A publication of the

NebraskaStatewide ArboretumSpring 2007

The SeedPlains-proven plants to know and grow

Nebraska Statewide rboretumarboretum.unl.edu

Justin Evertson

NotthatlongagomostNebraskacommunitieswerefulloflargeAmericanelms.Theirtall,archinghabit,fastgrowthandadaptabilitytoawiderangeofsoilconditionsmadethemapopularchoiceforplantingintownsfromFallsCitytoChadronandallpointsinbetween.Becauseofitswide-spreadinghabit,Americanelmwasespeciallypopularforplantingalongstreets.Oftenthecanopiesofindividualtreesmetoverthemiddleofthestreet,creatingaceilingofgreenthatwouldsometimesstretchforblocksatatime.UnfortunatelyDutchelmdiseaseracedacrossthestateinthe1960sand70sand,inwhatnowseemsliketheblinkofaneye,theelmsweregone.Andtheyhavebeensorelymissed. Althoughthebenefitsweren’tcompletelyunderstoodatthetime,thosewhoplantedtheelmsknewlargetreeswereimportanttoacommunity.Today,thankstoresearchfromacrossthecountry,wecannowquantifyeconomicallymanyofthebenefitsthatlargetreesprovide.Forexample,properlyplacedandwell-caredfortreescanincreasepropertyvaluesby10percentormorewhilereducingenergycostsbyupto15percent.Othermeasurablebenefitsfromtreesincludecleanerair,reducedatmosphericCO2,better-managedstormwater,extendedlifeofstreets,moreattractivecommunitiesandbetterhumanhealthandwell-being.Whenaddedtogether,thebenefitsoflarge-staturetreescanexceed$65/tree/year*. Ofcoursepeoplealsobenefitdirectlyfromtreesthroughthementalandphysicalcomfortstheyprovide.Thecoolnessoftheshadeonahotsummerday;thesoundsofrustlingleavesandsingingbirds;asquirrelflyingeffortlesslythroughthebranches;thewondrousfragranceoflindenblossomsinlatespring;thecolorfulchangeofleavesinautumn;andthemagicoffrostedbranchesonawintermorning…

The Value of Large Trees

Nebraska Statewide Arboretum Nonprofit Org.

P.O. Box 830715 U.S. Postage PAID

University of Nebraska Permit 46

Lincoln, NE 68583-0715 Lincoln, NE

Phone: 402-472-2971arboretum.unl.edu

arejustsomeofthewayswerelatedirectlytotrees.Thesephysicalandmentalcomfortsaresoupliftingthatmanypeopledevelopaverystrongspiritualconnectiontotrees.Whatelseexplainspeoplewhohaveclimbedorchainedthemselvestoimportanttreestopreventtheirdestruction?

The Big Tree Disconnect

Becausewenowknowhowtrulyvaluablelarge-growingtreesare,peopleandcommunitiesmustbedoingalltheycantoproperlyplantandcareforthem.Right?Wrong!!Infact,accordingtoresearchbytheNebraskaForestService,theamountoftreecanopycoverprovidedbylargetreesinmostNebraskacommunitieshasdeclinedsignificantlysincethedaysoftheAmericanelm.Whentheelmsdied,manywereneverreplaced.Andwherereplantingdidoccur,smaller-growingtrees—selectedprimarilyforspringflowersorfallcolor—wereoftenthechoiceforplanting.Thistrendtowardsmallertreeshasnowbeenbroadlyreferredtoasthe“dwarfingofthecommunityforest.” Anotherdisturbingproblemfacingcommunityforestsisthelackofspeciesdiversity.IfanylessonshouldhavebeenlearnedinthewakeofDutchelmdisease,itisthatabroaderdiversityoftreespeciesisvitaltothehealthofa

A Few Big Trees for the FutureBob Henrickson

OneofthebenefitsofworkingfortheNebraskaStatewideArboretum(NSA)istheopportunitytovisititsnetworkofarboretumsites,parks,historicpropertiesandotherpubliclandscapesthatspanstheentirestate.MostofthelandscapesthatmakeuptheArboretumarenotextensivelandscapesbutlocalarboretumsandparkswhereanimpressivevarietyoftreeshasbeenassembled.IhavevisitedmostoftheArboretumsitesovertheyearsandIlearnsomethingneweverytime. Bydefinitionanarboretumisaplacewheretreesforgrownforthepurposeofeducation,andwhatbetterplacetobecomefamiliarwithnewtreeselectionsoralternativesthanalocalarboretum?Peoplewanttoplanttreestheyarefamiliarwithandhaveseeninthelandscape.Theyalsowanttobeassuredthattheywillgrowunderregionalconditions.Alocalarboretumistheperfectplacetoobserveandlearnaboutplantstheymightnotbefamiliarwith. BelowisalistofsomeofthewonderfultreesI’veobservedorgrown.Generallytheyremainconfinedtoarboretumsandparks,butinmyopiniontheyhavealotofpotentialandhaveproventheyshouldbeplantedmore.Thesetreeshavestoodthetestoftime.It’stimetogetthemoutofthearboretumandintoourhomelandscapes.

