Fires and wood

The latest article for the Downsman.

Many folk in Handley use wood to heat their homes, either as their primary source of heating or for the reassurance and comfort that a fire brings. There is something about fire, we feel connected to it even in the modern world; we cling to it like an old friend. Light a fire in the absence of modern distractions and your eye is drawn and attention focused in a trancelike state upon those leaping flames.

Our ability to collect/control wild fire and ultimately make fire ourselves has influenced our evolution. Apart from the warmth and protection that fire brings, cooked food is easier to digest. You therefore need to catch or collect less. Time is freed up for more creative endeavours stimulating intellectual development and ultimately, through evolution, genes for larger brain development were selected. It’s not unreasonable to state that ‘we wouldn’t be human if we hadn’t formed a relationship with fire’

Timber suppliers are currently stockpiling wood cross cutting and splitting stacking back to dry. So come the autumn they are ready when we rush to our phones to call for our supply of split Ash and conifer kindling for the winter ahead. Maybe we source wood ourselves in which case we should be doing the same.

A useful poem was often used, which you may have heard, to remember the relative merits of different woods.

Conifers and birch get a bad review within this poem, and for good reason. They burn up quickly and fir spits quite badly. However it must be remembered that this poem was written when all house fires were open, the heat flaring up the chimney rather than being held in the embers. Different woods were also used for different fire types, i.e. birch bundles were used to heat up the bakers ovens.

Most people now use wood-burning stoves. These are much more efficient and spitting wood is not a problem. Wood-burners have been used in Scandinavia for 150 years, where they burn predominantly birch and conifers. Newer stoves are now made incredibly efficient by recirculating air-flow. New flues and flue liners reduce issues with tar build-up from conifers and ash build up in chimneys which can lead to chimney fires, in short you can burn any seasoned wood other than treated wood relatively cleanly and with less of a carbon footprint than conventional power generation. In fact it’s the ultimate renewable resource if managed well.

The Firewood Poem


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.

In this poem we find that ash is the best; but is it ?   The answer is yes; and no! In short it’s a wonderful wood for timber suppliers, during the winter it has the lowest moisture content of any standing wood meaning that it needs storing for less time and less carefully. However like all other woods it is better properly seasoned. It also splits very easily reducing processing costs and making it easier for clients to handle. But is ash the best wood for burning?

As you may know I have a background in science so lets get straight to the maths, its not overly complicated as we all have heating bills which are rated KWh a typical 4 bedroom houses uses 3200 KWh a year.

Wood is measured in KWh/m3 or per kg (kilowatt hours / m3).

Wood type Average Kwh/m3
Holly 3591
Hornbeam 3511
Beech 3032
Ash 2926
Oak 2926
Douglas Fir 2766
Birch 2660
Poplar 2022

The numbers in this table speak for themselves, but as we live in an area with a lot of beech it might be worth getting some, why not cut down that hornbeam hedge and burn, a replacement mixed fruit bearing hedge would be better for you and wildlife !

As these numbers are per m3 not by weight, you can burn any wood you like you just need more of it to get the same energy yield. So if you can negotiate a reduction for inferior wood have enough storage and don’t mind visiting the shed more often, go for it. There is also a certain wisdom in having a mixed pile so you can choose your wood depending on the temperature.

The figures are for energy contained in the fuel, even the best stoves are only 70% efficient which compared to 10% for an open fire is still good. Its also easy to forget that wood is incredibly variable even within a species there can be as much as 30% variance in density of growth depending on where and how the tree has grown. These figures are from Norway where wood is slower grown. I maintain that some of the best firewood is from old gnarled hawthorn and blackthorn hedge stools the wood is really dense and burns hot and slow.

You make up your own mind I will be burning a mixture of Ash, hazel, conifers and old hedge material because its what I have. If you can find well seasoned, Holly , Hornbeam or Beech snap it up, your wood pile will be much smaller.

Next:- Symbiosis in Ancient woodlands.

 

Good reads

Norwegian wood Chopping stacking and drying wood the Scandinavian way (Lars Mytting)

The man who made things from trees (Robert Penn)

The woodland way a permaculture approach to woodland management (Ben Law)

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