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ESSE WH-S (UK) R3 210225
FIREWOOD AND THE WOODBURNING PROCESS
Seasoning and Storing Firewood
Wood, which has recently been cut and is still full of sap and water is known as
"green" wood.
Green wood will generally burn poorly and inefficiently, because it can have over
50% water in its cells. It may be hard to light, smoulder, not put out any heat
and cause more than the usual amount of creosote to build up in your chimney.
So your aim should be to dry the wood out to below 20% moisture content. This
process is called seasoning. As the name implies, you should store your wood
for a season or so, while it dries, but there are things you can do to speed up
seasoning by cutting the wood now rather than just before you use it.
Wood is composed of bundles of microscopic tubes that were used to transport
water from the roots of the tree to the leaves. These tubes will stay full of water
for years even after a tree is dead. This is why it is so important to have your
firewood cut to length for 6 months or more before you burn it, it gives this
water a chance to evaporate since the tube ends are finally open and the water
only has to migrate a small distance to escape. Splitting the wood helps too by
exposing more surface area to the sun and wind, but cutting the wood to shorter
lengths is of primary importance.
Here’s how you can tell whether your wood is ready or not: Well seasoned
firewood generally has darkened ends with cracks or splits visible, it is relatively
lightweight, and makes a clear "clunk" when two pieces are struck together.
Green wood on the other hand is very heavy, the ends look fresher, and it tends
to make a dull "thud" when struck.
Another thing you can do to help is store your wood properly. Store it off the
ground by building the pile on some longer logs (or whatever method you can
devise). A shed or shelter with an open side makes an ideal storage place, as the
air can circulate around the logs and help to dry them out. Unventilated spaces
or plastic tarps, which never get taken off will prevent the drying and
evaporation process and cause moulds and rot. So, if a tarp is your only option,
take it off frequently to air the wood on fine days. And remember to put it back
on again. Seasoned firewood will reabsorb large amounts of water if exposed to
