Wind blowing over trees and grass in Unity 3

HI

I have created a tree by TreeCreator and then entered and applied it in terrain then created a wind by WindZone, but the tree didn't move. I mean the wind didn't have any impact neither on trees nor on grass I want to have trees movement by the wind that I had created

would you guide me please

Please give me the answer!

thanks

I can think of two things can be affecting: 1) Wind radius is too small or wind is not strong enough 2) Wind doesn't affect billboard trees, so you won't see any wind when camera is far away.