In order to apply tint always it's necessary to use Forest Color in the material. Some of our tutorials use Optimize Materials, but also can be assigned manually.
From here, you can specify the tint options in two ways: in the "Material" rollout of the Forest object, or directly in Forest Material enabling the "Override" checkbox. The first method applies the settings globally to all instances of Forest Material used by the object, and the second only the specified texture.
This would be the procedure to apply a map as tint:
1) Assign Forest Material to the diffuse slot of your material.
2) Turn on Tint->Override.
3) Set "Random Strength" to 100%-100%, or lower values for a subtle tint effect.
4) Set "Get Color from Map", and assign the swirl texture to the map slot just below.
5) Set "As texture on Surface".
6) Be sure you have a Surface assigned in Forest, since the UV coordinates are taken from it.
You can find a sample scene in the following post
. I hope that helps.