12- Finally, to add some color variation to the forests, add yet another layer set to overlay, filled with neutral gray and with the forest mask applied. Run a plasma cloud render with the turbulence set somewhere in the middle (I used 5.)

15- Texture a.JPG

This will result in multicolored forests:

16- Texture b.JPG

Set your colors to black and white again, and run a gradient map on the forest texture layer. The results should look something like this:

17 Color Variance.JPG

I hope this helps!