Weeping willow is a fast growing willow variety that will tolerate all kinds of soil as well as full sun or partial shade. Like many fast growing trees, willows have a short life expectancy. As willows die, one method to get rid of the wood is to chop it into firewood. But willows do not typically make good firewood.
Hardwoods vs. Softwoods
Willows are considered softwoods for the purposes of firewood. Softwoods are typically less dense than hardwoods with more air between the wood fibres. Because of this, softwoods will burn less hot for shorter periods of time. Hardwoods produce coals and over time produce more radiant heat. This helps to heat a home more efficiently than softwoods. Hardwoods are frequently used for wood stoves or for cooking, while softwoods may be used for starting fires and kindling.
Wet vs. Dry Willow
When willows are alive, they prefer wet environments. A willow that is planted near a water source will send its roots growing in the direction of that water source. When willows are cut down, their wood usually holds lots of water. For this reason, freshly cut wood will not burn at all. Willow wood must be seasoned or left to dry, for at least six months and preferably one year before it is possible to burn the wood.
Wood, like all fuel, is rated by BTUs, or British Thermal Units, a measurement of how much heat energy is needed to raise the temperature of 0.454kg. of water 1 degree Fahrenheit. BTUs of wood are typically expressed in energy per cord of wood. A cord is a stack of wood that is 4 feet tall by 8 feet wide and 4 feet deep or 128 cubic feet.
BTU of Willow
Willow has a low BTU compared to most other woods. The BTU of willow is 16.1. Comparatively, a hardwood such as ironwood has a BTU of 28.6. Despite this, if willow is all that is available locally, it may be more economically feasible to burn than a hardwood that must be hauled in. If local hardwoods are available to burn, they should be a primary choice for firewood. If no hardwood is available locally, willow is suitable for burning.