Burning Safety

Seasoning Wood

Wood should be seasoned (allowed to dry) before used as firewood. Moisture content of the wood should be below 20 percent. It usually takes at least six to nine months of drying time after cutting fresh wood to lower moisture content to this level. Burning wood with higher moisture contents produce more smoke and less heat. The smoke produced from burning “green” wood also adds to creosote buildup in chimneys that creates a potential fire hazard.

One way to estimate moisture content is to look at the ends of the wood pieces. If you see small splits in the ends, it is a good indicator its moisture content is low. You can also knock two pieces of wood together; dried wood has a distinct clinking sound, while green wood will have a more subdued sound.

Check out these characteristics of Illinois firewood

  • Red/Black Oak: Difficult to start | Generates few sparks | 24.4 million BTUs per cord
  • White /Bur Oak: Difficult to start | Generates few sparks | 26.5 million BTUs per cord
  • Shagbark Hickory: Moderate to start | Generates some sparks | 28.6 million BTUs per cord
  • Hard Maple: Moderate to start | Generates some sparks | 23.7 million BTUs per cord
  • Silver Maple: Moderate to start | Generates few sparks | 19.5 million BTUs per cord
  • Sycamore: Moderate to start | Generates few sparks | 20.7 million BTUs per cord
  • Osage Orange: Difficult to start | Generates many sparks | 30.7 million BTUs per cord
  • Black Locust: Difficult to start | Generates few sparks | 28.1 million BTUs per cord
  • Green Ash: Moderate to start | Generates few sparks | 23 million BTUs per cord
  • Black Walnut: Difficult to start | Generates few sparks | 22.3 million BTUs per cord
  • Cottonwood: Easy to start | Generates some sparks | 16.1 million BTUs per cord


Burning Safety


As with any appliance that works with high heat, regular maintenance of both the appliance and chimney is necessary for proper operation and to make sure there are no potential fire hazards.

  • Screens should be used in front of open fireplaces, to keep sparks from flying out onto combustible materials.
  • Fireplaces should be inspected each year to verify firebox integrity. Masonry fireplaces should not have cracks in the mortar or brick. 
  • With catalytic wood stoves, the combuster needs to be in good working order. 
  • In non catalytic stoves, baffles should be inspected.

If you are not sure what should be inspected, contact a professional. If you have someone clean your chimney, they are often trained to inspect the stove or fireplace as well.

Chimney Fires

One of the biggest safety concerns with wood burning is chimney fires. This occurs when exhaust gases cool and condense on chimney walls, creating creosote. This material is highly flammable. If allowed to build up, it can start burning in the chimney when heated.

  • Chimneys should be inspected and cleaned annually.
  • Creosote build -up can be decreased by making sure you use seasoned wood, having hot fires instead of long slow burning ones, or using low smoke producing systems.
  • Proper chimney caps should be in place to arrest sparks, and to keep your friendly neighborhood wildlife from visiting.
  • Ashes should be kept in a metal container with a lid. The container should not be placed next to or on top of combustible materials and should be outdoors.


Once the ashes have completely cooled, you can proceed to final disposal. If the ashes will be used as a soil amendment, be aware that most wood ash has a very high pH. It is best to spread the ashes out very thinly, usually not more than 15 pounds over 1000 square feet. Ash should not be used around plants that prefer acidic conditions. If you are not sure what your soil pH is, considered getting a soil test. If applying to compost, apply in 1/8 inch layers and mix. Wood ash is also accepted in landfills in Illinois.