Can I burn pine/conifer/willow/poplar, or softwood on my wood burner?
Yes, of course, you can, as long as it’s dry and you meet any local regulations (smokeless zones, etc.). You may have heard that some types of wood cause tar or sap problems in chimneys, but that’s not true.
ALL wood needs to be burned at a high enough temperature to burn off the volatile gases from the resins and tars in all wood types.
Softwood tends to be less dense, so you might need considerably more softwood to get the same heat output. A kilo of softwood will give about the same heat energy as a kilo of hardwood, but it will take up more space in your store because it’s less dense. Pine and conifer are not suitable for open fires as they tend to spit and spark.
It’s essential to use dry wood. It should contain 20% moisture or less. Logs should not be too large – 5 inches wide (125mm) will give the best result. Using large logs to make the fire last longer reduces the burning temperature.
This wastes the unburned fuel gasses up the chimney and causes unnecessary air pollution. Log size is important as it dictates the all-important surface area to volume ratio, which in turn dictates the rate at which the flammable gasses are vapourised from the surface of the wood. This surface area/volume ratio is why a big log burns with less flame and why kindling burns furiously.