Shadows.

I like the shot, but did you do any PS on it? Because there is something unnatural looking about it.

 

I see a flair @ 1 o-clock which detracts from the picture.

 

Slight saturation boost and slight highlight darken.

I know. I left it because A) I didn't know what to do about it and B) to me it looked like sunlight spilling through the trees.