Minnesota Public Radio: For trees, northern Minn. is something of a cross-roads. The state’s hardwood forests blend north into pine and birch, and then, in the northeast lakes area into cold climate species like aspen and jack pine. Cold tolerant trees are a signature feature of the Boundary Waters Canoe Area Wilderness and Voyageurs National Park. That is the southern stretch of the boreal forest, which continues north into Canada. However, according to researchers with the Nature Conservancy, the northern …