I have a lot of 15mm miniatures, but not much 15mm terrain, so I decided to make some forests. Quick and dirty, and on the cheap: the main component are these green pom-poms, 2cm diameter, that I stuck on matchsticks, then hot-glued on to various spare pieces of card and wood that I had lying around (I hate wasting material). A light brushing of yellow (not green) on the tips of the pom-poms creates the impression of depth at a distance, and some flock for undergrowth creates a sense of granularity at a distance. These are more "background" than "close-up" trees: they'll fill the edges of a board nicely and give some depth to photos. They are a bit on the small side, but I'm also making them with an eye to 10mm and possibly 6mm.