Trying for bigger trees

i have a concept for a new kinda camra system. Its long and chances are confusing but could make for an intresting game type i have in mind.... Anyway I was looking at some screenies and i realized that the trees were alot larger to unit comparison for some on the ground rpgs. Do people make the units smaller or make the trees larger. If they make the trees larger how so? i know how to make doodads come outta random sizes and hit Z yeah yeah i'm not a newbie. But i want to know if theres a way i can set a stand size? and i don't want to copy and paste cause i awnt random trees to pop out.

Edit the trees in the Doodad editor then, it includes a "minimum to maximum" scale value.