trees look shitty after build ?

after i build my game (meant for oculus VR)
my trees from the standard assets look (that i have made to move with the wind) look really bad
they are no longer 3D and move a bit to face the player.
only if i stand close a tree i see it normally. as if there is some kind of unwanted optimization

(also i have no resolution settings on game start- dont know if this is connected)
Thanks !,after i build my game (meant for oculus vr)
the trees from the standard assets wich i have made to move with the wind loor really bad
the are no longer 3D and the move to face the camera.
only if i walk right next to a tree i can see it normally
as if the game is doing some kind of unwanted optimization

(also i have no resolution window on game start- dont know if this is conected or not
Thanks !!!

They have been turned in to billboard trees. You are right that this is an optimization.
You can read more about it here.

If you want to increase the distance at which trees turn in to billboard you have to tweak the settings on the terrain. Select your terrain and click the cogwheel in the terrain inspector. There are sliders to control the distance at which trees turn to billboards and the amount of trees that are displayed.