Burning Black Walnut

I have burned tons of black walnut in the past 3 years. Not hyperbole, I have burned more than 4,000 pounds of this stuff.
I have 39 acres of the NC mountains and I have hundreds of black walnut trees.
They kill the garden also I whacked one to make a beautiful summer beam for my log cabin, lots of scrap from that big tree.

Black walnut is midway on the chart. Not as good as oak lots better than pine. Makes decent coals.
I have found it to be very good firewood, easy to start makes nice flame in my big Oslo. Gonna light the big Norwegian stove up with pine kindling, and black walnut, tonight.

I am not messing with any more of it on purpose, if one is in my way I will cut it up and burn but I have access to Oak and Hickory, why use black walnut if you can use Hickory.

Everyone in the northeast have BW occasionally. Its rare for a BW to be purchased. It if fair firewood and makes a lot of ash IMO.

It's good firewood but yes, lots of ash. Also I heard the ash can kill plants if you put it in a garden so I scattered the ash on the lawn to kill the crabgrass. No such luck.

I wouldn't be surprised if the ash would kill plants because that black walnut is some freaky wood.
I worked long and hard to make a garden up here, planted a bunch of blueberry bushes that cost $25 each, had a bunch of potatoes in there, corn, a bunch of stuff. And it all died.
A local guy was up here doing some back hoe work and he told me that the nearby black walnut tree had killed the garden.
So, that was the first black walnut to go into the wood stove.

Also, as I said I made a huge summerbeam for my log cabin addition, it is 24 feet long and 18 inches high. I am sitting beneath it right now and I must say it is beautiful.
But, it was hard to make. I cut it with my chainsaw. Let it set in the carport 2 years to cure.
On construction day I brought it into the house under construction and it was time to sand it down. Used a 7 inch disc grinder.
I put my helper on it, and I had him wear a respirator. In fifteen minutes he was about to pass out. I told him to go home, he was having an allergic reaction to that fine sawdust powder of the black walnut. There are toxins in the wood.

So I had to sand that beam down by myself and it took about 8 hours total. Of course I wore the respirator, the stuff made me a little sick but it didn't bother me as much as it did my helper.

Black walnut is a freaky tree with some powerful toxins in the wood.
As I said I have burned tons of it and never had a problem, breathing in a little smoke from the black walnut.

In my experience it has to be really dry and even then it still can charr more than burn with a nice flame, I would give it about a 7 or 7.5 out of 10. But years ago I cut some that had the bark off of it and was very solid and was a decent sized tree, and man did that one burn great, very lively and really threw the heat. I have seen that happen before, sometimes some trees in the same species burn better than others, but I will cut and burn it if it is available, I just don't go head over heels if I find it but I will take it.

I don't know, the comment about "it will char more than burn with a nice flame." I haven't had that problem, my black walnut like I said is easy to light and gives off a real nice flame in my Jotul Oslo.

Now my black walnut is very dry, go over to the adjacent thread and you will see what my badass woodshed will do even with hickory. Under the thread "13 Percent in 8 Months."

So if will get hickory that dry that quick I'm sure the black walnut it really dry.

when my black walnut was wet, it took a little longer to light, and it would just char up. now that it is really dry, it lights easy, but it does create a lot of ash.

Id rank it with cherry, I dont turn it away. Has a real pretty blue/purple flame when you turn the air down to get secondaries. It does produce white fluffy ash.... i wouldnt say more ash, its just this ash doent crumble and compress into dust like other hardwoods.

yooper08 said:

I have a cord of black walnut I'm burning this year. Just curious what others have experienced burning this stuff as I'm trying to figure out how this stuff burns. I'm assuming there aren't too many who have burned it since it usually gets sold for lumber.

I know its low on the BTU chart, so I'm using it during the shoulder seasons, but it seems like it doesn't burn with much a flame and also seems hard to start and/or keep going (it's certainly dry enough). Also lots of ash, probably due to the thicker bark than most other species.

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Burns fine, rots slow. Have tons of it here and will for years. I take the bark off when I can, just all around better- drier, fewer bugs, less messy. And generally the bark pops off after a season of drying. I spread the ashes thin on the "lawn", I'm not taking chances of poisoning my garden.

