To my eyes, those colors look like Burnt Umber and Burnt Sienna. Humans began using Ochre, Sienna, and Umber, all commonly occurring minerals, during ancient times for producing cave paintings. It is likely they also used them as clothing dyes and for body painting. When the first civilizations appear, those colors form the basis of most artistic works precisely because of their ready availability.
By the time World War II rolls around, all three of those colors become crucial to the manufacture of camouflage paints. If I recall correctly, Yellow Ochre and Carbon Black make Olive Drab used by the United States. Yellow Ochre is the basis of Panzer Dark Yellow. Burnt Umber is the basis of Panzer Chocolate Brown. Many other earth tone camouflage colors use varying degrees of those minerals as pigment.
Anyway, yeah, those are great colors for simulating earth tone colored things like wood. The use of colors over other colors really took off during the Renaissance, when artists worked out Color Theory and began using it to produce color gradients that mimics nature.
Anyone who really enjoys painting should purchase a color wheel and a good variety of earth tone paints. A color wheel allows the user to mix his or her own colors and shows how color transitions occur when placing a colored tint over a different colored base. Painting really comes to life when you learn how to form gradients in that manner.
Also, a color wheel will save you money. If you know how to mix colors, you no longer need to purchase the correct shade of this or that. You can mix most shades yourself using a few basic colors. Just make sure to keep a log of what you did. That way, if you produce a color you really like, you can easily make it again.
Any decent paint range will include basic earth tones so you need not weld yourself to one particular brand. You just need to learn how to thin whatever you use into a tint so you can put one color over another without pulling up the underlying layers.
For example, I am in the process of switching to Vallejo paints and experimenting on all sorts of miscellaneous junk just to see what happens and work out best practices. They have a product called Flow Medium that gives any of their paints the correct consistency for shading and tinting. Have a look at the mediums associated with whatever paints you enjoy and experiment.
Doug