a quick tutorial about making realistic pinetrees in h0 scale

h0 scale finescale realistic spruce forest for my model railroad layout. On the edge of the forest I want some smaller trees. But how to make smaller pines that don't look like a bottle cleaner? To obscure the opening in the backdrop through which my trains enter the layout, I'm building a forest. I want a forest that gives the viewer the impression of being in it. So, looking from the inside of the forest, and through the dense foliage of the forest edge you catch glimpes of the train as it enters the scene.