Create realistic Forests for regional Maps in Photoshop

[DonDozone]

I've been working on a regional map for our own fantasy-RPG. When I was trying to figure out how to create a good looking forests, I came upon this technique that I want to share with you:

Here is a picture how some forests made with this technique look like:



First of all, I want to give lots of credits to pasis, who gave me a lot of ideas for my maps! Thank you very much!

I've taken many ideas from his awesome tutorials Terrain creation guide and Bumpmaps in Photoshop.

So, finally to my mountains:

(I'm no native English speaker, so bear with me )

I start of with a plain color-layer containing the base color of the later forest (in my case I choose #3c6719).

Above that, add a layer with blending mode "overlay" and a fill it with 50% grey (Layer -> New -> Layer.. -> Choose "overlay" and checkbox "Fill with neutral color".)
Apply the filter "Add Noise". You can play around with the values, here are mine:

Decrease the opacity of this layer a little to around 80%

Now the trick is to add more structure to the forests:
Copy the noise layer, and add it as a channel. (In CS5 you click on the "Channels" tab and click "new channel" and paste the contents). Your result should look like:


Back to the layers add yet another layer with "overlay" and "50% grey" as explained above. Select the filter "Lightning Effects" (under "Render"). Here again you can play with the values, the goal is to achieve something that results in a approximately 50%-grey image. The important values are:
- Light: Diffuse
- Relief channel: Alpha 1 (or the name you have given your newly created channel)
- Height: Very low approximately 5-8
- You have to adjust the direction and intensity of the light in the left image. Here are the values I used:


To add even more structure, add another layer on top with mode "multiply" and apply the filter "clouds" (Be sure to have the colors of foreground and background to black & white, the shortcut is "D"). Lower the opacity of this layer to around 20%

And done! This is the structure you can now use for the forests! How do you paint them?
Easy:
Create a layer with mode "overlay" and add the texture as a smartobject and cut mask.


The trick, that you paint the forests with the brush "Dry Brush" from the default brushes set:

Now, paint the forests with very small strokes and you get the nice effect of the forest fading out and blending to its surroundings. Last step is to add the layer effects suggested by pasis:



Addition from Midgardsormr:

If you would like to smooth the texture a bit, apply a Gaussian Blur to the smart object with a very low radius. About .7 looks good on my test document. Since it's going on a smart object, the blur will become a smart filter, which can be altered later on if you want to tweak it.

This tutorial was somewhat created in a hurry, so if you have any questions regarding the techniques described here, please tell me and I will refine this tutorial.

Happy new year!