2012

Forest Health

Highlights

Michigan Department of Natural Resources
Acknowledgments

Forest Health Highlights is a summary of the condition of Mic2012 and the work done to preserve and protect them by ForDepartment of Natural Resources, www.michigan.gov/foresthWritten by: Michigan Department of Natural Resources Forest Resources Division staffPhotographs and design by:Michigan Department of Natural Resources Marketing and Outreach Division staff Forest Resources Division staffUnited States Department of Agriculture Forest Service Michigan Department of Agriculture and Rural DevelopmentMichigan State UniversityMichigan Technological UniversityMaps and other information provided by:Michigan Department of Agriculture and Rural DevelopmentUnited States Department of Agriculture Forest Service Animal and Plant Health Inspection ServiceMichigan State University Extension

The Michigan Department of Natural Resources is committed t

protection, management, use and enjoyment of the state’s natural 

for current and future generations. 

For more information, visit www.michigan.gov/
Table of C

Forest Resource Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Michigan Department of Natural Resources Forest Health Program . . . . . . . . . 5Feature: Harvesting Ash and American Beech Ahead of EAB and BBD Impacts . . . 6Insects & Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Heterobasidion Root Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

 Asian Longhorned Beetle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Beech Bark Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 BBD Research Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Resistant American Beech Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14  Emerald Ash Borer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Spring Defoliators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Eastern Larch Beetle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17  Hemlock Woolly Adelgid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Oak Wilt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Upper Peninsula Oak Wilt Control Project . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Spruce Budworm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Thousand Cankers Disease and Walnut Twig Beetle . . . . . . . . . . . . . . . . . 23 Jack Pine Budworm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Balsam Woolly Adelgid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Firewood Movement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Forest Decline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Maple Decline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30  Drought and Forest Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 White Pine Dieback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Invasive Plant Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Other Forest Health Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Locust Leafminer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 March Snowstorm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Duck Lake Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Miscellaneous Pests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Forest Resource Overview

Michigan is a state like no other in the nation, with its two peninsulas surrounded by the largest system of fresh surface water on Earth. From the warmer agriculture and urban areas in the south to the colder wooded lands in the north, the state off ers unique ecosystems and land uses and one of the most diverse forests in the United States. Nearly all of the forest land in Michigan was cut or burned during European settlement. The bulk of the lumber boom and most of the fi res 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. Since then, these forests have been maturing. Today, Michigan has more forest land than any other state in the Northeast or Midwest. The rich diversity of our urban and rural forests is being threatened, however, by exotic insects, plants and diseases fi nding their way into the state from around the world. Invasive organisms like emerald ash borer, beech bark disease and oak wilt are aff ecting thousands of acres in Michigan and killing millions of trees. Without a plan of action, entire species of native trees are at risk of disappearing from our forests. 

The solution to this growing crisis lies largely Understanding the role humans play in the acexotic pests into our forests is a vital fi rst step The 2012 Michigan Forest Health Highlights pto getting the word out about the work the DResources and collaborative organizations are exceptional forest resource.

• Among the 50 states, Michigan ranks 

 in forest land area. 

• Forest land accounts for 20.1 million a

 Michigan; 97 percent or 19.4 million a

• Sugar maple dominated forest types 

 birch and hard maple-basswood) are  types (26 percent of timberland/fores cedar (7 percent) and red pine (4 perc softwood forest types. 

• Of Michigan’s forest land, 62 percent 

 by families, individuals, private corpo groups. The remaining 38 percent (7.6  by federal, state and local governmen

• Sixty-fi ve percent of Forest Inventory 

 for nonnative species had at least one  species. Higher ratios of nonnative to  the Lower Peninsula. 

4 - 2012 Forest Health Highlights
Michigan Department of Natural Resources 

Forest Health Program

The Michigan Department of Natural Resources Forest Health Program grew out of a 1970s collaboration between Michigan State University, the U.S. Department of Agriculture (USDA) Forest Service’s Northeastern Area State & Private Forestry Unit, and the DNR’s then-Forest Management Division. This interagency cooperation still drives the Forest Health Program today. Our services are coordinated with all three Michigan forestry schools, the MSU Extension, the Michigan Department of Agriculture and Rural Development, the North Central Forest Experiment Station and the USDA Animal & Plant Health Inspection Service. Additionally, it includes strong cooperative ventures with other state forest health programs. The Northeastern Area State & Private Forestry program plays a strong coordinating role regionally and nationally. Beginning in the early 1990s, Michigan’s Forest Health Program became increasingly involved in multistate and national forest health issues. These eff orts were, in part, a response to a new era of exotic forest pest challenges and ever-increasing demands and needs for quantifi able, high-quality information about the health of our forests. In a 1997 eff ort to improve program utility and effi ciency, a team structure was adopted to better serve the demands of national and statewide initiatives and of local programs across all forest ownerships in Michigan. Forest health activities were divided between two new programs: Forest Health Monitoring and Forest Health 

Management, coordinated statewide by two These programs are supervised statewide by manager.In 2012, a forest health technician was added with fi eld activities statewide. The technician’conducting a variety of ground and aerial surprocessing survey data and assisting with foractivities.

Anna River Valley in Munising, Mich.
Harvesting Ash and American Bee

Ahead of EAB and BBD Impacts

Foresters from the Department of Natural Resources and Michigan Technological University are examining thousands of acres of state forest land with American beech and ash species doomed by the continuing spread of beech bark disease (BBD) and the emerald ash borer (EAB). As this forest resource is assessed and mapped, eff orts are being mounted to salvage at-risk timber values before they are lost due to impacts of these two exotic forest pests. 

This eff ort is funded in part by federal grants from the Great Lakes Restoration Initiative and the Pest and Disease Revolving Loan Fund, which are administered by the U.S. Department of Agriculture Forest Service’s State and Private Forestry, Forest Health Program.Since the discovery of 

BBD in 2000, and EAB in 2002, millions of beech and ash trees have been killed. In addition to timber values, beech is an important mast, 

wildlife, and a tree with great aesthetic appeal due to its smooth gray bark and large spreading canopies. It is also known as the “initials tree” as the smooth bark often hosts the names or initials of people wishing to leave a sign of their visit to a state park or other forested areas.Ash samaras (winged seeds) are important fobirds and small mammals. Cavities in both beby nesting birds and gray squirrels.Forest inventory of state-managed forest lanwith a few, to many, ash and/or American bee166,000 acres have ash and/or beech with an and comprise at least 10 percent of the standacres that ash/beech salvage eff orts will take Deciding which areas to harvest in the next fto harvest the targeted areas are the next chahave detected areas where ash and beech foand northern Lower Peninsula have not yet bCriteria used to make harvest decisions inclu

• Whether the resource is infested; Beech snap caused by beech bark disease.

