Mass placed trees on terrain look awfull in the distance (fully lit) and arent affected by wind.

Hello! Ive created a number of trees with unitys tree creator. Im using the Fog image effect for the camera making the trees silhouetting in the distance. Now when i drag out a tree prefab into the scene they are very well integrated. But when i try massplacing trees they are 1. Static, 2. Fully lit in the distance. I provide a picture taken that shows the difference. Is there any way of solving this?

Thanks!!