I started by putting in the pine trees first using various mixture of French ultramarine blue, raw sienna, new gamboge and cadmium yellow.

Burnt sienna and French ultramarine blue were used for the birch tree markings and branches.
A little more blue was added to the dark mixture and the maple tree was painted in beside the large pine tree.
Various mixes of cadmium yellow and raw sienna were used to put in the grasses and growies beneath the trees.
If you would like more information about ACEO please go to my post on 11 March 2010.
The ACEO shown here is an original watercolour painting using Artist quality Winsor & Newton paint on 140lb. Arches 100% rag, acid free watercolour paper. It is priced at $20.00 and sold unframed.