1994 Forest Health Highlights, Michigan

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1994 Forest Health Highlights

Michigan

The Resource

Forests comprise 53% of the land area of the State. These forests are a critical component of Michigan's

economy for the recreational opportunities and the products they provide. Forestry related industries and

manufacturing employ 134,000 people statewide with an annual payroll of $913 million. The overall

contribution of the forest resource exceeds $3.2 billion. In addition, Michigan's forests contribute to clean

air, water, and reduce soil erosion. For these and other reasons, maintaining healthy forests is important.

53% of the state is forested (19,280,000 acres)

Out of the forested area:

97% timberland

2% non commercial or reserved forest land

Special Issues

Gypsy moth, an exotic insect, defoliates millions of acres of trees annually in the eastern United States

and is one of the major forest pests in Michigan. Gypsy moth caterpillars feed on a variety of trees, but

favor oaks, American basswood, and aspen. Repeated defoliation can result in growth loss, tree mortality,

changes in forest composition, and loss of habitat for various animals. Gypsy moth can be found

throughout the Lower Peninsula and in a few areas in the eastern part of the Upper Peninsula. In 1994,

gypsy moth defoliated 97,287 acres. This was a significant reduction from 1993 levels, when 399,305

acres were defoliated. This marked reduction in defoliation was primarily the result of poor survival of the

gypsy moth because of the extremely cold winter. The primary objectives of the gypsy moth management

program in the Lower Peninsula are to preserve foliage and maintain populations of the gypsy moth

caterpillars at tolerable levels. In the Upper Peninsula, there is a Slow the Spread Project with the

objective of retarding the movement of the gypsy moth in the Upper Peninsula and to adjacent states. In

1994, a total of 149,908 acres of forests were treated to control gypsy moth in Michigan.

Oak decline has been a serious problem in the central portion of Michigan's Lower Peninsula. Oak

decline is a recurrent problem and impact is greatest on northern pin oak because it grows in areas with

shallow, droughty, nutrient-poor soils. Tree mortality has occurred over 387,000 acres of northern pin oak

forests and has ranged from 10 to 100 percent. The main causes of mortality have been drought, late

spring frosts, repeated gypsy moth defoliation, and old age. There was reduced mortality of northern pin

oak in 1994 compared to previous years. This reduction in mortality was due mostly to the return to near
1994 Forest Health Highlights, Michigan

file:///X|/netsite-docs/lps32615/1994%20Forest%20Health%20Highlights,%20Michigan.html[4/2/2015 11:21:42 AM]

normal or above normal precipitation and reduced gypsy moth defoliation.

In Michigan's Upper Peninsula birch decline and death have been major concerns. The causes of the

decline of birch include: previous drought, birch leaf miner, advancing age of trees, and often the poor

sites on which they are growing. Evaluations have shown that more than 15% of the birch volume has

been lost since the late 1980's.

Other Issues

The common pine shoot beetle continues to be found in new counties throughout the eastern United

States. This beetle, native to Europe and Asia, was first found in the United States in 1992. New adults fly

to the crowns of living pine trees and enter shoots and feed throughout the summer and fall. Attacked

shoots typically discolor, die, and eventually fall to the ground. Because of the potential for damage and

the beetles non-native status, APHIS has imposed a federal quarantine on all areas where it is known to

occur. The quarantine controls the movement of pine materials from infested to non-infested areas.

Quarantined materials include: Christmas trees, nursery stock, and logs or lumber with bark. The common

pine shoot beetle has been found in 37 counties in Michigan. Counties where this beetle was first found in

1994 are Bay, Clare, Huron, Kent, Lapeer, Sanilac, and St. Clair. Significant damage by this insect has not

occurred in Michigan. Effective control can be accomplished by sanitation and proper management.

In 1994, an outbreak of the cherry scallop shell moth occurred in the northern portion of Michigan's

Lower Peninsula. Black and pin cherries were completely defoliated in some areas. In addition, late last

growing season there were numerous reports of damage by the oak skeletonizer. Because of these reports

an early season outbreak of this insect is anticipated.

Regional Surveys

North American Maple Project - Michigan is a participant

in an international project to evaluate the health of sugar

maple forests in eastern North America. This project grew

out of a concern about sugar maple decline and mortality

expressed by foresters and sugarbush managers. A total of 18

plots have been established in Michigan and trees are

evaluated annually. Results indicate the condition of sugar

maples in Michigan has improved since 1988 and tree health

was not adversely impacted when managed for maple syrup.

Widespread decline or mortality of sugar maple has not

occurred in eastern North America.

Forest Health Monitoring - In 1994, plots were established

to monitor the health of Michigan's forests. This is part of a

nationwide Forest Health Monitoring Program in partnership

with the Environmental Protection Administration. The

motivation to begin monitoring the health of forested

ecosystems grew out of the concern over the potential effects

of air pollutants, insects, diseases, and other stressors, as

well as concern over the potential effects of global climate

changes to the composition and stability of forests. The

monitoring program includes a network of permanent plots and surveys of forest pests and other stressors.

In Michigan there are 247 plots, of which 133 are forested. In addition, surveys for Jack pine and spruce

budworms, pine tussock moth, and gypsy moth are done to supplement plot information. Monitoring will

be useful to look at current health and changes in forest conditions.

For More Information
1994 Forest Health Highlights, Michigan

file:///X|/netsite-docs/lps32615/1994%20Forest%20Health%20Highlights,%20Michigan.html[4/2/2015 11:21:42 AM]

Gerald Thiede, State Forester 

MI DNR 

Forestry Division 

P.O. Box 30028 

Lansing, MI 48909

(517) 373-1275

Forest Health Protection 

USDA Forest Service 

1992 Folwell Avenue 

St. Paul, MN 55108

(612) 649-5261

September 1995