Impact of beech bark County. 

or nut, producer for 

6 - 2012 Forest Health Highlights
EAB and BBD Impacts continued

• Proximity of uninfested resources to the nearest infested site; • Value and volume of the at-risk resource; and• Ease of access. 

A primary goal of this eff ort is to promote healthy forests through harvest prescriptions which remove most of the beech and ash, and replaces them with a desired mix of productive species. Desirable tree species have value in terms of forest products, as well as benefi ts to 

certain wildlife species. It is not the goal to remove all beech or ash, but to remove and replace many of these trees so that the impacts of anticipated mortality will not signifi cantly impair the quality or productivity of the remaining forest.In addition to the harvests, a portion of the federal funds for this project are being used to support the writing of forest management plans on private lands that have a signifi cant ash or American beech component. 

Ash tree mortality as a result of emerald ash bo
Insects & 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 are important for the maintenance of healthy and productive forests.

From “Michigan Forest Resource Assessment & Strategy”

June 2010

8 - 2012 Forest Health Highlights
Heterobasidion Root Disease

Eff orts to delimit the occurrence of Heterobasidion root disease (HRD) continued in 2012. Surveys were concentrated in the northwest Lower Peninsula in the region where HRD was confi rmed in 2011. Numerous pockets of pine mortality in actively managed plantations were surveyed this year. No new infections of HRD were confi rmed. 

Unlike many forest insects and diseases that are attracted to stands stressed by lack of 

management, HRD is most commonly found in actively managed forest 

stands. In Michigan, 

red pine, jack pine and white 

pine are most susceptible. Fresh cut stumps provide an ideal entry path for spores of HRD, which move through grafted roots to infect healthy trees. Infected trees suff er from thinned crowns and reduced height, diameter and shoot growth. Over time, circular pockets of dead and dying trees mark the progression of the disease. Caused by the fungus Heterobasidion irregularae

(formerly Heterobasidion annosum), this disease is 

considered among the most destructive fungi in North American forests. Eff ective control measures for HRD have been developed. Fungicides applied to freshly cut stumps prevent HRD from entering and moving to healthy trees through the root system. This approach, while eff ective, would pose additional costs and restrictions on the harvest of Michigan’s pine resources. 

With the discovery of an active HRD infection and with HRD being established across much Wisconsin, early identifi cation and containmebecome a forest health priority. In 2013 the Department of Natural Resources Technological University to conduct statewidpresence and distribution of HRD in Michigan

of pockets of pine mortality through routine survey will be important in developing an adHRD sites to aid in this statewide survey. 

Distribution of Heterobasidion Root Disease in the northeastern U.S. – 2
Asian Longhorned Beetle

With the detection of Asian longhorned beetle (ALB) in Bethel, Ohio – only a four-hour drive from Michigan’s southern border – the Department 

of Natural Resources has intensifi ed eff orts 

of early detection to prevent this destructive forest pest from becoming established in Michigan.In late April 2012, several staff from the DNR Forest Resources Division (FRD) and the Michigan Department of Agriculture and Rural Development traveled to Bethel to get fi rsthand experience 

with an active ALB infestation. The staff ’s impression was that this is a slow-spreading type of infestation that is very diffi cult to control. The potential for accidental spread by human activity, through the movement of fi rewood or other wood products, prior to detection means the potential for outlier populations is a serious concern. It is estimated that the infestation in Bethel had been established for more than 10 years before it was discovered. That is 10 years prior to the implementation of any quarantine restricting the movement of wood products out of the area. Ten years in which someone could have unknowingly spread ALB from the infested area. In cooperation with DNR Parks and Recreation Division employees and volunteers, FRD staff surveyed for ALB in 61 state parks and recreation 

areas in 2012. Surveys were targeted to high-susceptible host species: maple, elm, willow athese visual surveys, the DNR instituted a phethat specifi cally targeted campgrounds knowresidents of documented ALB areas. This was zip codes. Campgrounds are of the greatest concern anbecause ALB can easily be transported in fi rewand monitored throughout the period when they were present. No ALB were detected as a 

Asian longhorned beetle infested fi rewood.

10 - 2012 Forest Health Highlights
Asian Longhorned Beetle continued

Forest Health Program staff also inspected numerous sites to follow up on reports from concerned citizens whose descriptions of observations matched ALB symptoms. During the 2012 season, there was an increase in the number of suspect specimens being reported by the public to DNR offi ces across the state. In most credible cases these were the native white-spotted pine sawyer beetle – not ALB. The increase in reporting is encouraging in that it indicates an increased public awareness of the threat ALB poses to Michigan’s forests.Plans for 2013 are to expand and continue these cooperative eff orts at early detection of ALB in high-risk areas.
Beech Bark Disease

Since the discovery of beech bark disease (BBD) in 2000, this exotic disease has spread widely through Michigan’s forests. BBD is initiated by a scale insect that attaches to the tree and feeds on sap. Damage from this feeding allows one of two Neonectria fungi to invade the tree. The fungus inhibits the fl ow of sap through infested portions of the tree, causing a general decline in tree health – eventually killing it. Controlling the natural spread of BBD is not feasible because both the scale and fungus are moved by the wind.

where the beech resource has been greatly abeech resource is under attack as newly infesin the Lower Peninsula every year.

Scale-infested beech trees marked for salvage. According to the latest U.S. Department of 

Agriculture Forest 

Service Forest Inventory and Analysis (FIA) data for the period 2007-2011, there are 31.6 million American beech trees greater than 5 inches in diameter and 2.5 million standing dead beech in the same size category. The FIA report estimates annual beech mortality in this time period to be 5.3 million cubic feet of growing stock beech and 21.1 million board feet of sawtimber beech. Much of this loss is in the eastern Upper Peninsula 

12 - 2012 Forest Health Highlights

J.B. Wieferich and D.G. McCullough, 2012.
In 2012 we revisited beech bark disease (BBD) plots established in 

2002 and 2003 to document changes in beech scale density, tree mortality and crown condition, understory and overstory tree species composition, and down woody material.

