Which Types of Firewood are Toxic?

This question does not cross the minds of many campers, because of their excitement for one of the sweetest virtues of their next camping trip: the Bonfire. But to ensure the safety of all campers involved, this question needs to be addressed at length.

While most campers do not come across many complications when it comes to firewood, this question is an important one to consider for those with special health concerns. There are materials that should be avoided when making a fire for the benefit of all those present. The best material to burn for a bonfire is one that is not living, wood that is locally available, non-driftwood, non-poisonous, and is presently dry. 

What is “Firewood”, and What is Safe to Burn? 

In the scope of this article, I will mostly be focusing on talking about using wood to make a fire, since wood is typically the best material for campers to burn at their campgrounds. This is because wood is the most abundant material for most campers, it is overall the safest to burn, and it is the easiest to burn. 

Firewood is commonly broken down into two categories: hardwood and softwood. Hardwood is much denser than softwood, so they burn slower, hotter, and more intensely. This wood is best for creating a long-lasting fire for cooking; after, of course, the fire has been built up by softwood. Softwood is much easier to light than hardwoods, and they burn quicker with more smoke; perfect for starting a bonfire. Virtually all of the most common hardwood and softwood trees in North America are safe to burn. 

At the end of this article, I have listed three types of hardwood and three types of softwood and how to identify them in the wild. This will be helpful to know when you need to find the right wood to burn. Keep in mind, however, that many campgrounds may supply you with firewood so you won’t have to search for the right type of wood: but be prepared anyway.

Which Types of Firewood Are Unsafe to Burn?  

Most hard and softwoods that you run into in the forests of Northern America will be pretty safe to burn (note: do not bring wood from a different location with you camping. You will invite invasive wood pests or creatures to come to inhabit a new forest). According to the EPA, materials like driftwood, plywood, cardboard, pressure-treated wood, rotten/moldy wood, and anything that is covered by a poisonous material (glue, plastic, rubber, asbestos, animal remains, and certain plant matter) are off-limits for burning. 

Anything covered in a vine or containing poison ivy, poison sumac, or poison oak needs to be avoided, especially if you are planning to cook over this fire. If you are suffering from any sort of respiratory illness this will only underscore the importance of carefully considering what you are burning. 

Avoid Fresh Wood

One thing to avoid is fresh wood. If you are burning newly cut wood you are risking burning any accompanying vines, or the leaves themselves. When wood is fresh it has moisture and any accompanying toxins. Even if there were toxins in the wood and leaves, if the wood has been dead for over 6 months it should be safe to use.

I recently saw a little girl’s face that was red and swollen from an allergic reaction due to burning a pile of fresh wood. It’s impossible to know if it was a particular tree type–in any case, you run many more risks if you are burning freshly felled trees.

Besides the risk of toxins, fresh wood puts off so much more smoke–which isn’t very fun at all to be around.

Is Burning Rotten Wood Unsafe?

Rotten wood is full of moisture as it soaks up the water from the atmosphere and the ground around it. This will create a buildup of mold, and this is not something you want floating around by the food you are trying to cook. If only the outside of the wood is damp, but the heartwood inside is nice and dry, you may consider using this in your fire. If the whole piece of wood is soaked, then it is probably best to find a different piece of wood. Using drier wood is better for the life of your next fire as well as the lives of the people sitting around it. 

What Wood is Toxic for Cooking?

Truthfully, there are a few strange species that you should not cook over, and I have included a link to a site with complete details on all of those different species down below in “Possible Side Effects”. There are not many risks with most of the common types of trees around North America. When we are trying to smoke or cook meat, hardwood is the best bet.

Hardwoods such as Oak, Hickory, Maple, Pecan, and Cherry are all fantastic types to use if you can get your hands on them, but you shouldn’t worry too much about any toxic buildup on your food. I would advise, however, that you stray from using most pine trees to cook with because the sap will get on the food and create a sticky texture. 

If you would like some helpful starter information about cooking over a fire, we laid it all out and talked about lots of helpful tools and some caveats, you should check out our post about cooking over a fire if you’d like to know more.

If you have trouble getting the fire started, I actually use a couple gadgets I think are really cool. You can check out what I like to use here.

