I started by putting the sky in with a mixture of ultramarine blue and titanium white and as I got to the bottom of the painting I added a cobalt blue and pthalo blue into the sky colour for the snow on the ground and the snow shadows.

Using more of the paler yellow greens first, I put in the distant trees into the background and gradually darkened green mixtures as I put in the closer trees and added more details to them as I worked my way forward through the background trees.
On the closer trees on each side of where the trail divides I continued to darkened the colours and added more details to the trees.
Next I mixed a dark of ultramarine blue, burnt sienna and a little bit of alizarin crimson and put in some dark shadows at the base of the trees as well as a few of the bare tree trunks.