In the subalpine and alpine levels, the cold, snowy and windy climate as well as the short growing season can slow down the growth of certain isolated common spruces (Picea abies), like the one in the foreground of this photo. Shorter and more branched from their base, they are buried in snow. Stuck on the ground, their lower branches lay down (develop roots) and generate new stems whose lower branches will lay down in turn. These spruces then take a more massive form of slow-growing bush to better withstand the winter constraints.