In 2003, beech scale was present in only 23 of the 62 sites, including 14 sites in the Upper Peninsula (U.P.) and nine in the Lower Peninsula (L.P.). Beech scale is now present in 55 of the 62 sites, including 33 of the 34 sites in the U.P. and 22 of the 28 sites in the L.P. Overall, 44 sites are 

Beech Bark Disease Research UpdateProgression and Impact of Beech Bark Disease in MichiganJames Wieferich and Dr. Deborah McCulloughMichigan State University

While the total volume of down woody materisimilar, the proportion of the pieces that are resubstantially. This increase appears to refl ect bdown woody material, 94.3 percent of the piecof those, 68.3 percent were beech. In high moencountered numerous beech snags that have down woody material will likely continue to shto fresh beech logs as beech snags break and fBeech scale has become established across moU.P. and in much of the northwest and north cislands in Lake Michigan and Lake Huron. Between 2005 and 2007, beech scale infestatioaverage of 4 km and 1.5 km per year in the U.PMore recent data from 2008-2012 suggest beeextremely variable; some areas spread rapidly while spread in other regions was less than 1 kestablishment of satellite populations of beecthan 20 km from the nearest infested site probdispersal of beech scale by humans or birds. Mpopulations have now coalesced, which may iThe most recent infestation, discovered in Isabrelatively localized.Data from 2007-2008 suggested beech scale pnorthern face of beech trees compared to the infested areas. Some winter mortality occurs, b

Forest health specialists study the results of beech bark disease. heavily infested, including 26 sites in the U.P. and 

18 sites in the L.P. Most of the beech range in the U.P. is now infested by beech scale, with the exception of one site in an area west of Marquette that remains uninfested. On average, beech mortality has doubled since 2002 and is especially high in the eastern U.P. In the 14 U.P. stands that were infested with beech scale in 2003, 49.4 percent of beech trees are now dead. In contrast, only 8.5 percent of beech trees are dead in the nine previously infested stands in the L.P. Sugar maple and red maple seedlings dominated regeneration in the study stands. Beech dominated the sapling size class, accounting for 62.7 percent of all saplings, followed by sugar maple (18.3 percent) and ironwood (4.9 percent). 
14 - 2012 Forest Health Highlights

Since 2002, the Department of Natural Resources has been working with the Northern Research Station (NRS) of the U.S. Department of Agriculture Forest Service to select and breed American beech trees for resistance to beech bark disease (BBD). Beech trees that are resistant to BBD are resistant to the beech scale insect. Cuttings from potentially resistant beech are sent to the NRS where they are grown and tested for scale-resistance. Techniques to propagate resistant trees through grafting have been developed, and genetic tests of full- and half-sibling families have demonstrated that BBD resistance is heritable and breeding resistant beech is possible. These genetic studies indicated that when both parents are resistant, approximately 50 percent of the progeny can be expected to be resistant.Project eff orts are now focused on identifying, selecting and propagating resistant beech for establishing seed orchards. These orchards will provide seed to generate resistant seedlings for restoration plantings so that healthy American beech trees will persist in Michigan forests. Planting of the fi rst resistant American beech seed orchard began in 2011 at the Brighton Tree Improvement Center. To date, a total of 74 resistant trees have been planted. Unfortunately, heavy deer browsing and drought conditions claimed all but 39. Plans are to fence the orchard and install irrigation which will greatly increase survival and growth rates. Work continues to complete the Brighton seed orchard by 2014. A total of 170 trees will consist of 20 diff erent BBD-resistant genotypes, with eight or more ramets made from each genotype. A ramet is a vegetatively reproduced copy of a plant, so each ramet will have almost precisely the same genotype as the original parent tree. To create a ramet, a cutting is taken from a BBD-resistant beech tree, which is grafted to root stock to produce a plant with identical genetics.

So far, fi ve diff erent resistant parent combinatioaverage of 52 percent resistant progeny. Subsefamilies were out-planted in November 2011 in area heavily impacted by BBD. Their one-year s95 percent. They will continue to be monitored and scale-resistance. The original full-sibling fawere planted along with half-sibling families anat the Holden Arboretum in Kirtland, Ohio, in 2of these families was initiated so that correlatiothe early seedling screen scale-resistance phenotypes and the performance of the now 10-year-old trees growing in the fi eld. 

Resistant American Beech Project

Resistant beech tree 

at Brighton Tree 

Improvement Center 

seed orchard.
Emerald Ash Borer

The Department of Natural Resources is involved in many projects to prepare Michigan’s yet unaff ected urban and rural forests for the arrival of the emerald ash borer (EAB). The DNR is also working to cope with the loss of ash trees and implement restoration of aff ected forests and neighborhoods.During the camping season, DNR Parks and Recreation Division employees inspect all fi rewood brought in by campers entering state parks. When found, fi rewood that is not in compliance with the EAB quarantine is seized and burned.According to the latest U.S. Department of Agriculture (USDA) Forest Service’s Forest Inventory and Analysis (FIA) data for the period 2007-2011, there are 162.8 million ash trees greater than 5 inches in diameter, and 17.9 million standing dead ash in the same size category. This number does not include ash on non-forest lands, such as urban and suburban environments. The FIA report estimates annual ash mortality in forested environments of 35.8 million cubic feet annually, and 78.5 million board feet of ash sawtimber per year.Surveys and QuarantinesNo new Michigan counties were added to the EAB quarantine in 2012. The Michigan Department of Agriculture and Rural Development (MDARD) and the USDA Animal and Plant Health Inspection Service continue to survey uninfested counties in the western Upper Peninsula. They deploy purple traps baited with an aromatic lure called manuka oil. Traps are placed around high-risk areas such as campgrounds and sawmills and along travel pathways. There were no detections in the uninfested, nonquarantined counties of the western Upper Peninsula.

The USDA’s Animal and Plant Health Inspectiofederal order updating its EAB quarantine pounrestricted interstate movement of regulatefederal quarantine boundaries, with the exceprotected areas within the existing quarantineff ective on July 1, 2012. With these changes to federal regulations, Miremains in eff ect. EAB quarantine requiremenmoved entirely within Michigan are unchangRegulated articles, including all hardwood fi rewithout a compliance agreement in these circ

• Moving articles from the Lower Penin

 and 

• Moving articles from quarantined are

 Peninsula to nonquarantined countie Upper Peninsula. 

For those who move regulated articles across eff ects of the federal EAB quarantine include changes:

• A federal certifi cate or limited permit 

 ship articles regulated by the EAB qua Peninsula into or through Ohio or Ind the fi nal destination of the articles is o federal quarantine boundaries or into  Illinois or Indiana, a federal certifi cate  permit is still required.

