I agree that the composition is what makes this picture as strong as it is. I like how the house is small and off to the side and then the trees on the left are much larger in comparison. Nice contrast too, I like it.
I think the subject and composition are very good, but I'd look for more contrast across the grass, trees and building. It is a touch flat. The sky looks like it's gone quite grainy/noisy which can be a problem in B&W conversions.