This painting has a wonderful ‘Tiffany like’ two-value notan design.
The prominent slanting tree trunk serves as a contrast of line. The painting has so many vertical tree trunks that without that contrast the painting would be far less interesting.
The color harmony is quite beautiful here. He is using a combination of wide range analogous and basic complementary color harmonies. Most of the other colors in this painting are grouped around red, but in a very wide analogous range.
For the complementary color he is using some kind of cerulean blue, which is a blue green. The blue green is in the sky.
To Learn More
To learn more about color harmonies, see: Color: The Secrets To Beautiful Color Harmony