• A federal certifi cate or limited permit 

 move articles regulated by the EAB q Peninsula from areas inside of the con boundaries.
There is still a general advisory against moving fi rewood due to 

associated accidental introduction or spread of potentially devastating forest pests such as EAB, Asian longhorned beetle, oak wilt and others. People are encouraged to purchase fi rewood as close to where they will use it as possible and should not take any unused fi rewood home with them or move it to another camping location. Remember to “burn it where you buy it.”For more information on EAB, please visit www.emeraldashborer.info or visit the MDARD website at www.michigan.gov/mdard. Slow Ash Mortality ProjectA 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 two outlying infestations in the Upper Peninsula. These EAB outliers are in the St. Ignace/Moran area of Mackinac County and the Laurium area of Houghton and Keweenaw counties.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; and 

• Assisting local woodland owners and homeowners in making 

 environmentally and fi scally responsible decisions regarding their  ash trees and woodlands. 

Emerald Ash Borer continued

Three Asian wasps that attack EAB eggs or larvae have been released in areas of the Lower Peninsula and in two areas of the Upper Peninsula. The parasitoidsare Tetrastichus planipennisi, Spathius agrili and Oobius agrili. Although no additional wasps were released in 2012, evaluations of past releases report that all three parasitoids are surviving and being recovered at the Houghton County SLAM site as well as at the Garden Peninsula site in Delta County. For more information on SLAM, visit www.sla

Bark stripped by woash borer larvae.
Spring Defoliators

Populations of forest tent caterpillar, gypsy moth and other spring hardwood defoliators remained low in Michigan during 2012. Very little caterpillar activity was observed in forests around the state, allowing trees an opportunity to recover from the heavy defoliation suff ered during the 2009 and 2010 growing seasons in northcentral and northwestern regions of the Lower Peninsula. The eff ects defoliation has on tree growth and survival are a function of several factors, including: when during the growing season defoliation occurs; intensity of the defoliation; and whether other stressors, such as drought and frost damage, are also aff ecting trees.When less than half of a healthy tree’s leaves are lost to defoliation in the spring and early summer, there are relatively few long-term eff ects. The partially defoliated trees remain in this condition until fall, when leaves turn color and drop normally.Heavy defoliation, when more than half of the leaves are consumed, can have serious consequences to tree health. The re-fl ush of new leaves (that 

heavy defoliation often triggers) uses up energy otherwise use for growth, to heal wounds and tagainst attacks from insects and diseases. Repeated heavy defoliation, especially when it ocan lead to dieback and tree death, especially wstressed from other causes. Slow, irreversible decondition caused by multiple stressing events thdecline. Recent droughty conditions, along with periodiled to extensive tree decline in the northern Lowfeature article on ash and beech decline for morResearch indicates that trees can take up to fi ve negative eff ects of heavy defoliation once insec

Fortunately, forest tent caterpillar and gypsy moto remain low for several years now that populanatural enemies are high.

Eastern Larch BeetleImpacts of eastern larch beetle (ELB), Dendroctonus simplex, continue to be reported occasionally to the Department of Natural Resources. These impacts are on isolated pockets of tamarack (Larix larcinia) in the eastern and south-central areas of the Upper Peninsula. This bark beetle became an epidemic as tamarack was stressed by two consecutive years of defoliation by the larch casebearer (Coleophora laricella) in 2001 and 

2002. The repeated droughts of the last decade and associated stresses have contributed to continued ELB activity. With a return to normal rainfall, these satellite populations of ELB should diminish.
Hemlock Woolly Adelgid

The most common long-range hemlock woolly adelgid (HWA) dispersal occurs as a result of people moving or transplanting infected nursery stock or landscape trees. 

In March 2012, an alert landscaper notifi ed the Department of Natural Resources to report what he believed was HWA on a hedge of hemlock trees in New Buff alo. DNR forest health personnel contacted the Michigan Department of Agriculture 

and Rural Development (MDARD) who, with the help of the forest health staff , conducted a survey 

of the area surrounding the newly reported infestation. Survey crews confi rmed the reported HWA and discovered a second infestation within a half-mile of the original site. All infested trees were removed and destroyed. In addition, healthy trees in the immediate vicinity of the infestation received treatment with a systemic insecticide to ensure HWA eradication of the aff ected area. MDARD will continue to monitor and conduct follow-up surveys for the next three years. Trace-back investigations revealed that the infested trees were planted approximately 10 years ago – prior to the establishment of the HWA quarantine in Michigan. The second most common method of long-range HWA dispersal is by birds, with black-capped chickadees and nuthatches being active and abundant in hemlock forests. Forest health staff theorized that if HWA crawlers were already present in an area but at very low levels, not yet detectable, concentrated bird activity near a feeding station would eventually lead to detectable HWA 

levels in the immediate vicinity. This would occthrough repeated activity of the birds at the fee12 bird feeder stations were established in highMichigan shoreline and in the vicinity of previofeeders were maintained throughout the summare most active. The sites were surveyed for HWwas detected. Surveys for HWA at other locatioconducted throughout the year.

Cottony white HWA adults on balsam fi r twig.

18 - 2012 Forest Health Highlights
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 fi rst identifi ed in 1944. The extent of its impact wasn’t realized until the 1980s. Only in the last few years 

has oak wilt been reclassifi ed as an exotic disease. Although oak wilt can infect many species of oak, 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 fi rewood from killed trees produce these spores.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 fi rewood, 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 signifi cantly reduced dwhen a single tree is infected. Acorns producefood source of wildlife. More than 180 diff erenmammals use oak acorns, including popular sdeer, squirrels, turkey, wood ducks, woodpeckEff ective oak wilt management programs use the spread of oak wilt. Following is some basic guidance:

• Avoid wounding or pruning oak trees • Do not move infected wood off -site w

 or properly drying it. If infected wood  the following April, tightly cover cut lo tarps from April 15 to July 15.

Impact of oak wilt in Ogemaw County.
• Stop the underground spread of oak wilt by breaking root-graft 

 connections between likely diseased and healthy oaks. A  professional should be consulted to ensure proper placement of  root-graft barriers. Vibratory plows used to lay underground cable  are fi tted with a special blade which breaks root grafts to a depth  of 60 inches. All red oaks inside the root-graft barriers are  considered potentially infected and should be removed only after  root-grafts are disrupted.

• If oak wilt is detected in the year it was newly introduced via 

 overland spread, removing the infected tree and stump before  the next growing season removes oak wilt without aff ecting  adjacent oaks. The next growing season, the fungus moves  through root-grafts to neighboring trees – sometimes as much as  100 feet or more away, necessitating the aforementioned  treatments resulting in the loss of many surrounding red oak.

For more information on oak wilt management, use the following link:michigansaf.org/forestinfo/Health/E2764-OakWilt.pdf.

