Ash Management Guide for Private Forest Landowners

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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 =
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We gratefully acknowledge Melvin Ba
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Table of ContentsChapter 1A History
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The Delphi Survey ProcessThe Univer
Page 9:
The Emerald Ash Borer & Chestnut Bl
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Chapter 1A History of Minnesota’s
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Chapter 2MinnesotaAsh SpeciesIdenti
Page 16 and 17: How to tell an ash from an ashIdent
Page 19 and 20: Chapter 3Ash: A 21stCentury Resourc
Page 21 and 22: Ash wood has been gathered and shap
Page 23 and 24: igger, then ash is not the first ch
Page 25 and 26: Photo by Pennsylvania Department of
Page 27 and 28: Chapter 4The EmeraldAsh BorerA litt
Page 29 and 30: feed on ash leaves for a few weeks
Page 31 and 32: will likely reduce population build
Page 33: Chapter 5The Native PlantCommunitie
Page 36 and 37: Chapter 5The Native PlantCommunitie
Page 39 and 40: Wet Forest: Dieback and declineEmer
Page 42 and 43: Chapter 5The Native PlantCommunitie
Page 44: Chapter 5The Native PlantCommunitie
Page 49 and 50: Mesic hardwood forests have a diver
Page 51 and 52: the invasion of undesirable plants
Page 53 and 54: for ash roots to reach mineral soil
Page 55 and 56: and re-colonize a burned landscape.
Page 57: A general overview of ash species d
Page 61 and 62: Survey Recommendations: WildlifeUnt
Page 63 and 64: Chapter 7Other Implicationsof EAB a
Page 65: Windthrow MortalityAll hardwood for
Page 69 and 70: Appendix BQuestions & Answers about
Page 71 and 72: Appendix CMinnesota Department of N
Page 73 and 74: GLOSSARYabiotic: Nonliving parts of
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Ash Management Guide for Private Forest Landowners

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