It can be hard choosing between hardwood logs or softwood to burn in your stove or open fire. Here are some things to consider. Each of these wood-fuels have their own advantages and disadvantages. Choosing between hardwood and softwood logs will depend on moisture content, availability, budget, personal preferences, sustainability / timber source, calorific value and even the kind of fire you will burn them in.
Quality of Logs Moisture & Age
Regardless of whether you use hardwood or softwood you should only burn dry timber logs. At 20% moisture or below is best for burning. If you burn moist timber the fire will not reach as high a temperature. This will waste most of its heat energy turning the water to steam before the wood will ignite properly. This applys to both hardwood and softwood logs. However you dont need to buy kiln dried logs. Kiln dried logs are mostly imported timber often dired in kilns using unsustainable fossil fuel energy.
Most softwood doesnt store for as long as hardwood. So its best to source softwood felled in the past few years because fungi will begin to decay the wood faster than hardwood.
Timber Sources and Sustainability
Generally hardwoods take much longer to mature than softwood species. In Ireland in particular this means that hardwood for firewood is slowly running out because of our very low forest cover. This is due to high demand for hardwood. Its also because we dont plant enough hardwood species like Oak to provide a stream of forest thinnings. You must ask yourself then where does the hardwood that you burn come from? Some is imported. Currently a portion of hardwood on the market is from diseased forests affected by Ash dieback disease. This source of firewood will soon run out. The rest is from hedgerow trees.
You must always ask where your hardwood logs are sourced because most hedgerow trees are never replaced after being cleared by farmers. This is no longer acceptable as our countryside is being quickly denuded of trees. Make no bones about it. If you buy logs produced from hedgerow trees you are complicit in destruction of our countryside. So ALWAYS insist on knowing the source of your logs.
Softwood logs are generally sourced from thinnings from managed Sitka plantations which produce lumber for building and board production. We can talk all day about the good and bad of Sitka plantations. This is however a more sustainable / renewable source of firewood than hedgerows.
Calorific Value of Hardwood vs Softwood
The heat / calorific value you get from hardwood logs is greater per cubic metre than softwood. This is because in general hardwood is the denser wood. Without getting too techinacal this means you need 30% less hardwood logs to produce the same heat as a cubic metre of softwood. On the other hand softwood logs are normally 30% cheaper than hardwood. So you get what you pay for. Generally if you burn softwood you are being more sustainable than using hardwood (depending on the source of the wood).
One more thing to take into account when choosing hardwood or softwood logs. Softwood logs can spark. If you use a stove this will make no difference. However if you are still using an open fire you should use a spark guard just in case.
I hope this helps you choose what type of logs to burn in your fire. There’s a lot more to take into account than simply heat value. Sourcing sustainable firewood is more important than ever in our book. The choice is yours. More reading here.