Playing With Fire
11/5/2008 | | Lee Frelich studies forest fires and other ecological disturbances in the Bourndary Waters, sometimes while they're happening, such as during the 2007 Ham Lake fire. PHOTOGRAPH BY LAYNE KENNEDY |
By Greg Breining
In the spring of 2007, University of Minnesota researcher Lee Frelich paddled with two companions into the Boundary Waters Canoe Area Wilderness in northern Minnesota to tramp around some of his research sites on Seagull Lake. At midday, they noticed a plume of smoke to the south. Within two hours, smoke had darkened the sky and they had to flee to the north shore to escape the fire. The wind fanned the flames and pinned them in their campsite for two days.
The fire crept within just a few miles of their campsite, and on the second night, it was so bright they could walk around the woods without a flashlight. As they stood on the high cliffs by the lake, they watched a monstrous fireball in the southeast. Frelich knew that Wilderness Canoe Base near the end of the Gunflint Trail was going up in flames. After the wind died, Frelich and his companions escaped down Seagull River.
Frelich is director of the University of Minnesota’s Center for Hardwood Ecology in the Department of Forest Resources. He has studied forest fires his entire professional life but might best be described as a “disturbance” ecologist. He studies the various disruptive forces that affect the form and function of our forests. In the Boundary Waters—more than a million acres of wilderness and 1,000 lakes and streams—he observes these disturbances up close.
We often think of these disturbances as catastrophes or tragedies. Some are natural—forest fires set by lightning, for example. And some are man-made, such as logging, which was common in the Boundary Waters through the early 20th century.
With other disturbances, whether they’re natural or human-caused isn’t so clear. For centuries, if not longer, Native Americans groomed the forests with intentionally set fires to clear out underbrush or create more browse for game animals. Deer are changing the nature of the Boundary Waters forest by chomping white pine and northern white cedar, but they wouldn’t be there if not for logging and road-building. And the biggest disturbance of all is global climate change, a natural response to human actions.
Some of these disturbances are vital to the survival of the forest as we’ve come to know it, Frelich says. And others threaten to change the Boundary Waters until the area becomes something unrecognizable—perhaps in a single lifetime.
By his reckoning and the assessments of other ecologists and climate experts, within a century, the Boundary Waters will change dramatically within this century. Gone will be the iconic moose. Once vast stands of spruce and jack pine will dwindle to the point of nonexistence. Earthworms and other species will increasingly invade. Within 100 years, Frelich says, the Boundary Waters, one of the last, best examples of the great North Woods, will perhaps look like southern Iowa.
Forged by fire
“I’ve never seen the lake this calm in my life,” Frelich says upon returning to the scene of the fire this past summer. Much of the area he paddles through has been  | | Canoes destroyed by the Ham Lake blaze. PHOTOGRAPH BY LAYNE KENNEDY |
burned down to the pink granite. Charred tree trunks stand like poles. Others lie scattered among the tangle of verdant underbrush that has sprouted in the wake of the blaze.
Landing at Seagull Lake’s Three Mile Island, one of his permanent research sites in the Boundary Waters, Frelich steps out of the canoe and leads the way to a cluster of ancient cedars on a moist, sheltered shoreline. They range from 550 to 1,000 years old and have survived a montage of disasters. Frelich points to the location of each burn: the 2007 Ham Lake fire that had pinned him in camp for two days, the 2002 prescribed burn to clear out dead trees blown down in 1999, the intensely hot Cavity Lake fire in 2006, the 2005 Alpine Lake fire, and the 1976 Roy Lake fire, along an adjacent shoreline, where vigorous young stands of trees grow in its wake. The old forest of pines and other species that somehow escaped these fires, says Frelich, grew in the aftermath of a huge fire in 1801.
The history of Minnesota’s forests was written largely by fire, and the scientists studying that history have been legion. Back in 1948, conservationist Frank B. Hubachek established the Wilderness Research Center on Basswood Lake. (University of Minnesota Regents Professor Peter Reich holds the F.B. Hubachek Sr. Chair in Forest Ecology and Tree Physiology.) Ecologists and authors Clifford (M.S. ’48) and Isabel Ahlgren worked at the center for many years studying the effects of human endeavors, from logging to prescribed burning, on the character of the forest.
About 50 years ago, Swedish scholar Magnus Fries began studying the charcoal and pollen buried in north-country lake sediments to reveal the fire and forest history on the surrounding landscape. Soon others followed him into the nearly pristine lakes of the Boundary Waters, including University of Minnesota researchers Eville Gorham, Herb Wright, Alan J. Craig (M.S. ’70), and Margaret Davis and Albert M. Swain (Ph.D. ’75) of the University of Wisconsin. Reading cores of lake-bottom sediments, these researchers demonstrated that fire played a nearly continuous role in the evolution of the forest since Ice Age glaciers retreated more than 10,000 years ago. Prairie once covered northern Minnesota and then retreated. The present jackpine–black spruce forest became established in northern Minnesota just in the last 1,000 years.
