christmas, 21st December to January 1st. What seems unclear is how the tree was treated before Yule, some accounts suggest it was freshly harvested however the use of oak (Quercus) in England as a favoured Yule log suggests at least two years planning ahead to allow the wood to dry sufficiently to burn well!
A magnificient ancient oak in the New Forest, Hampshire, U.K.
There is much interest now in the use of wood to heat homes in the UK because this is seen as a renewable fuel with a low net carbon output. Different woods are known to have different burning properties, some burn well even when freshly cut while others need two years of seasoning (drying) after cutting. One issue with wood is the carbon cost of fuel to fell it and transport it on an industrial scale – this means it is not a truly carbon neutral fuel.
A widely quoted poem atrributed to Honor Goodhart (Punch 1926) gives a valuable summary of the properties of many UK native timbers.
Logs to burn; logs to burn;
Logs to save the coal a turn.
Here’s a word to make you wise
when you hear the woodman’s cries;
Never heed his usual tale
That he’s splendid logs for sale
But read these lines & really learn
The proper kind of logs to burn.
Oak logs will warm you well,
If they’re old and dry.
Larch logs of pinewoods smell
But the sparks will fly.
Beech logs for Christmas time;
Yew logs heat well;
‘Scotch’ logs it is a crime
For anyone to sell.
Birch logs will burn too fast;
Chestnut scarce at all;
Hawthorn logs are good to last
If cut in the fall.
Holly logs will burn like wax,
You should burn them green;
Elm logs like smouldering flax,
No flame to be seen.
Pear logs and apple logs,
They will scent your room;
Cherry logs across the dogs
Smell like flowers in bloom,
But ash logs all smooth and grey
Burn them green or old,
Buy up all that come your way
They’re worth their weight in gold.
Honor Goodhart, 1926
Alongside these historic aides memoires there is much modern information on which wood to use for log burning stoves and open fires. The company ‘Flaming Fires’ has published a list including many species not mentioned in the poem above and the Forestry Commission have a detailed document on choosing firewood.
References
Chambers Book of Days (1832)