raycruzer said:

In my neighborhood of N.E. Los Angeles (Mt. Washington), the tree of
heaven (Ailanthus altissima) is rapdily encroaching on vacant hillsides
on both sides of my property and attempting to invade my own garden, as
well.

snip

Any suggestions
on how to restrain or destroy these heavenly devils will be
appreciated.

Cut them down and swab the stump with brush killer.
Even then, be on the lookout for sprouts from distant roots.

This plant aggressively resprouts from any bit of root. And I've had
apparently dead stumps send up shoots after a whole year of inactivity
(however impossible that seems, I swear it happened).

The seedlings grow deceptively slowly the first year. All their energy
seems to go to producing a massive root system.
--
Pat in Plymouth MI ('someplace.net' is comcast)

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)