James Peek (Ph.D. ’71) and Larry Irwin of the University of Minnesota documented the proliferation of deer and moose in the aftermath of the 14,000-acre Little Indian Sioux fire in 1971, and the U’s Richard F. Wright (Ph.D. ’74) studied the fire’s effect on releasing nutrients to the waters of lakes in the burn area.
Among the most comprehensive and detailed studies of the role of fire in shaping the northern forest was the work of Miron “Bud” Heinselman. As a forest ecologist with the U.S. Forest Service, Heinselman laboriously traveled the Boundary Waters, boring into the trunks of standing trees to count the rings and look for signs of fire scars. From thousands of cores he  | | Fireweed grows a year after the 2006 Cavity Lake fire. PHOTOGRAPH BY DAVE HANSEN |
constructed detailed fire-history maps that dated the ages of the trees as well as the dates of secondary fires in the stands. On average, he found, any given acre in the Boundary Waters burned once a century. Vulnerable ridgetops burned more often; shorelines and swamps much less, if at all. “The landscape-vegetation mosaic is like a giant kaleidoscope, with fire being the principal force that periodically rearranges the patterns of vegetation types,” Heinselman wrote. “In turn, these vegetation patterns largely determine the habitats available to all land-based wildlife.”
Before the common use of computers, Heinselman translated his data onto color-coded maps, showing the dates of origin of nearly every stand of trees in the Boundary Waters. Frelich remembers watching Heinselman spread the maps out at his Falcon Heights home, crawling over couch and coffee table to lay out the entire wilderness area in his living room. “It was like playing a game of Twister,” Frelich recalls. “It was a great time with Bud, no matter what you were doing.”
Not long before Heinselman died in 1993, he and Frelich traveled up the Gunflint Trail to the Boundary Waters and paddled out to Three Mile Island, where Frelich would continue some of Heinselman’s pioneering work.
Blown away
Frelich and his graduate student began by studying how 200-year-old pines give way to other species, such as balsam fir. Then disaster struck. Their laboratory blew down.
On July 4, 1999, a freakish windstorm with gusts up to nearly 100 miles an hour leveled 25 million trees in a third of the Boundary Waters, a 30-mile-long swath reaching from just northeast of Ely to the end of the Gunflint Trail. In places, trees were flattened for as far as the eye could see. Dead wood formed a tangled, well-ventilated mat so thick a person could stand on a horizontal trunk and still be 12 feet above the ground. Among the casualties were most of the mature trees on Three Mile Island. Says Frelich, “Our old-growth study became a blowdown study.” Student Roy Rich (Ph.D. ’05) had put out 750 plots to monitor the big blowdown, determining which tree species were most susceptible and tracking the forest’s recovery.
If Frelich wanted to study natural disturbances, he certainly picked the right spot. In 2002, the U.S. Forest Service burned Three Mile Island to consume the dead wood and avert a huge fire later on. Then, in quick succession, came the other fires, quite by accident. Some burned hot. Some skimmed the surface. The combination of windstorm and fire produced entirely different effects than did fire alone. The confluence was creating a forest once found 100 miles south.
“It’s a changed forest, and it’s going to be changed forever by the blowdown-fire combination,” Frelich says, “and that’s what’s going to happen more often with global warming.”
Climate change is already affecting the appearance of the forest—although in ways so subtle most people don’t notice. Red maple in the heart of the Boundary Waters is one sign. Another  | | Black spruce trees near the Gunflint Trail that survived the 1999 blowdown. Photo taken in September 2000. PHOTOGRAPH BY DAVE HANSEN |
is the dieback of birch trees due to too-warm soils—most apparent along the North Shore but reaching north into the Boundary Waters.
To get a better look at what the future might hold, Frelich and his ecology colleagues consulted with global climate modeling experts who used the average of 16 global circulation models to predict what the climate on the North Shore and in the eastern Boundary Waters might be in the year 2039 (resembling the St. Croix Valley) and in 2069 (northeastern Iowa’s). A climate like southern Iowa’s, Frelich says, isn’t far behind.
