Natural History

Geology

Sitting on a low plateau at the southern end of the Canadian Shield, an ancient slab of rock stretching from the Great Lakes up to the Arctic Ocean, the Boundary Waters [1] are a unique Ice Age relic.

The glaciers that swept south over the last two million years bulldozed right down to the bedrock, and since they last retreated some 10,000 years ago, only a very thin skin of soil—six inches on average—has formed.

In many places, particularly lakeshores, the eroded bedrock is still exposed, lending a unique beauty to the area. This Precambrian crust is estimated to be 2.7 billion years old, making it some of the oldest exposed rock in North America.

The gouging glaciers left a noticeable (if you look on a map) northeast “grain” across most of the area. Glacial meltwater filled these long, narrow basins, forming the myriad lakes that cover nearly a quarter of the Boundary Waters Canoe Area Wilderness’s area.

Flora and Fauna

The Boundary Waters Canoe Area Wilderness lies in a transition zone between the temperate deciduous forest and the coniferous northern boreal forest, though the latter predominate. This mixed “North Woods forest” features white and red pine surrounded by spruce, balsam, jack pine, aspen, and birch, and because of the early limits on logging, there are still many old-growth stands.

Summer is berry time, and blueberries, a favorite of both humans and black bears, ripen throughout most of July and early August. Wild raspberries peak about the same time, while wild strawberries are ready weeks earlier. The odd, dead-looking plants clinging to nearly every large rock in the forest are lichens, a symbiotic union of fungus and algae. Of course, the storm of 1999 has changed the forest considerably, and it will be decades before anyone knows exactly how.

As you’d expect, this wild corner is one of Minnesota [2]’s best wildlife-watching destinations, but the most enduring animal memories are usually not the ones seen, but those heard. The common loon is surprisingly common on these lakes—nearly all have a nesting pair—and their echoing wails on a still summer night are reason enough to pitch a tent.

The territories of several wolf packs extend into the Boundary Waters Canoe Area Wilderness [1], and if you’re lucky, their plaintive howls will float past your campsite too. White-tailed deer and moose are a wolf’s primary prey, and spotting the latter grazing in streams and shallow bays is not a rare event.

Beaver and otter are common in the water, while bald eagles frequently soar above it, and you will probably see several large-eared woodland deer mice scavenging around your campsite at night. Other common critters include great blue heron, herring gull, spotted sandpiper, broad-winged hawk, ruffed grouse, gray jay, white-throated sparrow, a variety of ducks, snowshoe hare, and the chattery red squirrel.

You’d be very lucky to see a mountain lion, bobcat, lynx, fisher, pine marten, mink, northern flying squirrel, star-nosed mole, spruce grouse, black-backed woodpecker, boreal chickadee, or red-backed salamander, but they are all out there. In total there are around 200 species of bird, 45 mammal, 12 amphibian, and 7 reptile in the Boundary Waters Canoe Area Wilderness.

Bears deserve special mention. Hundreds of the lumbering giants roam the Boundary Waters Canoe Area Wilderness and, unfortunately, the place you are most likely to see them is in camp. Keep your site clean, however, and you probably don’t have to worry about them crashing your party.

The Blowdown

On July 4, 1999, a fierce storm with straight-line winds in excess of 90 miles per hour whipped across northern Minnesota [2], and though it lasted only 20 minutes its effect will be felt for a lifetime. The hurricane-strength maelstrom toppled 600,000 acres of forest across Minnesota and Ontario, more than half of it in the Boundary Waters Canoe Area Wilderness [1]. The storm’s ground zero was a 4- to 12-mile-wide and 30-mile-long swath right along the Canadian border between Ely [3] and the end of the Gunflint Trail [4] — 80 percent of the trees in this area were knocked over or snapped in half.

It was one of the largest blowdowns ever recorded in North America. Though the scale of the devastation brought tears to the eyes of many, it must be remembered that these events, however extraordinary, fit in a forest’s natural ecological cycle. The sunlight, once blocked by the mature trees, will allow new trees to grow and this emerging forest is actually beneficial to much wildlife, including moose, lynx, and wolf.

The biggest problem is fire. The additional fuel available to burn increases not only the likelihood of wildfires, but also the severity. Millions of dollars have already been spent on storm recovery, and fire mitigation, including prescribed burns, will continue for several years. Blowdown area–related closures and campfire restrictions have been reduced in recent years, but will continue — always check on these before beginning a trip.

Also, don’t pitch a tent under damaged or leaning trees. In some BWCAW campsites there are no longer trees, so bear-proof food storage containers are highly recommended.

While many paddlers, understandably, now try to avoid blowdown areas, this is not entirely necessary since even in the hardest-hit spots some stands of trees were not toppled, especially on shorelines — scientists suspect that growing up with more winds strengthened these trees — and so out on the lakes you might not even notice the damage.

The Forest Service or your outfitter will be able to tell you what to expect in specific locales.