Mic

ic

Forest Health High

orest Health High

Michigan Department of Natural Resources and 
Forest Health Highlights is a summary of the condition of 

Michigan's forests during 2010 and the work done to preserve and protect them by Forest Management Division, Department of Natural Resources and Environment. Written by Department of Natural Resources and Environment Forest Management Division staffPhotographs and design byDepartment of Natural Resources and Environment Marketing, Education and Technology Division staff Forest Health ProgramUnited States Department of Agriculture Forest Service Michigan Department of AgricultureMichigan State UniverstiyMichigan Technological UniversityMaps and other information provided byMichigan Department of AgricultureUnited States Department of Agriculture Forest Service Animal and Plant Health Inspection ServiceNational Oceanic and Atmospheric Administration National Climatic Data CenterMichigan State University Extension

Acknowledgements cknowledgements Table 

able 

Forest Res

 Insects & D

Annosu

 Asian 

 Beech  Emera Forest  Gypsy  Hemlo Jack P Oak W  

Sirex n

 Spruce  Thous Upper  Tree Declin Aspen  Hickor Maple  White  Drought . .  Invasive Pla

2 - Forest Health Highlights 2010 
• Among the 50 States, Michigan ranks 

 22nd in land area but 10th in forestland  area.

• Forest land accounts for 19.3 million acres 

 or 53 percent of land in Michigan; 97  percent or 18.7 million acres is  timberland.

• Sugar maple/beech/y

 the predominate for of timberland). Aspe second most abunda Northern white-ced and red pine (5 perc most abundant softw

• All prominent specie

 moderate to high pe annual net growth to 

• Of Michigan’s forestla

 or 11.9 million acres  lands are owned by  private corporations groups. The remaini (7.4 million acres) is  state, and local gove

Forest Resource Overview

Michigan is a state like no other with two peninsulas. From the warmer agriculture and urban areas in the South to the colder wooded lands in the North, the state offers unique ecosystems, land uses, and one of the most diverse forests in the United States. Nearly all of the forestland in Michigan was cut and/or burned during European settlement. The bulk of the lumber boom and most of the fires occurred in the late 1800s and early 1900s. By 1920, the lumber boom had ended and secondary succession was in full swing with the recovery of the forests. Today, Michigan has more forestland than any 4 - Forest Health Highlights 2010 other state in the Northeast or Midwest. Michigan’s state forests and a number of large private ownerships are certified as practicing sustainable forestry through the Forest Stewardship Council (FSC) and the Sustainable Forestry Initiative (SFI). The U.S. national forests are managed under the National Forest Management Act and National Environmental Protection Act. There also are numerous assistance programs to help small forestland owners.
Annosum R

Insects and Diseases nsects and Diseases

Healthy and productive forests are comprised of a diversity of native tree, 

shrub, and herbaceous plant species, as well as an even larger number of faunal species for which forests provide habitat. Forested ecosystems have continuously adapted and evolved over thousands of years, as insect, plant, and animal species are naturally, intentionally, or inadvertently introduced or extirpated from ecosystems. Prevention and mitigation of invasive plants, insects, and disease introductions is important for the maintenance of healthy and productive forests.

 From ‘Michigan Forest Resource Assessment & Strategy’

June 2010

Michigan continues evaluatired pine trees for the preseannosum. To date, H. annosum has not been detected north of Lansing, Michigan (south central part of the state). Annosum root rot was first reported in the Lake States in 1971. It win Wisconsin in 1993, and ncounties there. Annosum rocommonly observed on re

An

Asian Long

As

c

The asian longhorned beetlinsect that attacks 11 genera maples, elm, willow, birch, horse chestnut, London planetree, aspen, ash, and mountain ash. The 2008 discovery of a 62 acre ALB infestation in Massachusetts involving thoprovided reason and momedetection efforts. The Department of NaturaEnvironment (DNRE) screevisitor database for visits in tfrom Worcester, MA. They from ALB-infested areas of in the Lower Peninsula (MuCounties), and two in the U(Chippewa and Luce Countwere intensively surveyed. in Michigan in 2010. 

