The message
from (P Verstege) contains these words:

What did work was to excavate around the stump and then drill numerous
holes through the stump as far sown as possible. Then I snapped it off
and filled in the hole. a Lot of work and only a small stump.

But what if Iwant to plant another tree there? Will the rotted
(rotting?) roots kill off any new roots? That's why I was thinking of
burning them out - so I can clear the ground for something else

No, but it might attract honey fungus.

If you want to plant something soon, don't use sulphuric acid on the
stump. Otherwise you can drill some deep holes into the wood and pour in
battery acid, and that will reduce the stump to (eventually) carbon, but
to a brittle mass fairly quickly.

Next time, take most of the branches off a tree you want out, cut round
the roots and attach a rope to as near the top as possible (taking into
consideration the strength of the trunk there) and using the height of
the tree as a lever, pull it over.

Then you'll have a rootball from which you can dig/crowbar/pickaxe the
earth from it.

--
Rusty Hinge http://www.users.zetnet.co.uk/hi-fi/tqt.htm

Dark thoughts about the Wumpus concerto played with piano,
iron bar and two sledge hammers. (Wumpus, 15/11/03)