Are Michigan's Trees in Trouble?
by Jeff Gibbs ~ 9188 E. Hoxie Rd. ~ Cedar, MI 49621
231-941-0825 ~

Clarence Kroupa's woods are stunning.  Bass, ash, and beech are branch-free for nearly a hundred feet.  "Not many people have their own private park."  Indeed, few parks are as pristine as Clarence's.  But there is the matter of the "black hearts in the ash." And Clarence's basswood look a bit ragged.  

Warning signs, or just a forest in need of a tune-up?

No one disagrees that Michigan's trees have been hit hard in recent years. Gypsy moth defoliated 700,000 acres in 1992.  Half the oaks on about 45,000 acres of oaks are dead, and from 1991 to 1998 about ten percent of Michigan oaks and aspens died, according to a University of Michigan study.  Beech bark disease may wipe out beech trees, joining elm and chestnut on the list of trees which have disappeared from our state.  As summer progresses Michigan travelers can observe a variety of trees along our roadways which are dead or dying, and forests which may lose their foliage to pests.

Charles Little, author of The Dying of the Trees, believes these are not isolated problems, but warnings that Michigan's forests, and those all over America, are in fact dying.

"I can introduce you to scientists who believe that the entire Eastern hardwood forest is dead ecologically, that it can never mend itself aright because of leached out nutrients from acid- deposition and the resultant ecosystem changes," Little says.  According to Little the culprit is acid rain, which along with other airborne pollutants like ozone, halocarbons, and heavy metals, create a deadly brew inhospitable to forests.  He sees pests like gypsy moth as opportunists attacking trees weakened from environmental factors.

The question was posed to several experts: are Michigan's forests in trouble?

Roger Mech, Forest Health Specialist, Forest Management Division, Roscommon say that, "Generally most forest types are in good shape in the Lake States."

Russell Kid, District Extension Forestry Agent for Michigan State University Extension in Roscommon thinks we are not seeing the effects of acid rain just yet.  "In 1988 a severe drought really affected the trees; other years warm springs and late frosts.  I am more concerned about the introduction of exotic pests than acid rain."

But Doug Cornett, Executive Director of Northwoods Recovery agrees with Little that the forests are in trouble.  "All around Marquette the trees are dying.  It's especially bad where I live, on a hill between two coal-fired power plants.  I was in Traverse City recently and could see dead maples all along the road.  Those trees are only 70 to 100 years old, young trees really.  There's a whole bunch of things going on, but what comes out of the sky is the most frightening.  Acid rain probably plays the major role.  Normal ph is 5.5 to 6, but twenty years ago levels started coming in between 5 and 4."

Murray Daley, an environmental activist in Lake Orion, says, "Since reading the Dying Of The Trees I have paid particular attention to the trees everywhere I go in Michigan and around the country.   It is impossible not to.  It is similar to the scenario where a person buys a new car, then begins to see that car everywhere.  All one has to do is look. The upper limbs and branches go first I have noticed.  The oaks, the maples, the pines.  It is a slow death.  They say that tree death is natural--and it is. But trees don't die naturally at ages of 30, 40, 60 or 80 years old."

Remember acid rain?

A United States Geological Survey report lists the acidity of precipitation in Michigan as ranging from 4.9 to 4.4 at monitoring sites last January.  A pH of 4.4 is one hundred times more acidic that 5.4.  The Environmental Protection Agency, on their official website, states that: "Pure water has a pH of 7.0.  Normal rain . . . has a pH of about 5.5.  As of the year 2000, the most acidic rain falling in the US has a pH of about 4.3. . .  Acid rain can contribute to forest damage by impairing the ability of some types of trees to grow and fight disease.  Acid rain also can strip forest soils of essential nutrients, which hurts the productivity of forests."  

Cornett feels that little attention is being paid in Michigan to the impact of acid rain. "Although the U.S. Forest Service is supposed to monitor acid rain in their plan for the Ottawa National Forest under the National Forest Preservation and Trust Act, over the last fifteen years they have never done so."

Ann Woiwode, Mackinaw Region Sierra Club Program Director says, "We don't know much about airborne pollutants in Michigan.  Fifteen years ago there was more research about acid rain, mostly about the effects on lakes.  Forest ecosystems were felt to be a buffer, but on what basis I do not know.  If we wait for serious problems before we decide to study it, that's not good.  It's crazy to assume that their are no effects of pollutants."

Eastern forests hit hard

Elsewhere the data seems clear.  According to a CBS news report, "Researchers said acid rain has contributed to a decline in red spruce trees across the eastern United States and to sugar maples in central and western Pennsylvania.  Earlier reports had blamed acid rain for damage only to red spruce trees at high elevations, saying its effect on other trees was inconclusive.  Since the 1960's, more than half the canopy of red spruce trees in New York's Adirondack Mountains and Vermont's Green Mountains and one-quarter of those in New Hampshire's White Mountains have died.   The report suggested white ash and basswood trees may also be susceptible."

I asked Little about the rate of decline in Michigan oaks and aspen.  "According to Orie Loucks, the forest ecologist a ‘background mortality rate' before the age of pollution in West Virginia and Kentucky was 0.5 to 0.7 a year. Your annual rate is about 1.4 percent a year, two or three times higher than normal if your hardwood ecology is the same as the more southerly woodlands.  As a generality, ‘anything over 2 or 3 percent death each year,' says Loucks, ‘is a disaster.'"

In some ways it's incredible we have any forests in at all, according to Woiwode.  "Michigan has already experienced one of the worst environmental disasters ever when the ancient forest was eliminated, then fire swept through, denuding the land.  It was incredibly bad. The forests were stripped down to the mineral soil."  We lost nearly all the original forests of hardwood and pine, including white pine, which grew to heights of two hundred feet.