6 - Forest Health Highlights 2010 
Beech bark disease appears as white dots 

on the outer bark.

Beech Bark Disease 

grafting them onto beech root stock. Fifteen grafts for each of the 20 resistant trees will be used to establish an orchard of 300 resistant trees. In the fall of 2010, the USDA Forest Service, in cooperation with Michigan State University and the DNRE Tree Nursery, began planting Michigan’s first American Beech seed orchard using this resistant stock. Ultimately, the seed produced at this orchard will be used to restore beech trees to the forests impacted by BBD.

Since its discovery in Michigan in 2000, beech bark disease (BBD) continues to pose a serious threat to Michigan’s forests. This disease is initiated by a scale insect that attaches to the tree and feeds off sap from the inner bark layer. Damage from this feeding allows one of two Neonectriafungus species to establish itself inside the tree. The fungus prevents the flow of sap, killing infestedportions of the tree and eventually the entire tree. Controlling the spread of the disease is difficult because both the scale and fungus can be transported by air. Michigan Technological University received a USDA Forest Service grant in 2009 to continue surveys to mark and protect American Beech in newly affected areas of BBD.The area of infestation continues to spread east and west in the Upper Peninsula and to new areas in the Northern Lower Peninsula. Spot infestations of the scale insect have been found far outside the primary infestation front. Since the fungus cannot invade the tree without the scale, researchers are focusing on trees resistant to the scale. The USDA Forest Service Research Facility in Delaware, Ohio, and the DNRE Forest Management Division have been collecting cuttings from scale resistant beech and 

8 - Forest Health Highlights 2010 

Beec
• Assisting local woodland owners and 

 homeowners in making environmentally  and fiscally responsible decisions regarding  their ash trees and woodlands.Three Asian wasps that attack EAB eggs or larvae were released in Southern Michigan in 2007: Tetrastichus planipennisi, Spathius agrili and Oobius agrili. An MSU researcher found another pest that attacks EAB, Atanycolus hicoriae. Two of 

the three wasps, Tetrastichus and Oobius, were 

released in the Upper Peninsula in 2010 at the Houghton and Delta/Schoolcraft county sites.For more information on SLAM, visit www.slameab.info

Emerald Ash BorerSlowing infestation

A pilot project was initiated in 2008 to 

test the latest concepts for managing EAB populations. The project is called SLAM which stands for “Slow Ash Mortality.”

The areas selected for this study include three 

outlying infestations in the Upper Peninsula (See map). The primary goals of the project include: 

• Reducing EAB population growth and 

 rates of tree mortality in the core areas. • Detecting and preventing satellite  populations from expanding and becoming  core populations.

• Developing and maintaining regular 

 communications and consistent messages  with the local landowners in and around  the project area. 

The DNRE is involved in many projects to survey and prepare Michigan’s urban and rural forests for arrival of the emerald ash borer (EAB).SurveyingThe Michigan Department of Agriculture (MDA) in cooperation with the USDA Animal and Plant Health Inspection Service, continue to survey the uninfected counties in the Western Upper Peninsula. They deploy purple traps baited with an aromatic lure known as Manuka Oil. Traps are placed around high-risk areas such as campgrounds and sawmills and along travel pathways. Traps are also placed in a few areas in the Upper Peninsula (Houghton, Alger, and Chippewa Counties) near remote single-tree infestations. 10 - Forest Health Highlights 2010 

E

The current emerald ash boencompasses all of the Loweight of the fifteen Upper P(see map). There are still arPeninsula, especially the Nohave not yet been impacted although it is legal to move the Lower Peninsula, it is admovement of ash firewood Peninsula as much as possibinformation on the EAB quaMDA website at: www.mic

Galleries below ash bark made by EAB larvae.

