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Ash Management Guide for Private Forest Landowners

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We gratefully acknowledge Melvin Baughman of the University ofMinnesota Extension and Alan Jones of the Minnesota Department ofNatural Resources for support for the project. Special thanks to JohnC. Almendinger of the MN DNR for providing information on nativeplant communities and for helping us learn; Gary Michael, MN DNRfor his understanding; and to Mike Albers and Jana Albers, MN DNR,for their invaluable knowledge and guidance.


AcknowledgmentsPrimary Investigators & Project Managers• Angela Gupta, Extension Educator,University of Minnesota Extension• Julie Miedtke, Extension Educator,University of Minnesota ExtensionExpert Panelists• Mark Abrahamson, Research Scientist,Minnesota Department of Agriculture• Cheryl Adams, Forest Ecologist,UPM-Blandin Paper Company• Paul Ahlen, Plant Health Specialist,Minnesota Department of Agriculture• Mike Albers, Forest Health Specialist,Minnesota Department of Natural Resources• John Almendinger, Forest Ecologist,Minnesota Department of Natural Resources• Mike Benedict, Forestry Management and Inventory/PlanningForester, Bureau of Indian Affairs Midwest Region• Greg Bernu, Carlton County Land Commissioner• Charlie Blinn, Extension Specialist, University of Minnesota• Dave Chura, Executive Director,Minnesota Logger Education Program• Tony D’amato, Assistant Professor, University of Minnesota• Andy David, Associate Professor, University of Minnesota• Paul Dickson, Consulting Forester,Minnesota Association of Consulting Foresters• Lee Frelich, Research Associate, University of Minnesota• Jeff Hahn, Extension Entomologist,University of Minnesota Extension• Kurt Hinz, Private Forest Management Forester,Minnesota Department of Natural Resources• Louis Iverson, Landscape Ecologist, US Forest Service• Keith Jacobson, Wood Product Utilization & MarketingProgram Leader, Minnesota Department of Natural Resources• Mark Johnson, Executive Director,Minnesota Deer Hunters Association• Steve Katovich, Insect Ecologist, US Forest Service• Rick Klevorn, Silviculture Program Coordinator,Minnesota Department of Natural Resources• Jeff Lightfoot, Regional Wildlife Manager,Minnesota Department of Natural Resources• Ken Nichols, Private Forest Landowner• Art Norton, Itasca Field Representative,The Nature Conservancy• John O’Reilly, Private Forest Landowner,Minnesota Forestry Association• Brian Palik, Research Ecologist, US Forest Service• Dave Parent, Private Forest Landowner,Minnesota Forest Resources Council• Mike Reichenbach, Extension Educator,University of Minnesota Extension• Eli Sagor, Extension Educator,University of Minnesota Extension• Elon S. (Sandy) Verry, Chief Research Hydrologist,US Forest Service (retired)• Dave Wilsey, Extension Educator,University of Minnesota Extension• Diomy Zamora, Extension Educator,University of Minnesota ExtensionContributing Authors• Mark Abrahamson, Research Scientist,Minnesota Department of Agriculture• Jana Albers, Forest Health Specialist,Minnesota Department of Natural Resources• Mike Albers, Forest Health Specialist,Minnesota Department of Natural Resources• John Almendinger, Forest Ecologist,Minnesota Department of Natural Resources• Melvin Baughman, Extension Forester,University of Minnesota Extension• Mike Benedict, Forestry Management and Inventory/PlanningForester, Bureau of Indian Affairs Midwest Region• Lee Frelich, Research Associate, University of Minnesota• Angela Gupta, Extension Educator, University of Minnesota• Maya Hamady, Nongame Wildlife Specialist,Minnesota Department of Natural Resources• Steve Katovich, Insect Ecologist, US Forest Service• Jeff Lightfoot, Regional Wildlife Manager,Minnesota Department of Natural Resources• Doug Miedtke, Fire Behavior Specialist,Minnesota Department of Natural Resources• Julie Miedtke, Extension Educator,University of Minnesota Extension• Mike Ostry, Research Plant Pathologist, US Forest Service• Dave Wilsey, Extension Educator,University of Minnesota Extension• Kathleen Preece, Better Forests Magazine• Elon S. (Sandy) Verry, Chief Research Hydrologist,US Forest Service (retired)• Steve Vongroven, Wood Product Utilization & Marketing,Minnesota Department of Natural ResourcesEvaluation Specialists• Amy Mayer, University of Minnesota• Thomas Barthlomay, University of MinnesotaEqual Opportunity StatementThe University of Minnesota Extension shall provide equal access to and opportunityin its programs, facilities, and employment without regard to race, color, creed, religion, national origin, gender,age, marital status, disability, public assistance status, veteranstatus, sexual orientation, gender identity, or gender expression.Printed in U.S.A. on Anthem recycled and recyclable paper with at least 10% postconsumer material.Published June 2011.


Table of ContentsChapter 1A History of Minnesota’s Ash Resource:Current Extent and Abundance of Ash ..................... 7Chapter 2Minnesota Ash Species Identification...................... 10Chapter 3Ash: A 21st Century Resource ................................... 15Chapter 4The Emerald Ash Borer: a littlepackage carrying big trouble ..................................... 23Chapter 5The Native Plant Communities ................................. 29Ash in the Wet Forest System .................................. 32Ash in the Floodplain Forest System ..................... 38Ash in the Mesic Hardwood System ...................... 44Ash in the Forested Rich Peatland System ........... 48Ash in the Fire Dependent System ......................... 50Chapter 6Wildlife Among the Ash ............................................. 54Chapter 7Other Implications of EAB and Ash Trees .............. 56Green ashFraxinuspennsylvanicaAppendicesAppendix AMinnesota Department of Natural Resources:Guidelines for managing sites with ash to addressthe threat of emerald ash borer on DNRForestry-administered lands ...................................... 60Appendix BQuestions and Answers about Quarantinesand Compliance Agreements .................................... 63Appendix CMinnesota Department of NaturalResources Rare Species Guide .................................. 65Appendix DReferences and Resources .......................................... 66Glossary .......................................................................... 67Throughout this publication, words in bold italicscan be found in the Glossary on pages 67-68.1


General Ash ManagementGuidelinesIntroduction: Walking the TalkThere is a lot of talk about how to manage Minnesota’s ash trees. The ‘talk’ has become thefocal point of professional management discussions and policies, as well as the news around thebreakfast tables of those who own nearly 50 percent of the forested land in the state: YOU, theprivate forest landowner.Natural resource professionals reviewed ash management recommendations, includingthose for state land, developed by the Minnesota Department of Natural Resources (AppendixA). Those resources professionals wanted to offer you, the family forest landowner, anotherapproach. This Guide will discuss some specific guidance on ash management. It was developedcooperatively with insight from many different fields related to forestry and ecosystem management.A detailed, multi-process survey allowed experts to apply their knowledge several times tooffer useful management tips for the complicated and unprecedented future that faces Minnesota’sforests. As a result of this effort there are some basics you should use as the foundation tobuild upon in your management decisions.The following are a few baseline tips shared by a diversity of public and privateprofessional resource managers:• Seek and use the advice of a professional forester/forest plan writer.• Closely monitor stands with ash.• Plan for forest conversions when ash is a major component of your forest.• Work with neighboring landowners to address threats on a larger scale.• Actively discourage invasive plant and insect species; manage for native species.• Think outside the box. Contemplate a wider choice of tree species appropriate to yoursites and needs. Diversify the species you select. Tree and plant diversity will help preventfuture large-scale mortality the next time we discover a major pest attacking a tree species.• Think about replacement tree species before the ash dies.• Underplanting. Consider planting shade-tolerant trees beneath canopies of existing trees.• Minimize harvest damage by using the services of a professional logger who has takentraining with the Minnesota Logger Education Program. Ask for credentials and references.• Keep in mind - you can’t call a logger and expect him/her to be out harvesting at your sitein the next week or month. In most cases, you are going to need to set the plans in motion2-3 years before the timber is harvested.• Be extremely careful if using heavy equipment on very wet sites. It may be best to leavethe ash alone in these areas.• Be familiar with, and apply Best Management Practices.Following is a detailed background of ash as a resource, ash tree identification, emerald ashborer information and identification, and ash in our woodlands and recommendations on how tomanage ash forests through this transition. We hope this Guide is useful and informative as weface this unprecedented forest change together.2


The Delphi Survey ProcessThe University of Minnesota Extensionand the MN Department of Natural Resources(DNR) recognized a need to offer practical andtimely ash management recommendations forfamily forest landowners in the emerald ashborer (EAB) era. However because EAB is sucha new pest, first discovered in Michigan in 2002,and trees grow slowly – the average life spanof an ash is 200 years – and science takes time;we were tasked with the nearly impossible: topredict the future. We did our best to make recommendationsto manage for this uncertainty.Extension took the lead in exploring options onthe best way to predict and plan for an unknownfuture. After much consideration and consultationwith Extension’s evaluation experts, a surveyprocess called a modified-Delphi was chosen.This process is a systematic, interactive, anonymous,structured survey method to facilitate apanel of experts to offer recommendations oropinions from many areas of expertise.For this Ash Management project Extensionfacilitated three rounds of the modified-Delphisurvey. Of the 31 participants not all participatedin each round. This process was extensive, Round1 (84% response rate), consisted of 19 open endquestions. Participants were given two weeks tocontribute to the survey. Following those twoweeks Extension had two weeks to tally surveyresponses and create the next round of thesurvey based on feedback offered in the previousround. Round 2 (81% response rate) waslarge, 103 questions all generated from Round1. Round 3 included all the results from Round2 plus new information generated in Round 2.In total, Round 3 (68% response rate) was 98questions. The results of this survey processare wide reaching, but they are not exhaustive.When consensus couldn’t be reached we didn’treport that recommendation. It is very importantto remember that none of us has a crystal ballwhich we can see the future of Minnesota’s ashforests. This is our best effort to find a methodand experts to offer help. However it will be veryimportant for everyone, landowners and naturalresource professionals alike, to stay abreastof current research and information becauserecommendations are likely to change as the sciencescatches up.Forty-one experts, mostly from Minnesota,were asked to participate. They were experts insilviculture, forest hydrology, the MN DNR’s ecosystemclassification system, timber harvesting,family forest landowners, forest regeneration,forests and climate change, wood utilization andlogging, forest wildlife, woodland communication,EAB quarantine, EAB, cultural aspects ofash, and forest genetics. Deliberate effort wasmade to find experts from different organizationsincluding the University of Minnesota, DNR,US Forest Service, private industry, Bureau ofIndian Affairs, Minnesota counties, and privatelandowners. However, survey facilitators hadlittle control over who actually participated inthe survey. Of the 41 invited to participate 31actually contributed in any of the three rounds.All response rates are based on the 31 expertsthat actually participated in at least one of therounds.Funding and resources for this project,beyond the valuable and extensive time contributedby the panel of experts, were offered bythe University of Minnesota Extension, the MNDepartment of Natural Resources, Forest StewardshipFunding, and the Renewable ResourcesExtension Act.3


In order to clearly offer you, the reader, with a quick way to assess the difference between important resource informationand recommendations generated from the survey, all Survey Recommendations will be featured in these eye catching calloutboxes. Although attributed to an individual, these recommendations in the call-out boxes were approved by groupconsensus using the modified-Delphi process.Suggestions from the experts during the Survey• It is important to remember that for all ash stands considered in this survey: The effects of global climatechange are too variable to make stand level decisions.• Landowners should minimize harvesting damage; harvest using current Best Management Practices; andunless otherwise noted, harvest using current standard silvicultural practices; recognize that new practices maybe developed and landowners should stay abreast of new research.• A quarantine expert commented: “These may need to be modified for mostly pure ash stands. If EABinfestation is widespread or imminent, damage to residual timber, snag tree retention guidelines, and clearcutacreage limitations might not be important when compared to the alternative.”• Additionally, landowners should actively discourage invasive species. They should manage for native specieswhile preparing for an increase in secondary insects and disease on dying ash and a decrease in total standbiodiversity and changes in wildlife species using the stand.• One expert pointed out it’s very important for landowners to stay aware of where EAB is in the state. Oneexpert on landowner communication stated, “I favor strongly encouraging management when feasible (e.g.,removal of ash in conjunction with other harvests.)”• “We should emphasize to family forest owners that change is coming and using some of the wood would begood rather than letting it all die and rot.”• Along that same line an entomologist stated, “The goal should be to think about replacement before the ashdies because that is when the landowner has the best hopes of influencing the results.”• A general rule of thumb for landowners should be to remove dead/dying ash trees. “If the trees are in an areawhere the falling trees will be a hazard to people or property then they should be removed, or at least cutdown,” according to one entomologist.• Ash mortality will cause hazards to recreational trails.• Landowners should begin now to assess the threat to their land, map out a management strategy and takeaction to get that implemented.• Efforts to leave some ash for genetic stock are more likely to survive if “neighboring threats are reduced.”• Leave a mixture of qualities and species of ash trees for genetic diversity.• One forest geneticist said, “If (a) harvest is in advance of EAB or far from proximity of infection point. Thisallows for retention of species and genetic diversity in event that EAB is controlled.”• Another entomologist pointed out, “There are trees that have escaped attack in southeastern Michigan – wedon’t know why they have escaped attack - it is possible that a variety of modes of resistance to EAB attack arepresent in the gene pool.”• On the bright side, one expert mentioned: After ash morality has occurred berry product in small shrubs andtrees may increase. Raspberries, highbush cranberries, Juneberries would all be stimulated by increasedsunlight.4


