As promised, here is the completed painting, "Tulips and Poplars," 24 x 12." The transition from the initial block in of color/value entailed an abundance of layering with the pastel. This network of layers makes it possible to soften or strengthen the color quality, lose or find edges, modify values, and unify or separate objects in the composition.
My original idea was based on having a large poplar shape heavily weighted on the right, along with the tulip fields. With the addition of similar groupings of poplars, the solitary (largest and darkest value) tree on the right is now part of a pattern that pulls you through the fields to the distant structures. Using the Golden Section really helped fine-tune the proportions and placement of these shapes--then it was easier to build the fields, foothils, and pathways to appropriately fit the trees.
The balance of vertical and horizontal shapes, potentially dramatic vertical format and a quiet feeling, and sunny but subdued (cool) light--this was the goal.
Now on to the next painting!