I'm painting this witer scene. But I have some problems with the tree. I think it is hard to paint reasonsble trees!

In the reference picture I'm using, the trees are darker (almost black) and you cant see very mutch details in the trees. I want mine to be lighter. I have noted that Oliver often paint trees with a crown altough there is a winter scene and it would not be to many leaves on the tree. Maybe that approach would improve my trees? What do you think? Any thoughts about hiw to improve my trees? I would be very happy about some piece of advice!

The painting is obviously not finished. And I have to many mistakes on it. It is not a keeper, but I keep going anyway to learn by, more various problems.