So what will the Boundary Waters look like in a 100 years? “With unmitigated global warming—and that’s probably what we’re going to have—say it warms up in the summer by 4 or 5 degrees Celsius, I’d expect it to be a lot more shrubby,” Frelich says. Signature trees such as jack pine, red pine, spruce, balsam fir, and even paper birch might all but disappear. White pine and northern white cedar might endure, but only if deer don’t eat their seedlings to nubs. Some areas would evolve to bur oak savanna. In others, red maple and oak would form a hardwood forest.
A warmer climate will likely aid the proliferation of invasive species, since most are advancing from warmer regions. Among these aliens are emerald ash borer, Asian longhorn beetle, and sudden oak death. The mountain pine beetle could wipe out white, red, and jack pine. “There’s no reason it couldn’t run through the entire jack pine belt to the Atlantic Ocean. It couldn’t do that before because it was too cold in the winter,” Frelich says. “It’s amazing the predicament we’ve gotten ourselves in, with the tree diseases we’ve brought in from other continents.”
Then there are earthworms. After the Ice Age, Minnesota had no native worms. Earthworms in the state today come from Europe or Asia, transported here through gardening and farming or, as is the case in the Boundary Waters, as fishing bait. “It’s a different class of invader,” Frelich says, calling them “ecosystem engineers.” They consume the duff that insulates soil and change the nature of the topsoil, leading to a loss of diversity of native plants. Earthworms can’t live in the acidic soil of jack pine and black spruce forests, Frelich says, but as those species decline, earthworms will advance.
The range of moose, perhaps the most enduring symbol of the north woods, will shrink into Canada as the animal succumbs to ticks, heat stroke, and brainworm (carried by whitetail deer, harmful to moose, and lethal to woodland caribou, which disappeared from the area a century ago). Gray wolves, beavers, and bobcats will survive by shifting their diets. But the stunning Canada lynx will vanish—into Canada.
What can be done to keep such iconic creatures as the lynx? “If it’s disappearing because of global warming, I wouldn’t make any effort to protect it,” Frelich says. “You have to recognize what you can and cannot do. You can’t make a lynx live in an oak forest.”
Wilderness rules
Not that Frelich would do nothing. To the contrary,  | | Frelich (left), leading a workshop on Fishhook Island in Seagull Lake, and participants used black spruce trunks for benches. Photo taken in September 2000. PHOTOGRAPH BY DAVE HANSEN |
he believes the Forest Service should more aggressively manage the Boundary Waters wilderness. Unfortunately, public attitudes and federal laws governing what is appropriate in wilderness areas prevent it.
For example, during most of the 20th century, Smokey Bear ruled. Forest fires, no matter when, where, or under what conditions they occurred, were snuffed out. As a result, species that depended on fire to propagate—white, red, and jack pine—gave way to shade-tolerant species, such as spruce and fir. Since the 1970s, the Forest Service has tried to allow forest fires their historic role in shaping the forest, but did so in a passive way, letting wildfires burn if they were started by lightning and didn’t endanger private property and if the conditions, such as damp weather and calm winds, gave the firefighters a chance of containing them.
That policy isn’t getting the job done, Frelich says. With so many criteria, hardly any natural fires have been allowed to burn. Lack of fire set the stage for huge, dangerous blazes, such as the 32,000-acre Cavity Lake and 76,000-acre Ham Lake fires. “I’m in favor of a policy to just continue with the controlled burns they started after the blowdown and just rotate through the entire wilderness,” Frelich says. But intentionally setting a fire (except to clean up the blowdown) doesn’t square with federal wilderness policy.
Frelich would also like to see the Forest Service plant red and white pine to replace what loggers removed a century ago. “The problem,” he says, “is the Forest Service interprets the wilderness act very strictly and would consider that manipulation of the wilderness not allowed by the wilderness law.”
However, in the future, according to Frelich, global warming will justify a lot more meddling in the wilderness. “Even large wilderness areas as big as the Boundary Waters are not capable of dealing with the magnitude and number of changes that are coming about because of people.” Some plant species will disappear unless humans transplant them because they won’t be able to move north to follow the advancing climate. Invasive species, on the other hand, will have a field day.
“They’re invasive because they can deal with anything. They have a lot of seeds. They can move fast. They can deal with a lot of different climates. That’s why they’re invasive,” Frelich explains. “I can visualize a future with a million acres of buckthorn in the Boundary Waters. It could be an ecological disaster.”
Though Frelich occasionally veers toward the apocalyptic, he has the calm objectivity of the scientist and takes the long view. “Everything is interesting in terms of the ecology and science of it,” he says. Trees will persevere. Over time, he says, “the boreal forest has gone back and forth from Tennessee to Hudson Bay.”
Sometimes, he has to take a really long view. “After people are gone, new species will evolve and on a longtime scale the earth will recover just fine.”
Greg Breining is a St. Paul–based freelance writer.
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