Today's comment by Ted stated that Krumholtz are pines. In fact Krumholtz is merely a term that roughly translates as twisted wood and can be used to describe any of a number of species of trees that grow, often prostrate, at the upper limits of tree line. In the whites the dominant species within the Krumholtz are black spruce and balsam fir, neither of which is a pine. Both of these trees have extreme cold tolerance and, I believe it is the black spruce, can send out roots where branches touch the ground allowing them to grow in dense mats capable of surviving the punishing winds and extreme icing.