The Crow’s Path Blog

Paper birch had the lowest temperature when exposed to the sun. It also has bright white bark and one of the farthest north distributions of any hardwood tree. Other white barked trees (e.g. quaking aspen, balsam poplar, and gray birch) also extend well into the boreal forest (see range maps below, if these don't show up, you can find them here) indicating that having white bark is a specialized adaptation for coping with extreme cold.