TuliptreeLiriodendron tulipifera NativetotheeasternhalfoftheU.S.,thetuliptreeisastatelytreeforlargespaces.Theleavesarewaxyandsmooth,retainingacleanappearancethroughthesummerandturningbrightyellowinfall.Theflowersarethesizeandshapeofgardentulips,bloominginMayafterthefirstleaveshaveexpanded.Thebeautifultwo-tonedorange-yellowpetalsareoften

The Value of Large Trees continued on page 5

A Few Big Trees continued on page 2

Forest Lawn Cemetery in Omaha is home to many stately trees, including this large tuliptree.

community’streeresource.Havingawidervarietyofspeciesgreatlyreducestheriskofamassivedie-offoftreeswhenthenextdiseaseorinsectcomesalong.Incredibly,theDutchelmdiseaselessonwassomehowforgottenandonceagainasinglespeciesofshadetree,thistimegreenash,hascometodominate

Large trees frame roads in Nebraska City’s Steinhart Park.

Inside

The Truth about Roots

An Ode to Hackberry

Pine Wilt Disease and Emerald Ash Borer

Trees with a Split Personality

The Simple Act of Planting Better Trees

Return of the Elm

Ten Elms to Try

Fifty Large-growing Trees for Nebraska

Tree-planting for Success

2

hiddenbythefoliageandarebestviewedfromatwo-storywindow.TherearebeautifultreesgrowingonthecampusesattheUniversityofNebraskainLincoln(UNL)andatMidlandLutheranCollegeinFremont.TheNebraskachampionislocatedinOakland,abig,impressivetreewitha4’diametertrunk.AnotherlargespecimenislocatedinachurchcourtyardinHumphrey,Nebraska.Thistreehasperformedwellintheeasternhalfofthestateanddeservestobeplantedmore.

AmurcorktreePhellodendron amurense Thishandsomemedium-sizedtreehasdeepgreen,shinyleavesthatremaincleanallsummer.Thebarkonoldtrunksisridgedandfurrowed,formingabeautifulcork-likepattern.Oneofthebestfeaturesofthistreeisthebroad-spreadinghabit,opencrownandhorizontalbrancharrangements.ThistreeisnativetotheAmurRiverregioninChina,thesameareaasAmurmapleandAmurchokecherry.BeautifulspecimensofcorktreearegrowingatUNL,PeruStateCollege,SteyerParkinBlairandMemorialParkinTekamah.AnAmurcorktreehasbeenperformingwellintheKimballarboretuminwesternNebraskaforover12years.Themaleselections‘Macho’and‘HisMajesty’arefruitlessandnotedfortheirthick,leatheryleavesandspreadinggrowthhabit.

OvercupOakQuercus lyrata Overcupoakisthesoutherncounterparttoswampwhiteoak,nativefromthesoutheasternU.S.westtoMissouriandOklahoma.Thisisoneofthemostflood-tolerantoaksanditgrowsnaturallyonpoorly-drained,heavyclaysoils.Theacornisalmostfullyenclosedbythecupandfallsfromthetreeintact.Thecupsprovideflotationandhelptodispersetheseedsunderfloodedconditions.Thedarkgreen,leatheryleavesturndullgoldinfall.WehavecollectedseedsfrommaturespecimensofovercupoakonthegroundsofSt.Joseph’sCatholicChurchinAuburn,Nebraska.SeedlingprogenyofthesetreesarebeingevaluatedbyparticipantsinourResearchConsortiumprogramandnurseriesarebeginningtocarrygood-sizedtrees.Ahealthy50’treeisthrivinginaLincolnneighborhoodandinthearboretumoakcollectionattheLincolnRegionalCenterArboretum.MichaelDirrfeelsthistreecouldbecomeanimportantlandscapetree,sayinghe“doesnotrememberanunworthyspecimen.Withitsadaptabilitytowetsoilsitmaybeadaptedtosimilarurbanconditions.”

BurgambelOakQuercus macrocarpaxgambelii Theburoak,Quercus macrocarpa,isoneofourmostvariableoakspeciesandispronetohybridizewithotherwhiteoaks.Manyintermediateformsshowgeneticinfluencesfromswampwhiteoak,whiteoakandothers,includinggambeloak.Naturalhybridpopulationsofburoakandgambeloak(Quercus gambelii)canbefoundinColoradoandWyoming.Theburgambeloakhybridisoneofthebestforacornproductionanddevelopsacompact,bushycrownto40’high.Ifyouarelimitedinspacebutstillwantthedurabilityandadaptabilityofaburoak,thenplantburgambeloak.Thistreehasalotofpotentialforharsh,drylandscapesthroughoutNebraska,butespeciallyinthewesternhalfofthestate.Itmakesitsbestgrowthindry,sandywell-drainedsites.SeveralyoungtreesarethrivingontheUNLcampus.

