The photo is definitely underexposed.
I didn’t get the impression, on my screen, that it looked bad underexposed. The exposure chosen fits the mood well I think.
It’s interesting to see different opinions regarding the same picture. I prefer the original as it depicts a cold, dreary scene with low exposure. Also, I agree with @jamesstaddon on including the entire tree in the frame. The branches and twigs are well silhouetted against the white background. However, the branch closer to the centre of the frame appears to be clearer (sharper) than the other branches. Perhaps the focus was on that left branch.
This picture of a tree out in the snow shows a lot of negative space
This is an ideal picture for including text (such as a Bible verse) in the negative space.