"Our Michigan native habitat is some of the most endangered in the world.  The National Biological Service estimated that only .005 percent of our virgin hardwood and pine habitats remain.  In the 19th century people were convinced it would take hundreds of years to clear Michigan's forests.  I feel harsher towards people who think there is nothing we can do today," Woiwode said.

How far are we from restoring the functioning forests we had?  

"We're a very long way away from seeing that happen.  We are just now beginning to recover, but the baseline was very bad," Woiwode stated.  "The question is, what do the people of our state want the forests to be?  The answer seems to be commodities."

Daley said, "They don't want to acknowledge that over-cutting can be a problem."

In contrast Mech sees poor forest management as culprits where trees are experiencing problems.  "Competition between trees is a factor.  Unhealthy trees need to be thinned so healthier trees can thrive.  Private landowners who think they do not need to manage their woods can be a problem.  Some trees are not as thrifty as others and landowners should plant more appropriate species."

Kidd said, "The global economy has introduced several pests, and the arrival of new ones does not seem to be slowing up.  Pests somehow know what trees are stressed and go to those trees.  Trees are resilient and can handle a single stress."  

Mech has an explanation for the dead trees along the highways.  "Road salt causes dieback.  It gets into the groundwater and root zones.  Trees in wet areas are especially vulnerable.  From the air you can see the zone (of dead or damaged trees) extending out along the highways. "

Trees under siege

Whatever the cause or causes, the lists of tree species under attack in Michigan is formidable.

According to the experts black and pin oak are attacked by the two-lined chestnut borer and Armillaria root-rot.  Oak wilt hits in the middle of July, especially red oak.  Oak skeletonizer, a green caterpillar, shreds oak leaves.  Oak decline (a general deterioration of oaks) extends from Manistee to West Branch to Alpena.

Spruces are attacked by spruce budworm.  Hemlocks are being attacked by the wooly adelgid, an aphid like creature that is often lethal.  Hemlock and northern white cedar are also not regenerating in part due to heavy browsing by deer.  (Woiwode said there are no cedars in Michigan under 40 years old because they are a favorite food of deer.)  White birch have been hit hard by birch miner.  Jack Pine can be attacked by jack pine budworm.  White pine are still facing trouble from white pine blister rust.

This year's outbreaks are expected to include two native insects according to Kidd.  Forest tent caterpillars, which do NOT make tents, defoliate sugar maple and aspen.  Eastern tent caterpillars, native to Michigan, and do make tents, are also on the upswing.  They are found in cherries or fruit trees, old fields.

A recent arrival, Beech bark disease, really an insect which weakens beech trees and a fungus which finishes the job, has been seen most commonly in recreation areas, beginning with Ludington State Park.  Mech said no one knows how it spreads: perhaps by birds, campground firewood, even state employees.  As it stands now we can expect that beech will disappear from Michigan in coming years.

It might not be an exaggeration to call two new pests not yet in Michigan potentially catastrophic in their impact.  Kidd and Mech grew animated when warning about the Asian Longhorn Beetle.  "It's really something to be concerned about.  It attacks all hardwoods.  It can kill healthy trees," Mech said. "It's a good looking insect, as big as your hand, with grubs as big as your finger.  Right now it's in Chicago and Central Park in New York City.  It might travel in firewood."

Then there is the Asian Gypsy Moth, currently on the west coast.  Mech said, "First it's not picky, it will eat everything.  Secondly, unlike the European Gypsy moth, the female can fly, so it can spread very rapidly."

What can be done?

Kidd says that in general harvest older trees, thin out the woods to let the healthiest trees thrive, plant something different or more suitable for the soil if needed.  Think twice before transporting firewood, and if you do check the wood.  Look for Beech scale on beech.

Mech advised that people take care not to damage trees, especially breaking the bark,  creating entry points for insects and diseases. Be careful backfilling around trees or bumping into trees with equipment. He recommend that people not prune in May and June.

Cornett sees forest management itself as a problem.  "In forestry school you are trained not to look at the big picture, that there is an explanation for everything, that it is insects and disease and that trees are over-mature.  That non-management is bad.  But these ‘managers' are cutting down the forests.  The woods did just fine without us."

Woiwode said, "There seems to be a sentiment in this state more than others, that nature didn't get it right, that forests have to be continually managed aggressively and that if we don't their won't be much wildlife.  They are mistaken.  There was a lot of wildlife before we starting fooling around with the forest.  The forests are so disturbed that people don't know what else to do."

"Our forests are the canary in the coal mine, "according to Cornett.

CBS News in it's report on the problems in the Northeast said, "Only deeper reductions in nitrogen oxide and sulfur dioxide emissions -- the pollutants which cause acid rain -- are likely to help the Northeast recover, scientists said in the report released Monday."

Little considers what might help.  He says that planting trees will help only a little.  He recommends reducing pollution, not to 1990 level's as Clinton had proposed, but to pre-1950's levels at least.   But Little thinks we need more: "So we might begin a process--requiring at least a century, though likely more--of environmental repair, of letting nature heal herself.   But I must tell you. . . it's going to be a bumpy ride."

Back at Clarence's paradise the joy of trees and the satisfaction of a lifetime of nurturing those trees seems only slightly tainted.  Even the Gypsy moths skipped Clarence's upland woods.  But the trees that trouble him--ash and basswoods--are two of the species in trouble out east.  Clarence and his wife plan on passing their "park" on to their children and grandchildren.   Let's hope we can do the same with the rest of Michigan's forests.

Northwoods Recovery:
Sierra Club (Michigan chapter):
Information on tree pests:



. . . to Eco Systems' Home Page


Contact Gerry Hawkes: