I've been trying out to figure all day (time i've been at my computer at least), and still struggling... I asked for help in the mod help forum.... but nothing yet. I would have thought that something as simple as creating a tree would have taken very little to have an answer, but seems it is complex. Actually, I'm not a big fan of billboard trees, its supposed to trick the eye, but all I see is them turning around to face me. In the worst case where I can't swap them, I'll try to work on the texture instead and improve their look... they look a tad washed out, but they aint that bad. Nice variety and so on.