The Emerald Ash Borer & Chestnut Blight: A historical perspectiveIf you have been a Minnesota resident during the pasthalf century, you likely remember the ‘great depression’ ofcommunity trees when Dutch Elm disease took its toll. Boulevardtrees, back yard trees, and trees along parkways andriverwalks had to be removed because of this disease thatvirtually wiped out the state’s elm tree population. There arelessons to be learned. Read on.Emerald ash borer is often compared with Dutch elmdisease. There are good reasons for this comparison. Minnesotanshave a cultural memory of the decline and lossof American elm in our cities. Dutch elm disease was firstdiscovered in St. Paul in 1961, with massive death of the treesand removal not occurring until the 1970s. Many communitiesreplaced at least some of their lost elms with ash. So it isnatural to make the comparison of emerald ash borer (EAB)to Dutch elm disease, particularly in our cities. But is thatreally a good comparison?Let’s look further back into our forest’s history for a differentexample: chestnut blight and the loss of American chestnut(Castena dentata). Chestnut blight led to the first largescale loss of a forest tree. American chestnut is a large, statelynative tree found from Maine to Mississippi. It succumbedalmost completely to chestnut blight between 1900, when theblight was first discovered in New Year City, and 1940 whenthe blight had invaded all the commercial stands of easternchestnut and killed most of the trees.So what is the impact of these pests on the forest? Emeraldash borer attacks and kills virtually all ash (Fraxinusspp.) trees greater than 1” in diameter. Chestnut blight, whilenot actually killing all the trees, reduced the presence of theAmerican chestnuts in the Appalachian forest to small bushlikesprouts growing from the truck and roots of formerlymajestic and dominate trees. This species is functionally lostto our forests.Dutch elm disease, on the other hand, has a mortality rateof about 80%. While elm now makes up a significantly smallerpercent of our urban and forested trees than before Dutchelm disease invaded, elm still exists in urban environmentslargely because of fungicidal treatments. In forested environments,it remains as a small understory tree. This situationis very different than the functionally nonexistent Americanchestnut in the eastern forest. Additionally it is important tolook at the actual spread rate of these pests. Chestnut blightspread and killed chestnut trees at 32-40 km/year (Tainter& Baker, 1996). Actual spread rates for Dutch elm diseaseare harder to find, but it was first identified in Ohio in 1930and eventually arrived in St. Paul, Minnesota in 1961. Eventhen, the first seven years it was in St. Paul there were only 30reported cases.Emerald ash borer, on the other hand, was first reportedin Detroit, Michigan in 2002 – although dendrochronologicalanalysis places the insect there as early as the mid-1990s(Siegert, McCullough, Liebhold, Telewski, 2008). Dendrochronologyis the science of dating trees, and associatedenvironmental events, using a tree’s growth rings. In thiscircumstance, researchers in Michigan took ash trees fromvarious locations throughout southeastern Michigan, datedtheir growth rings, and noted the year of attack by EAB. Theythen cross referenced that data with weather patterns to betterassess when EAB first arrived in Michigan.Although its “first date” in the United States is still unknown,we do know EAB was here years before it was identifiedand reported, and before management and quarantineswere started.In a time span of about 15 years, EAB has spread to 14states from Minnesota to Virginia and Missouri to NewYork. Unlike chestnut blight, Dutch elm disease and EAB arebeing spread long distances in similar ways, mainly via humantransportation of wood materials. Chestnut blight wasspread predominately through natural movement. The futureprospect for ash is not bright. Data from Michigan indicatesthere is little residual ash in a stand after EAB has attackedan area, and the ash seed bank survives only up to eightyears. Scientists and volunteers have been working to collectand preserve ash genetic material in Minnesota for years sothat science will have genes from which to work after EABhas come through.Ash trees comprise over 50% of some stands in northernMinnesota. Conversely, elm, while an important tree speciesin several forest types, was almost never a majority of thetrees in a stand. And, in some forest stands in Appalachia,American chestnut comprised 25% of the trees. Thereforethe stand-level impact of Dutch elm disease was likely lessthan the anticipated stand-level impact of EAB in some ashdominated sites in northern Minnesota. However, interestingly,ash now comprises a higher percent of some Minnesotantimber types than ever before, likely due to the loss ofelm. Ash filled the ecologic niche created when the elm died.It is ironic that one of the ten tree species in seven of the ninetimber types by geography recommended in this Guide is theintroduction of disease resistant American elm to replace ash.One could conjecture that the forest is coming full circle; oneinvasive species removed most elms from the forest to thebenefit of ash, now another invasive species will remove ashto the potential benefit of disease resistant elm.In summary, while Dutch elm disease was and is a majorforest pest in Minnesota and was devastating for both theurban and forested elms, emerald ash borer is likely to bean even bigger problem. It is expected to hit certain foreststands much harder than Dutch elm disease did – likely moreon the scale of American chestnut – something for which wehave virtually no living cultural memory.It is important to remember, however, that science is movingfaster than ever and genetic research has progressed markedlysince the turn of the century. Foresters are now beginningto plant blight resistant American chestnuts in the forests ofAppalachia, and there are disease resistant American elms wecan replant in our forests. With careful monitoring, the help ofscience, and supportive funding the forest can grow again.For References, See Appendix D, page 665


Chapter 1Page 6: Black ash near TwoHarbors, MinnesotaA History ofMinnesota’sAsh ResourceCurrent Extent and Abundance of AshAsh is one of the mostwidely distributed plantsin Minnesota.All 87 counties in the state have onevariety of ash or another. There are threeash species in the state: black, green, andwhite. Ash is found in all terrestrial nativehabitats, and it is widely planted inyards and along boulevards.The current ash population in Minnesotais about 176 million trees, some8.6 percent of all forestland trees (>5”diameter at breast height –“dbh”). Ashis a significant tree on 866,000 acres offorest land. In a little more than half ofthese forests (463,000 acres, 53%) ash isjust a component of the forest, mixedmost often with other deciduous trees.However, ash is the dominant and sometimesthe only tree on some 406,000acres of land. Losing ash to emerald ashborer (EAB) on these lands will be obviousand locally devastating. The populationof small, regenerating ash (1-4” dbh)is incredibly high – roughly 795 millionash or roughly 5 saplings per every ashtree. If one were to consider also germinatingash (


Chapter 1A History of Minnesota’sAsh ResourceGLOSSARYpaleoscientist: Scientists whostudy organisms of the past.Historic Abundance and Change inAbundance of Ash in MinnesotaThe history of ash in Minnesota is“old as dirt” – literally. Black ash wasamong the hardy pioneers to occupyfresh soil while glacial ice slowly meltedfrom the landscape some 16,000 to11,500 years ago. We know this becauseblack ash pollen is preserved along withthe pollen, wood, and leaves of othertrees in the oldest sediments of ourlakes. The assemblage of plant fossilsincludes abundant remains of spruce,with lesser amounts of ash, tamarack, fir,sage, ragweed, grasses, and sedges.Most paleoscientists agree that thisassemblage of fossil plant communitieshas no analogue in the modern vegetationof North America. Even where wehave glaciers, we don’t see this particularcombination of plants. This suggests thatthe climate of the late-glacial period inMinnesota and the American Midwest,was unique to that time. Ice cores fromGreenland tell us that the temperaturefluctuated during that time; scientistsdebate about the strength of seasonality– but everyone agrees that it was wet.It is no stretch for a botanist to imaginespruce, black ash, tamarack, fir, grasses,and sedges occurring in wet habitatsbecause they occur in such places today.The amount of ash pollen in late glacialsediments (~10-15 percent) is the mostthat we see in any lake sediments fromMinnesota. When Minnesota was icefreeand experiencing a much warmerclimate (the modern Holocene Epoch),other native trees eventually migratedinto the state. Competition with thesenew species, the maturation of soils, andconsiderably drier conditions helped todiminish ash populations. Sedimentsyounger than about 11,000 years havelittle ash pollen, but it is steadily present.Apparently, the wet forest niche that favorsash has been a stable component ofMinnesota’s landscape since the glacierswere here. Before the arrival of EAB andconcern of global warming, the 11,000-year pollen record assured Minnesotan’sof an ash resource.White settlers have significantly impactedash populations during the courseof settlement and agricultural developmentof Minnesota. When settlers firstShown here is a FloodplainForest, referred to in the NativePlant Community classificationas an “FF.”Photo: Michael Lee8


Photo: Bill SwindamanChapter 1A History of Minnesota’sAsh ResourceThe habitat of the green heron issmall wetlands in low-lying areas.The species is most conspicuousduring dusk and dawn. They preferto be active at night, retreatingto sheltered areas during thedaytime.arrived in the state, ash was a componentof roughly 1,221,000 acres of forest land.Some 902,000 of these acres were directlylost to conversion of the land to somethingother than forest. However, thisloss is partially offset by a gain of 548,000acres where forests lacking ash were convertedto types with ash.On land that has been forestthroughout the settlement period, therelative abundance of ash to other treeshas gone up from 1.5 percent of forestland trees to 8.5 percent– nearly sixtimes its historic abundance. These gainshave occurred almost exclusively in habitatswhere ash is dominant. The acreageof monotypic ash forest has increasedfrom 229,000 to about 406,000 acres.Why? Ash was excluded from habitatswhere fire was a chronic influence. Firesuppression has undoubtedly allowedash to increase in Minnesota’s westernand southeastern forests. But this doesn’texplain the shift to monotypic forest.More likely is the fact that swamps arenot prime real estate or agricultural land.Uplands were developed leaving richblack ash, tamarack, and cedar swamps,undeveloped but not untouched.Tamarack and cedar were heavilyexploited during settlement for railroadties and rot-resistant building materials –while ash was “good firewood.”In addition, Minnesota’s tamarackpopulation was devastated by Europeanlarch sawflies between 1900 and 1950.Apparently, Minnesota’s rich swampforests with ash were left alone, and manywith tamarack and cedar have succeededto pure ash. In recent times, tamarackand cedar have shown little natural abilityto regenerate in rich swamps.GLOSSARYmonotypic: Referring toconservation biology andsuccessional changes leading toa single species.9


Chapter 2MinnesotaAsh SpeciesIdentificationAsh trees are difficult to describeand can be tough toidentify. Out inthe woods, ash trees donot have the flashy,distinctive whitebark of birchtrees, nor are theymajestic giants thateasily tower above thecanopy like our stately whitepine. However, ash does have itsown distinction. They are one of thelast tree species to leaf out in the springtime- and one of the first trees to dropits leaves in autumn.Learning to identify Minnesota’sash trees will deepen your appreciationof our woods, and for a landowner, it’sthe first important step in learning howto care for your land. Take your timeand practice throughout each of Min-Avoid ConfusionBoxelder (Acer negundo) is a memberof the maple family and has oppositebranching and 3-5 compound leaves.There are other woody plants thathave ‘ash’ in their names and are nottrue ash species, like prickly ash ormountain ash. These are not susceptibleto an attack by EAB.nesota’s four seasons - and when all elsefails ask your kids!The classical Latin namefor ash is “Fraxinus”meaning“spear.” Ash aremembers ofthe Oleaceae,or theolive family.The flowersfrom the treesare pollinated frominsects or through wind.Members of the ash familyhave the ability to reproducethrough seeds, and vegetativelythrough stump sprouts.There are about 65 species of ashtrees, mainly found throughout thetemperate regions of the NorthernHemisphere, but also ranging southwardinto the tropics. Minnesotaforests are home to three of the 18species found in the United States:• White ash• Black ash• Green ashLet’s take a closer look:White ash- Fraxinus americanaWhite ash stands tall as a for-White Ash10


est tree; its crown is relatively small.Compared to black and green ash, it isrelatively uncommon, largely restrictedto mesic deciduous forests in the southeastand east-central parts of the state.You will usually find white ash insmall groves, as scattered individuals,or mixed with northern red oak,basswood, or green or black ash. Itis unlikely you will find white ash onactive floodplains or in wet areas. Itprefers fertile, loam soil on slopes alongmajor streams.Its seedlings like the deep shade ofa mature forest, but will eventually dieunless they obtain light from an openingin the canopy. The fruits of whiteash mature by the beginning of Septemberand are released during the autumnand winter. These are among the lasttrees to leaf out in the spring.Black ash - Fraxinus nigraLike the whiteash, black ash is talland slender witha relatively smallcrown. Its barkhas a silvery graytone and, unlikethe other ashes, itsbark is fine textured,somewhat scaly, andnot furrowed. Like allashes, its leaves are oppositeon the twig. However,black ash leaves are large andrather droopy, looking muchlike those of a walnut.Black ash is commonlyfound in Minnesota’s forests,especially northward. It prefersmoist forests, especially streambanks, moist depressions, andswamps. The roots are shallowand spreading making the speciesprone to windthrow.In upland areas, it is foundintermixed with basswood, tremblingaspen, white spruce, and maples. In theseenvironments, it can grow quite large,sometimes exceeding 100 feet. In contrast,in wet, lowland habitats black ashis a stunted, small, and spindly tree, oftenno more than 30 feet high with only afew branches. Black ash seedlings aremore tolerant of shade than green ash.Unlike white ash, it does not aggressivelycolonize open lands.Black ash seeds are recognized as animportant seed source for game birds,songbirds, and small animals, and isused as browse by white-tailed deer andmoose. Flowers on black ash are generallyformed by the end of May, withseeds appearing in late September. Somepeople think the fruit has a ‘spicy’ odor.Black Ash(Continued on page 13)Green AshOhio State Univ. Extension Julie MiiedtkeMN DNRMN DNROhio State Univ. ExtensionChapter 2Minnesota AshSpecies IdentificationSimple identificationfeatures common toall ash:• OppositeBranching andBud Arrangement:Branchesand buds arelocated directlyacross fromeach other (opposite), notstaggered (alternate). Note thatsometimes buds, twigs andbranches are lost from winddamage etc.• CompoundLeaves: Eachleaf is composedof5-11 leaflets,depending onthe species.Leaflet margins may be smoothor toothed.• Winter Buds:Have largescales andlook like deerhooves.• Bark: Youngash trees havesmooth bark.Older treeshave differentpatterns, generallyfurrowed.• Seeds: Called“samaras”, theseeds look likecanoe paddles.They mature inthe fall and canpersist throughwinter.11


How to tell an ash from an ashIdentifying characteristicsLeaf Scar/Bud Bark Leaves FruitsWhite Ash2-3 pairs of scales, rusty to darkbrown. Terminal bud 1 ⁄5” long. Lateralbuds are set within the leaf scar.Buds are paired with a leaf scar beneaththe bud that looks like the letter“C” turned on its side.Julie MiedtkeLight gray-brown bark is characterizedby having deep, narrowridges that form a diamondshaped pattern.8 to 12 inches long with 5 to 11leaflets (usually 7); margin entireto partially serrate. Leaflets arestalked.Light-brown samara, about 1”long; wing partially surroundingthe seed.Black AshBuds are very dark brown in color.Generally, there is a space betweenthe end bud and the nearest lateralbuds.Ohio State University ExtensionGrayish in color and smooth whenthe tree is young, attaining some ofthe same furrows that can be seenin the bark of both green and white,but usually not as deep.10 to 16 inches long with 7 to11 leaflets; margin finely serrate;leaflets have no petiole.Samara are broad to oblong,usually 1 to 1 1 ⁄2 inches long,blunt at the base.Green Ash12Bark rusty brown, woolly, set aboveleaf scar. Leaf scars nearly straightacross the top. Buds are paired witha leaf scar beneath the bud that lookslike a sideways “D” (like a smile).Very similar to that of white ashbut not quit as deeply furrowed.6 to 10 inches in length with 7 to9 leaflets; margin serrate alongentire length of leaflet.Samara typically 1 1 ⁄4 to 2 1 ⁄4 incheslong and 1 ⁄4 inch or less in width.The wing of this samara is morepointed than that of white ash.All photos from MN DNR-Welby Smith, unless indicated otherwise


Green ash - Fraxinus pennsylvanicaGreen ash is one of the mostcommon of the ashes, particularly inthe southern part of the state. Unlikeblack ash, green ash does not grow inswamps; however, you will find blackand green ash growing side by side onupland sites. You will find green ashin basic (calcareous sites) or soils thatare slightly acidic. You will find greenash in sand, silt, clay, or loam soils, butnot in peat. Young trees grow rapidlyand will resprout if they are damagedor cut. They produce large numbers ofseeds and are vigorous colonizers ofabandoned agricultural and urban lands.Green ash seedlings do not survive underdeep shade.Chapter 2Minnesota AshSpecies IdentificationGLOSSARYcalcareous: An adjective usedin a wide variety of scientificdisciplines, referring to thedeposit of calcium carbonateor lime. In some cases it mayrefer to a layer of sediment orsedimentary rock, a limestonedeposit. Calcareous soils arerelatively alkaline, in otherwords they have a high pH.This is because of the very weakacidity of carbonic acid. Notethat this is not the only reasonfor a high soil pH.peat/peatlands: Organicsoil material that originatesfrom plants.A mesic ash standPhoto: DNR/Tom Klein13


