Not sure if it's your style of terraining, but something I always did was scale trees to actual size in comparison to the other doodads, scale was always a big factor for me, mabye try making the trees larger to a realistic size, then let your imagination reign free for what is below them, also will give you more ground space, and will prevent you from using an overload of trees as a filler due to the akwardness of colliding doodads |