Stumps do present a challenge big stumps especially but green or dry they can be burned completely away with a little TLC. The main thing is you can't get in a big hurry unless you have a large piece of equipment like a excavator or a Cat 955 or larger. If you are like me you don't have such a luxury and have to rely on a smaller tractor or maybe even just an old Bronco like I have to.
The key is to get the stumps in a pile as tight as you can get them. Don't worry they don't have to be perfect just get them arranged so that they are stable and slightly leaning inward and don't try to burn the whole pile at one time. Trying to do that with minimal equipment will only lead to frustration and burning up a whole bunch of wood for nothing other than just to see some smoke.
It's best to do two or three at a time and try to arrange them with the root balls facing out and the stump butts (cut off parts) facing inward towards the center of the pile. build a fire in the middle to get some coals built up and once you get a good fire going (it doesn't have to be a gigantic 30' high roaring inferno just big enough to get to the point where when the coals are hot enough and you throw in new wood or brush it burns freely and not just sit and smoke. soon you will find that one or two stumps in the pile will seem like they are getting burned faster than in other areas of the pile so aim you main effort to this area at this point it don't take a lot of wood to do a lot of damage just keep throwing wood up tight against the stump or stumps that are burning the best and then take a break.
If you do have a tractor to work with all the better but even then don't get in a hurry and try to re-pile or push too hard you just want to push the burning stump and coals to the center on to the parts that are not burning as well most times just a slight bump is all that's needed to be effective. The main thing is to not push too hard because if you do you may push the stump on the other side over and out of the pile and when this happens you most times have to start all over. What you want to do is to keep working the fire into the center and as you do you will at a point have all three or four close enough to where they will be leaning inward and burn themselves up as they lean in on each other. When you get to this point you may see holes or spaces that are open in-between the stumps and it is helpful to stuff what wood you have laying around into these places to keep things going and at night when you are ready to go in for the night make sure you have some good sized pieces of wood cut you can lay on top of any open holes to keep the heat inside and in the morning you will probably find that at least two of the stumps are mostly gone and you then pull out the small easy to handle roots out and pile them on to what is left and start all over again. There is a lot of heat in the ground where the pile was and if you have a way to shake out what is left of last nights pile the that is great just bring in three or four new ones and arrange them the same way you did the others and start all over again using what is left to get the new pile going.
There is always going to be one stump that no matter what you do just wants to be a hard head. It is best to not fight it just burn that one right where it is, bring the pile to him and arrange other stumps and large pieces of wood neatly around this bully and keep adding wood and smaller stumps on top until it's gone. I have had stumps like this that took 15 or 20 other stumps and ho knows how much other wood and brush to finally get it down to size that could be use to start another stump pile going. When you go up against a really big hard head you may have to resort to really drastic measures. Fill up stump hole with brush and wood then pull the tree back up and have it rest on the burning pile of wood. I call this the hot foot method, it's kind of unorthodox and probably not should be tried at home but it will get the job done.:laughing: Once I got a good fire going under this tree it burned for a week when it was over only dirt and the main log was left.
Take your time, I like to just piddle around and enjoy the time outdoors while cleaning up and sometimes that includes a weeny roast with the grand kids or burn a marshmallow or two.