Chapter 3Ash: A 21stCentury ResourceMinnesota’s ash trees areabundant in our rural andwildland areas, typicallysupplying between 30,000 and 40,000cords of wood each year, mainly forpulp and paper, but also for firewoodand specialty products such as cabinets,furniture, and veneer.Let’s wander through the aisles of a variety of ash products:Economic significance and uses of woodWorking PropertiesBlack and green ash have lower specificgravities and lower strength propertiesthan white ash, but they are still mod-erately strong, hard, and stiff comparedto other Minnesota native hardwoods.They also split easier, shrink more, andare average in workability and gluing.When an ash log is pounded, thegrowth rings come off in thin layers,providing the material needed forbasket making.Opposite page: Green ashlumber showing emerald ashborer defect.Photo: U of M Extension/David WilseyPhoto by James Solomon, USDAForest Service, Bugwood.org15


12 16Photo: Christopher Cotrell


Ash wood has been gathered and shapedinto snowshoes of varied design by manycultures that inhabit the boreal and subborealforest ecosystems. Ash wood lendsitself to manipulation and retains its givenform once dry. Ash is also lightweight,making it ideal for snowshoes, toboggans,and vessels. The wood properties of ashhave made them a fiber source for a fewMinnesota-made products:Pulp and Paper: Two of Minnesota’spulp and paper mills use small amountsof ash mixed with other species to createpaper pulp. These mills used about 10,000cords of ash in 2007.Engineered Wood: Ash is used byone Minnesota mill to manufacture hardboard.Solid Wood Products: Over 100Minnesota sawmills use some ash, butthe overall consumption is low. Total ashuse in 2007 was about 9,000 cords. Thereare several exporters for black ash veneer.The volumes are small but these exportsare high value.Minnesota’s ash paneling industryis viable, particularly when it comes toblack ash. Black ash is sawn into panelingand flooring when quantities are available(and that may not be regular or often).Ash has always been an offering in thepaneling and flooring industry. Black ashis also used as a craft wood both in nichemarket items and traditional Minnesotacrafteditems such as snowshoes andbaskets. Also, ash is popular for firewoodas it is easy to split.While the industry that producespaneling and pallets is big, their use ofash isn’t. There are a couple reasons forthis. The size and quality of the raw ashmaterial is undependable. Not very muchash makes it to sawlog or veneer size. Thesupply just doesn’t lead to a consistentdemand.Another reason is that harvesting opportunitiesare limited to the season whenthe ground is frozen or dry, because ash ismost often found in lowland areas. Thosein the timber industry tend to focus theirefforts in the winter season on speciesthey are certain they can market.While a number of factors makeharvesting ash undesirable, other characteristicsmake Minnesota ash desirable forvarious industries. Ash has a unique, variablegrain pattern that appeals to many.It is not a “light-colored” wood, butit is not a “dark” wood either. It is somewhatvulnerable to fashion swings. Iflight-colored paneling is “in” to make theceilings look higher and the room lookChapter 3Ash: A 21stCentury ResourceAsh trees are common ‘urban trees,’ liningthe streets and boulevards of communitiesthroughout Minnesota. And, as with mosturban tress, ash trees bestow beauty, cutenergy costs, and absorb and filter stormwater – services estimated to be worthover $290 million each year to Minnesotacommunities.Photo: DailyinventionMost often, discussion centers on the largeproportion of ash trees that comprise urbanand suburban landscapes. Ash specieswere used to replace elm trees after Dutchelm disease wiped out what was once thepredominant urban landscaping tree. Ashtrees sometimes comprise one quarter ormore of the trees in municipal areas.17


Photo: John Zasada18


igger, then ash is not the first choice. Butit has enough character that it can swaythe opinion when it comes to choosing.It has the “bend” that craftsmen like(e.g. in making snowshoes); the growthrings come off in thin layers when a log isWhat about dead/dying black ash, afterinvasion of Emerald Ash Borer?pounded, thus providing the material forbasket making; and the wood color andunique grain pattern provide value anduniqueness in the creation of specialtyitems (e.g. ash bowls).Firewood will be a primarymarket for dead ashIn many stands of ash the tree trunksare small in diameter, which makesthem appealing to markets that use fiberrather than needing larger logs to createa solid wood product. The BTU value ofash makes it a desirable firewood source,particularly in rural Minnesota. Anotherattribute of ash for the home heatingcrowd, is the fact that it splits very easily,thus making it a preferred choice overother species of wood.Marketing experts expect that thesheer volume of smaller diameter ash, aswell as the size and location of naturallyoccurring ash stands will drive utilizationin the direction of firewood.Because of ash’s splitting characteristics,homeowners are more apt to purchasetruckload quantities in 100” or treelength and do their own processing intofirewood. Loggers will achieve a betterproduction rate with this type of processing.They will not have to apply extraeffort during logging and delivery, sowill be more likely to harvest ash stands.Moving firewood is not recommended. Seepages 21 and 25 for details.It is important to note that there aremarkets for medium and larger ash logsas saw material and veneer logs. Sortingof larger material to higher value useswill result in greater economic returns.Chapter 3Ash: A 21stCentury ResourcePage 18: A white ash strippack basket constructed byMike Benedict; Inset: Black ashwoven bowls crafted by DennisChilcoteGLOSSARYBTU: British Thermal Unit,is a basic measure of thermal(heat) energy. One BTU is theamount of energy needed toheat one pound of water onedegree Fahrenheit.Survey Recommendations: Wood MarketsFirewood and biomass will be the main market for dead ash. Ash prices will decrease.Several experts pointed out that the transportation distance to markets and local quarantineswill play a major role in future ash markets. It was also pointed out that highvalue ash markets will be impacted by decay fungi as ash die. Landowners shouldharvest ash when considering an already scheduled harvest. Landowners shouldassess their ash inventory and plan a replacement strategy now. One entomologistsummarized several recurring comments this way: “I think landowners in the entirestate should get the recommendation to consider management to reduce the amountof ash if they have a lot and they should not delay. But they also don’t need to panic.As the land gets closer to known EAB infestations the urgency increases. But I am notso sure the management recommendations would change much- reduce ash- don’teliminate ash. Management recommendations in and around communities may bedifferent but that will depend on the situation and how the community is dealing withEAB.” The expert panelists recommend: Do not liquidate ash immediately. Effortsto leave some ash for genetic stock are more likely to survive if neighboring threatsare reduced.” Reduce ash populations in their stands to reduce EAB impacts.Photo: Julie Miedtke19


20Ash logs destined forbaseball bat production.


Photo by Pennsylvania Department of Conservation andNatural Resources - Forestry Archive, Bugwood.orgInformation on QuarantinesWhen ash has been killed by EAB,county-by-county quarantines will beput into effect by the Minnesota Departmentof Agriculture. A quarantine is atemporary rule intended to help preventa potentially dangerous or destructivepest or disease organism from spreadingoutside a known infested area into newareas. In the case of EAB, the quarantineis designed to limit the movementof potentially infested firewood or othermaterials such as live ash trees that mightharbor EAB larvae.The regulations for transportingwood out of a quarantined county will requireactions that will add cost to the rawwood material harvested from the forest.For many wood products, this extraprocessing will be cost prohibitive. Theleast expensive action to enable ash to betransported out of a quarantine countywill involve chipping the solid wood inorder to destroy the medium that EABuses to reproduce.Chipping will add the least costto harvested ash wood as markets willSpecialty markets significanceBurls are abnormal growths thatprovide a wonderful source for decorativewood with fanciful grain or figuring. It isbelieved that a burl is created when thereis an injury or other external stimulus thataffects the growth pattern ofreadily accept chips. Markets for chipsin Minnesota include biomass burningfacilities, located in both rural andurban settings, a few pulp mills, and oneoriented strand board mill. By far, themarket for fuel chips will absorb most ofthe volume produced by this method.Ash prices will decreaseIt is possible that large volumes ofash will be killed at the same time, necessitatingthe removal of more volume thancould be absorbed by current markets.The effect of an oversupply of any commodityis that the unit price of that commoditydrops. This situation could easilyhappen with ash.It is likely that this condition wouldbe short-lived and last until the volumeof dead ash is reduced. At that point, itseems probable that, because of a scarcesupply, the price of ash would begin torecover to former levels, perhaps evenincreasing to a premium level. Ash hasnever garnered a very high price in thewood stumpage market. The affect ofquarantines on the movement of ashresources will potentially be major.the tree and results in a deformity. Woodgrain patterns may be wavy, swirled,marbled or feathered depending on thetype of burl.Ash is considered one of the best ofthese “character woods;” burls on ashtrees are highly sought after. Ash displaysa pronounced grain, with a wide to broadrange of grains and color that make ituniquely the most consistent choice forthose looking for character wood orreal “wood” feel. Ash takes stainextremely well and its grainChapter 3Ash: A 21stCentury ResourceGLOSSARYquarantine: A temporaryrule intended to help preventa potentially dangerous ordestructive pest or disease organismfrom spreading outsidea known infested area. In thecase of the emerald ash borer(EAB), quarantines are designedto limit the movement ofpotentially infested firewood orother materials such as live ashtrees that might harbor EABlarvae. For more informationon quarantines see AppendixB, pages 63-64.biomass: Harvesting thewood product obtained(usually) from in-woodschipping of all or some portionof trees including limbs, tops,and unmerchantable stems,usually for energy production.oriented strand board: Alsoknown as OSB or waferboard,is an engineered wood productformed by layering strands(flakes) of wood in specificorientations.burl: An abnormal growthof woody tissue protrudingoutward from a tree stemor trunk.character wood: Woodprized by artists or craftsmanbecause of its unique ordistinctive grain patterns orform. Examples of characterwood include burls andcrotch wood.Ash burl, “Fraxinus cornu”Photo: Tim Byrns21


Chapter 3Ash: A 21stCentury ResourceGLOSSARYbole: The trunk or main stemof a tree.A hand-woven,black ash baskettaking shapecharacteristics allow it to highlight abeauty only nature can provide.Although the quality of burl is notknown until you begin working with it,Cultural significancePhoto: U of M Extension/David Wilseyburl wood can be used for veneer or frequentlyturned to create high end productslike clocks, mirrors, knife handles,wood bowls etc.The unique characteristics of blackash have made it a staple of the traditionalAmerican Indian basket-makingindustry. U.S. Bureau of Indian Affairsforester and basket maker Michael Benedictpredicts: “If and when emerald ashborer gets to the state’s remaining stands,the material will be very rare or nonexistentin some areas.”Ash holds cultural significance to certaincommunities. Many woodland communitiesprize ash for its characteristicsand feature ash wood in practical tools,many of which have become elevated toart forms. Black ash, in particular, is prizedin basketry because of the straight andsmooth trunks. Once it has been felled, thetree bole, or trunk, is pounded to removethe sapwood layers.Pounding the tree separates thegrowth rings into strips about the thicknessof a nickel. Pounded strips aresoaked, cleaned, and separated again intothinner strips. Depending on the thicknessof the original strip, this process canoccur several times, each yielding thinnerand finer “ribbons” of wood.Larger strips are used to form thebasket’s base and sides. Thinner strips, orweavers, are used to weave the basket’sbottom and sides. Black ash baskets havea rich tradition. Ash baskets make excellentpack baskets and were likely used totransport goods by the voyageurs. Ashbaskets bring high prices in the marketplace:large baskets can cost thousandsof dollars. Basketry is not a quaint relicof the past. Today, people use this earlytechnology to create and sustain forestbasedenterprises.For further information on Cultural Signifcancesof Ash, see Appendix D, page 6614 22


Chapter 4The EmeraldAsh BorerA little package carrying big troubleEmerald ash borer (EAB) is anon-native insect that kills ashtrees; it was found in St. Pauland near Houston County, Minnesota in2009. EAB is the focus of efforts to guidemanagement of ash stands on public andprivate forested lands. The discoveryof this invasive insect in Minnesota isone of the main reasons this Guide wasdeveloped.Life cycleEmerald ash borer starts out as a flat,rust-colored egg, just a smidge biggerthan the period at the end of this sentence.A single female will lay 80 eggs orso on the bark of ash trees in summer.A lanky white larva emerges, burrowsinto the bark, and begins eating tissuesbetween the sapwood and bark. In theprocess, it cuts off the conduits that carrynutrients from roots to leaves and sunmade sugars from leaves to the rest of thetree. It will feed and grow all summer.The next spring the larva morphsinto a pupa. In early summer the pupadevelops into an adult beetle. Two orthree weeks later, the beetle bores out ofthe bark, leaving a telltale D-shaped escapehole. Preparing to overwinter, a larvaechews a shallow hole in the sapwood(< 1 ⁄2 inch deep). Newly emerged adultsAdult EAB (actual size1 ⁄3 - 1 ⁄2 inch)Photo: Jeff Hahn23


Emerald ash borer shown in ash tree;size compared with a man’s finger.Serpentine larval galleries exposed bywoodpecker activity.Actual EAB larvae inside ash tree.Thinning foliage in crown of ash tree.24“D” shaped exit hole of EAB shown on bark of white ash.Background Photo: Jeff HahnInset Photos: Mark Abrahamson


feed on ash leaves for a few weeks beforemating and starting the cycle again.Infestations can be recognized bydead and dying trees that have serpentinegalleries on the surface of the sapwoodof branches and stems, D-shaped exitholes in the bark and signs of woodpeckerattack such as stripped bark on branchesand stems. Eventually twigs, branches, andultimately the whole tree dies.Adult females can re-infest the tree orfly to a new location. Natural spread mayoccur up to four miles per year. An infestedash stand can be 96% dead in six years.What you need to knowEAB kills ash trees and it does soin great numbers. Already it has killedmillions of ash trees in North America.EAB will have a huge effect on Minnesota’slandscape and the 937 million ashtrees that grow in our cities and forests.• You can expect EAB to spreadthroughout Minnesota, eventually; itmay take decades.• EAB kills all species of ash trees inMinnesota: black, green, and white.• EAB kills 99% of North Americanash trees.• There are some trees with resistanceto EAB located in China.• Cold temperatures in Minnesota mayslow EAB down, but will noteliminate them.Photo: DNR• Planning ahead and managing ash beforeEAB arrive will give you more timeand will help keep your land forested.• Natural enemies of EAB exist inChina; some of these insects are beingreleased in Minnesota to help slow thespread of EAB.• Recognize the signs and symptomsof an EAB infested tree: heavywoodpecker activity on tree, dyingbranches in the top canopy, sproutsaround the tree base, vertical cracksin the bark, S-shaped tunnels underthe bark, and 1 ⁄8 inch D-shaped exitholes in the bark.• If you have ash trees on your property,now is the time to plan for a futurewith fewer ash trees.GLOSSARYChapter 4The EmeraldAsh BorerHeavy woodpeckeractivity on a tree isoften a sign of EABinfestation.serpentine galleries: Trailsthat wind and twist, like asnake.sprouts: Shoots arising fromthe base or sides of a woodyplant.Do NOT transport firewood!Do not transport firewood, even within Minnesota. A major culprit inspreading EAB and other insect pests is firewood. Larvae and pupaecan hide beneath the bark and then escape as adult beetles after beingtransported many miles. Look at the map on page 28 of where EABhas been found. How did it hop from one state to another? Many of theplaces where it was found are parks and campgrounds. People carriedEAB with them when they brought firewood on a picnic or camping trip.25


