Removing tree stumps is a very sore point with me at present. I have a problem with the local council and one of their tenant's regarding a series of tree's placed alongside a fence that I have on a property I own. The tree's have caused damage to my property and fencing.
Due to the practices undertaken, the tree's were removed (cut down) from ground level, and it was promised that some form of chemicals would be used to kill the roots, due to the difficulty in 'digging out'. Now it would seem, the council are taking no further action, because on the advice of their Parks Department, "the roots would die naturally and cause no further harm".
It was also mentioned that using chemicals "might or will" damage other 'plant life' in the area, and this apparently is not acceptable to damage growing items?.
Once again, its battle stations between the council and myself, and a situation I could do well without.
Regarding getting a professional firm with a stump grinder, then in most cases they only grind to surface level, and the tree stump remains stay intact and at ground or slightly below ground level. Unless the stump is higher, and you decide to make the remains into a table/seat or such like, as Aitchbee neighbour as done!.
Be careful if drilling holes and filling with chemicals. I breathed in some of the fumes whilst doing that to a tree stump many years ago. The effect was loss of memory for a few hours afterwards. Very scary for my family but I was just away in the clouds somewhere. Good job my daughter got a doctor to me pretty quickly. So my advice is wear a gas mask if that is your chosen method.
woodchip - Diesel can contaminate the ground and is best avoided.
sunnystaines - An arborist recommended Vitax SBK to me (especially when dealing with ash saplings). It's main ingredients are Triclopyrtriethylamine salt and Triethylamine. But you have missed the best time which autumn/winter.