A crackling fire is a great way to stay warm in the cold months, but using the right firewood is essential. While some types of wood produce unpleasant odors, others can be hazardous to your health or the environment.

This guide reveals the types of wood to never burn in a fireplace. Whether fire heats your home or you simply want a campfire to toast marshmallows, check this list first.

What types of wood should I never burn?

Never use wood from endangered species or trees with the word “poison” in their name as the smoke could be toxic. While it’s possible to burn rotten, wet, or moldy wood outdoors, it will result in a smelly, smoky fire.

Wood that has been treated, painted, or processed should never be tossed in the fire. Avoid non-local firewood as it may harbor pests and diseases that haven’t reached the area where you live.

1. Unseasoned wood

Unseasoned wood hasn’t had the chance to dry out properly. It may contain over 50% water content which isn’t ideal for burning. Green wood uses most of its energy to evaporate moisture instead of giving off heat. That means you get an inefficient fire that doesn’t keep the room warm.

A log of unseasoned wood chopped into pieces.

Unseasoned firewood causes other problems for a fire. Instead of burning clean, most types of wood will smoke, spark, and give off excessive creosote.

Depending on the local climate and tree species, seasoning can take anywhere from six months to two years. We strongly recommend allowing enough time for the split logs to dry out. 

2. Non-local wood

Pests and diseases can rapidly wipe out tree populations, so they need to be contained. Firewood that gets transported around the country is the biggest cause of diseases and invasive insects spreading.

Always check with firewood suppliers that their product is locally sourced. If nearby towns are being invaded by insects like the Asian longhorned beetle, emerald ash borer, or goldspotted oak borer, then avoid buying wood from even a few miles away. You may bring more than firewood back to your home.

Campers should never collect firewood and take it home. This is common way threats to trees disperse into new towns.

3. Ocean driftwood

Salty driftwood from the ocean can release harmful or toxic fumes, such as dioxin, as it burns. Source. The elderly, children, and asthma sufferers are especially at risk from using this fuel source.

Driftwood should never be used in wood stoves. The salty water within the wood will become corrosive steam as it’s heated. Steel and cast-iron wood burners will have a shortened life when using an abrasive variety of wood.

Driftwood lying on the beach

4. Endangered species

Endangered trees have enough to deal with without us chopping them down too. Make sure that you check before felling a tree.

Some endangered trees include the American chestnut, Maple-Leaf oak, Fraser fir, Blue ash, Florida yew, and Kentucky coffeetree. Of course, if the tree has fallen, don’t let it go to waste.

5. Rotten wood

Rotten or moldy wood is a terrible option for a fire. As it burns, the fire will give off a foul stench ranging from cat pee to vomit.

There are also health risks from burning wood covered in mold. The smoke may cause allergic reactions, asthma, and other respiratory issues. 

Closeup of mold and moss growing on an old log

6. Poisonous trees

Some wood contains oils like urushiol that can cause various health complications. Trees, shrubs, and any plant that has poison in its name shouldn’t be burned.

Some examples include poison oak, poison sumac, and poison ivy. Other steer-clear species include the Mexican or Black Elder and the Oleander (aka nerium).

7. Painted wood

If the temperature drops and you don’t have a stash of firewood sorted, don’t resort to leftover painted or stained wood. They probably contain toxic chemicals you don’t want to breathe in.

Old timber with yellow paint peeling off

8. Wood pallets

Wooden pallets are excellent for stacking firewood on as they allow airflow underneath. But they’re not recommended for burning as the chemicals used to treat the timber can be harmful.

If you don’t need pallets for stacking firewood on, consider using them for coffee tables, shoe organizers, or even a bookshelf!

9. Construction materials

Manufactured wood like particle board (aka chipboard) or plywood is toxic and should be taken to a landfill or recycled. These materials contain various chemicals and glues that may cause reactions or produce carcinogenic smoke when thrown into a fire.

Plywood offcuts in a pile

10. Pressure-treated lumber

Wood that’s been pressure treated contains preservatives to ward off insects and rot. It isn’t meant for burning and will produce noxious fumes. Instead, use this lumber for other projects or toss it into landfill.

11. Christmas trees

While it’s often not a problem to burn softwoods like pine, remember that Xmas trees haven’t been seasoned. They’re loaded with sap and resin, so you’ll get a smoky fire and a lot of creosote.  

What non-wood materials should stay out of the fire?

  • Trash: Unwanted rubbish gives off foul smells as it burns and can release unhealthy chemical emissions. This includes food scraps, wrappers, juice cartons, and cereal boxes.
  • Plastic: Burning plastic is terrible for the environment, releasing unpleasant black smoke and hazardous fumes. It also makes a mess of your fireplace.
  • Cardboard: Besides the toxicity of burning cardboard, pieces can float out from the fireplace and create a much bigger, unwanted fire.
  • Magazines: Used reading material contains ink that isn’t meant for burning. Try to give your used mags to a library or local small business.
  • Styrofoam: Used everywhere in packaging, styrofoam doesn’t burn well and releases black sooty smoke that is highly unpleasant.
  • Clothing: Materials used to make clothes will stink as they burn and line your chimney with creosote.
  • Coal: If you’ve got a wood-burning stove, then avoid coal. It burns much hotter than firewood and can damage the stove.
  • Accelerants: Don’t be tempted to start the fire quicker with the help of kerosene or gasoline. They are highly flammable, and the flare-ups could start an unwanted fire or cause burns.

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