How to get stumps to burn?

[CalG]

We had a three inch snow fall the other night, and with a "OK to burn when snow is on the ground" approval, I set the brush pile ablaze.
This was not a particularly small brush pile, about 8 feet high and 15 feet around. Started on a bunch of stumps I dug out over the years, with the first one about 8 years ago. The branches and brush just kept getting piled on.

It took about a gallon of old waste oil to get everything going, but the stuff did catch. At times the heat was too much to face even 20 feet away. I tended the burn for over four hours, always trying to get the core that defined the stumps as fuel rich and as hot as possible. The breeze picked up through the afternoon and the fire in that core got mighty hot!

Well, I left the fire when all the small stuff in the area was consumed. (Over four hours)
I went back after supper and "poked the bear", and got more flame licking around the stumps.

This morning I went out hoping to see just a pile of ashes. Hope dashed, the lions share of the stumps were still there. Fire trimmed for sure, but still big old hemloc stumps.

I guess I will just have to bury them!

 

[4570Man]

Dirt doesn’t burn. You have to pick them up with an excavator and drop them to knock the dirt out. 16” or so stumps will clean pretty good but the big ones are slow to deal with.

 

[Larry Caldwell]

Wood is pretty fireproof because of the water content. You tried burning them the wrong time of the year. Try in the fall after they have a chance to dry. If you want to help them along, drill a big hole, at least 1", into the heart and fill it with potassium nitrate. Amonium nitrate would be preferred, but it's hard to buy because it is explosive.

 

[CalG]

Dirt doesn’t burn. You have to pick them up with an excavator and drop them to knock the dirt out. 16” or so stumps will clean pretty good but the big ones are slow to deal with.

I've rolled these stumps around the back area plenty of times. letting the dirt fall. There was some dirt and rocks still, but not much.

Not any where near as much as wood left untouched would suggest.

 

[4570Man]

I've rolled these stumps around the back area plenty of times. letting the dirt fall. There was some dirt and rocks still, but not much.

Not any where near as much as wood left untouched would suggest.

It also takes a long time for a big stub to burn off. I find it helps to cut them off as short as possible before burning is attempted. I mostly just leave them in a pile or have them hauled off now. You’ll have to mess with a fire for a week straight to make any progress.

 

[Rockbadchild]

In stumps the wood density and water retention just make them almost impossible to burn. You should have tried to split them in a few pieces it would've helped, also the combination of small branches and big stumps don't work well, they end up at the bottom of the fire, covered in ashes and ashes are a good insulator. A big brush fire do emit lots of heat but its all flames and radian heat the actual fire is not that hot, relatively speaking.

So to answer the question ''How to get stumps to burn? '' that be by splitting them in as much as possible, burn with bigger wood (split and unsplit) with it to increase the inner heat, density and longevity of the fire and trying to elevated the stumps so it's not at the bottom of the fire (putting wood under it), you might have got it but regardless Stumps are still a b!@#$ to burn.

 

[RandyT]

If you think trying to burn stumps that are dug up are bad. Wait till somebody tries to burn the stump out of their yard and find that it works about once out of a thousand times, and you get the call afterwards to go grind the stump with all the ash and debris from them trying to light it.

 

[mikester]

Get it hot enough and everything will burn

 

[Mtsoxfan]

If you can plunge cut a hole through, or long drill, it will burn through faster. Fire needs air, and once you get a hole, any size cut into it, the stump will burn from inside out as well. I've done it on smaller, 24" thick stumps, positioned the cut vertically, and that hole gets larger as it burns. I've found it easier to cut/drill against the grain vs. from the "top" down.

 

[Richard]

I've burned many a stump..... I've never burned any stumps of size, in one fire. I know going in it might take 2-3 burns but in the end, they've always gone up in smoke.

First burn is to start drying them out and the second/third burn are the burns that actually get rid of them.

 

[lman]

I use a leaf blower to get the fire hot enough to start the stump and then pile dry wood around it. You will have to use the leaf blower occasionally to burn the stump.

 

[JJT]

Bury them. Now that they are scorched, they are pretty much fire proof

 

[Molalla1]

We had a three inch snow fall the other night, and with a "OK to burn when snow is on the ground" approval, I set the brush pile ablaze.
This was not a particularly small brush pile, about 8 feet high and 15 feet around. Started on a bunch of stumps I dug out over the years, with the first one about 8 years ago. The branches and brush just kept getting piled on.

It took about a gallon of old waste oil to get everything going, but the stuff did catch. At times the heat was too much to face even 20 feet away. I tended the burn for over four hours, always trying to get the core that defined the stumps as fuel rich and as hot as possible. The breeze picked up through the afternoon and the fire in that core got mighty hot!