Chapter 4The EmeraldAsh BorerWhat About the Cold?Scientists are still studying EAB’swinter survival in northern Minnesota.People with significant amounts of ashshould not dismiss the threat of EAB,regardless of where their stand is located.However, data from 2009-2010 field seasonshows evidence that winter survivalof EAB is poorer in northern areas, andSurvey Recommendations aboutEAB cold hardinessMore research is needed on the hardiness of EAB; however there is enoughuncertainty that landowners should know EAB may spread more slowly innorthern MN. Based on preliminary research, EAB survival in northern Minnesotawill be lower than in southern Minnesota and will likely reduce populationbuildup and spread of EAB. One genetics expert pointed out, “Thereis evidence to suggest that winter survival of EAB in northern MN could beexpected to be lower than in southern MN. That says nothing about how lowersurvival rates may impact spread of the adults.” “Natural spread is not the primary(or sole) issue of concern.” Also according to a silviculturalist, “It’s alwaystrue that bugs reproduce less in colder areas, but EAB lives in some areasin China that are much colder than MN (even northern MN), and some fairlymild areas. However, the bug might be able to undergo selection for cold tolerancein several generations, and climate change might also come into play.”Ash management recommendations should be based on the distance toa known EAB infestation. One word of caution from a harvesting expert is“please consider proximity to major roads of people moving in from EAB occupiedzones. And hardiness information as it becomes more available fromplaces like Michigan.” One entomologist also pointed out that shifting climatepatterns may alter EAB spread for various locations throughout the state. Ifmanagement zones are desired, create them based on proximity to known EABlocations and likely next occurrences. Thoughts from another entomologist are,“the distance to a known EAB infestation and hardiness zone information rightnow should only affect the urgency for doing something, not the types of managementrecommendations. Hardiness of EAB in northern Minnesota shouldonly influence the urgency of doing something not what is actually done.”In addition to hardiness, research about EAB and black ash may also affectfuture management recommendations. An important point to remember thatis because EAB is a relatively new exotic pest our knowledge of the insectand our management or control recommendations will change over time, andsometimes this may change quite rapidly.” Another comment from an entomologist,“I am also somewhat reluctant because we were told that Dutch elm diseasewouldn’t be a problem in northern Minnesota and that gypsy moth wouldnot be as much of a problem in northern Minnesota as in southern Minnesota.Insects and diseases have a way of surprising us.” Another recommendationfrom the panel of experts is that ash management recommendations shouldbe based on both distance from a known EAB infestation AND hardiness zoneinformation.26


will likely reduce population build-upand the spread of EAB.It is also VERY important that landownersstay abreast of this research asthe results may have drastic impacts onash management in northern Minnesota.Landowners should consider boththe distance their land is from a knownEAB infestation, likely EAB introductionsites (possibly along roads), as well asinformation from the newest research inEAB cold tolerance.Chapter 4The EmeraldAsh BorerPreliminary data suggests that EABsurvival may be lower in northernMinnesota than in southern Minnesotabecause of extremes in lowtemperatures in the north.Photo: clgregorWhat do I do if my trees become infested?If your ash tree is infested with EAB or is showing othersigns and symptoms, visit the University of Minnesota ExtensionWeb site: www.extension.umn.edu/issues/eab/To report a possible EAB infestation, contact the Arrest thePest Hotline at arrest.the.pest@state.mn.us, 651-201-6684,or 888-545-6684.Consider insecticide treatments only when your property is within15 miles of an EAB infestation.27


Chapter 4The EmeraldAsh BorerGLOSSARYphloem: A layer of cells justinside the bark of plants thatconducts food from the leavesto the stem and roots.Manage ash trees to keepEAB populations lowEmerald ash borer is considered aphloem-feeding insect. Phloem tissue isbasically the inner bark in trees. A singlelarge tree will have much more phloemtissue than a small tree simply becauseof its greater bark surface area. We canestimate how much phloem tissue isavailable on any given acre by countingthe number of ash trees and their size.The amount of phloem available willdictate how many emerald ash boreroffspring could be produced in any givenarea. The concept is actually quite simple,the more food that is available for emeraldash borer larvae, the greater the numberof offspring that can be produced.Ash phloem reduction is an attemptto reduce the amount of food availableto EAB. A lack of food could limit howquickly an EAB population expands.Phloem reduction is generally recommendednear locations where EABis newly introduced and would generallybe considered an EAB managementstrategy not necessarily an ash manage-SurveyRecommendationAsh phloem reduction strategy ismeant for EAB management not ashmanagement, but it could be consideredwhen managing these stands asone of many considerations.ment strategy. Many stands in the wetforest and floodplain forest types havelarge amounts of ash and therefore largeamounts of ash phloem. This makesthem highly vulnerable to EAB once theinsect does arrive in the area.Therefore, some professionals suggestthat forest management in these areasmight include some level of ash removaland replacement with other site appropriatespecies as a stand management tacticthat could also accomplish long termphloem reduction on those sites.Emerald ash borerlocations in Midwestand eastern states.Key:Red dots =positive for EABBlue outlines =federal quarantinearea28


Chapter 5The Native PlantCommunitiesThe Minnesota Department ofNatural Resources and the U.S.Forest Service have developeda system of classifying areas of land thatdisplay similar ecological features. Thesystem helps land managers and researchersidentify, describe, and map a unit ofland that has uniform ecological features.The system uses associations ofbiotic and environmental factors, forinstance: climate, geology, topography,soils, hydrology, and vegetation to comeup with ecological patterns for areas aslarge as North America or as small as asingle timber stand.Following are descriptions of the fivesystems in which ash in Minnesota willoccur. A more common term for theseecological systems is ‘native plant community.’We will use the term “nativeplant community” in this guide, insteadof ecological classification system. Readon for a more in-depth description of anative plant community.What is a native plant community?The purpose of this classification isto help land managers make decisionsand understand how native ecosystemsfunction. Nearly all land managementactivities affect vegetation and the nativevegetation provides important clues asto the potential that land has to providetimber, wildlife habitat, and recreationalopportunities. Equally important, theNative Plant Community (NPC) classificationtells land managers about criticalhabitats that Minnesota’s rarest plantsIdentifying Your Native Plant CommunityThere are many kinds of vegetated areas that are not native plantcommunities. These include places where native species have largelybeen replaced by exotic or invasive species such as smooth bromegrass, buckthorn, and purple loosestrife. Also, planted areas suchas orchards, pine plantations, golf courses, and lawns arenot native plant communities.Areas not considered to be native plant communities includeareas where modern human activities such as farming, overgrazing,non-sustainable logging, and development have destroyed orgreatly altered the vegetation.GLOSSARYbiotic: Pertaining to livingorganisms and their ecologicaland physiological relations.hydrology: The study of themovement, distribution, andquality of water on Earth andother planets, including thehydrologic cycle, waterresources and environmentalwatershed sustainability.native plant community: A nativeplant community is a groupof native plants that interactwith each other and with theirenvironment in ways not greatlyaltered by modern human activityor by introduced organisms.These groups of native plantspecies form recognizable units,such as oak savannas, pineforests, or marshes that tendto repeat over space and time.Native plant communities areclassified and described by consideringvegetation, hydrology,landforms, soils, and naturaldisturbance regimes.Photo by Muffet29


and animals need to survive into thefuture. In this Guide, the NPC classificationis used as a framework for organizingthoughts and facts that concern the ashresource. The classification is used to helplandowners understand why ash treesgrow where they do and to provide guidanceon management strategies.For some Systems, there is much todo; for others, there is little that we can do.So, what is a native plant community?A native plant community is a group ofnative plants that interact with each otherand with their environment in ways notgreatly altered by modern human activityor by introduced organisms. These groupsof native plant species form recognizableunits. For instance, if you were walkingthrough a woodland, you might immediatelyidentify that you were walkingthrough an oak savanna, a pine forest, ormaybe sloshing through a marsh.Native plant communities are namedfor the characteristic plant species or for acharacteristic environmental feature containedwithin them. Examples of nativeplant communities in Minnesota includeDry Barrens Oak Savanna, Red Pine-White Pine Forest, Bulrush Marsh, SedgeMeadow, and Mesic Sandstone Cliff. Forpurposes of this Guide, you should knowthat ash will potentially be found in one offive native plant communities or systems.Two systems: Forest Rich Peatlandsand Fire Dependent typically containminimal ash, but were included in thesurvey so are included here. The five systems,or native plant communities, are:• Wet Forest System• Floodplain System• Mesic Hardwood System• Forested Rich Peatland System• Fire Dependent SystemChapter 5The Native PlantCommunitiesPage 30: Floodplain ForestSystem, Somerset WildlifeManagement AreaPhoto: Brian Lockhart, USDA ForestService, Bugwood.orgGLOSSARYMesic: Sites or habitatscharacterized by intermediatemoisture conditions.Hydrology and Minnesota Native Plant CommunitiesSoil moisture in forest soils is definedby conditions during the summer growingseason. The order from dry to wet in forestsdominated by ash or with a significantcomponent of ash is: Fire-Dependent,Mesic Hardwood, Floodplain Forests, WetForests, and Forested Peatlands. FlooplainForests are, of course, flooded duringthe spring runoff period and occasionallyduring other times; however, in mostyears during the summer months, soilsare less wet than summer soils in the WetForest system where mucks, peats, clays,and high water tables maintain wet-mesicto wet soil moisture regimes. FloodplainForest soils tend to dry some as the waterlevel in the river drops from flood stage(bankfull) to summer, low flow conditions.The average position of the growing seasonwater table below the soil surface alsodetermines the tree species and herbaceousspecies associated with ash. Forestedpeatlands are wet year round becauseof restricted outflow from the peat basin.Peatlands with the highest peatland slopeshave the tallest trees because the downslope movement of water is quickenedand the peat soil is thus better aeratedduring the summer growing season.Photo: MN DNRGreen ash leaflet, showingthe compound leaf31


Chapter 5The Native PlantCommunitiesWet Forest SystemAsh in the WetForest SystemGLOSSARYpure stands: Forest, crop, orstand composed principally ofone species, conventionally atleast 80 percent based onnumbers, basal areas, orvolume.Red-osier dogwood isan indicator of the WetForest System.The range(blue) of WetForests inMinnesota andthose that includeash (dots).Wet Forest (WF) communities occurcommonly in narrow zones along themargins of lakes, rivers, and peatlands;they also occur in shallow depressionsor other settings where the water table iswithin reach of plant roots. The suppliesof groundwater and runoff typically areat their peak early in the spring and thendiminish throughout the growing season.The contribution of runoff to these systemsis greatest in northeastern Minnesota;it lessens in the southwest to the pointwhere wet forests there are fed entirely byupwelling groundwater. Black ash acts likea hydrologic pump, lowering the watertable as summer progresses. The seasonalvariability in soil moisture is a hallmarkof the WF System. This variability controlsthe availability of the oxygen.This oxygen is essential for:• roots to respire;• decomposition of organic litter; and• release of nutrients in forms that areusable by plants.This physical environment is problematicfor most of Minnesota’s trees,except for ash and northern white cedar.Consequently, it is specifically these twospecies: ash and white cedar, that tendto dominate WF sites. Oftentimes, theyare found as pure stands of those species.All plant communities designatedas “WF” sites have some ash regeneration,and over 75% have ash trees in thecanopy. Black ash is the WF specialist,occurring in 69% of all wet forests, andthe average stand is 36% black ash trees.Common Trees:• Black ash• Northern white cedar• Green ash• Balsam firPhoto: Paul Wray/Iowa State University, Bugwood.org32


• American elm• Red mapleUnderstory species:• Rough alder• Mountain maple• Beaked hazelnut• Red-osier dogwood• Swamp red current• Red raspberryGreen ash occurs in 9% of wet forestsand comprises 11% of the trees whenpresent. White ash does not occur inwet forests. In addition to ash and cedar,wet forests are usually mixed (83%) withsome other trees. Balsam fir, Americanelm, and red maple are the most importantspecies to also occur in wet forests.The ground in wet forests is coveredwith a luxurious growth of herbaceousplants that is usually dominated by eitherferns or grass-like plants.Herbaceous plants:• Lady fern• Oak fern• Shield fern• Crested fern• Woodland horsetailGrasses & Sedges:• Bluejoint grass• Graceful sedge• Bristle-stalked sedge• Bladder sedge• Long-stalked sedge• Awl-fruited sedgeWildflowers:There are two distinct seasons forwildflowers in wet forests – springand fall.In the spring, plants adapted towaterlogged soils thrive. Most noticeableare the yellow cowslips that definethe extent of wet forests on the landscapeand lend the first blush of color toa brown world recovering from winter.Annual plants that have waited all seasonfor the soils to dry can dominate the fallwet forest. The most common are:• Jewel weed• Beggar’s ticks• Dwarf raspberry• Naked miterwort• Alpine enchanter’s nightshade• Sweet-scented bedstraw• Common strawberry• Canada mayflower• Bunchberry• Water horehound• Goldthread• Red-stemmed asterPhoto: J.C. LucierWet forests are Minnesota’s mostdiverse kind of forest. On average, 50 differentspecies of plants can be found inan area the size of an urban back yard; itis not uncommon to find more than 100species. There are three reasons for thisdiversity. First, wet forests are often linearinclusions in uplands and some terrestrialplants find refuge in the driest habitatsavailable in wet forests, but many wetforest plants can’t tolerate upland conditions.Second, wet logs, pools of water,Lady fernChapter 5The Native PlantCommunitiesWet Forest System33


Wet Forest: Dieback and declineEmerald Ash Borer or Dieback-which is it?Many hardwood tree species haveexperienced periods of branch dieback,often called “decline.” Symptoms includeslow growth, thin crowns, and misshapenor discolored leaves. Characteristic of thesedecline episodes is that one single ‘cause’of the decline cannot easily be identified.Instead, evidence suggests that trees havebeen stressed and were then invaded by oneor more organisms that are not normallydamaging to those trees. Biotic agents suchas defoliating insects or abiotic factors suchas severe drought can predispose trees to anumber of pathogenic organisms that furtherdamage trees. However, not all affectedtrees will die. Once the stress is removed,many trees are able to regain normal vigorand growth.Dieback of black ash is an example ofa condition affecting trees in many areas ofthe Lake States and especially in northeastand north central Minnesota. For years,dieback, thin crowns, and in some stands –tree mortality have been observed. Addingto the appearance that this species isin decline is that black ash has a late leafflush and early leaf fall, therefore the treesseemingly never have full, vigorous crowns.In recent studies, it has been foundthat the most seriously affected trees werenearest to roads and on the wettest sites;even then, tree mortality was relativelylow. No causal agent was found affectingtrees with dieback, and on many treescrown recovery (multiple years of newbranch growth) was occurring.Distinguishing between the symptomsof decline or crown dieback and EAB isextremely difficult and critical.Landowners, especially those in thenorthern Wet Forest (WF) systems areencouraged to work with professional forestersto diagnosis, monitor, and carefullymanage these sites.Epicormic branching: Erratic growthfrom adventitious buds sprouting ontrunks of trees may indicate dieback. It’s acoin toss as to whether the tree is recoveringand beginning to rebuild its crown ordying. Epicormic branching may also bea symptom of a tree infested with emeraldash borer.Chapter 5The Native PlantCommunitiesWet Forest SystemGLOSSARYdieback/decline: The progressivedying from the extremity ofany part of a tree.abiotic: Nonliving parts of anecosystem, such as soilparticles, bedrock, air, andwater.leaf flush: The time in theseason during which leavesappear on a tree.crown dieback: Decline of thebranches and limbs in the canopyof a tree sometimes used asan indicator of tree health.adventitious: Pertaining toa plant part that developsoutside the usual order of time,position, or tissue — e.g., anadventitious bud arises fromany part of a stem, leaf, or rootbut lacks vascular connectionwith the pith; an adventitiousroot arises from parts of theplant other than a preexistingroot, e.g., from a stem or leaf.epicormic branching: A shootarising spontaneously froman adventitious or dormantbud on the stem or branch ofa woody plant often followingexposure to increased lightlevels or fire.Ash dieback in northernMinnesotaPhoto: Juile Miedtke35