Oak Wilt continued20 - 2012 Forest Health Highlights
The U.S. Department of Agriculture Forest Service, Forest Health 

Protection Program continued providing Oak Wilt Suppression funds in 2012. Michigan Technological University’s Department of Natural Resources and the Environment joined the Michigan Department of Natural Resources in an eff ort to rid the Upper Peninsula (U.P.) of oak wilt. The long-term objectives of this eff ort are to: 

• Remove oak wilt from the U.P. by detecting and treating infection 

 centers on all ownerships;

• Educate aff ected communities to prevent the reintroduction of 

 oak wilt; and 

• Demonstrate an approach for detecting and eff ectively treating 

 oak wilt infection centers throughout Michigan. 

A vibratory plow was used to establish approximately 20,000 feet of root graft barriers to isolate and remove oak wilt pockets in Menominee and Iron counties. Although much has been achieved, oak wilt is still active in areas of both counties and in southern Dickinson County. About 300 infection centers have been successfully eliminated to date. Oak wilt was detected in Iron County for the fi rst time in 2010. A big obstacle to the 

DNR’s eff orts to stop the spread of oak wilt is the movement of infected fi rewood and logs.Confi rming oak wilt as the cause of oak mortality is not always easy. Not all oak mortality is oak wilt-caused. Oak mortality and decline in the last decade is the result of drought, late-spring frosts, two-lined chestnut borer and a mature to over-mature northern pin oak resource. The DNR has stepped up eff orts to detect and confi rm oak wilt where symptoms are found. Knowledge of the number and distribution of oak wilt pockets is crucial to understanding short-and long-term impacts of oak wilt on Michigan’s oak resource. This knowledge is also needed as we seek funding to combat the continued spread of oak wilt and resulting loss of oak resources.

Michigan State University Extension evaluatesuppression eff orts in 2011. Many treated areDickinson counties remain free of oak wilt. Alachieved, there remain untreated oak wilt pothese untreated oak wilt pockets serve as a socontinued overland spread to adjacent oak reareas via movement of fi rewood and logs.

Upper Peninsula Oak Wilt Control Projec

Department of Natural Resources fi re offi cers inwith a vibratory plow in Menominee County.
Spruce Budworm

Epidemics of spruce budworm, Choristoneura fumiferana, periodically 

cause extensive damage and tree mortality in spruce and fi r forests across the northeastern United States and Canada. 

Historically, epidemics have occurred on a 30-year to 50-year cycle. The last epidemic ended in Michigan in 1982. Outbreaks typically last 10 to 15 years and result in the loss of millions of trees.The vast majority of Michigan’s spruce and fi r resources are 

in the Upper Peninsula (U.P.) and new areas of budworm defoliation were discovered there in 2012. This outbreak follows a reduction in spruce budworm activity in 2011, which followed alarmingly widespread infestations in 2010. The western U.P. has the largest area of budworm activity due to the abundance of over-mature spruce/fi r forest. Top kill and tree mortality is common in these stands. It is uncertain if the increase in spruce budworm activity over the last few years in the U.P. is a precursor to the next largescale event.Historically, balsam fi r was the species most severely damaged by the spruce budworm. Spruce mixed with balsam fi r was more likely to suff er budworm damage than spruce in pure stands. However, in the last few years, spruce plantations without a balsam fi r component have been heavily defoliated. Stresses from persistent drought over the last decade are likely contributing to increased spruce budworm activity, especially in spruce 

plantations. A return to more normal precipitvigor of our spruce and fi r resources. Departmstaff is also seeing declines in spruce plantatibudworm activity.Heavy spruce budworm damage in Dickinson CPeninsula.

22 - 2012 Forest Health Highlights
Thousand Cankers Disease 

and Walnut Twig BeetleIn May 2010, the Michigan Department of Agriculture and Rural Development (MDARD) established a quarantine to protect walnut (Juglans spp.) from thousand cankers disease (TCD). TCD is an insectdisease complex involving the walnut twig beetle, Pityophthorus juglandis, and a fungus, Geosmithia morbida.TCD currently occurs in Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Washington and Utah – states where the walnut twig beetle is native. The disease aff ects only eastern black walnut trees that have been transplanted in these western states; native walnut species appear to be resistant. Walnut twig beetles carry the fungus to black walnut trees where cankers form at the feeding site. Heavily infested trees produce an abundance of cankers which eventually kill the trees. It appears that the range of this beetle is slowly spreading eastward, 

threatening walnut trees in eastern states. In 20were added to Tennessee as states east of the MIn 2012, Ohio reported fi nding the walnut twig beetles were found in the traps. Offi cials have qfrom leaving the site of discovery. At this time, there have been no trees determined to be infested with TCD in Ohio. Michigan’s quarantine restricts the movement of the following from TCD-infected states into Michigan:

• All plants and plant parts 

 of the genus Juglans,  including but not limited  to: nursery stock, budwood, 

 scionwood and green 

 lumber; other living, dead,  cut or fallen wood,  including logs,  stumps, roots and  branches; composted  and non-composted chips;

• Hardwood fi rewood; or• Any article, product or 

 means of transportation  that risks the spread of 

 walnut twig beetle or fungus.

Walnut twig beetle emergence holes.

TCD canker
Thousand Cankers Disease 

and Walnut Twig Beetle continuedArticles that are not a threat and are exempt from the quarantine include:

• Nuts, nut meats and hulls;• Processed lumber that is 100 percent bark-free 

 and kiln-dried with squared edges; and

• Finished wood products without bark.

In 2012, to support the TCD quarantine, the Department of Natural Resources conducted a walnut twig beetle pheromone-trapping survey. Following established guidelines of the United States Department of Agriculture, pheromone traps were installed and maintained at 18 locations across southern Lower Michigan. One additional trap was located in the northern Lower Peninsula. No walnut twig beetles were detected in trap samples from the 2012 season. Tree canopy surveys were also conducted at these and other sites to look for signs of walnut decline that might indicate the presence of TCD. No symptoms of TCD were detected.In 2013, MDARD will expand walnut twig beetle pheromone-trapping surveys to cover the 27 southernmost counties in the Lower Peninsula. 
Jack Pine Budworm

