Scripts on tree prefab don't respond?

I made a tree prefab with a script that tells it to fade out when it's too close to the camera. It works when I simply pull the prefab onto the terrain, but not when I load the tree into the terrain editor, and paint them to the terrain. Why is this? I like where I have placed my trees using the terrain editor- I just want them to fade out when/if there in they're blocking my view. Is there a way to still accomplish this with the terrain editor?