It's great to see so many people are burning wood to heat their homes. It makes a lot of sense, long may it continue. It seems though that my comment about softwood seemed to have raised a few questions. No problem everyone has their own point of view. If softwood hits your price point then go for it. But please read the following to understand some of the risks involved in burning high sap content wood.
Another type of wood that should not be in your fireplace, (specifically fireplaces with a chimney), are sap-saturated timbers.
Wood types that have a lot of tree sap or pitch in them, such as Cedar and Spruce, can increase the risk of a chimney fire. That’s because that thick resinous tree sap can collect in the soot lining your chimney flue. This can cause chimney blockages, which in turn can cause a fire.
What About Leylandii? This Wood Is Safe To Burn In A Fireplace, Right?
Leylandii tree sap can sometimes cause severe skin irritation. But, you’d have to burn a lot of Leylandii lumber (all at once) for heat-vaporised sap to become a real problem for you.
But, this alone should be a good enough reason to skip over using this particular tree for firewood. Nevertheless, if that isn’t a good enough reason, then the fire hazard Leylandii poses should be.
Burning this tree in a fireplace is not a good idea. And why is that? Well, because this tree’s lumber has a lot of sap in it.
In fact, it has enough thick tree resin in it to make it unsuitable for an indoor fireplace. What’s more, that excess sap will also produce a lot of extra thick smoke (as the sap evaporates).
Still, another reason to skip over Leylandii firewood, is the fact that it doesn’t produce that much heat.
And How Much Heat Does Leylandii Produce?
When it comes to firewood, if you want to know how much heat it produces, you need to check it’s BTU.
The BTU (British Thermal Unit) rating of a wood species refers to how much energy it takes for fire to burn that wood.
The higher the BTU, then the more energy it takes. And the more energy it takes, then the longer that wood will burn.
And if wood takes a long while to burn, that means it will produce heat for a lot longer too.
Now, when it comes to Leylandii, (also known as the Leyland Cypress), this wood has a decent 21.7 BTU. And to be perfectly honest, for a fairly soft timber, that BTU level is actually not too bad. It certainly isn’t low enough to dismiss Leylandii softwood as merely kindling.
Still, Leylandii doesn’t compare to traditional hardwood firewood. For example, White Oak has a BTU of 25.7, and Birch wood has a 23.6 BTU rating.
I'm just trying to help. If you are invested in softwood go for it. But having had chimney fires and having had to replace a chimney once in Canada, although not through softwood burning but rather not having access to chimney sweeps in a very rural area, I can tell you when you hear the sound of a jet airplane /blast furnace taking off in your chimney late at
night get ready and hold on. A tip, block off the oxygen.
I have also gone through this discussion with friends about using eucalyptus, which I have a lot of here. Slightly different problem, but although when properly seasoned you do lose the sap unfortunately the oil stays. It's another tree that will never burn in my home.