EAB Adult (actual length is 1/2-inch
The forest tent caterpillar (FTC) continued 

to make life miserable for homeowners and woodlot owners across much of the Northwestern Lower Peninsula this year. FTC defoliated 444,772 acres in Northwestern Lower Michigan. Defoliation was very heavy in areas around Gaylord, Cadillac, Traverse City and Petoskey.Widespread outbreaks of FTC occur at approximately every 10 to 15 years. In the past, outbreaks peaked in 1922, 1937, 1952, 1967, 1978, 1990, and 2002. While statewide caterpillar populations may remain high for up to 5 years, outbreaks in any one locality normally last for 2-3 years. Outbreaks decline quickly once parasites and other natural enemies become active. FTC is a native defoliator of a variety of hardwood trees and shrubs. It feeds primarily on sugar maple, aspen, oaks, and birch but occasionally feeds on other associated hardwoods, particularly during outbreaks. Defoliation normally begins in late-May with the greatest leaf loss occurring in the first three weeks of June.  Defoliation from FTC generally causes little damage to tree health. Heavily defoliated trees develop a second set of leaves a few weeks after being defoliated. These new leaves and leaves formed the year following an outbreak are often smaller than normal. 

Forest Tent Caterpillar

County 

Cheboygan Antrim Montmorency Charlevoix Wexford Otsego Manistee Alpena Alcona Emmet Missaukee Grand Traverse Benzie Kalkaska Crawford Osceola Oscoda Ogemaw Lake Leelanau Mason Dickinson Mecosta 

2010 Fore

Caterpillar D

by Cou

Trees rarely die from FTC defoliation unless weakened by drought, late spring frost, or other stressors. During outbreaks, FTC caterpillars can number from 1 to 4 million per acre. They create an extreme nuisance to people living or vacationing in infested forests. Young larvae spin a thread and fall from trees onto picnic tables, patios, and people. Mature larvae wander across the ground in search of food, making for slippery roads and 

walkways. Mass flights of tein late June and early July aroutbreaks. The FTC overwinters in an host trees. Eggs hatch in the the time of bud break. As care easily identified by the wor footprint pattern along th

12 - Forest Health Highlights 2010 

Forest tent caterpillars clustered on an aspen tree.

Forest tent caterpillars
Gypsy Moth 

Hardwood forests across much of the Northern Lower Peninsula suffered moderate to heavy defoliation again this spring, although signs are positive that populations will decline dramatically beginning in 2011. The gypsy moth feeds on the foliage of a variety of hardwood trees, including oak, aspen, willow, basswood, birch and dozens of other species. It is common for a population of gypsy moths to defoliate, or eat most of the leaves off trees. When moth populations are high and competition for food increases, they will feed on other tree species, including conifers like spruce and pine. Fortunately, trees usually recover from defoliation as long as they are growing well and have adequate water and nutrients available. Even repeated defoliation rarely kills a tree, unless drought, old age or other stressors have weakened it.

Since then, a natural system predators, and fungi has beto speed the collapse of ougypsy moth populations low time. In many Michigan forebehaves like a native insect, outbreaks followed by exteactivity.This current outbreak is expsubsiding in 2011. Cool, wespring will encourage the spmaimaiga, a fungus that kills gypsy moth caterpillars befointo adults and lay eggs. For more information abou

In 2010, gypsy moth numbers increased dramatically across Michigan’s northern Lower Peninsula and parts of the Upper Peninsula, where defoliation was detected on approximately 943,000 acres of forestland. In some areas, gypsy moths and forest tent caterpillars were found feeding in the same forests, particularly where oak and aspen grow together. Native to Europe, the gypsy moth was accidentally introduced to Massachusetts in the late 1800’s and was first detected in Michigan in the 1950’s. Populations spread steadily in the 1970’s and, by the late 1980’s, gypsy moths were devouring hundreds of thousands of acres annually. 