The jack pine budworm, Choristoneura pinus, is an insect native to North America. Jack pine budworm populations play a historic role in the 

perpetuation of jack pine forests. Periodic outbreaks lead to dieback and mortality in older jack pine stands. This makes these stands more susceptible to catastrophic fi res which, in turn, results in the dense regeneration of young jack pine stands. Modern fi refi ghting 

eff orts and current management practices prbefore it becomes over-mature and susceptibThis has minimized the impacts of budworm periodically across Michigan’s jack pine forestJack pine budworm populations appear to be north-central Lower Peninsula. While jack pinolder were historically at highest risk, defoliatacross a wide range of age classes. Mortality common in older jack pine stands that have bdefoliated in two or more consecutive years. in recent years could exacerbate these eff ectconditions may determine if this buildup prowe see a return to normal population levels.
Balsam, of course, has been a popular Christm

400 years. Wildlife also relies extensively on thiMoose rely on balsam fi r as a major food sourcBalsam fi r provides a minor part of the diet for the ruff ed grouse. Buds, tips and needles are coccurs in winter than in summer. Thickets of baboth of these grouse species. The use of balsam shelter is also well documented.The balsam woolly adelgids infest fi rs in southern Canada and the United States, where they occur in the Pacifi c Northwest, Northeastern states and in the Appalachian Mountains as far south as North Carolina. Adelgids appear as white, woolly dots about the size of pin heads on the surface of the tree’s bole, limbs and buds. The distribution of BWA was thought to be limited in its northern distribution by cold weather. However, in talking with experts from aff ected areas of Canada and the United States, it is believed that BWA could overwinter in Michigan as it survives well in areas of eastern Canada. In locations that get really cold (minus 10 degrees Fahrenheit or colder, for example), the adelgids survive beneath the cover of snow.For more information on BWA, go to www.na.f

Balsam Woolly Adelgid

With the support of the Department of Natural Resources, the Michigan Department of Agriculture and Rural Development is drafting a balsam woolly adelgid (BWA), Adelges piceae, quarantine. 

Introduced from Europe around 1900, BWA is 

considered a serious pest of all true fi rs in the genus Abies, including balsam and Fraser fi r. Balsam woolly adelgids were fi rst noticed in Maine in 1908. Since that time, billions of board 

feet of fi r timber have been killed by balsam woolly adelgids in North America. BWA is now distributed throughout eastern and western North America, aff ecting fi rs in forests, seed production, landscaping and Christmas tree farms. To date, this insect has not been found in Michigan. Balsam woolly adelgids secrete an irritating salivary substance, which is injected into the host tree as the insect feeds. This substance causes unusual growth, such as swelling or “gouting” which distorts the tree’s normal growth pattern. A heavy stem attack may kill an otherwise healthy tree in three or four years. As the tree dies, portions of the crown or the entire crown will turn red. The wood of heavily infested trees becomes darkened and brittle.Balsam fi r is an important source of pulp and dimensional lumber. The U.S. Department of Agriculture Forest Service’s Forest Inventory and Analysis Program reports Michigan’s balsam fi r resource to comprise of 1.9 billion trees greater than or equal to 1 inch in diameter. This equates to a volume of 903 million board feet of sawtimber, or 463 million cubic feet of wood fi ber. 

Balsa

26 - 2012 Forest Health Highlights
Firewood Movement

Firewood movement continues to be of concern as a pathway for the movement of invasive pests into and around Michigan. A large number of invasive pests are known to hitch a ride on fi rewood that’s moved from infested areas to uninfested locations such as camps, campsites and individual homes. The list of pests spreading via fi rewood includes emerald ash borer (EAB), Asian longhorned beetle, beech bark disease, gypsy moth, Sirex woodwasp, various bark beetles, oak wilt, Dutch elm disease, butternut canker and sudden oak death (to name a few). Fortunately, only some of these are currently found in Michigan.Michigan is known as a playground for outdoor recreation in the Midwest and eastern United States. Travelers come regularly from distant points to engage in various forms of “Pure Michigan” outdoor recreation. Many of these folks bring fi rewood, as it is a tradition. Also, Michiganders are known for “going up north” to get away from it all. Many of us traditionally brought fi rewood to favorite campsites, camps or cottages. Michigan learned a hard lesson with EAB: moving fi rewood rapidly 

spreads invasive pests over long distances. Twith other invasive pests merely compoundmore of the natural beauty so many Michigadistances to enjoy.Michigan currently has an EAB quarantine thfi rewood movement from the Lower Peninsube generally infested, to the Upper Peninsulpartly infested; and from certain parts of the infested, to other parts of the Upper Peninsuash fi rewood can’t be brought onto state lanby order of the director of the Department oNational Park Service has banned the practicthe Sleeping Bear Dunes National Lakeshore private campgrounds also do not accept fi reimmediate area.In a cooperative eff ort, the Department of NDepartment of Agriculture Forest Service (UDepartment of Agriculture and Rural DeveloUniversity and Michigan Technological Unive“Don’t Move Firewood” message in various foCampaigns supported primarily by USDA-FS and Farm Bill funding focused on Asian longthe public keenly aware of the dangers of mThe public continues to want to move fi rewodiligent about moving it only short distancerestrictions, and moving it only in a safe manconcern is largely due to the intense outreacrelated to EAB. However, the ever-increasing fi rewood movement have prompted considerestrictions are strong enough, or if more res
Firewood Movement continued

Evidence continues to accumulate indicating oak wilt is being spread to even more locations, and the fear of an Asian longhorned beetle invasion in Michigan due to fi rewood originating from out-of-state infestations – Ohio, for example – is making foresters and regulators consider additional prevention measures. As the list of pests transported on fi rewood continues to grow and the list of invasive species near our borders expands, fi rewood movement must be scrutinized even more carefully. Many other states have fi rewood quarantines, or bans on fi rewood movement both into and 

within the state. A review of current fi rewood restrictions in Michigan has been proposed for 2013, and managers in key agencies are considering the proposal.

