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]

I don't know what is 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 from the fire (putting other 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