Tagging Trees placed by tree paint

Hi i'm very new to Unity.

I used a prefab to have colliders on all trees that i place with unity, this works, but if I want to have a tag at a tree it don't work :/

i have made a simple collider detection to test that the tags do work

function OnControllerColliderHit (hit : ControllerColliderHit) {

if(hit.gameObject.tag == "Tree") { print("Bumped into a Tree!"); } }

i have test it on other products, but with the tree tag it doesn't. I also discovered that if you make a trigger of the collision detection with you trees. They still do collide with my character.

Do somebody know how to fix this?

thank you