Is Wood Smoke Toxic? 

Burning things such as Sumac, Oleander, Rhododendron, and Poison Ivy are all known to create toxic smoke and in some cases even cause lung damage. These are obviously not good materials to be burning in your next fire, but there also comes a risk from burning regular types of wood.  According to the Department of Ecology of the State of Washington, “Wood smoke contains tiny particles and gases that can have serious health effects when breathed…Much like cigarette smoke, wood smoke contains hundreds of air pollutants that can cause cancer and other health problems”. 

When you have to burn wood, make sure you use the driest wood available. Living wood is prone to releasing much more smoke into the air, so stay away from greenwood. Also make sure to keep the fire burning hot by giving the fire room to “breathe”, or exposing it to more oxygen. Low-temperature fires will tend to not burn as well and actually create a higher level of smoke as they die down. 

Possible Side Effects 

For a complete list of the health concerns when it comes to choosing the right wood for your fire, feel free to check out this useful site. For now, here is a list of the possible complications with burning unknown wood: 

  • Irritant
  • Nausea 
  • Giddiness
  • Vomiting 
  • Sensitizer
  • Nervous System Effects 
  • Asthma
  • Sneezing
  • Nose Bleeds 
  • Pink Eye
  • Excessive Thirst
  • Rash
  • Lesions
  • Swelling Skins 
  • Blisters 
  • Stomach Cramps 
  • Bronchitis 
  • Headaches
  • Boils
  • Wheezing
  • Coughing
  • Hives
  • Fainting

Types of Hardwood: 

Oak: These trees are extremely common in North America. All oak trees can be identified as such if they have acorns, lobed leaves that have rounded or pointed knobs extending out from their centers, and small, scaly pieces of bark that looks like the back of a reptile.

Birch: These trees are naturally found in cooler, northern climates, and they all are easily identified by their paper-thin peeling bark that is normally a mix of white, silver, and black. Their leaves are usually 2-3 inches long and are oval-shaped with saw-toothed edges. 

Ash: Ash trees are easily mistaken for other types of hardwood trees, (which are all excellent for a slow cooking fire) such as black walnut, hickory, and elm. Ash trees have an “opposite branching arrangement” in their branches, meaning that the branches on both sides of the tree are directly across from each other.

If a branch has fallen off, check for a bud where the branch should have been. Ash trees also have distinctive “compound leaves” with 5-11 leaflets per compound. This means that 5-11 leaves come off of a single stem. Lastly, these trees have a diamond-shaped pattern bark that tends to be gray-brown.

Types of Softwood: 

Cedar: Western Red Cedars have reddish-brown bark with vertical ridges up the tree, and cones that are reddish as well. Their leaves grow in pairs at a 90-degree angle, so that it creates a flat-looking structure. These trees are found mostly in the Pacific Northwest at a lower elevation. 

Pine: These trees obviously have needles instead of leaves, and these needles grow in clusters in either 2s, 3s, or 5s. They are also home to hard and thick cones, as opposed to other conifers that have flaky feeling cones. 

Larch: These trees prefer the colder climates of high mountains and in the Northern parts of North America. They are one the only coniferous trees to lose their needles in the fall, and they can be identified by their needle cluster and single cone combination per shoot. 

Last Thoughts

When it comes to building a fire at your next campsite, whether its for heat, cooking, or simply for social reasons, make sure to create it inside of a prepared fire pit. Most campsites have these set up for you, but at some primitive sites you might have to create one by building one by making a small circle of rocks away from anything flammable.

Even the type of rocks you choose for your fire could be dangerous! Rocks actually explode! It’s a well-documented phenomenon. If you want to learn which rocks are safe to use for a campfire, check out our post here.

Most sites will have collections of wood ready for you to use, but be prepared to scavenge for more scrapes of dry wood if necessary. Take some time to study the types of hardwood and softwood trees that were listed out so that in a pinch you can gather the best wood for your next adventure. 


Peter is a software developer who loves to take every opportunity to go outside that he can get. Peter grew up going on long backpacking excursions with his family every Summer and now enjoys staying at the beautiful Texas State Parks and swimming in the amazing Texas Rivers.

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