The biggest problem with your wallpaper is that it's too busy. Unless you are going to place an effect over it to remove some of it's intensity I'd recommend using a less 'noisy' texture. Since you're working in Black and white, you want to focus more on the values of your image and where you want them to lead the viewers eye, just something to think about

and the tree looks great, but I think you'll lose a lot of detail on that if it is too far away or too small in the image.