You can't. But you can trade with someone who has a treeko!
The forest in Pal Park
You can't.
Hi I'm afraid you cant catch a Treeko but it is a starter Pokemon in Ruby, Sapphire, and Emerald.
you can't
you can't catch it in any version
Treeko cannot be caught, only gotten as a starter.
you must pick it as your starting Pokemon or trade someone who did
None - Pal Park from 3rd Gen.
evolve your treeko noob
evolve Treeko or trade over wi-fi
You can only catch treeko as a starter Pokemon or fight it on your rivals team if you choose mudkip.
you cannot get a treeko in platinum but you can get it if you migrate from leaf green.