Gypsy moth larva

Gypsy moth egg mass

14 - Forest Health Highlights 2010 

www.fs.fed.us/ne/morganto

Gypsy moth
an important 

component of Michigan’s forests. Based on inventory data, it exists in over 12% of the state’s timberlands. The hemlock wooly adelgid (HWA), Adelges tsugae, is a small aphid-like insect. This insect is native to Asia and was transported to the United States on trees brought into the U.S. from that region. The HWA feeds by piercing small branches of hemlocks and feeding on the sap within. Infested needles turn brown and die. Infested hemlock trees often die within several years. Drought conditions, and damage from other insects or diseases can increase the rate at which trees die.HWA was found on naturally-growing hemlock near Harbor Springs, Michigan in August 2006.This is the third time this pest was found in Michigan and the first time the insect was 

Jack Pine BThe number of acres defolipine budworm increased in below average annual defoliation levels for the period 1999 through 2008. Typically, budworm populations remain high for 2 to 3 years and then decline quickly due to egg and larvadeath of larvae during the wnumber of acres can remaiyears as budworm populatiwhere trees are at risk due stressors.The budworm is the most jack pine in North Americabecome more susceptible t

an importantcomponentof Michigan’sforests. Based on inventorydata it exists inThe Eastern hemlock is Hemlock Wooly Adelgid

Adult HWA on branch

Jack Pine 

16 - Forest Health Highlights 2010 

reported outside of nursery stock. It is believed the insect arrived with infested landscape trees that were shipped from outside Michigan. HWA has been attacking Eastern and Carolina hemlock in the Eastern forest since its initial discovery near Richmond, Virginia in 1951.Since 2006, the DNRE and Department of Agriculture have cooperated in early detection surveys for the HWA. The surveys in 2007, 2008 and 2009 found no additional infections. In 2010 however, surveyors found new infestations on ornamental hemlock trees in three counties: Emmet, Macomb, and Ottawa. A second insect, the elongated hemlock scale insect (EHS) is believed to increase the damage caused by HWA. This insect arrived from Japan in the early 1900s and has been documented in Michigan. Health decline in hemlocks has been documented in the Eastern forests where populations of EHS are high, but not in Michigan. Some evidence indicates that damaging outbreaks of EHS can occur where HWA feeding is heavy. EHS surveys are being conducted along with HWA surveys in Michigan.

Hemlock Wooly Adelgids
Oak wilt is established widely in the Southern 

Lower Peninsula with spotty distribution in the Northern Lower and Upper Peninsulas. One method of spread is by movement of firewood, so as the public moves northward into forested areas, the risk of spreading this disease grows. Cut wood is used on camping trips where it can be a source of fungus the following year.Property values can be significantly reduced due to the loss of many trees when a single tree is infected. Acorns produced by oaks are a valuable food source of wildlife. More than 180 different kinds of birds and mammals use oak acorns; including popular species such as white-tailed deer, squirrels, turkey, wood ducks, woodpeckers and others. Effective oak wilt management programs use a variety of strategies to limit the spread of oak wilt.

• Avoid wounding oaks from April 15

 to July 15.

• Do not move infected wood off-site 

 without debarking, chipping, or properly 

 drying it. If infected w destroyed before the  tightly cover cut logs  with plastic tarps from 

• Stop the undergroun

 by breaking root-gra between likely diseasOak Wilt InThe USDA Forest Service cooak wilt suppression funds, sExtension and DNRE efforts Peninsula of oak wilt. The obprogram are to: 

• Remove oak wilt from 

 by detecting and treat

• Educate affected com

 the reintroduction of 

• Demonstrate an effec

 detecting and treating  Michigan. In 2010, a vibratory plow wgrafted oak roots and establiwilt areas in Menominee and About 270 oak wilt areas haeliminated to date. A second grant from the USbe used to detect, confirm a

Oak Wilt Oak wilt (Ceratocystis fagacearum) is one of the 

most serious tree diseases in the Eastern United States, killing thousands of oaks each year in forests, woodlots, and home landscapes. Oak wilt was first identified in 1944. The extent of its impact wasn’t realized until the 1980’s. Only in the last few years has oak wilt been reclassified as an exotic disease. Although oak wilt can infect many species of oak trees, trees in the Northern red oak, pin oak, black oak, scarlet oak, and red oak hybrids are most susceptible. Infected red oaks die within days or weeks of being infected. Members of the white oak group are much less susceptible and rarely die from the disease. Oak wilt spreads from tree to tree through connected root systems. Untreated, the fungus spreads to adjacent red oak trees, often killing large groups of trees within a few years eventually killing all nearby, root-grafted oaks. Oak wilt spores that can spread the disease overland are produced only in the year following tree mortality. Insects move these spores to fresh oak wounds from April through July. Trees, logs and firewood from killed trees produce these spores.

