We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Gib Bogle
saying something like:

After cutting down the kind of tree that
will otherwise happily resprout, I drill holes into the stump (near the
bark) and inject glyphosate - it does the trick.

I've successfully used a handful of neat fertiliser granules down a
series of 1"x5" holes in a stump to kill it.