I generally paint my trees and armatures with an airbrush. I am using Super tree material. I use three shades of green and paint the leafy area first. Russian Primer, Pale green on top for highlights and an alternate green to add depth. For the trunks I then use a brown first (ammo tracks primer), then use a grey black over the top lightly (Ammo Rubber Tires).
I paint through the foliage keeping the airbrush close to the trunk to paint the upper trunk. I will then dry brush with a light grey to add texture if I use the tree as is, or it will get broken up and used on a larger sage brush armature for a feature tree
[ Guests cannot view attachments ]