If you're going for realism, then in contrast to what the user above me said, the trees lend it too much of a cartoonish feel. They're not scaling properly with the perspective given by the vanishing road; they're lined up too perfectly, which wouldn't be a problem (trees are often planted along roads), except they don't follow the curve of the road; and they're all straight-trunked but tipping different ways. Trees tend to bow away from the mountain due to the winds that blow down from the slope.
Secondly the clouds. Again this is if you're going for realism. There's a cloud in front of the tree on the right, and that cloud merges in with the rest of the clouds, making them all seem to be on the major foreground of the painting which distorts the perspective. If you're trying to make fog, you should look up some pictures of it, they're usually smooth, flat, and ground level not tree-top level.
The mountains look great, if a bit messy around the edges, nothing an eraser tool can't clean up quickly though.
The lighting is consistent, but there's no shadows or highlights on the foreground cast by trees or anything else.
Lastly, contrast may help you distinguish foreground from background, lending the much needed emphasis on a focal, but I don't think it'd do much good without color as well. You're probably going for black and white either for the charcoal painting feel or an old photograph feel, but faded color on the foreground and monotoned minute shades of blues in the background would really help enhance the depth.
These are all improvements I see that can help the outcome. Whether you keep up on how I critique here or not, I feel I should remind you I deliberately don't waste time on all the great things about it because that doesn't help you improve. With that said, it's a great work in progress if you haven't already deemed it finished (I figure not since you said you're working on contrast), and I can't wait to see it finished. Well done.