First, I lightly sketched in a few trees into the background as well as a distant hillside.
Next, I mixed various different greens using combinations of Antwerp blue, cerulean blue, French ultramarine blue, raw sienna, aureolin and new gamboge.

Using various mid tone greens, I put the needles onto the background trees, being careful to leave spaces to put in the tree trunks and dead branches.
I put the mid tone green needles on the branches in first, followed by the darker greens on the branches of the foreground tree.
For the trunk and branch colours, I used light and dark mixes of burnt sienna and French ultramarine blue.
If you would like more information about OSWOA please go to my post on 12 March 2010.
The OSWOA shown is an original watercolour painting using Artist quality Windsor & Newton paint on either 300lb. Arches 100% rag, acid free watercolour paper. It is priced at $40.00 and sold unframed.