Oak leaves showing signs of oak wilt.

18 - Forest Health Highlights 2010 

Oak wilt
Sirex noctilSince its detection in New YoEuropean wood wasp, Sirex noctilio, has been confirmed at trap sites throughout the Eastern Great Lakes region of Ontario, Canada. This exotic wood wasp (commonreferred to as horntail wasp) native to Europe, Asia and Nwas collected in Fulton, New 2004, the first time the insect American forests. This wasp is rarely a pest in it confines its attacks to dead trees. In areas where it has bhowever, Sirex poses a possthat are already stressed due competition from other treepopulations may build up in then spread to areas of healtoutbreaks have occurred in AZealand, South Africa and SoFemale Sirex are attracted to they dig into the outer bark, introduce a toxic mucus and areolatum). Larvae feed on ttogether with the mucus, kilof Sirex infestation include:

• Exit holes approximat

 in diameter.

• Tree needles turning 

 yellow to reddish bro late spring or early su

• Larval galleries (tunne

 packed with a fine po produced sawdust).

• Beads or streams of r

 seeping from holes in 

In 2010, the DNRE received American Recovery and Reinvestment Act (ARRA) funds to identify and treat oak wilt outbreaks in high-use recreation areas and in high-value stands of red oak in the Northern Lower Peninsula. As oak wilt establishes in new areas, spores produced by the fungus increase the likelihood of transmission to healthy oak trees. The risk of movement of oak wilt through spring and early summer wounds and firewood are at historic highs. Early detection and treatment of oak wilt outbreaks in urban, rural and forest landscapes can slow the spread of the disease and minimize the potential impact to Michigan’s oak trees. Through a combination of aerial and ground surveys, staff identified oak wilt on 3,026 acres of state forestland in Crawford, Missaukee, and Grand Traverse Counties. Active pockets of oak wilt were defined and trees showing symptoms of Oak Wilt – ARRA Project 

oak wilt were marked as potential spore-producing trees. Root graft barriers were established between infected trees and healthy trees using a vibratory plow. Over 47,000 feet of plow line was installed. Infected trees were cut and destroyed or sold for timber. Trees moved out of the forest are handled in a way that ensures the disease will not spread to new areas. In some state forest campgrounds, herbicides were applied to cut oak stumps to eliminate sprouting of oak trees that would be susceptible to the disease in the future. Oak wilt poses a unique threat in recreation areas where dead and dying trees can create hazards. Because the fungus can remain in root systems for up to 3 years, treatment areas will be monitored during this period to ensure that the disease has been eliminated.

Counties with Oak Wilt 2010

20 - Forest Health Highlights 2010 
Thousand C

The spruce budworm outbreaks periodically cause extensive damage and tree mortality in Northern spruce and fir forests across the Eastern United States and Canada. Balsam fir is the species most severely damaged. Spruce mixed with balsam fir is more likely to suffer budworm damage than spruce in pure stands.Defoliation of white spruce and balsam fir increased significantly in Michigan’s Upper Peninsula in 2010. Repeated defoliation of mature and over mature spruce and fir has occurred in isolated areas. Top kill and tree mortality is common in these stands. Periodic outbreaks are part of the natural cycle associated 

Spruce budworm damage to a forest.

