I like this art style. I use pen and charcoal for the majority of the picture, and then color pencils for what I think should be the focal point, in this case the leaves on the oak tree. Color greatly adds to the amount of time it takes to do a drawing, so I can save a lot of time by limiting it to the focal point. I also think it makes the focal point stand out more. I’ve been working on drawing trees in this way for a while, I’ll try to add more as I create them.