Chapter 5The Native PlantCommunitiesWet Forest SystemSurvey Recommendations: Wet Forest• If site does not have natural drainage, tree loss is likely to increase watertable depth.• Fire danger will increase when ash sites are replaced with grasses orcattails especially if the late summer or autumn is dry; fire intensity willincrease.Harvesting Wet Forest sites is very sensitive and extreme care should betaken when considering such an activity. Harvest when ground is frozen ordry. Clearcutting is not recommended. However several experts commentedthat strip or patch cuts may be appropriate especially when dealing withstands mixed with conifers.Use harvesting methods appropriate to allow for desired regeneration.Consider ash phloem reduction thinnings in conjunction with a sound regenerationplan and when EAB is known within 15 miles of a site. Accordingto one silviculture expert, “Use what works. You still have to deal with highwater tables, EAB or not.” Expect increasing water tables after ash has diedor is harvested.Because of the degree of uncertainty, new silvicultural practices need to beexplored for Wet Forest stands because of EAB. According to one expertpanelist in Ecosystem Classification System, “The concern is greatest in WetForests where black ash is dominant. The collapse of a local, dominant populationwill leave considerable niche-space open for other plants. Unfortunately,this will not always be trees. Only white cedar is similarly adapted to wet forestsites and regeneration of cedar has been nearly non-existent due to deer depredationand adequate safe sites for seedling germination and survival. In allother systems, there are other trees that can fill the niche void when ash die.”Regeneration strategies could include both natural colonization and planting.It was noted that regeneration in these stands can be tricky because of standhydrology, so attention to micro sites and persistence will be important.Recommended replacement trees, as ranked by the experts:Opposite page: Generaldecline in wetland black ashnear Cloquet, MinnesotaNorthern Wet Forest:(11 out of 21 species)• Tamarack• White cedar• American elm (disease resistant)• Black spruce• Balsam poplar• Yellow birch• Balsam fir• Red maple• Quaking aspen• Ash (for genetic material)• Silver mapleSouthern Wet Forest:(10 out of 21 species)• American elm (disease resistant)• Silver maple• Basswood• Red maple• Willow• Bur oak• Yellow birch• Ash (for genetic material)• Box elder• Red elm36Steven Katovich, USDA Forest Service, Bugwood.org


Chapter 5The Native PlantCommunitiesFloodplainForest SystemAsh in the FloodplainForest SystemGLOSSARYfloodplains: The level ornearly level land with alluvialsoils on either or both sides of astream or river that is subjectto overflow flooding duringperiods of high water.riverine: All wetlands anddeep water habitats containedwithin a natural or artificialchannel that periodically orcontinuously containsmoving water, or that formsa link between two bodies ofstanding water.The statewiderange (darkgreen) of floodplainforests inMinnesota andthose that includeash (dots).The Floodplain Forest (FF) occurs onfloodplains, creek bottoms, and riverineterraces. These landforms are essentiallyflat, following the river’s gradient. Thesoils in a floodplain are developed on riversediment, and the surface is commonlyfluted with shallow channels and levees ina complex, swirling pattern. Floodplainsare annually inundated by spring runoff;terraces and bottoms are inundatedoccasionally during flood events. Evenat low water, the water table is normallywithin reach of tree roots, meaning thatFF trees must solve the same problem ofroot respiration as the trees in the WetForest Plant Community. FF differ fromCanada moonseed is a plantfound in the Floodplain ForestSystemPhoto: J.C. Lucier38


Chapter 5The Native PlantCommunitiesFloodplainForest SystemThe Cerulean warbler hasshown the steepest decline ofany warbler species accordingto the Breeding Bird Survey. Ithas suffered an 83% declineover the last 40 years. Thedecline is attributed, in part, tothe loss of bottomland habitat.WF because organics (non-living materialderived from living organisms) do NOTtend to accumulate on the surface. Thatmeans there is a water flow that deliversincredible amounts of nutrients to the FFsites. To live on an active floodplain, a treemust:• tolerate inundation, root and boleburial by sediments;• resist erosion;• survive wounding from ice floes; and• be able to invade open, fresh-soilhabitats.Common Trees:• Silver maple• Green ash• Black ash (northern MN)• White ash (southern MN only)Occasional Tree:• American elm• Basswood• Box elder• HackberrySilver maple is the tree most adaptedto Minnesota floodplains and it stronglydominates the forest. However, creekPhoto: Greg Lavatybottoms, abandoned terraces, andhigher microsites on the active floodplainapproach WF habitat - and ashdoes well there. Ash seedlings occur in95% of all FF, and ash trees are found in88% of them – indicating that the ashhas good success at recruiting seedlingsto the canopy. Green ash is most common;occurring in 53% of all FF and itcontributes 16% of the trees on average.Black ash is frequent; occurring in 38%of all FF, accounting for about 21% of thetrees on average.In general, black ash is more commonin northern Minnesota and greenash more common in the south. Whiteash is limited to southern Minnesotaand occurs in just trace amounts on FFsites. In addition to silver maple andash, most (95%) floodplain and terraceforests are mixed with some other trees.No Minnesota conifer is tolerantof flooding, and thus you will not findthem in the FF community. Shrubs andsmall trees are essentially absent fromany surface that floods regularly; rathervines are more likely to be found thanare woody understory plants.GLOSSARYmicrosites: A small part ofan ecosystem that differsmarkedly from its immediatesurroundings.conifer: A cone-bearing tree(e.g. pines, firs, spruce, cedars,redwoods, larches etc.).39


Chapter 5The Native PlantCommunitiesFloodplainForest SystemVines:• Wild grapes• Virginia creeper• Canada moonseedHerbaceous plants:• Ostrich fern• Wood nettle• Stinging nettle• Tall coneflower• Honewort• Jewel weed• Carrion-flower• Sweet-scented bedstraw• Side-flowering aster• Ontario aster• Kidney-leaved buttercupGrasses:• Rice cut grass (native)• Virginia wildrye (native)• Reed canary grass (invasive)Terrace and floodplain forests inparticular are not especially diversecommunities. On average, 33 species ofplants are found in 400m 2 . Because ofthe abundance of moist mineral soil, asignificant portion of the flora consistsof germinating plants – many of whichwill not survive for long. Thus, the averagenumber of persistent plants is ratherlow, the lowest of any system with ashtrees.Some rare plants and animals aredependent upon floodplain and terraceforest habitat in Minnesota.Photo: Fred HarrisWater & Wood: Good & BadRiparian forests provide a long corridorfor animal habitat and migration.Natural EAB movement will be easiestalong riparian corridors, effectively spreadingit locally at 2-4 miles per year. Riparianforests are important because theyprovide shade to cool streams and normalamounts of fallen trees for wood habitatin the water. This is especially importantin sand-bedded streams that lack cobbleand gravel sites for spawning, rearing, andinvertebrate attachment. These corridorsalso provide overhead cover.Wood in rivers is a good thing; however,too much wood can cause silt andfine sand to cover spawning and rearingWood jams occur approximatelyevery 300-400 feeton the Rat Root River innorthern Minnesota.Opposite page: FloodplainForest standPhoto: Sandy Verry40


occurs leading to extensive bank failurescausing high turbidity levels in thestream water.Trees can help reduce the amount ofbank failure because their roots extend 5to 7 feet below the bank. They bind thesoil and keep the bank drier during thegrowing season with their high evapotranspiration.Bank failures may extend10 to some 300 feet away from the riverdepending on how deeply the river hasincised.Along the Littlefork River in northernMinnesota near the town of Littlefork,the river has downcut nearly 8 1 ⁄2 feetand yields one of the highest turbidityratings in the state. Bank failures alongthe Littlefork River extend up to 350 feetfrom the river. Along incised river channels,forests should be managed for latesuccession forest stands with near 100%forest canopies. The width of these forestsshould be about the width of bankfailures seen along the channel.Special wildlife considerationsSpecies that are most likely associatedwith the Floodplain Forest includethe Cerulean warbler, red-shoulderedhawk , red-bellied woodpecker (southexpanding north), great blue heron,green heron (more south), blue-graygnatcatcher (south), prothonotarywarbler. Amphibian and reptile speciesinclude: blanding’s turtle, wood turtle,wood frog, leopard frog, and minkfrog. Mammals include the red bat andsilver-haired bat. Note that many ofthese species use other habitats, in additionto the floodplain forest.Chapter 5The Native PlantCommunitiesFloodplainForest SystemSurvey Recommendations: Floodplain ForestHydrology is impacted more by natural drainage than tree loss. Death orremoval of ash will change stream morphology. Better water drainage in thesesites will promote tree replacement.When a harvest is viable, select harvest may be the best silvicultural practicein the Floodplain Forest. Harvest only when ground is frozen or dry. On qualitysites continue to manage for quality ash. On poor sites do not harvest unless aharvest achieves specific objectives. Ash phloem reduction strategy is meantfor EAB management not ash management, but it could be considered whenmanaging these stands as one of many considerations.Recommended replacement trees (as ranked by the experts):GLOSSARYmorphology: The externaland internal form andstructure of whole plants,organs, tissues, or cells.select harvest: A cutting thatremoves only a portion of treesin a stand.Northern Floodplain Forest(10 out of 17 species)• American elm (DED resistant)• Silver maple• Basswood• Bur oak• Swamp white oak• Balsam fir• Box elder• Cottonwood• River birch• Paper birchSouthern Floodplain Forest(11 out of 17 species)• Swamp white oak• Cottonwood• American elm (DED resistant)• Silver maple• Basswood• Black walnut• River birch• Bitternut hickory• Box elder• Hackberry• Rock elm43


Mesic hardwood forests have a diversearray of wildflowers. Some of theseplants, the ephemerals, make their entireliving in a few weeks before and duringleaf-out of the maples.Wildflowers:• Spring beauties• Dutchman’s breeches• Wild leeks• Dwarf raspberry• Large-leaved aster• Sarsaparilla• Yellow & sessile-leaved bellworts• Canada mayflower• Early meadow rue• Clayton’s sweet cicely• Rose twistedstalk• Hog peanut• Wild ginger• Wood anemone• Yellow violets• Sweet-scented bedstraw• Zig-zag goldenrod• Bluebead lily• Hairy Solomon’s seal• Maryland black snakeroot• Hepatica• Starflower• False Solomon’s seal• Wild strawberry• Red baneberry• Jack-in-the-pulpit• BloodrootGrasses and sedges are not normallyabundant and the most common are:Pennsylvania sedge, peduncled sedge,and mountain rice grass. Where exoticearthworms have infested MH forests,Pennsylvania sedge can form large, continuouslawns. Mesic hardwood forestsare diverse plant communities. On average,one can find 43 different species ofplants in 400m 2 .Some rare plants and animals aredependent upon mesic hardwood foresthabitat in Minnesota.Earthworms should be consideredas a serious threat to native regenerationin the Mesic Hardwood Foresttype.Mesic HardwoodSystemGLOSSARYChapter 5The Native PlantCommunitiesephemerals: Ephemeral plantsare marked by short life cycles,usually 6-8 weeks. Ephemeralmeans transitory or quicklyfading.A MesicHardwood forestPhoto: MN DNR45


Chapter 5The Native PlantCommunitiesMesic HardwoodSystemA Mesic stand inearly SpringGLOSSARYduff: The partiallydecomposed organic materialof the forest floor beneath thelitter of freshly fallen twigs,needles, and leaves.Earthworms & Ash: Making the ConnectionsPhoto: Julie MiedtkeEarthworms may be ‘tool of the trade’when it comes to fishing Minnesota’slakes. And they are considered rathergood friends in the vegetable garden.However, earthworms are an unwelcomeintruder in Minnesota’s hardwood forests.Minnesota’s mesic hardwood forestsdeveloped in the absence of nativeearthworms. These forests grew after thelast glaciers retreated. They contained athick forest floor that served, and continuesto serve as a perfect rooting mediumfor many species of forest herbs and treeseedlings.Minnesota has no native earthworms.In the 1800s European settlers arrived,bringing with them European earthwormspecies in potted plants. Europeanearthworms have been part of the habitatssurrounding human habitation eversince. The European earthworm invasionchanges the structure of forest soils. Theduff layer is consumed by the worms sothat the seedbed conditions on the forestfloor change from deep leaf litter to baremineral soil during summer. The soil isalso compacted, leading to more runoffduring heavy rainfall events; the availabilityof nitrogen and phosphorus isreduced.Earthworm invasion accentuates thealready negative impact of deer browsingon native plant and tree species. Combined,these changes make trees moresensitive to drought, make regenerationof some species like sugar maple andred oak difficult, lead to reduction in thediversity of native plants, and facilitateDo NOT release earthworms!Earthworms should be considered as a serious threat to nativeregeneration in the Mesic Hardwood Forest type. Earthworms arean unwelcome intruder in Minnesota’s hardwood forests.46


the invasion of undesirable plants likebuckthorn, tatarian honeysuckle, andgarlic mustard.Although it is not possible to reversethe continued migration of the earthworms,there are things people can do tohelp the forests recover:1. People have always been told worms aregood for the environment, so at the endof fishing vacations they dump the leftoverworms near the lake. Don’t do this.2. Replanting native plant species isanother way to help forests recoverfrom earthworm damage. Native plants,grown from locally harvested seeds, arenow available. Native woodland plantspecies are becoming available throughboth public and private sources.Hydrology and soil conditionsof Mesic HardwoodsHarvests of Mesic Hardwood ash forestsshould follow Minnesota Best ManagementPractices (BMPs) using eitherrelative dry or frozen conditions that willsupport harvesting equipment withoutrutting soils more than 6-inches deep fordistances of 100 feet or more. Managementon these sites can target a managementoutcome of early-succession forests(usually beginning with a clear cut and,dominantly, aspen regeneration) developinginto late-succession forests (withsugar maple, birch, balsam fir, basswood,white spruce, silver maple and ash) or theperpetuation of late-succession forests.GLOSSARYChapter 5The Native PlantCommunitiesMesic HardwoodSystemBest Management Practices:BMPs are practical guidelinesaimed at lessening non-pointsource pollution from forestmanagement activities, such asroad construction, skid trails,and log landings.Survey Recommendations: Mesic Hardwood ForestGap phase dynamics will dominate forest regeneration. Ash decline and death willhave limited impact on hydrology. One silviculture expert expressed concern aboutthe hydrologic impacts of harvesting due to rutting and compaction in stands withperched water tables.Ash should be harvested to minimize the impact of EAB in the Mesic Hardwoodforest. On quality sites continue to manage for quality ash. Two experts pointed outthat these sites are productive with high quality trees that are likely to have the mostvaluable ash which may also warrant their harvest and more management. Ashphloem reduction strategy is meant for EAB management not ash management, butit could be considered when managing these stands as one of many considerations.Earthworms and deer browse should be considered as serious threats to nativeregeneration in the Mesic Forest type.Recommended replacement trees (as ranked by the experts):Northern Mesic Hardwood Forest(11 of 29 species)• Basswood• White pine• Bur oak• Northern red oak• Sugar maple• American elm (DED resistant)• Big-toothed aspen• Quaking aspen• White spruce• Paper birch• White cedarSouthern Mesic Hardwood Forest(10 out of 29 species)• Northern red oak• White oak• American elm (DED resistant)• Bitternut hickory• Black cherry• Shagbark hickory• Black walnut• Bur oak• Sugar maple• Basswood47


