2021-12-17T14:37:00Z updated. Game engine v1.1.1 used.
Background RGB 117,115,90
Dirt (gravel roads, farm yards, etc locations) RGB 178,164,142
Asphalt road RGB 150,150,150
River / water RGB 153,199,228 there are couple of other shades oo, overall "light blue".
Tree center mass RGB 78,99,53 its not solid single color, it fades a bit, but largest part is that.
Forest background and animal mud (animal dealer) RGB 98,85,78
Building rooftops RGB 129,121,109 there are couple of other shades oo, overall "light brown/gray".
Railroad tracks RGB 49,52,49
Using the above RGB colors to paint your own overview.dds image in GIMP and you'll get similar look as Giants FS22 default terrains Erlengrat, Haut-Beyleron and Elmcreek.