The trees were a good choice to provide depth of field for this image. They make a frame, and the lack of leaves mean they don't obscure the subject. Now I think the clouds are a problem - not enough color contrast between the subject and the background. One of the goals of photography is usually to isolate the subject and simplify the image enough that the surroundings add to rather than detract from the subject. Now the other thing. When I shoot a subject I usually try to get it into some kind of context - in this case you could have included the ground. Now I know you didn't for a reason, but there you are. It usually helps to include the context. The Washington monument was a good choice for a subject - clean lines, and easy to identify.