Once the trees have been taken down the stumps can be treated to prevent re-growth, or we can grind out the main stump. In both instances the remaining roots will die off and rot away so no further action will be needed.

I've done a few jobs like this and what I done was cut trees down leaving a half decent stump and then used my 3 tonne digger to dig around and remove the whole stump plus roots surrounding it(biggest roots) The rest will then die off. Depending on how deep the whole is quality top soil would be re introduced or if deeper type 1 stone then soil

It simply just depends on the size and type of trees as some are shallow rooted some are deep rooted pick around the roots leave at least 3 foot stump for leverage it should rock out with a little help from a pinch bar

Best way to remove a stump is with a stump grinder if access is available but if you didn’t want the cost of stump grinding there is a stump treatment service using eco plugs nice easy and safe way to prevent your stump from ever growing again