For me the limiting factor was actually the stud-on-4-sides bricks
I really like the look of these pine trees. The PaB walls have recently had the 1×1 brick with 5 studs (in black). I got a cupful earlier this summer and I have lots of the flower stems so I can definitely make some of these trees. Very cool. I find that any type of tree is unstable during transportation. I never try to build my trees in advance; I realize that I just have to build them on site.