28 - 2012 Forest Health Highlights
Forest D

Forest decline refers to a gradual loss of tree growth 

trees often have some combination of off -color le

poor growth and dieback of twigs and branches. T

progresses slowly over several years. During t

susceptible to some combination of insect attacks, 

weather conditions like drought and late frosts. These 

reduce growth and may increase the likelihood 
Maple Decline

Michigan Technological University, USDA Forest Service Evaluation Monitoring Project, Maple Decline in the Western Upper PeninsulaPhD. Candidate Tara Ball and Dr. Andrew StorerSugar maple dieback continues to be seen in Michigan’s Upper Peninsula (U.P.), northern Wisconsin and eastern Minnesota. In 2012, the average sugar maple dieback the U.P. was 12.4 percent with more than half (56 percent) of plots having 10 percent dieback or greater; and 11 percent of plots having 25 to 76 percent crown dieback (with 94 maple health plots primarily in the western U.P.). A vigorous sugar maple stand should have less than 10 percent dieback. Average percent dieback is down from 19.6 percent in 2011 in the same western U.P. plots. Old dead twigs and branches that have previously been recorded as dieback have likely decayed and dropped over winter. Soil and foliar nutrient analysis suggest specifi c site variations in defi cient, toxic or 

antagonistic levels of soil calcium, magnesium, phosphorus, potassium, manganese and aluminum and other metals that may have predisposed trees to decline. Moderately dry drought conditions in recent years, especially in the western U.P., have likely further contributed to maple dieback and decline. Tree ring analysis indicates a decreasing trend in annual maple growth for at least the past six decades with strong correlations to precipitation and snow cover. Climatic and other factors such as sugar maple borer, soil pH and texture, and management history are continuing to be analyzed. The progress of maple dieback will continue to be monitored in the region, with the ultimate goal of incorporating fi ndings into updated management plans to prevent or mitigate timber loss from maple dieback in northern hardwood forests. 
2012 Maple Decline in Michigan

Although reports from the Michigan Technological University Maple Decline Evaluation Monitoring Project show that maple decline in study plots was down from 2011 levels, several new areas of severe decline associated with management practices on stressed sites were reported in 2012. Several areas of maple decline resulting in signifi cant maple mortality were detected in the northwest region of the northern Lower Peninsula (Kalkaska, Missaukee, Wexford, Grand Traverse and Benzie counties); and in the north-central U.P. (Marquette County). Approximately 500 acres of high-quality northern hardwood sites in the northern Lower Peninsula were impacted. In addition to sugar maple mortality, high-quality northern red oaks when present in these northern Lower Peninsula stands were also aff ected. Drought continues to be a major factor contributing to maple decline. Management also appears to be a factor in reported 2012 decline and mortality. All of the stands that experienced mortality in the northern Lower Peninsula were thinned or selectively harvested a year or two before, or during the heavy forest tent caterpillar defoliation from 2009 to 2010. Trees stressed by drought, management and heavy defoliation were at increased risk of decline and mortality due to below threshold energy reserves caused by the combination of stressors. Tree decline and death can result directly from a loss of energy reserves, but more commonly, this predisposes (weakens) trees to attacks by secondary invaders (insects and diseases) such as Armillaria root rot or, in the case of oaks, the two-lined chestnut borer.Maple Decline continued
Drought and Forest Health

How dry was it in 2012? It was so dry that:

• Lake Michigan water levels are currently within 2 inches of the all- 

 time low set in 1964; 

• By the end of June, the drought ranked as the sixth largest since 

 weather records began in 1895; and 

• Moderate or greater drought covered 56 percent of the nation.

Drought years have contributed greatly to many of Michigan’s forest declines and to the buildup of secondary pests such as the forest tent caterpillar, gypsy moth, spruce budworm, Armillaria, two-lined chestnut borer and jack pine budworm. By lowering the tree’s energy reserves, drought increases a tree’s susceptibility and vulnerability to attacks from insects and diseases. Stressed trees recover more slowly from such attacks. 

Although drought is known as a major stressaff ecting a tree’s susceptibility and vulnerabitree age, management activities, defoliation infestation of insects mentioned above.In the past decade we have reported declineoak, spruce and white pine in Michigan. We cin these tree types, especially in areas aff ecte

areas of the western Upper Peninsula and mexperienced drought conditions in 2012. Othto close-to-normal rainfall reported diff ering it takes years for trees to rebuild energy resedefenses to pest attacks.

32 - 2012 Forest Health Highlights
White Pine Dieback

Dieback and mortality of understory white pine continued to expand during 2012 in the north-central Lower Peninsula. First detected in 2006, this decline is associated with white pine growing below oak and aspen trees on sandy soils adjacent to the Au Sable and Manistee river corridors. Needle discoloration and branch dieback are also occurring on large white pine trees in these areas.In addition, what appears to be similar damage was observed for the fi rst time on understory white pine in the Munising District of Hiawatha National Forest in the Upper Peninsula.Branch fl agging and dieback appear to be associated with stem cankers, often found below lichen attached to the aff ected branches. To date, two fungi – Diplodia and Therrya spp. – have been isolated from these cankers.

Eff orts are needed to determine the role of fungal pathogens in this problem (and their association with common white pine lichen species) and to assess whether drought and other stressors are predisposing white pine to this decline. 

Collecting branches from white pine aff ected by 
Invasive Plants

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.34 - 2012 Forest Health Highlights
Invasive Plant Control

American Recovery and Reinvestment Act Project Follow-up Evaluation of 2010 and 2011 Treatment of Select Ecological Reference Areas

Four sites in Michigan were surveyed and treated for invasive plant control in 2010 and 2011, utilizing funding from the American Recovery and Reinvestment Act (ARRA). These sites were: Maxton Plains Alvar (Chippewa County); Shakey Lakes Oak-Pine Barrens (Menominee County); Van Etten Floodplain (Iosco County); and select locations along the North Branch Au Sable River (Crawford and Otsego counties). Observational surveys were conducted in 2012 near the end of the fi rst growing season following treatment of these sites. The observational method was used due to funding restrictions making more formal surveys impractical. To determine eff ectiveness of treatments, transects were walked, where practical, that intersected the more dense areas of invasive plants, as well as locations where threatened and endangered species had been noted. An area approximately 8 feet on either side of the transect lines was carefully observed for evidence of living invasive plant species originally mapped on the area. Generally speaking, only scattered individual plants were found of any invasive species. Maxton Plains Alvar: No regrowth of leafy spurge was observed on the treated acreage. Shakey Lakes Oak-Pine Barrens: Spotty resprouting of leafy spurge in a previously heavily infested 20-acre area was observed. Giant hogweed returned in the form of smaller plants and lesser numbers than the pretreatment population. Retreatment is planned for spring 2013 for both the leafy spurge and giant hogweed. For both Shakey Lakes and Maxton Plains, even heavily infested areas from the initial surveys contained only widely scattered individual plants 

of St. John’s wort, spotted knapweed, commthistle in 2012. Roadsides were particularly fNatural revegetation by noninvasive plant spmost of the treated areas. None of the previoand endangered species appeared to be harVan Etten Floodplain: Common burdock w

numbers of small plants in treated areas. A lothe resprouting burdock in the fl oodplain in 

Common mullein plants reinvaded a site treatesmaller numbers.
cover was also signifi cantly reduced with only very small individual 

patches returning following treatment. Au Sable River: A local volunteer group is committed to removing purple loosestrife from along the river. In 2011, loosestrife fl owers and seed heads had been clipped and disposed off -site. In 2012, volunteers pulled the remaining loosestrife plants as well as any resprouted plants from other previously treated areas along the North Branch Au Sable River. 

