Rob Davison expounded: Not meaning to offend anyone, but I'm not sure I
entirely understand
the 'horrid weed tree' attitude.

You're in New Zealand, where things may be under better control. You would
understand if you spent hours every spring pulling Norway maple seedlings out
of your flower beds, or if you saw the migratory birds going hungry because the
purple loosestrife crowded out their food plants.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"A tree never hits an automobile except in self defense." - Woody Allen