ABSTRACT
Biodiversity is as important as climate to a healthy, sustainable and prosperous planet. For Erik Solheim, the head of the United Nations Environment Program, biodiversity has to be protected therefore for spiritual, ecosystem, and economic reasons. The climate in northeastern North America is also influenced, especially in winter, by a fourth air mass: the cold, moist oceanic North Atlantic air mass generated by the waters off Newfoundland, Labrador, and Greenland. The northern half of the continent is covered with deposits such as tills and moraines that reflect the action of the ice sheets on the terrain. Grassland vegetation is dominated by herbaceous plants that form one or two canopy layers. Woody plants are restricted to local areas of distinctive topography, soil, or protection from fire. A central section, much richer in tree species, extends from the southern Alaska–British Columbia border to the Oregon-California border.
