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.)

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This will result in multicolored forests:

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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:

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I hope this helps!