Best Wood for Burning

By Thembi Borras

What is the best tree species for firewood? The answer is a function of abundance, availability, splitability, presence or lack thereof of messy sap, density and energy content.

The most abundant hardwood in the managed timberland on which I work is tanoak. The most available species for a low price or free are the less dense hardwoods and conifers, in fact I have found it hard to give pine and willow away. The most splitable woods are species that tend to have straight grain. Others have entangled fibers and can be very difficult to split. Some wood splits easiest when green such as live oak, madrone and tanoak and some split much easier when dry and brittle, such as fir and some pines. Obviously the conifers have the messy sap, and are not preferred because of their sap. Many people believe that burning sap will lead to excessive accumulations of creosote. However, if the wood burning system is functioning properly, above normal levels of creosote should not accumulate. The easiest and best fire is built by using a mixture of both softwoods and hardwoods. Softwoods start burning easily, and the hardwoods provide for long burning and good "coaling" qualities.

All wood, regardless of species, has about the same energy content per pound. The different species vary only in density. The higher the density, the higher the energy content per cord. A cord is 4' high by 4' deep and is 8' long. Energy content is often measured in British Thermal Units (BTUs). The following are the approximate number of BTUs produced per cord burned of local species: willow 18, redwood and grand fir 19, big leaf maple 22, western hemlock 23, California bay, black walnut and Douglas-fir 25, tanoak, white oak and black oak 27, madrone 30 and live oak 35.

Most folks will say madrone is the best tree species for firewood, but I encourage you to consider other species, which may be more available, less expensive and may be burnt regardless, in slash piles or wildland fires, without the benefit of heating your home. Ultimately, it is more important to have wood that is cut and split to the right size and properly dried than it is to get the most dense wood available.

For more information, visit the website http://www.woodheat.org/ and http://www.consumerenergycenter.org/homeandwork/homes/inside/heatandcool/fireplaces.html, from which this production was gleaned.