Well, I left the fire when all the small stuff in the area was consumed. (Over four hours)
I went back after supper and "poked the bear", and got more flame licking around the stumps.

This morning I went out hoping to see just a pile of ashes. Hope dashed, the lions share of the stumps were still there. Fire trimmed for sure, but still big old hemloc stumps.

I guess I will just have to bury them!

Dirt doesn’t burn. You have to pick them up with an excavator and drop them to knock the dirt out. 16” or so stumps will clean pretty good but the big ones are slow to deal with.

This is key . . . I've burned some huge DF stumps (6-8) at a time . . . as 4570Man has stated, and I do the same is take an excavator and drop the stump many (as many as it takes) to clean all dirt off. I use some diesel (most) and some gas to start the burn off. Now I add a little air (backpack air) if needed. Now we all know that a bunch of DF stumps can and will burn for a few days . . .

 

[Bearsixty7]

Dirt doesn’t burn. You have to pick them up with an excavator and drop them to knock the dirt out. 16” or so stumps will clean pretty good but the big ones are slow to deal with.

I used a grapple on the T754C and it was able to make a huge amount of the dirt and rocks fall out. Sometimes I actually use the grapple to "grab" at the dirt ball and tear it off, sometimes I hoist it as high as possible and drop them.

We just burned 1 of 3 dozer piles last week, started Sunday evening and it burned until Wednesday with me restacking everyday with the grapple, then what was left smolder until Thursday when the rain came. We were really happy with how well it all burned down and have maybe 5% of the stumps left that will get piled onto the next dozer pile.

 

[nyone]

I typically leave the root ball up for about 1-2yr and let the rain wash off alot of the dirt and dry the stump out a bit. You still will need alot of brush for them to stay burning. Also just burning a single stump dosnt work unless you keep feed the fire. I also use a electric leaf blower to blow ash away.

 

[EddieWalker]

I've been burning stumps for the last 20 years in my burn pile. I just keep adding wood to the fire and eventually the stump disappears. It usually takes several burns for this to happen, but I'm also adding new stumps to the pile, so it's a never-ending process.

For me, I know it's not going to happen the first, second or even third time. But I also know that not all the logs I put on the burn pile are going to burn the first or second time either.

 

[oosik]

I have 100% pine on my property. Just for the hell of it - I burned one stump - still in the ground. It took at least 4 or 5 big fires to finally turn the stump to ash.

A side problem cropped up. At the very last burning - I noticed "little smokes" showing up. They were anywhere from five to twenty feet away from the stump. Then I realized - the major roots were burning also.

Not a good thing. I worked on putting these root fires out for over a month.

All this effort and it was not necessary. My stumps are all over 150 yards from the house and completely out of sight. NOW - Mother Nature takes care of any and all my stumps. They will rot away in 15 to 20 years.

 

[civilian]

I have 100% pine on my property. Just for the hell of it - I burned one stump - still in the ground. It took at least 4 or 5 big fires to finally turn the stump to ash.

A side problem cropped up. At the very last burning - I noticed "little smokes" showing up. They were anywhere from five to twenty feet away from the stump. Then I realized - the major roots were burning also.

Not a good thing. I worked on putting these root fires out for over a month.

All this effort and it was not necessary. My stumps are all over 150 yards from the house and completely out of sight. NOW - Mother Nature takes care of any and all my stumps. They will rot away in 15 to 20 years.

A local wild fire was started that way quite a few years back. Guy was burning a stump in the ground in the fall. Snow came thought it was out. Following spring winds kicked up, snow gone and a fire started if a pine forest. Quickly spread, lost some home and out buildings. That is one reason I won't burn stumps in the ground. Jon

 

[ponytug]

Not having a tool to get stumps out of the ground easily, I tend to leave the stumps in place.

For in ground stumps, I have helped speed up the decomposition process by drilling some large vertical holes 3/4-1.5" in diameter into the stumps and then filling the holes with urea or other high nitrogen fertilizer. Even in this dry climate, it really accelerates the decomposition. Great mushrooms as well.

All the best, Peter

 

[EscapedSuburbia]

The ubiquitous 24" Chinese PTO stump grinders are cheap enough that they're worth having if you don't want to leave stumps in the ground. I grind them in areas I mow and just cut them off short and leave them in areas where I don't. The only time I've dug them out is in the area where I'm building my pole barn. I had the excavator set them off in the woods to rot and they're much too heavy for my tractor to move to the burn pile. One of them is a cottonwood stump that's over 8' in diameter. Even moving it with the excavator was a dicey proposition.