I have to cut down suckers every year on my three crabs. My suckers are just coming up from roots of the rootstock that are close to the surface. I cut them down every year and they return every year. They are diminishing, but slowly. I find that mulch helps. There is also a 'sucker' killer' spray you can buy. I have never used it. Mrs. G

Thanks for your response Mrs.G
I just added 2 pictures, showing the tree (about 12" diameter) and suckers. 5 or 6 suckers had become saplings of 2-5" diameter, which I cut off close to the root after the pic. My question is about all the nubby wood that developed because the suckers were ignored. Other than a few leaves, all the light colored areas are where suckers were growing. How much of that extra wood can I remove without hurting the tree?

here's the 2nd pic

I use a Felco hand saw and saw off the nubs! I saw them down, as close to the ground as I can get. It is important so that you don't trip over them for starters! First I add about four inches of soil, then use four inches of pine bark mulch (black is my preferred color) around the trees. My trees are only 12 years old so the trunks are not as large as yours but the problem is. I use enough mulch to make a four foot circle around each tree. I do this every two years and the problem is cut in half every year. No pun intended. Mrs. G

Thank you for your suggestions. I have completely removed the large suckers that had grown some inches away from the trunk. It is the hypertrophy close to the trunk that I am asking about. This is not my tree; I am a volunteer at a public property, so it isn't feasible to add enough topsoil and mulch to cover all the suckers. Also, I understood that putting so much over the roots and "coned" up the trunk is not healthy for trees and may even encourage sucker growth.

I never mentioned 'coned' up mulching, that is a bad idea. Keep your mulch four inches from your trunk. Mrs. G

I have no experience with what you are doing, but I have some thoughts. Being on a public property the trip thing is a big deal, right? so worth more risk? I think I would take a grub hoe or an axe (not a nice axe) and remove that to below ground part over a little time. Remember trees get a lot of damage naturally and survive. I would pick 25% or less of what is in that one photo and go after it and see how much root you wind up disconnecting from the tree. then decide if you can do more now. You can also prune it to balance out the loss of root

The big suckers that were trip hazards out on the tree roots have been sawed off. If this tree was on my property, I would do radical surgery on all the "bubbles" at the base of the tree and accept the consequences. Under the circumstances, cckw's suggestion to remove 25% (and also prune the top) seems reasonable. I probably removed that much, so I'll let it be for this year. Thanks -