Spruce Budworm

County Acres Defoliated

Ontonagon 49,742Iron 27,882Chippewa 27,237Mackinac 15,855Gogebic 15,170Dickinson 11,371Schoolcraft 11,010Houghton 7,109Menominee 4,414Presque Isle 3,162Baraga 1,776Marquette 1,201Cheboygan 657Delta 566Keweenaw 398Huron 166Alcona 127Kalkaska 113Grand Traverse 66Alger 54Mecosta 14

2010 Spruce Budworm

Defoliation by County

with maturing trees. Since 1909 there have been recorded outbreaks of the budworm in both the Eastern United States and Canada. Outbreaks typically last 10-15 years and result in the loss of millions of trees. It is too early to know whether the current buildup of spruce budworm in Michigan is the beginning of a major budworm epidemic. Drought cycles over the last decade may have contributed to the current buildup. If the trend continues significant loss of trees can be expected.

Counties with Spruce 

Budworm Defoliation in 

2010

In May, the Michigan Departestablished a quarantine to pspp.) from thousand cankers is an insect-disease complex twig beetle, Pityophthorus jug

Geosmithia morbida. TCD currently occurs in ArizColorado, Idaho, Nevada, NWashington, and Utah, statetwig beetles are native. The Eastern black walnut that has these Western states; native to be resistant. Walnut twig fungus to black walnut trees at the feeding site. Heavily atmany cankers, which eventuappears that the range of thieastward, threatening walnuJuly 2010, TCD was found eKnoxville, Tennessee.

22 - Forest Health Highlights 2010 
During October, the DNRE 

received numerous reports 

of Ixoides scapularus adults, 

commonly known as the deer tick, in the Marquette 

 vicinity of North Central  Upper Peninsula. This is the 

tick that carries Lyme disease. Identification of adult ticks brought to DNRE offices confirmed these reports. This expands the DNRE’s understanding of the distribution of Ixoides from the Southern 

portions of the Central and Western Upper Peninsula Northward to the most northern reaches of the Central Upper Peninsula.

European snout beetles on Grand IslandThe European snout beetle (Phyllobius oblongus L) defoliated sugar maple on Grand Island for the second year. Maples in some local areas were completely stripped of leaves. This is an uncommon occurrence.Ixoides adults in the Northern Upper Peninsula

Sirococcus reemerges in Alger CountySirococcus shoot blight (Sirococcus strobilinus Preuss) affected a small pocket of 10-12 foot red pine south of Munising in Alger County. Sirococcus had been recorded about a mile west of this site in the past, but was thought to have been eradicated three years ago.Sirococcus shoot blight affects conifers, especially seedlings and saplings, in the Northern United States and Southern Canada. The fungus infects new shoots. Sirococcus shoot blight has become increasingly widespread since the early 1970's. When favorable conditions for infection occur, tree mortality and shoot death increase. Maple Tar SpotThe number of Norway maples and their varieties (e.g. Crimson King, Schwedler) affected by maple tar spot decreased in 2010. Maple tar spot is an unsightly leaf disease caused by a fungus, Rhytisma spp. There were still some scattered reports of maple leaves covered with large tar spots beginning in August. Maples are not harmed by this late season loss of leaves.

Upper Peninsula Forest PestsIxoides scapularus Photo by Scott Bauer

Sirococcus destroys needles on red pine.

Tree declintrees often growth anslowly ovecombinatiodrought anincrease th

European snout beetle

Photo by Gyorgy Csoka,

Hungary Forest Research .

24 - Forest Health Highlights 2010 
Mortality of larger aspen is often associated with 

Hypoxylon canker. Significant periodic defoliation by the forest tent caterpillar, gypsy moth and the large aspen tortrix in the last decade has also contributed to this decline in aspen vigor and overall health. The aspen leafblotch miner (Phyllonorycter apparella) and Septoria leaf spot discolored aspen canopies in many parts of the state in 2010.

Aspen Decline Aspen decline continues to be reported in many areas of the Lake States. The first reports were recorded in 2008.

Observations include: • Thin crowns with small leaves. • Increased rates of top kill and tree mortality.

A similar decline in aspen was observed after the extreme 1976-77 drought. It is thought that the droughts of the past decade, most notably in 2002-03 and 2006-07 and some areas of the Upper Peninsula in 2008, have predisposed aspen to attacks by secondary pests. These problem areas occur in pockets, likely corresponding to aspen clones, site conditions and/or older clones. A similar decline in aspen was observed after the extreme 1976-77 drought. Other observed pests included Armillaria root rot, the 

bronze poplar borer (Agrilus lirgus), and Septoria

leaf spot (Septoria musiva).

