Tree colliders are not working

Hello, when I create a terrain with trees and tree collider is enabled, the character controller passes through. I have Unity4.2 on Windows7.
My character controller is fine and is blocked by any mesh colliders.

I don’t believe trees in the package have colliders by default so I’m guessing you gave it one yourself. Make sure Is Trigger isn’t checked. Other than that I don’t know what it could be.