What it the best and most efficient way to poison unwanted leylandii trees?

Question

What it the best and most efficient way to poison unwanted leylandii trees?

Answer 1

I would advise AGAINST poisoning the trees because the toxins could

1) stay in the soil for a long, long time

2) accidentally poison other flora that you want to keep

3) poison pets and/or underground water

Why not just have the trees cut down, roots and all?

Answer 2

PEE ON THE TRUNK AHAHAHAHAHAHAHA

Answer 3

Chainsaw and shovel.

If you poison them, you have dead trees and still need the chainsaw and shovel to get rid of the corpses.