How do I change a game object prefab tree to allow it to move in the wind?

Hello, sorry for the basic question, I'm still trying to work out how to use Unity. I need my trees to be game objects rather than painted onto the terrain. Is there any way to make them move in the wind, similar to those painted on the terrain? As when I'm using a basic unity prefab tree, I can't find any way to adjust the bend in the tree, allowing it to move. Thanks, Laurien