During the winter, a breeze coming from the south, is a warm breeze. I would welcome the warmth.
Are the evergreens blocking big south facing windows? Are you intending to install thermal
solar heat collectors? If yes, I would cut them immediately. There are few things as pleasant during an Idaho winter as sunlight streaming in through a large south facing window.
I don't much care for how much snow/cold/ice collects and remains on the north side of evergreens during the winter.