There are 21 species of walnut trees around the world, but black walnut and English walnut are two of the most popular varieties in North America. They provide excellent wood for furniture and produce delicious, healthy nuts; but is walnut firewood any good? In this guide, we’ll take a close look at whether you’re okay to burn it.

Is walnut firewood okay for burning?

Walnut makes decent firewood that will burn clean when sufficiently seasoned for 6-24 months. It also provides a pleasant aroma and is easy to split. Compared to common firewood options like beech and hickory, walnut doesn’t produce as much heat, making it better suited to the shoulder season in colder regions.

  • A good-performing hardwood with a pleasant aroma.
  • The wood is an average performer on heat output, and it burns fast.
  • Creates a lot of ash which means more clean-up time.
Infographic of black walnut firewood data
A close look at the black walnut data.

Walnut firewood burn qualities

1. Heat output

The amount of heat provided by firewood is an important criterion for most of us. Whether you’re sitting around a campfire, curled up on the couch, or cooking on a pit, you need decent heat.

Walnut firewood produces 22.2 million BTUs per cord which makes it an average performer. It doesn’t heat as well as apple, oak, or pinyon, but it’s better than spruce, pine, and willow.

A good option is using walnut with another type of firewood that gives off more heat. You can also use it for shoulder wood when you only need to take a little chill off the air.  

Check out the following table comparing the heat output of elm to various other common types of firewood.  

Wood varietyHeat per Cord (Million BTUs)
Spruce15.5
White pine15.9
Walnut22.2
Apple27.0
Pinyon27.1
White oak29.1

As you can see from the table above, oak is excellent for heat output. But how does it score on the other criteria? Find out how oak compares to other firewood is this guide.

2. Smoke

Walnut doesn’t produce much smoke, so you won’t have to worry about stinging, red eyes from the fire. It outperforms wood like Douglas fir, sycamore, and pine as a clean-burning fuel.

You may hear people mention their walnut firewood is smoky, but that mostly results from green wood that hasn’t been given time to fully season. 

3. Ease of splitting

Most people will find splitting walnut is easy as the wood fibers are often straight. Like most types of trees, some will grow out and become twisted and knotty, making the job of splitting much harder.

You’ll want to get to work splitting your walnut firewood as soon as possible. This will speed up the drying process significantly, thanks to the increased surface area exposed to wind and sunlight. 

4. Sparks

Walnut doesn’t spark and pop when it burns which is an important consideration when choosing firewood. Some wood like pine is packed with sap and resin, making it prone to shooting out embers like a firecracker. This can be unsettling and it’s also a fire risk, whether you’re indoors or out in the wilderness sitting around a campfire. Learn more about whether pine is good firewood here.

5. Aroma

Walnut produces a pleasant fragrance that most people enjoy. It is deep and earthy with a slight nuttiness. While everyone has their personal smell preferences, many rate hardwoods like hickory, maple, and apple as better-smelling firewood. 

6. Coaling

Walnut produces excellent coals that’ll keep your fire producing heat for longer. It outperforms some varieties like basswood, white fir, and spruce firewood.

You’ll also find that walnut firewood creates a lot of ash. While some look at this as more work to clean up, it is ideal for use as garden fertilizer or sprinkled onto the lawn. This ash will reduce the soil’s acidity and add helpful nutrients.  

7. Creosote build-up

Creosote is a type of black tar that builds up inside chimneys. While harmless in small amounts, it can become a health hazard if allowed to build up over the years.

Like most hardwoods, walnut burns clean and doesn’t produce a lot of creosote. If given time to season, it will burn cleaner than softwoods like pine, cedar, and fir.  

Tips for seasoning walnut firewood

Seasoned wood has had most of its water content removed during the drying process. Burning walnut that hasn’t been seasoned is not a good idea unless you have no choice. The fragrance and smoke could be unpleasant.

Seasoning will be much quicker if you’re in a state like Texas. The hot, dry climate is ideal for seasoning. If you don’t have weather on your side, follow these tips to speed up the seasoning of walnut.

  • Cover the wood: use a tarp to protect the stacks from rain and snow while keeping one side exposed to the wind.
  • Space out the rows: create a series of stacks with a 3-5” gap between each one to assist with air circulation.
  • Stack in the right place: accelerate drying time by positioning the face of the stack towards the wind and avoiding shady areas.
  • Split the firewood: by splitting the logs, you increase the surface area that gets exposed to sunshine and wind.
  • Raise the wood: lay the wood on some planks or pallets to allow airflow under the wood.

Pros and cons of walnut firewood

Pros

  • A clean-burning wood with decent heat output
  • Emits a pleasant fragrance that most enjoy
  • Usually easy to split

Cons

  • Not always an easy type of firewood to find in the U.S.
  • May have better uses like in woodworking

Commonly asked questions

Why do walnut trees grow segregated?

Walnut trees produce juglone, a toxin that stops other trees and plants from using the soil nearby. This feature helps walnut trees to develop dense wood, ideal for woodworking and firewood. 

Can I burn green walnut firewood?

It is fine to burn small amounts of green walnut wood as kindling. Burning larger pieces of unseasoned walnut will generate a lot of smoke and most of the heat will be wasted evaporating the excess water.

A walnut tree chopped into logs
A single walnut tree can produce over a cord of firewood.

Fast facts about walnut trees

  • Large black walnut trees can provide a cord of firewood or more.
  • The walnut tree is a large deciduous with lush foliage and can grow to over 140 feet in height.
  • Walnut trees have the botanical name Juglans and are part of the family Juglandaceae.
  • Their bark is dark and ridged while each leaf is divided into smaller leaflets (pinnate).
  • Black walnut trees are popular for use in the furniture industry, which has made them a scarce commodity.

Summing up

Although walnut doesn’t match up to popular firewood like oak or hickory for heat output, it’s still a reasonable choice for firewood. People often choose to use walnut in the shoulder seasons. It also burns well, making it a handy option for combining with other hardwoods that burn hotter.

If you hear people complaining about walnut giving off smoke, that’s usually because it hasn’t been dried for long enough. Be sure to age it sufficiently and if you can’t wait, only use it for getting fires started.

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