The Boreal Forest: Earth's Green Crown

Photo: Bill Van Geest

For many, the archetypal boreal landscape is the undulating patchwork of slow-growing evergreen forests, weatherbeaten knobs of ancient granite and innumerable lakes, bogs, marshes and other wetlands found in the Canadian Shield region, which sweeps in a broad arc southeast from the Northwest Territories through northern Alberta and Saskatchewan and then curves up through most of Manitoba, Ontario, Quebec and Labrador. The image above, taken along Manitoba's Blood Vein River, shows a typical Shield landscape.

Few places wear geologic history on their sleeves as plainly as Canadian Shield country. Stand anywhere on this fascinating mosaic of granite, aquamarine lakes and forest and you are amid a landscape both immensely old and nearly new. The rock exposed in this region is among the oldest anywhere, with some formations dated to 3.9 billion years ago. The shield is in fact the core of North America -- the central mass of rock around which the rest of the continent coalesced. The exposed surface of this rock, however, was sculpted, scarred and pockmarked by the glaciers of the Pleistocene Ice Age a mere 6,000 to 9,000 years ago -- barely a New York minute, in geologic time.