[Marxism] How global warming is changing Minnesota: Prairies are replacing forests

David Thorstad binesi at gvtel.com
Thu Aug 12 11:44:39 MDT 2010


  BWCA blowdown and aftermath show how global warming is changing
  Minnesota: Prairies are replacing forests

          By Steve Berg | Thursday, Aug. 12, 2010

Last Saturday was too hot and muggy for a 30-mile bike ride. But since I 
was never the smartest kid in class, there I sat, dismounted, panting 
and sweating on a bench in Mears Park, thankful for a cold soda from the 
drink cart and all those tall, shady trees.

This is my favorite urban park in the Twin Cities, an island of green 
loveliness surrounded by some of St. Paul's most beautiful historic 
buildings. Yet on a day so sweltering, not even this spot could keep my 
mind from drifting toward cooler climes. I imagined the piney shores of 
Lake Superior and the sparkling lakes of the Boundary Waters before 
recalling Lee Frelich and his disturbing discovery about what's 
happening to Minnesota's north woods. It kind of took the edge off my 

Remember the big blowdown of 1999? Starting on the afternoon of July 4, 
a massive derecho packing violent winds of more than 90 mph swept along 
the U.S.-Canada border for 1,300 miles. In all, the storm lasted 22 
hours. It blew down nearly a half million acres of trees in the Superior 
National Forest, including about 40 percent of the trees in the Boundary 
Waters Canoe Area Wilderness.

For Frelich, director of the University of Minnesota's Center for 
Hardwood Ecology, the blowdown and its aftermath of fires and forest 
regeneration confirmed on a massive scale what he had long suspected: 
The new north woods growing up to replace the millions of blown down 
trees isn't really a north woods at all but something more akin to the 
grassland savannahs farther south. Indeed, over the last decade or so, 
the blowdown has become a giant laboratory for measuring the ecological 
effects of a warming climate and the role humans are playing in 
accelerating the change.

*Prairie replaces forest*
Most of the trees lost in the storm were pines and aspens, Frelich told 
me this week. By normal succession, they would be replaced initially by 
varieties of spruce, fir and cedar. But instead red maple, basswood and 
other species normally found farther south are sprouting on the forest 
floor. "Recently I was at Snowbank Lake near Ely and I was just amazed 
to see all the red maple coming up," he recounted.

Frelich admits that until the last few years his observations greatly 
depressed him. He loves the woods, after all. He grew up in the grip of 
Sigurd Olson's lyrical writings about the magic of the northern 
wilderness. To realize that Minnesota's thick, dark canopy of conifers 
would be replaced by, in Frelich's words, "a scrubby, species-poor 
landscape" was not a pleasant prospect. But he's no longer angry. He 
tries to see the blowdown in a broader perspective ? as part of the 
paleo-ecological record and as an opportunity to gather more data to 
chronicle the changes ahead. He holds out little hope than humans will 
alter their carbon habits enough to prevent the intrusion of prairie 
into the forest.

A journal article to be published next month in Frontiers of Ecology and 
Environment <http://www.frontiersinecology.org/> further documents 
Frelich's findings. He and his U colleague Peter B. Reich, professor of 
forest ecology and tree physiology, explore likely changes over the next 
50-100 years in the composition of northern forests due to global warming.

"Under a scenario of human-induced global warming, the prairie biome 
will shift to the northeast and displace existing forests," the paper 
declares. Here's a summary of its observations:

Think of Minnesota as having an ecological border running across it 
diagonally, northwest to southeast. To the northeast, boreal forests 
dominate the landscape. To the southwest, savannahs ? prairies with 
small trees that do not close to form a canopy ? prevail. Over the last 
million years, the border has shifted eight times, but this time is 
different; the conifer forests are retreating to northeast farther and 
faster than before because there are higher levels of carbon in the 
atmosphere (twice the pre-industrial concentration).

*A perfect storm of events*
Likely accompaniments to this ecological trend? A warmer, drier climate 
that outstrips the ability of tree normal species to keep pace with the 
change; a greater rate of evaporation; more severe wind storms; a 
greater number of severe fires that give warmer-climate plants a better 
opportunity to invade; more exotic insects and diseases affecting trees; 
an overabundance of deer that browse woody plants that would otherwise 
grow into trees; and the further invasion of earthworms that disturb the 
forest floor's ability to hold moisture. (As it turns out, nightcrawlers 
and angleworms, imported to use as fishing bait, are not native to 

"All of those factors are pushing the forest in the same [northeast] 
direction," Frelich told me. "My best guess is that the BWCA Wilderness 
will look more like a savannah than a boreal forest within five to 10 

Altogether, he and Reich report in their writings an expectation that 
the lost of forest along the prairie-forest border of central North 
America could equal an area twice the size of California.

"There's no doubt that human activity has made this a unique, 
super-charged event," Frelich said.

*Inpact on the urban landscape*
Frelich describes what might be called an ecological reset. Higher 
levels of CO2 in the atmosphere have set off a chain of events. Plant 
life adjusts to changing conditions. Forest becomes prairie. Habitats 
change. Animals adjust.

Maybe it runs parallel to the reset taking place in the world of human 
settlement. Jim Erkel, land use and transportation director for the 
Minnesota Center for Environmental Advocacy <http://www.mncenter.org/>, 
offers the analogy. Conditions for humans are changing. Not only do we 
have a warming climate and an unstable energy supply, we have a 
faltering economy and significant demographic shifts toward smaller 

What's required is a reset, Erkel suggests, citing the Austrian 
economist Joseph Schumpeter's theory of "creative destruction." 

Economic crises sweep away outmoded companies, practices and systems, 
clearing the way for entrepreneurs to introduce new technologies and new 
ways of doing things that reignite growth.

In that context, we can't build cities the same old way, Erkel said. 
Conditions require a spatial fix, a new development pattern that's more 
that's more compact and energy efficient. Some people will resist these 
changes, complaining about loss of basic freedoms, the rising price of 
gasoline or the falling values of large suburban homes, for example. But 
maybe, said Erkel, moral values aren't really involved. Maybe changes in 
the urban form should be viewed as similar to the ecological adjustments 
being made in Minnesota's northern forests.

"There is no right or wrong in the way nature resets itself to changing 
conditions," he said. "It's just the way it happens."

More information about the Marxism mailing list