Chapter 5The Native PlantCommunitiesForested RichPeatland SystemAsh in the ForestedRich Peatland SystemThe range(purple) ofForested RichPeatlands inMinnesota andthose that includeash (dots).Forested Rich Peatland (FP) forestsare dominated by conifers, tamarack,northern white cedar, black spruce,and balsam fir. They occur on organicsoils that are deep, actively formingpeat. Sphagnum moss is the principlepeat-forming plant, although the woodyremains of trees and shrubs contributesignificantly to peat volume. Peat formsbecause FP sites are continuously waterlogged.By comparison to the atmosphere,water offers very little of the oxygen thatis needed to decompose plant remains -thus the buildup of organic peat. Furthermore,Sphagnum moss depletes thegroundwater of its dissolved nutrients,leaving the site acidic and so poor thatthe site cannot sustain large populationsof decomposing microbes even thoughthere is a large supply of “food.” FP sitesare, in general, poor habitat for ash trees.Like many environments, ash seedlingsare fairly common, appearing in 31% ofall FP forests. But, the chances of growinginto a tree are slim – just 4% of FP forestsactually have ash trees and, when present,they account for only 4% of the trees.Achieving tree status probably occurs onmicrosites where the peat is thin enoughSurvey Recommendations: Forested Rich PeatlandsThere will be minimal effect on Forested Rich Peatland Systems because coniferswill continue to dominate these stands. Harvest when ground is frozen ordry; however, ash is too small a component of the forested rich peatland systemto manage for its replacement.Recommended replacement trees (as ranked by the experts):Forested Rich Peatland (north only): 10 out of 11 species• Black spruce• Tamarack• White cedar• Balsam fir• White spruce• American elm (DED resistant)• Paper birch• White pine• Quaking aspen• Red maple48


for ash roots to reach mineral soil. Nearlyall occurrence of ash on FP sites is blackash. Green ash is rare and white ashdoesn’t occur in the northern part of thestate where Minnesota has its peatlands.Diversity in FP forests is 40 species in400m 2 . Some rare plants and animals aredependent upon forested rich peatlandhabitat in Minnesota.Common Trees:• Tamarack• Northern white cedar• Black spruce• Balsam fir• Paper birch• Red maple• Black ashTall shrubs:• Rough alder• Bog birch• Red-osier dogwood• Alder-leaved buckthornHalf-shrubs:• Labrador tea• Creeping snowberry• Cranberries• Mountain fly honeysuckle• Red raspberry• Velvet-leaved blueberryFerns:• Marsh fern• Crested fern• Shield fernWildflowers:• Dwarf raspberry• False Solomon’s seal• Bunchberry• Naked miterwort• StarflowerPhoto: Joy Viola/Northeastern University, Bugwood.org• Goldthread• Canada mayflower• Cowslips• Twinflower• Tufted loosestrife• Sweet-scented bedstraw• Marsh cinquefoil• Water horehound• Red-stemmed aster• Marsh bellflower• Willow-herbs• Great water dockGrasses & Sedges:• Bluejoint• Fowl manna grass• Soft-leaved sedge• Bristle-stalked sedge• Three-fruited bog sedge• Interior sedge• Poor sedgeChapter 5The Native PlantCommunitiesForested RichPeatland SystemBunchberries areindicator plants of theForested Rich PeatlandSystem.49


Chapter 5The Native PlantCommunitiesFire-dependentSystemAsh in theFire-dependent SystemGLOSSARYhydrophobic: Having little orno affinity for water molecules.The range(red) of firedependentforests in Minnesotaand thosethat includeash (blackdots).Many forest types, like jack pinesavanna are fire-dependent. The onlyway to maintain these types on thelandscape is by reintroducing fire.Fire-dependent forest and woodlandcommunities (FD), as the name implies,are strongly influenced and shaped bywildfires. Fire is important because it isthe main source of mortality that selectsamong the species and causes the forest toregenerate. Fire is the principal means ofreleasing nutrients and reducing carbonstores. It does this in a way that is episodicand unpredictable when compared to systemsthat are adapted to annual cycles ofnutrient availability. Fire creates situationswhere nutrients are lost rather permanentlyfrom sites by leaching them belowthe rooting zone and by lateral transportto wetlands, lakes, or streams.FD communities occur on sites thatcannot retain very many nutrients ormuch water, and fires contribute furtherto this by producing hydrophobic (waterrepelling)compounds that end up in thesoil. The plants that live in these communitiesare obviously able to survive firesRed pine stand with ashin understory.Photo: Julie Miedtke50


and re-colonize a burned landscape.Ash is poorly adapted to fire and thenutrient-poor soils of FD sites. However,fire-suppression efforts have opened FDsites to modest invasion by ash. About 20%of all FD forests have ash regeneration,but just 3% have ash trees – meaning thatrecruitment is poor. When present, ashtrees account for about 8% of the trees onFD sites. Green ash is the most successfulspecies in FD forests, with regeneration in15% of the sites. As a tree, it occurs in 3%of FD forests and about 16% of the treesare ash when it is present. White and blackash occur in trace amounts on FD sites.Common trees:• Jack pine• Red pine• White pine• Quaking aspenShrubs:• American hazelnut• Poison ivy• Tall blackberry• Sand cherry• Wintergreen• Prairie willow• Wild rose• Juneberry• Grey dogwood• Snowberry• Pipsissewa• BearberryHerbaceous plants:• Common oak fern• Running clubmossChapter 5The Native PlantCommunitiesFire-dependentSystemSurvey Recommendations:Fire-dependent SystemThe effect of ash mortality due to EAB will be minimal in Fire-Dependent System.On quality sites continue to manage for quality ash. Gap phase dynamicswill dominate regeneration. In areas in close proximity to EAB do not assume anunlimited number of growing years for ash trees. Reduce the ashcomponent to less than 20%. Ash should be scattered throughout the standrather than having areas with high densities of ash. Prepare for replacement toinvasive species, for example buckthorn.Recommended replacement trees (as ranked by the experts):Northern Fire Dependent(10 out of 31 species)• Jack pine• White pine• Northern pin oak• Quaking aspen• Bur oak• Northern red oak• Paper birch• White oak• Big-toothed aspen• Red pineSouthern Fire Dependent(10 out of 31 species)• Northern red oak• Northern pin oak• Black oak• White oak• White pine• Bur oak• Shagbark hickory• Black cherry• Jack pine• Bigtoothed aspen51


Chapter 5The Native PlantCommunitiesFire-dependentSystem• Ground pine• Lady fernGrasses and Sedges:• Bluejoint grass• Big bluestem• Slender wheatgrass• Poverty grass• Fringed bromeWildflowers:• Sweet coltsfoot• Blue giant hyssop• Northern bedstraw• Hoary puccoon• Wild bergamot• Wood betony• Lead plant• Pale vetchling• Veiny pea• Pale bellwort• Starry false Solmon’s seal• Yarrow• Pussytoes• Spreading dogbane• Cow wheat• Bastard toadflax• Tall meadow rueBlack ash-conifer swamp locatedin Big Island Scientific and NaturalArea, Pelican Lake in St. LouisCounty.Photo: DNR/Kurt Rusterholz52


A general overview of ash species dominance in Minnesota’s forest systemsWet Forest system Floodplain ForestsystemMesic HardwoodsystemForested RichPeatland systemFire-DependentsystemMain tree speciesin systemAsh species andits dominanceCharacters thatshape thissystemGreen and black ash,northern white cedar.Sometimes balsamfir, American elm, redmaple.Ash and white cedardominate these sites. Allsites have ashregeneration and 75%have ash trees on them.In an average stand, ashcontributes 34% of thetrees.Found along margins oflakes, rivers and peatlands.Stands can alsooccur in shallow depressionswhere the watertable is high. Waterpeaks in the spring anddecreases in depththroughout the summer.This seasonal variabilityof water is the hallmarkof the wet forest system.Soils Soils are under wateror saturated during thegrowing season. Thislimits the oxygen andnutrient availability andthe rate of decomposition.So a mucky layer iscreated on the surface ofthe soils. Peat, if formed,only reaches a depth of10 to 40 inches.Shrubs and vines Rough alderMountain mapleBeaked hazelnutRed-osier dogwoodSwamp red currentVirginia creeperDwarf raspberrySilver maple, Americanelm, green ash, blackash, hackberry, basswood,boxelder, whiteash.Ash seedlings occur on95% of the sites. Ashtrees are found on 88%of the sites. Green ashaccounts for 16% of thetrees. Black ash, in thenorth, accounts for 21%of the trees.Regular inundation byspring floods. Commonlyfound on flatlands along streams andrivers. Tree stems androots must withstand alot of mechanical damage.Lots of nutrients aredeposited in soils witheach flood. Mucky layersdo not accumulateon the soil surface.Wild GrapeVirginia creeperCanada moonseedNote:Shrubs are generallyabsent from floodplainforests.Sugar maple and basswood,paper birch, quakingaspen, red oak, yellowbirch, white ash, greenash, black ash, ironwood,red maple.Ash is common. 66% ofsites have ash seedlings.Ash occurs as trees on25% of the sites. In anaverage stand, about 10%of the trees are ash; green,black and, rarely, whiteash which only occurs inthe southeastern counties.Wildfires are very infrequent.The limiting factoris sunlight because thecanopy is continuous,dense, and multi-layered.Soils are able to retain waterso many tree speciescan grow there. Nutrientsare rapidly recycled.Beaked hazelnutMountain mapleChokecherryPagoda dogwoodPrickly gooseberryDowny arrowwoodJuneberryFly honeysuckleLowland conifer dominated;tamarack, northernwhite cedar, black spruce,balsam fir, paper birch, redmaple and black ash common,but considered to be‘misplaced’ or ‘off site’.Poor habitat for ash. Itspresence is likely where ashroots can reach the mineralsoil. Seedlings are commonbut only 4% make it to treesize.Occur on deep and activelyforming peat. Sphagnummoss is most common peatformer.Deep peat soils. Soils arecontinuously water-loggedso they are acidic, havelow oxygen and are poor innutrients.Rough alderBog birchRed-osier dogwoodCranberryLabrador teaCreeping snowberryMountain flyHoneysuckleAlder-leaved buckthornPredominately upland conifers.Jack, red, and whitepines, quaking aspen, paperbirch, white spruce, bur oak,northern pin oak, northernred oak, bigtooth aspen, redmaple. Some balsam fir.Historically, ash was veryinfrequent. With fire-suppressionin the last century,ash has an increased itspresence. Primarily greenash. 20% of sites have ashseedlings but only 3% haveash trees.Wildfires kill trees, set conditionsfor regeneration,episodic release of nutrientsover decades of time.Dry soils that are nutrientpoor due to a long history ofwildfires. Nutrients also lostthrough leaching down intothe soil.American hazelnutPoison ivyTall blackberrySand cherryWintergreenPrairie willowWild roseJuneberriesGrey dogwoodSnowberryFerns and related Lady fern Ostrich fern Lady fern Marsh fern Lady fernThis is your field copy – take it with you into the woods and ID your ash system.


Chapter 6WildlifeAmong the AshGLOSSARYcavities: Holes in treessometimes used for nestingand reproduction by wildlifespecies, most frequently birdsor small mammals.Ash stands and ash trees are usedby a variety of wildlife speciesincluding large and small mammals,birds, reptiles, and amphibians.When ash stands and trees are older, theyprovide value as feeding sites for woodpeckers,nuthatches, and chickadees.Cavities in these same trees, whenfound near permanent wetlands, are alsoused by several species of waterfowl includingwood ducks, hooded mergansers,and goldeneyes.In northern Minnesota, large cavitiesmay also be used by fisher as den sites.Several species of birds use ash standsas nesting sites including great blue andgreen herons, and Cerulean warbler.Birds, however, tend to be linked to habitattype not tree species so while birdsmay be temporarily impacted by the lossof ash, they are likely to adapt and moveto other trees in the surrounding area. Asyounger trees or stands, ash is an importantsource of food for white tailed deerand moose. Forest landowners shouldmanage for a variety of age classes whenmanaging their ash resource becauseof the various values those resourcesprovide in different age classes or growthstages.For more informationon rare species on yourproperty, see AppendixC, on page 65.Moose are onemammal speciesfound in ashsystemsPhoto: Douglas Brown54


Survey Recommendations: WildlifeUntil snags fall due to ash mortality aerial predation may increase on some birds.One wildlife expert pointed out, “This will be dependent on the density and ageof other components in the stand.” Secondary insects and diseases on ash willincrease after EAB arrives in a stand. According to one entomologist “secondaryinsects will not play a significant role in increasing ash mortality; however,once these trees die, the wood boring insects and decay fungi will increase foodfor foraging wildlife. These dead trees may provide some opportunity for cavitynesters but experience from Michigan has shown that dead trees fall downquickly.” In the short term, more snags will result from tree mortality. Temporarilydowned woody material will increase salamander habitat. Woodpecker numberswill increase. One entomologist pointed out, “I get the impression that woodpeckersare not food limited - which also limits their effectiveness in controlling EABnumbers. When there are 300 EAB in a stand and the woodpeckers eat 200 itis great, but when there are 3000 EAB and the woodpeckers eat 200, it doesn’thelp much.” In the short term cavity nesting birds will increase but several expertspointed out these trees aren’t likely to remain standing for very long.Chapter 6Wildlife Amongthe AshPlant and animal speciesdesignated as “Rare, Threatened,and/or Endangered”may be found in any of theash systems discussed in thisGuide. If you wish to look upthese species, refer toAppendix C: “RareSpecies Guide,” page 65.After ash mortality, cowbird predation will increase in open canopy forests;however, two experts observed that cowbirds are typically more problematic infragmented landscapes rather than solid forest blocks. Neo-tropical song birdmigration stop-overs would be impacted. According to one ecologist this may bea problem “to a small extent in some stands with high ash dominance in the northor possibly to a large extent in certain river floodplains in the south where an ashstand might be the only forest in an agriculture dominated landscape.”Another wildlife export pointed out it’s not clear how ash motility may impact birdmigration routes. Beaver may increase after ash replacement has begun. Ashflower gall may decline. One final note from a forest ecologist, “A lot of uniquemicrohabitat structures are present and stands are very important for biodiversity(amphibians, plants). Particularly if invasive plants take over, then the habitat willnot support as many wildlife species and native plants.”HoodedmerganserPhoto: Darek Bakken55


