Drawing Study: Silhouetted Trees

I've attempted this drawing several times, in the past, and have never been happy with it. This effort turned out a lot better.

The main reason for the unhappiness was that the background mountain/rock was always too dark. This forced the foreground tree to totally disappear. As with many drawings, problems are usually due to inaccurate measures or incorrect values. For the previous drawings, the values were not correct.

Overall, I like this drawing. The parts that work out pretty well are the shadowed trees, the cliffs that the trees are perched on and the light background mountain trees.