You can't find them in the wild. You have to evolve pineco. If
you havent got a pineco, then go to pewter city and headbutt trees.
Pineco should fall out at around level 5, which is bad news cos
they evolve at around level 30
To get Forretress you need to evolve a Pineco.
To get a Pineco you need a Pokemon that knows Headbutt. Use
Headbutt on a tree and a Pokemon will fall out. This can be a
Ilex Forest is an example where you can come upon Pineco by
Use headbutt on a tree and catch a pineco. then evolve it.
Get a Pineco via Headbutting a tree. You can headbutt trees at
places such as Ilex Forest to get one. Level it up to level 31 and
it should evolve into a Forretress.