We use [parts] of real plants for trees. Usually, the process of spraying them with hair spray or other substances to seal them preserves them as well. Also learned a trick of using glycerin to preserve them. This tree is a balsa trunk with preserved Ming Fern for the boughs.
The trees closer to the track in this cut were made from cuttings from a bush in a member's front yard. They were sprayed with hair spray and sprinkled with coarse and medium turf ground foam from Woodland Scenics.