Chapter 7Other Implicationsof EAB andAsh TreesFLegal & Financialalling dead trees may injurepeople or damage vehiclesand equipment, so cut downhazardous trees along trails and roads.Such actions will reduce the chances of anaccident occurring which may result in alawsuit that seeks a damage payment.The loss of trees killed by EAB doesnot constitute a casualty loss reportableon income tax returns. A casualty lossmust be sudden and unexpected, but infestedash trees may live for several yearsand their death is expected.If you are managing your woodlandas a business or investment, then you mayhave inventoried your timber near thetime it was acquired and set up a timbercapital account showing the timber volumeand the cost you incurred to acquireit. When trees are killed by EAB, yourvolume is reduced, but your cost basis fortimber will remain the same.Your depletion unit will rise, however,since you have a lower volume over whichto spread your cost basis. A depletionunit is the cost per unit of timber (cordsor 1000 board feet) that you incurred toproduce your timber. When you sell timber,you can deduct a depletion allowancefor the volume sold.Ash log withEAB larval galleriesPhoto: MN Dept. of Agriculture/Mark Abrahamson56


Chapter 7Other Implicationsof EAB and Ash TreesThe result of anemerald ash borerinvasionPhoto: Di BedardWildfire, EAB, and AshThe Emerald Ash Borer’s Effectson Wildfire PotentialAsh mortality may result in increasedpotential for wildfire during the earlyspring and late fall months when theherbaceous vegetation is dry. Ash speciesare generally associated with vegetationcommunities that are considered to befire resistant except during periods ofextended drought. Therefore, in those areaswhere ash grows in association withother tree species, such as in northernhardwood stands or in mixed balm ofGilead/white cedar/red maple lowlandsthere will be little noticeable change infire potential when the EAB invades foreststands and kills ash trees.Standing snag trees will lose theirbark and shed branches within a fewyears, minimizing fire hazard. Coarsewoody debris will decompose quicklyand become punky (soft and crumbly),keeping fuel moisture at levels too highto support efficient combustion. Othertree species will quickly fill in the gapsleft where ash once grew, as was the casewhen the American elm component waslost in these stands 30 to 40 years ago.The situation could be different in purelowland black ash stands where typicallya brush understory is lacking and grassesand sedges dominate the herbaceouslayer. Since these ash types are considereda climax community, recruitmentof other potential overstory species maybe delayed. The existing herbaceous layerwill respond to increased sunlight andwill likely increase in density and mass.Wind exposure will also increase as theoverstory declines.GLOSSARYsnag: A standing, generally unmerchantabledead tree fromwhich the leaves and most ofthe branches have fallen.punky: Soft, crumblydecayed wood that hasbeen attacked by fungus,sometimes used as tinder.57


Chapter 7Other Implicationsof EAB and Ash TreesEpicormicbranchingDefects in ash treesThere are as many ways for trees tofail as there are trees. An ice storm canoverload all the branches on a tree, ablustery wind can blow down a tree if itsroots are restricted or a cracked tree canfail just under its own weight.Trees are designed to easily withstandthe normal windstorms and winterstorms that occur, yet we have all seentrees that have failed. Trees fail when theload (weight and motion of the crown)exceeds the mechanical strength of theirbranches, stems or root systems. This istrue for both sound and defective trees,Photo: Ed Czerwinskibut defective trees can only withstand afraction of the load that sound trees canwithstand. Defective trees fail soonerthan sound trees.A sound tree becomes potentiallydangerous when the tree’s woody structureis weakened by one or more defects.Most defects can be linked to pastwounding and decay, pest infestations,severe storms, or to growing conditionsthat limited the root system. Sincedefects, the old injury sites and nearbywood, are structurally weaker thanuninjured wood, the tree is predisposedto fail at the location of the defects.Defective trees can be found growinganywhere. Management of a defectivetree is at the landowner’s discretion. It issuggested that if defective trees or deadtrees could fall onto structures, yards,fences, driveways or recreational trails,a landowner might consider removingthem. On the positive side, defective andfallen trees provide wildlife habitat andother important ecological services. Asa species group, ash are susceptible totwo main defects; root system failureand branch failure. In many soil types,ash root systems are quite shallow,making the trees prone to windthrow.Commonly the entire tree and much ofits root system tip over during strongwinds, especially in exposed locations.Branches are likely to fail at the junctionof the branch and the stem due to thepresence of bark growing inside the treeand/or the presence of serious decay inthe same location. Branch failure is moreprevalent in large diameter trees.For information on where to find the full resourceon defects in ash trees see Appendix D, page 66.58


Windthrow MortalityAll hardwood forests in their latesuccessionstages (older ages) can beperpetuated where a closed canopy ismaintained over decades. Regenerationis by seedling release in canopy gaps(chronic windthrow), or by thinningoverstocked stands. Thinning removestrees to where remaining tree canopiesoccupy 50 to 80% of the land area. Forprotection against excessive windthrowand provision of favorable riparian andstream attributes, thinning down to acanopy closure of 80% is recommended.Exposure of stands along long edgeswill greatly increase the likelihood ofexcessive windthrow. Studies of strip cutforests in Minnesota show the balancebetween stand growth and tree mortalityis a function of the total stand edgeand the height of the trees. Along streamcorridors the stream produces one standedge and cutting of forests landward ofa forest next to the stream produces asecond edge. Maintaining continuouscanopystands along the stream or riverat least 125 feet wide will ensure that normalwindthrow mortality will not exceedstand growth over time. A wider standwill maximize stand growth. Many riparianforests in the Lake States have poorstocking (low canopy closure and notenough trees); though studies of the causeof this poor stocking are needed, excessivewind mortality is a prime candidate.Chapter 7Other Implicationsof EAB and Ash TreesGLOSSARYwindthrow: A tree uprootedor broken by wind; also called“blowdown”.Blowdown in theBoundary Waters CanoeArea Wilderness, 1999Photo: Eli Sagor59


AppendicesAppendix AGuidelines for managing sites with ashto address the threat of emerald ash boreron DNR Forestry-administered landsBACKGROUNDThe ash genus (Fraxinus) in Minnesota comprises some900 million trees and is the second most common hardwoodtree genus in the state. EAB was discovered in the United Statesin 2002 and is now present in 13 states and 2 Canadian Provinces.It was found in Minnesota in 2009. EAB populations canspread rapidly in infested firewood, logs, and ash nursery stock.Therefore, it is assumed that EAB will soon infest Minnesota’sforested areas and cause significant impact to the ash resource.Experience from other states has shown that EAB kills 99+% ofthe ash in a stand once that stand becomes infested. This levelof impact is greater than what occurred with American elm followingthe introduction of Dutch elm disease to Minnesota.To date there has been no evidence of resistance to EABwithin any North American ash species. Resistance does existin some Asian ash species. Subtle differences in susceptibility toEAB between white, green, and black ash have been reported,but those differences are minor and should not influence managementoptions. All three ash species in Minnesota will likelysuccumb to EAB attack.SCOPEThis document applies to:• Forested stands classified as ash covertype• Forested stands with an ash component of at least 20% ofstand basal area but not typed as an ash covertype. Nativeplant communities where ash is and can be significantinclude: FDw44, MHs49, MHw36, MHc47, MHn46, FFs58,FFs59, FFn57, FFn67, WFs57, WFw54, WFn53, WFn55,WFn64.• Forested stands with ash that are free of EAB occurrenceand are greater than 25 miles from the closest known EABinfestation. This distance will allow multiple entries into astand based on an average, “natural” movement of EAB of~2 miles per year.ASH MANAGEMENT OBJECTIVES• Landscape perspective: Manage ash populations in thelandscape to protect sensitive wetland ecotypes, reduceoutbreak costs, and restrict emerald ash borer introductionand spread without eliminating ash within forest ecosystems.• Stand perspective: Create conditions that will reducepotential impacts and increase the resiliency of forestedstands by• Keeping forested sites forested• Maintaining an ash component but reducing the size andnumber of ash in the stand.• Increasing tree species diversity.• Management objectives should focus on ecosystem healthand management, not on the emerald ash borer. The intentis to limit habitat attractiveness to EAB.• The Division of Forestry will work within its nurseryprogram and with other partners for maintainingrepresentative samples of genotypes but not for processingseeds for reforestation.CAVEATS• There is a likelihood that the vast majority of ash trees inMinnesota will be killed by EAB regardless of the type ormagnitude of actions taken.• The large extent of the ash resource, particularly black ash,will likely mean that sufficient management actions will notoccur in all stands prior to EAB becoming established inMinnesota. Forested sites will be altered or lost.• Little is known through research and experience how tomaintain black ash forested sites as forested communitiesonce the black ash is killed or removed. On-going researchand knowledge gained through experience that can bepassed along to all managers will be critical to meeting longterm ash management objectives. Therefore, this documentpresents interim guidance that will change as knowledgefrom research and experience is gained.Managing forested stands with ash• INTERIM DIRECTIVE FOR ALL STANDS WITH ASHThe current scientific evidence does not support investmentsin artificial regeneration of ash species or managementpractices implemented to expand or regenerate ashpopulations. These activities could also compromise efforts toprotect sensitive wetland ecosystems through canopydiversification, reduce forest vulnerability and potentiallycompromise EAB response efforts.• Ash species should not be planted on DNR administeredlands for ornamental, shade or reforestation purposes. Inimplementing forest management practices do not structureoperations to intentionally favor the regeneration orreestablishment of ash.• Rationale: In order to avoid perpetuating habitat for EABfor future generations, the current objective is to diversify ashdominated plant communities now and into the near future.• Actions• Do NOT plant ash seedlings on state administered lands orrecommend ash seedlings for reforestation on private lands.• Do NOT use ash seed in the mix for direct seeding on stateadministered lands or recommend ash seeds for direct seedingon private lands.60


• Create conditions favorable for regeneration of non-ash treespecies. Ash regeneration can be aggressive, particularly fromstump sprouting; chemical application may be necessary toreduce ash on some sites.• Prioritize opportunities to implement management practicesin stands with ash immediately irrespective of EAB outbreaks.• Rationale: Given the magnitude of the ash resource inMinnesota today, forest managers must make ash managementa higher priority. The proximity of EAB and the uncertainty ofknowing where EAB is currently infesting ash necessitatetaking immediate actions to ameliorate some of the negativeconsequences that have been documented in other states.• Actions• Ash stands on the annual stand exam list should be scheduledfor a management action that addresses the objectives above.Do not defer stands with ash for a later action. Scheduletreatment as soon as possible.• Work with the department’s planning groups to revise SFRMPobjectives and stand selection criteria to address the objectiveslisted above.• GUIDELINES FOR ALL STANDS WITH ASH• Reduce the stocking and average diameter of the ash component• Rationale: Ash phloem is the larval food source for EAB. Morephloem can support greater populations of EAB within anygiven area. The larger the tree, the greater potential to supporthigher EAB populations. Reducing the ash component mayreduce future impacts and may help slow the spread of EAB.• Actions• Reduce the ash component to no more than 20% of currentstand basal area.• Focus on reducing the average diameter of the residual ashcomponent. Focusing on reducing larger trees will be moreeffective than removing only poles and saplings. However, ifscattered larger diameter trees are left to meet leave treeguidelines or wildlife considerations, remove a largerproportion of smaller diameter ash so that the overallaverage diameter of the residual ash is reduced from theaverage ash diameter before treatment.• Leave other species as residuals during harvesting orregenerate other, non-ash species to maintain a forested cover.• Use intermediate stand treatments that focus on a dominantthinning technique where larger trees are selected to be cut toreduce the size and amount of ash.• Intermediate stand treatments are often precommercial. Thecut material can be left on the forest floor if biomassopportunities are limited or non-existent. EAB will not utilizedead ash trees as host material. Leaving uninfested stems onthe forest floor will not create EAB habitat.• Multiple entries may be necessary. When non-ash reproductionis at least 2 - 3 feet in height, consider another ash reductiontreatment.• Reduce the concentration of ash.• Rationale: A dispersed ash component can lessen the impactsto the stand by reducing the likelihood of EAB killing largeareas of ash which may or may not have an understory of othertree species. Work to create and maintain scattered ashthroughout the stand rather than maintaining pure or nearlypure ash areas within the stand.• Actions• In homogeneous ash areas, focus on thinning dominant andcodominant trees where all ash above a prescribed diameterlimit are cut resulting in a reduction in the size and number ofash in the stand. See basal area and diameter guidance above.• Use scattered ash in the stand to meet the basal area goalabove rather than relying on pure ash areas to meet this goal.• Transition sites to a composition that favors non-ash species• Rationale: Despite all management efforts, currentexperience seems to indicate that EAB will kill 99% of theash in the stand regardless of ash tree size and spatialoccurrence within the stand. The ultimate strategy must beto move stands away from ash and maintain the forestcommunity by depending on other species.• Actions• Use the native plant community field guides to determinethe growth stage and refer to Silviculture Interpretation,Table PLS-2, Abundance of trees throughout succession toidentify favorable ingressing species. The DNR web sitefor ECS information is: http://www.dnr.state.mn.us/forestry/ecs_silv/interpretations.html• Consider the regeneration strategies (tolerance) of non-ashtree species already on the site.• If non-ash species are few or nonexistent, consider artificialregeneration. Try aerial seeding non-ash species as well asunderplanting non-ash species even in the absence of anyother kinds of stand treatment.• Consider creating canopy gaps through hand felling orgirdling to provide light conditions more suitable for theestablishment of underplanted or seeded non-ash species.However, openings greater than 60 feet in diameter mayencourage ash regeneration.• Use the NPC tree table, Silviculture Interpretation Table R-1,Suitability ratings of trees, to select non-ash species bestadapted to the site.• ADDITIONAL GUIDELINES FOR BLACK ASH• Protect the hydrologic functions of the site to maintain atree cover.• Rationale: The guiding principle for all black ashmanagement decisions is to protect the hydrology of thesite. Black ash, because of its abundance on some sites,often controls water levels in the stand. If the black ash iscut or dies off, water levels often increase and there is achance sites will convert to wet meadows or becomedominated by alder. The greatest concerns are black ashcommunities classified in the wet forest system (WF).• Actions• Use the Native Plant Community information along withstand site index to help guide management decisions. Thegreater the site index, the more flexibility in applying amanagement treatment that will not cause long-termalteration of the site.• General site index guidance:• SI =


seeding of non-ash species.• SI = >55: Consider management for timber with thecautions listed below for specific NPCs. Ash reduction,salvaging, and regeneration by planting, underplanting, anddirect seeding to non–ash species may be appropriate. Usethe NPC tree table, Silviculture Interpretation Table R-1,Suitability ratings of trees, to select non-ash species bestadapted to the site.• When working in black ash stands, always monitortreatment results and apply lessons learned to future blackash management opportunities.• PRECAUTIONS FOR SPECIFIC NATIVE PLANTCOMMUNITIES AT RISKThe following communities are at risk for hydrologic damage ifthe tree cover is significantly altered. Generally, managementactions should be lightly applied, and follow up monitoring ismandatory.WFn55 – Northern Wet Ash Swamp• When there is substantial aspen or balm of Gilead (bam)in the stand, use partial harvesting techniques such as2-step shelterwood and strip clearcut, or use dominantthinning when the stand is not merchantable. Suckeringaspen and bam will help avoid swamping the site.• When substantial aspen or bam is lacking:• Stands with a site index of 55 or greater, partial harvestingand dominant thinning are possible. However, extreme careshould be taken by removing not more than 50% of thebasal area at one time.• Stands with a site index under 55, avoid harvesting andintermediate stand treatment but consider establishingnon-ash species.• Underplant or aerial seed appropriate species listed in theNPC tree tables, Silviculture Interpretation Table R-1,Suitability ratings of trees, to select species alternates toash. Browse protection will be necessary.• In the absence of any harvesting or intermediate standtreatments, consider hand felling or girdling to create gapsfor the establishment of non-ash species.WFn64 – Northern Very Wet Ash Swamp• Avoid harvesting or intermediate stand treatments.• In lieu of any harvesting, consider underplanting or aerialseeding appropriate species listed in the NPC tree tables,Silviculture Interpretation Table R-1, Suitability ratings oftrees, to select species alternates to ash. Browse protectionwill be necessary.• Consider creating small gaps by hand felling or girdlingwhen underplanting and seeding.WFs57 – Southern Wet Ash Swamp• This is a rare community often found near springs, mostlyin rugged topography of the Blufflands Subsection andalong the tributaries of the Minnesota and St. Croix rivers.• Avoid any harvesting or intermediate treatments in orimmediately adjacent to these communities. Allow othertree species to naturally seed or develop in the understory.62


