The lonely tree is a popular cliche and so it may have less impact merely because of its familiarity.
And this one doesn't look so lonely because we can't really see it isolated, it's in a nice congenial spot next to a river and there is lots of greenery around.
From a photographic viewpoint, the image is rather low contrast and the lone tree sort merges with the background plus there is lots of featureless sky.
On the whole, I think this is a shot that gets most of its impact on you from personal allusions.
What a wonderful area to live near. I agree with Lew that the tree gets lost, but I think there's a nice photo here.
Certainly worth going back and exploring - maybe morning light would provide more dramatic shadows and textures.
I used B&W to enhance the near and far tree and accentuate some of the shadows in the distant field. And cropped out the lovely sky some
Hope you don't mind.