The size of trees and shrubs

[Lisen801]

Yes I have searched a bit but have not found any description, so I try to post here. If this is the wrong forum, so sorry.
Some trees and shrubs might have different sizes. Is there a way to control this or is it totally random?
Grateful for answers and advice.

[Volvenom]

You just click one more time and hope for a different size ... or download something more fitting.

[morphius1]

Yep. That's what I do, too.

[BloomsBase]

or download this mod:
http://mahamudosim3.blogspot.tw/2012/07/omsp-resizer.html