I burned a bunch of it near the end of last season. It made heat and a good loadof big splits would leave me plenty of coals after being gone 10-12 hours. The smoke seems to have a odd smell. Not bad just diffrent, sharper with a kind of tang to it.

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Yeah, I know what you mean, the smoke has a kind of tang to it. Doesn't smell bad, just different from the other wood.

I love the smell (smoke)of BW.

I cut a 30” BW on a fence row this summer. It had been dead so long the smallest limb on it was 4”. The rest had fallen off. I was shocked at how hard that wood was. The crotches worked my splitter over!! Some of them stopped my splitter. I don’t think that has ever happened. Moisture was 25% when I split. I will see how it burns next year


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I burn it mixed with something else. It leaves the finest powdered ash in your stove. Like baby powder. If you split from huge rounds the heartwood is very dense and burns really nice. All this is totally seasoned. 2 to 3 years. I have walnut seasoned 10 years and still hard and dense..

Here is my black walnut summerbeam. It is 24 feet long, 18 inches high and 8 inches thick. The king post is also black walnut.
Very good work to work with, for the carpenter, except that the sawdust is toxic.

Simonkenton said:

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Here is my black walnut summerbeam. It is 24 feet long, 18 inches high and 8 inches thick. The king post is also black walnut.
Very good work to work with, for the carpenter, except that the sawdust is toxic.

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Beautiful work there, Simon.

But if BW sawdust was toxic, I’d be dead. I’ve worked with plenty of black walnut, machining with router, table saw, etc. I also processed and burned about 20 cords of it 2011 - 2014. Several beams in my house are black walnut, not a particularly good beam material, but it’s what they had to clear on this property back when this house was built and then expanded (1738-1779).

But, it is toxic. I had a real good helper, we had to sand down that big beam using a 7 inch disc grinder. This generates about 5 pounds a day of sawdust, real fine powder like flour.
My helper had a respirator on, that face mask with two circular filters on it costs about 30 bucks.
In fifteen minutes Adam was so sick he had to go sit down. I told him to go home.
I had to sand it myself and it made me sick too. Just not as sick as my helper. Sanded that beam for about 8 hours.

Now, I sawed that giant beam from the big black walnut tree trunks with my big chainsaw, ripped the sides off of it and the kingpost too. Probably 3 hours of sawing.
No problem with that big wet sawdust but that fine powder from the dry beam made both of us sick.

For a comparison, we sanded the entire interior of the log cabin with the same sander. Same deal, respirator on. The walls are 11 feet high, the cabin is 20 feet by 24 feet so there is ten times, twenty times as much wall surface as the surface area of the black walnut beam.
Forty hours or more of sanding the walls. The logs are white pine. No problem with that fine sawdust.

Interesting. I wonder if it's toxicity, or allergy? Working with red cedar gives me symptoms similar to hay fever and hives, I clearly have some sort of cedar allergy. No issues with Black Walnut for me, but I don't do a ton of sanding, either. When I do, it's usually less than 30 minutes with the RO sander and dust collector attached. I'm also not doing this professionally, just a hobbyist woodworker and old house guy.

Simon is right, the sawdust is toxic to some anlmals..
Good friend of mine had a boarding stable for 30 years, they used sawdust for the stahls, if there was any black walnut in the sawdust it can kill a horse..

How about that, the sawdust would kill some of the horses.
When I sawed out that summerbeam, I was using the big Stihl for hours, and I would be covered in sawdust. Of course this was big chainsaw sawdust from a green tree trunk, the sawdust was wet. Didn't bother me a bit.

That is why I was so surprised two years later when that dry powder sawdust from the same tree hit me so hard and hit my helper even harder. It is some freaky wood.

Here I am sanding the summerbeam.




Here is where I sawed out the summerbeam with the big Stihl. I had to whack the sides out as soon as I got it out of the woods because it was too big to move with my home made log cart.
I put this beam in the carport and let it dry for 2 years it lost a lot more water weight, probably lost 100 pounds there in the carport.

This big beam was 19 feet long, 18 inches high and 8 inches thick. The summerbeam is in two pieces, they are spliced together above the king post, the other part is 8 feet long.
I liked working with, sawing the black walnut and cutting the slots for the beams to fit in to, I enjoyed sawing that huge timber out of the big trunk.

Only thing I didn't like was sanding it down.