So far, from the bottom up I have used:
Broken Polystyrene pieces, Plaster bandage, yellow oxide coloured plaster, drizzled red oxide very diluted paint, drizzled very diluted burnt umber paint, lightly dabbed/drizzled very diluted black paint, sand coloured flock, light brown flock, light green flock, dark green flock course lumpy green glock, forest mix flock (more like fine grass clippings, tallus stone (crushed) soaked in the diluted paint washes (for rock debris) black (grey) coloured plaster (for roads) black artist sand (for bitumen), white artist sand, brown lichen, light green lichen, dark green lichen (bushes/shrubs) tee-tree twigs with stuck on lichen (trees) Thats taking it from baseboard to treetop! Now what else can I use...... hmmmmmm.
that doesn't include the balsa wood risers & roadbed, cork roadbed, ballast, track, wiring, lights etc etc..
and 1 litre of PVA glue to stick it all down!!
TOOT!