Appendix BQuestions & Answers about Quarantinesand Compliance AgreementsQ1. What is a quarantine?A1. A quarantine is a temporary rule intended to help preventa potentially dangerous or destructive pest or diseaseorganism from spreading outside a known infested areainto new areas. In the case of emerald ash borer (EAB), thequarantine is designed to limit the movement of potentiallyinfested firewood or other materials such as live ash treesthat might harbor EAB larvae.Q2. As of November 2009, what areas of Minnesota arecurrently quarantined for emerald ash borer?A2. As of October 2009, the EAB quarantine in Minnesotaconsisted of the counties of Ramsey, Hennepin and Houston.See the most current EAB quarantine in Minnesota.(www.mda.state.mn.us/en/plants/pestmanagement/eab/eabquarantine.aspx)Q3. What are regulated articles?A3. The following are three categories of regulated articles:• The emerald ash borer (Agrilus planipennis),• Ash trees (Fraxinus sp.), ash limbs and branches, ashstumps and roots, ash logs, ash lumber, ash chips andash bark chips, and• Firewood of any hardwood (deciduous) species.Q4. What is the definition of firewood?A4. Firewood means wood that is cut to lengths less thanfour feet long. This includes firewood cut for personal use.Q5. What is a Compliance Agreement?A5. A Compliance Agreement is a document that describeshow a company will properly treat regulated articles to mitigatethe spread of EAB and adhere to the quarantine law.A MDA representative is available to discuss ComplianceAgreements in more detail at the request of any businessor other entity involved in moving regulated articles. MDAcan provide free training on EAB and also help determinehow any business can lower the risk of spreading EAB withthe least amount of disruption to business practices.Q6. Do I need a Compliance Agreement?A6. If you are moving regulated articles (e.g., ash materialor hardwood firewood) out of a quarantine area youwill need a Compliance Agreement. Ash material thatoriginates from a non-quarantine county and transits thequarantine may require a Compliance Agreement, and it isrecommended you contact MDA for further information.Q7. How do I get a Compliance Agreement?A7. You can contact the Arrest the Pest Hotline at 651-201-6684 in the Twin Cities or 888-545-6684 in greaterMinnesota, or e-mail us at arrest.the.pest@state.mn.usand say you are interested in a Compliance Agreement foremerald ash borer. An MDA official will work with youto determine which Compliance Agreements, if any, areneeded, explain the requirements, and work with you toimplement any needed quarantine restrictions.Q8. Why is all hardwood firewood regulated instead ofonly ash firewood?A8. Once a log has been cut and split, it is extremely difficultto identify ash wood from other hardwood species.While this is especially true for the casual firewood userand homeowners, the experience of other EAB regulatoryagencies across the nation have shown that the same hasoften applied to firewood businesses, too. Therefore, dueto the potential risk associated with moving EAB-infestedfirewood, all hardwood firewood is regulated. There areno EAB quarantine restrictions on coniferous species offirewood, such as pine, spruce and fir.Q9. Does the quarantine affect movement of hardwood(non-ash) nursery stock or hardwood (non-ash) woodproducts?A9. In regards to EAB there are no restrictions on theintrastate movement of non-ash hardwood products suchas nursery stock, logs, branches, green lumber or chips inMinnesota. However, the movement of all hardwood firewoodout of quarantined counties is regulated.Q10. Does the quarantine affect the movement ofmaterial within the quarantine areas?A10. There are guidelines or best management practicesfor working with ash in known infested areas (PDF).There are no legal restrictions for the movement of regulatedmaterials within the quarantine.Q11. What can I do with my ash material from aquarantined county?63


A11. There are multiple options available:• Ash material can be brought to a disposal site withinthe quarantine. Download a list of known tree wastedisposal sites (PDF).• Material can be utilized within the quarantine for anylegal purpose.**If removing ash material or other regulated articles fromthe quarantine, the following options may be used but requirea Compliance Agreement with MDA and / or USDA.We advise that this Compliance Agreement be in placebefore beginning processing operations. **• Material can be chipped to 1 inch or less in twodimensions (two of three measurements-length, widthand thickness-must be 1” or smaller).• Material can be debarked, which means complete barkremoval plus ½ inch of wood.• Material can be composted; material must reach atleast 140 degrees Fahrenheit for four days and the pilemust be turned after four days.• Material can be heat treated; the center of the wood mustreach at least 160 degrees Fahrenheit for 75 minutes.• Material can be kiln dried; must meet USDA guidelines.• Material can be fumigated by a licensed fumigator.• Material can be transported to an approved facilityduring the period of September 1 to April 30.Q12. If I sign a Compliance Agreement, will I berequired to keep records?A12. Yes. If your company ships regulated articles undera compliance agreement or with MDA certification, youwill need to maintain those shipping and/or certificationrecords for 36 months, unless otherwise specified.Q13. Do I have to keep records of shipments or treatmentsthat do not involve regulated articles?A13. MDA does not require records for treatment or shipmentof non- regulated articles.Q14. Can I bring firewood from a non-quarantined areainto a quarantined area?A14. There are no legal restrictions on firewood that originatesfrom a non-quarantined county. At this time onlyRamsey, Hennepin and Houston counties in Minnesota arequarantined. Firewood is allowed to come into those countiesfrom a non-quarantined county. Once the firewood entersinto a quarantined area, it becomes a regulated article.Q15. If I have further questions about EAB or complianceagreements, or if I think I have found EAB, who doI contact?A15. The Arrest the Pest Hotline is available for a widevariety of questions related to emerald ash borer. Contactus at the Arrest The Pest Hotline at 651-201-6684 (MetroArea), 888-545-6684 (Greater Minnesota), or arrest.the.pest@state.mn.us.Credit to: Minnesota Department of Agriculture64


Appendix CMinnesota Department of Natural ResourcesRare Species GuideYou may search for rare plant, mammal, reptile, bird, and amphibian species potentially found in the Wet Forest, FloodplainForest, Mesic Hardwood, Forested Rich Peatland, and/or Fire Dependent system plant communities by going tothe Minnesota of Department of Natural Resources Rare Species Guide. http://www.dnr.state.mn.us/rsg/index.htmlA “Filtered Search” allows you to search for rare species by habitat. You can choose to limit your search results by:• species groups (e.g., just plants);• status (endangered, threatened, special concern);• county;• Ecosystem Classification Subsection; and/or• watershed.Once you generate your species list, click on individual names to link to species’ profiles. Profiles includes photographs,range maps, phenology information, and text.Shown is the result of a sample search for rare, threatened and/or endangered mammals and vascular plants in theWet Forest System.65


Appendix DReferences and ResourcesPage 5EAB and Chestnut BlightR. Hauer (Personal communication 1-21-11)Kashian, D.M. & Witter, J.A. (2010). Assessing the potential for ash canopy tree replacement via current regenerationfollowing emerald ash borer caused mortality on southeastern Michigan landscapes. Forest Ecology andManagement, 261, 480-488.McCullough, D. (2008). Putting the pieces together: Can we solve the emerald ash borer management puzzle?Proceedings 19th U.S. Department of Agriculture Interagency Research Forum on Invasive Species 2008.Retrieved February 10, 2010 from www. nrs.fs.fed.us/pubs/gtr/gtr_nrs-p-36.pdfSiegert, N., McCullough, D., Liebhold, A., & Telewski, F. (2008). Reconstruction of the establishment and spread ofemerald ash borer through dendrochronological analysis. Proceedings 19th U.S. Department of Agricultureinteragency research forum on invasive species 2008. Retrieved February 10, 2010 from www.nrs.fs.fed.us/pubs/ gtr/gtr_nrs-p-36.pdfSiegert, N., McCullough, D., Liebhold A., & Telewski, F. (2010). Resurrected from the ashes: Reconstruction of theestablishment and spread of emerald ash borer. Proceedings of the Continental Dialogue on Non-NativeForest Insects and Diseases Meeting.Tainter, F.H., & Baker, F.A. (1996). Principles of Forest Pathology. New York: John Wiley & Sons, Inc.Page 10-13Minnesota Ash Species IdentificationSmith, Welby R. Trees and Shrubs of Minnesota (2008). University of Minnesota Press.Rathke, David M. Minnesota Trees (2001). University of Minnesota Extension Service.Page 22Cultural SignificanceFurther Reading:Weaving a Story. (2009, August 20). Article posted to http://www.oneidaindiannation.com/culture/53831632.htmlWilsey, D. (2011, May 26). EAB a Different Perspective. Article posted to http://www.myminnesotawoods.umn.edu/2010/03/3767/Page 35Emerald Ash Borer or DiebackPalik, B., Ostry, M., Venette, R., & Adbela, A. (2011). Fraxinus nigra (black ash) dieback in Minnesota: Regionalvariation and potential contributing factors. Forest Ecology and Management, 261, 128-135.Page 58Defects in Ash TreesUS Forest Service Northeastern Area. (1992). Urban Tree Risk Management. (Publication No. NA-TP-03-03). St. Paul,MN. Retrieved May 26, 2011 from http://www.na.fs.fed.us/spfo/pubs/uf/utrmm/urban_tree_risk_mgmnt.pdf66


GLOSSARYabiotic: Nonliving parts of an ecosystem, such as soil particles,bedrock, air, water. See “biotic.”adventitious: Pertaining to a plant part that developsoutside the usual order position or tissue — e.g., an adventitiousbud arises from any part of a stem, leaf, or root butlacks vascular connection with the pith; an ad- ventitiousroot arises from parts of the plant other than a preexistingroot, e.g., from a stem or leaf.anoxia: Meaning lack of oxygen.Best Management Practices: BMPs are practical guidelinesaimed at lessening non-point source pollution fromforest management activities such as road construction,skid trails and log landings.biomass: Harvesting the wood product obtained (usually)from in-woods chipping of all or some portion of treesincluding limbs, tops, and unmerchantable stems, usuallyfor energy production.biotic: Pertaining to living organisms and their ecologicaland physiological relations.bole: The trunk or main stem of a tree.BTU: British Thermal Unit, is a basic measure of thermal(heat) energy. One BTU is the amount of energy needed toheat one pound of water one degree Fahrenheit.burl: An abnormal growth of woody tissue protrudingoutward from a tree stem or trunk.calcareous: An adjective used in a wide variety of scientificdisciplines, referring to the deposit of calciumcarbonate or lime. In some cases it may refer to a layer ofsediment or sedimentary rock, a limestone deposit. Calcareoussoils are relatively alkaline, in other words theyhave a high pH. This is because of the very weak acidity ofcarbonic acid. Note that this is not the only reason for ahigh soil pH.canopy: The foliage cover in a forest stand consisting ofone or several layers.cavity: Holes in trees sometimes used for nesting andreproduction by wildlife species, most frequently birds orsmall mammals.character wood: Wood prized by artists or craftsmanbecause of its unique or distinctive grain patterns or form.Examples of character wood include burls, crotch wood.co-dominant: Defines trees with crowns forming the generallevel of the main canopy in even-aged groups of trees,receiving full light from above and comparatively littlelight from the sides.conifer: A cone-bearing tree (e.g. pines, firs, spruce, cedars,redwoods, larches etc.).crown dieback: Decline of the branches and limbs in thecanopy of a tree sometimes used as an indicator of treehealth.deciduous: Perennial plants that are normally more orless leafless for some time during the year.diameter at breast height (dbh): The diameter of thestem of a tree measured at breast height (4.5 ft or 1.37 m)from the ground. On sloping ground the measure is takenfrom the uphill side.dieback/decline: The progressive dying from the extremityof any part of a tree.dominant trees: An individual or species of the upperlayer of the canopy.duff: The partially decomposed organic material of theforest floor beneath the litter of freshly fallen twigs,needles, and leaves.early succession: The process by which one plant communityis gradually replaced by another plant community.This may happen ‘early’ in the process or ‘late;’ thus theterms “early succession” and “late succession” are used todescribe this process.ephemerals: Ephemeral plants are marked by short lifecycles, usually 6-8 weeks. Ephemeral means transitory orquickly fading.epicormic branching: A shoot arising spontaneously froman adventitious or dormant bud on the stem or branch ofa woody plant often following exposure to increased lightlevels or fire.floodplain: The level or nearly level land with alluvialsoils on either or both sides of a stream or river that is subjectto overflow flooding during periods of high water.hydrology: The study of the movement, distribution, andquality of water on Earth and other planets, includingthe hydrologic cycle, water resources and environmentalwatershed sustainability.hydrophobic: Having little or no affinity for water molecules.67


incised streams: Slopes along a creek, stream or river areeroded in a downward fashion.leaf flush: The time in the season during which leaves appearon a tree.mesic: Sites or habitats characterized by intermediatemoisture conditions.microsite: A small part of an ecosystem that differs markedlyfrom its immediate surroundings.monotypic: Referring to conservation biology and successionalchanges leading to a single species.morphology: The external and internal form and structureof whole plants, organs, tissues, or cells.native plant community: A group of native plants thatinteract with each other and with their environment inways not greatly altered by modern human activity or byintroduced organisms. These groups of native plant speciesform recognizable units, such as oak savannas, pine forests,or marshes that tend to repeat over space and time. Nativeplant communities are classified and described by consideringvegetation, hydrology, landforms, soils, and naturaldisturbance regimes.oriented strand board: Also known as OSB or waferboard,is an engineered wood product formed by layeringstrands (flakes) of wood in specific orientations.paleoscientist: Scientists who study organisms of the past.peat/peatlands: Organic soil material that originatesfrom plants.phloem: A layer of cells just inside the bark of plants thatconducts food from the leaves to the stem and roots.punky: Soft, crumbly decayed wood that has been attackedby fungus, sometimes used as tinder.pure stands: Forest, crop, or stand composed principallyof one species, conventionally at least 80 percent based onnumbers, basal areas, or volume.quarantine: A temporary rule intended to help preventa potentially dangerous or destructive pest or disease organismfrom spreading outside a known infested area. Inthe case of the emerald ash borer (EAB), quarantines aredesigned to limit the movement of potentially infested firewoodor other materials such as live ash trees that mightharbor EAB larvae.riverine: All wetlands and deep water habitats containedwithin a natural or artificial channel that periodically orcontinuously contains moving water, or that forms a linkbetween two bodies of standing water.select harvest: A cutting that removes only a portion oftrees in a stand.serpentine trails: Trails that wind and twist, like a snake.shade tolerant: Having the capacity to compete for survivalunder shaded conditions.snag: A standing, generally unmerchantable dead treefrom which the leaves and most of the branches have fallen.sprouts: Shoots arising from the base or sides of a woodyplant.windthrow: A tree or trees felled or broken off by wind.Also called “blowdown.”68

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