As I remember, the Easy Tree kits are plastic armatures. Theybare about 4-5" high. Best to dry brush them with some gray and/or brown to eliminate the shiny plastic look. Easy to work with and for any of these instead of the expensive kits, get some poly fiber to stretch over the branches, then some flock or "leaves" of choice and sprinkle on. Cheap hairspray is a good adhesive. Super trees are very, very thin armatures and can work well for bushes but for O scale trees can be more difficult. Then don't have a lot of structure to support themselves but with a matte medium dunk they get stiffer. Sage Tree armatures can be great (I use a lot of real sage picked at the end of the season) as they really look like trees but to buy them in any reasonable size can be quite expensive. Hope this helps.
Jerrman