Invasive Plant Control continued

Leafy spurge did not return to the DNR’s treated site in 2012.

Giant hogweed (like the example shown here), fall of 2011, regrew much smaller plants in 201plant can cause swelling, blistering and perma

36- 2012 Forest Health Highlights
Other Forest Health Highl

From a wildfi re in the Upper Peninsula that burn

acres, to a snowstorm that caused extensive dam

Lower Peninsula – Michigan’s natural resources w

continue to recover from, the extremes of 2012. T

discusses the Department of Natural Resources’ wo

monitoring the events and pests that impacted the 
Lower Peninsula

Locust Leafminer

Defoliation from the locust leafminer, Odontota dorsalis, was common 

throughout much of the southwestern part of the Lower Peninsula in 2012. Locally, heavy defoliation was found in and around Calhoun and northern Kent counties. Locust leafminer larvae mine through leaf tissue causing foliage to turn gray or brown, sometimes giving the appearance of early fall colors in heavily aff ected areas. The 2012 damage was apparent along many roads and highways throughout southern Michigan. The locust leafminer is a late-season defoliator that generally causes minimal loss of growth and very rarely, in combination with other stress factors, may cause occasional tree mortality.

38- 2012 Forest Health H ighlights
The northwest Lower Peninsula experienced an extraordinary snowstorm 

in early March that dumped more than 20 inches of heavy wet snow on parts of Leelanau, Benzie and Grand Traverse counties. The storm caused extensive damage to trees and local utility providers worked for more than a week to clear lines of broken trees and branches. Damage to forest resources was widespread across the region. Softwoods, especially pines and aspen, were most severely aff ected. Several red pine plantations that had recently been thinned experienced signifi cant amounts of main stem breakage. Jack pine plantations experienced both breakage and severe bending from the weight of the 

snow. White pine appeared more prone to bsusceptible to main stem breakage. Aspen sabent over completely to the ground. Salvage utilize some of the damaged pine product frHeavy accumulation of fresh pine debris in erisk of pine bark beetle population buildup. of producing three generations per year and persisted through spring and summer contrin bark beetle populations. Numerous small due to bark beetle infestations were observe

the region aff ected by the storm. Bark beetle populations can fl uctuate weather will play a major role. With pewill likely see a continuation of the cuIf drought conditions ease and massivpine material are not present, next yeashould begin to return to normal leveBark beetle populations can fl uctuate weather will play a major role. With pewill likely see a continuation of the cuIf drought conditions ease and massivpine material are not present, next yeashould begin to return to normal leve

Lower PeninsulaMarch Snowstorm
A fi re that started with a lightning strike in Luce County in the Upper 

Peninsula on May 23, 2012, expanded 11 miles north and six miles east and west until it was stopped by Lake Superior. The fi re burned until June 13, 2012. A total of 21,069 acres of forest land burned, with 15,700 of those acres on state-managed land. The southern end of the zone contained hemlock, birch and red maple. A few miles north, red and white pines were mixed with jack pine. And toward the sandy north end, mature jack pine dominated the dune-like ecosystem at the Lake Superior shore. There were 141 properties within the perimeter of the fi re. Of those, a total of 136 structures were lost.The fi re burned so hot in many areas that it removed what little organic matter could be found in the sandy, sterile soils. Regenerating trees on Upper PeninsulaDuck Lake Fire

some of these areas will likely pose a challenge. Timber was quickly assessed and sales set up to salvage about 10,000 acres of charred timber. It was a race against the clock to remove logs before they were infested by pine sawyer beetles, Monochamus scutellatus, and bark beetles. In tpulp were sold. This equates to 2,100 logging tabout half of the acreage had been harvested. In the northern part of its range, the pine sawywhite-spotted sawyer) requires almost two yeaPine sawyer beetles generally begin laying eggthrough the summer to early September. As the larva grows, its galleries become wider asurfaces of the wood. By mid-to-late summer twood cylinder. An oval-shaped entrance hole mbegins moving deep into the wood. By midsumits deepest point of penetration, which may va6 inches from the surface of the wood. A check of sawyer beetle activity in late Augusformed entrance holes in trees in a few of the bstop feeding with the onset of freezing tempe

40 - 2012 Forest Health Highlights
the following spring as temperatures rise. The goal is to have all the logs 

harvested by spring 2013, before borer activity resumes.Although one might expect a buildup of bark beetles, very little occurrence of bark beetle activity was detected within the burn area during the late summer survey. In the many acres of charred pine seedlings and small saplings of 1 inch to 5 inches in diameter killed by the fi re, there were no signs of borer or bark beetle activity. These heavily charred trees were apparently cooked suffi ciently that they off ered little suitable substrate for larval development. Harvesting a signifi cant portion of the larger, merchantable trees via timber sales before next spring will slow beetle population buildup. The beetles that infested the harvested logs will be removed from the area. The Department of Natural Resources will continue monitoring both sawyer beetle and bark beetle activity in 2013.Upper PeninsulaDuck Lake Fire continued
Web-Spinning Sawfl y

A persistent infestation of web-spinning sawfl y, Cephalcia spp., on a 

20-acre red pine plantation was suppressed with a Dimilin 25W treatment in 2012. Dimilin is in a family of insecticides called insect growth regulators (IGR). An IGR interrupts growth by preventing development of the exoskeleton, leading to premature death of the insect. Dimilin and other IGR have less of an eff ect on benefi cial insects than traditional 

chemical insecticides, and are considered more environmentally friendly. The red pine had been defoliated for six consecutive years due to the sawfl y infestation. The treatment is expected to reduce populations to below damage thresholds, thus enhancing tree growth and reducing time to crown closure. It should also reduce future sawfl y impacts and sawfl y population potential. 

Miscellaneous Upper Peninsula PestsWestern Conifer Seed Bug There were many reports of the western conifer seed bug, Leptoglossus occidentalis, in and around Michigan homes in 2012. This critter is also known as “leaf-footed bug” due to the appearance of its hind legs. This is a species of “true bug” (Heteroptera) in the family Coreidae. It was originally 

native to the warm-temperate western states of California, Oregon and Nevada. In recent years the western conifer seed bug has expanded its range in the United States and has also become an invasive pest in parts of Europe.The western conifer seed bug frequently congregates on the outside of buildings in late summer and early fall, commonly observed around windows and doors. An infestation of this bug reduces the quality and viability of conifer seed crops.

42 - 2012 Forest Health Highlights