@Bob: no here I added a masked (by PF+transform) surface shader with some orangy color, under the default shader.
There's 3x pinus sylvestris, 2x oak, 2x linden, 2x beech, some dead trees and shrub, and I used a masked PF+transform to take the leaves of some of the fallen pinus sylvestris. In the latest render, which I still have to finish, I have changed the rotation values so, some trees (from 1 pop) are still standing, other completely down.
I thought about mosses and rot and must on the dead trees, and indeed have a (again, PF+transform) on the dead trees with moss color added. Maybe I have to slide it more to the mossy side.