Decline of aspen caused by some combination of disease, insects 

and environmental stresses.

Poplar borer

Aspen Leafblotch Miner

Hickory DeDecline and death of bitterncordiformis, was reported in time in 2010. Hickory declinin several Northeastern statefor the past 5 years. The decby thinning crowns with smaThis problem has historically outbreaks of the hickory barquadrispinosus, during extenddrought. Recently a new funsmalleyii, associated with the numerous bark cankers. The trees’ ability to transport wat

Cankers underneath t

26 - Forest Health Highlights 2010 
White Pine 

For the past five years, white trees have been dying in MicLower Peninsula. Smaller white pine trees growing along the Manistee and AuSable rivers have been most severely affected. Several opportunistic fungi – pathogens that do nobut can cause problems in stbeen identified on these treespittlebug and Diplodia scrobicauses stem cankers) are comPine spittlebug is a sap-feedinin the Lake States, where pobuild up during dry periods ato die. The DNRE has also id

a root rot fungus that frequehardwood and conifer trees

Canker underne

28 - Forest Health Highlights 2010 Maple Decline in the Western Upper PeninsulaMaple decline has been reported for the last few years in Michigan’s Western Upper Peninsula. A combination of soil conditions, management practices and drought are thought to have been factors.In order to determine the causes and rate of spread of maple decline, Michigan Technological University received a grant from the USDA Forest Service. The grant will also be used to determine the distribution of maple decline. One hundred and twenty plots have been established on public and private lands in Michigan, Wisconsin and Minnesota. 

Sixty of the plots, established in 2010 in sugar maple forests, showed a loss of 5 to 28 percent of the trees. Information gathered on each plot include: trunk conditions, leaf coverage, earthworm density, soil nutrients and leaf nutrients. Staff collected tree borings to examine the growth rings. The DNRE will use the information to select forest management practices that will reduce or halt the decline of maples.
Following the 2006-2008 drought, rainfall returned to near normal levels beginning 

in 2009. Areas in the extreme Southern portion of the Lower Peninsula are currently experiencing moderately dry conditions (See Michigan Drought Monitor Map). Although we are in the second year of near normal rainfall, it takes years for trees to rebuild food reserves. The drought has been a major influence on tree health, especially in the Western Upper Peninsula and parts of the Northern Lower Peninsula, which saw consecutive years of extreme drought. 

Drought Droughts can trigger significa

canopy health. Hardest hit ain light, sandy soils or on lowsignificant water table fluctuastressed trees are susceptible pests and diseases. As a resu2010 tree mortality increaseby the two-lined chestnut bopaper birch was affected by t

2010 Droug

30 - Forest Health Highlights 2010 
Invasive Plant Projects nvasive Plant Projects

The existence and health of Michigan’s natural places depends on controlling the introduction and spread of invasive plants. Invasive species are foreign to the ecosystem and are likely to cause economic, environmental or human harm.

American Rand Reinve

In 2010, the Michigan DNRinventory and removal of invfrom five forest areas (MaxtoLakes, Van Etten Flood Plainand locations along the AuSafunding provided by the AmReinvestment Act (ARRA). Sspecies of invasive plants, incknapweed, purple loosestrifJohn’s-wort, Canada thistle, sweet clover. In some locations, a numbeendangered species were alinvasive species, requiring caremoving the invasive plantsspecies encountered include

32 - Forest Health Highlights 2010

Monitoring Controlling The DNRE Wildlife Division Invasive Plant Strategy in 20priorities identified in this plaof spotted and diffuse knapwcontracted the release and mcontrol agents shown to be these plants. There were fivSchoolcraft, Missaukee, CrawJackson Counties. The objective of this project knapweed by introducing naLarinus minutus, a knapweed Cyphocleonus achates, a knaThe goal is to restore these that flower in midsummer ansources used by Michigan’s h