Painting is a series of layers that are added one atop the other until the final result is achieved. In the last stage the colors were blocked in with broad strokes. Now more attention has been given to build up the overall setting. to give the illusion of depth in a landscape painting elements such as the trees have to overlap and become less and less detailed. Using lighter values and less contrast also helps to push the background back in the setting. Another way to achieve depth is to use cooler colors in the background and warmer colors in the foreground. Everything in the foreground needs to be slightly larger in scale then the elements that can be observed in the background. It's a constant push and pull until everything slowly falls into place. It's now time to work more on the foreground again to bring out more of the details there.