Nick Maclaren wrote:
Cut it off 3-4' above the ground, remove the stump and plant a
more suitable tree :-)

If you do decide to fell them, then my technique is to leave the trunks at
least 2m tall so you can lever the root out of the ground with them. Dig
round, and under, and then use the exposed length to rock them about to
break them loose of the soil. In bad cases I have run a chain from the top
of the stump to the car towing hitch, and loosened them like that. Try to
get all the roots out to avoid honey fungus.