TurkishFilbertCorylus colurna Thisuncommontreeishandsome,sturdyandtrouble-free.Thedeepgreen,toothedfoliageremainscleanthroughoutthesummerandseemstobefreeofinsectanddiseaseproblems.Thegray-brownbarkisheavilytexturedandthebranchesdevelopaveryattractiveformaloutline.Inearlyspringtheclustersoflongmalecatkinsdanglefromthebarebranchesliketarantulaspiders.ThoughnativetoEuropeandAsia,itseemstothriveinNebraskaandanumberofoutstandingspecimenscanbeseenatUNLandattheNebraskaGameandParksCommissionheadquartersinLincoln.Outwest,ayoungtreeisthrivinginLexingtonattheDawsonCountyfairgrounds,butthebestspecimeninthestateisa50’beautyattheGlenViehmeyerArboretuminNorthPlatte.Thistreeisunderusedandcanbedifficulttolocateincommerce,butit’sworththehunt!

BitternutHickoryCarya cordiformis Thisrelativelyfast-growing,beautifultreeisnativetosoutheastNebraskaalongtheMissouribluffsandalongcreeksandriversasfarwestasWahooandBeatrice.Inrich,woodlandsitesthebitternutstypicallydevelopseveralprimaryverticallimbs,forminganarchingshape.Theirtight,relativelysmoothbarkandbrightyellowfallcolorarereasonenoughtoplantthistree.Inspring,thelongmalecatkins“hangliketinselfromthebranchesandarevisiblebelowtheleaves”(GuySternberg,Native Trees for North American Landscapes). Hickoriesdeveloplongtaprootsandcanbedifficulttotransplant,howeverwithtoday’sair-pruningpotsandroot-restrictingfabrics,therootsystemsproduceabranchingrootsystem.OurnativeseedsourceshouldyieldamoreadaptabletreeforareasthroughouteasternNebraska.ThestatechampionatWyukacemeteryinNebraskaCityisanimpressivespecimenandan80’treehasthrivedfordecadeslessthanablockawayfromoneofLincoln’sbusieststreets.Agroveoffine,youngbitternutscanbeseenatUNL’sCatherGarden.

Someofthesetreesmaynotbereadilyavailablefromlocalnurseriesbutthat’slargelyamatterofsupplyanddemand.Whenpeoplebecomefamiliarwiththesetrees,I’mconfidentthey’llstartaskingforthem,andwhencustomersstartaskingforthem,nurserieswillstartcarryingthem. ThisisasmallexampleoftheincrediblevarietyoftreesthrivinginNebraska.Ifyouhaven’thadtheopportunitytoseethesetrees,youcancountonNebraskaStatewideArboretumaffiliatestointroducethemtoyou.Formoreinformationaboutwheretoseethem,call402/472-2971orvisitarboretum.unl.edu/affiliate.Thesetreesmayberareinourhomelandscapesrightnow,buttheywon’tbeoncethewordgetsout!

For more

information on

recommended trees:

arboretum.unl.edu/plantinfo

From top: Gary Zimmer, Curator of Gilman Park Arboretum in

Pierce and Kristina Jensen, NSA Nursery Technician, stand next to

a widespreading Amur corktree (Phellodendron amurense)

at the Morton Arboretum near Chicago.NSA volunteer Bob Vogel with the

Nebraska state champion biitternut hickory in Auburn.

Close-up of tuliptree blossom .Early spring catkins of Turkish filbert.

Overcup oak acorn.

A Few Big Trees continued from cover

3

Eric Berg, Nebraska Forest ServiceBob Henrickson, Nebraska Statewide Arboretum

It’shardtooveremphasizetheimportanceofatree’srootsysteminmaintainingahealthytreeand,ultimately,ahealthycommunityforest.Atthesimplestlevel,themainfunctionsoftreerootsaretosupportthetreeandtotakeupthewaterandmineralsessentialtooverallplantvigorandhealth. Probablybecausetheyareunseen,therearemanymisconceptionsandmythsaboutthisinvisible,underappreci-atedandessentialpartofthetree.

Myth: Tree roots are tough and woody. Reality:Themajorityofrootbiomassismadeupofveryfinefeederroots,typicallyaveragingonly1/16”indiameter,whichareresponsibleforwaterandmineraluptake.Structuralrootslocatednearthetrunkhelpsupportthetreeandaretypicallylargeandstrong,butfeederrootsrepresentthemajorportionoftherootsystem’ssurfacearea.Therootsystemofatreecanbethoughtofasapermanent,structuralwoodyframewith“disposable”finerootsthatmaylastforonlyoneseasonduetopoorsoilgrowingconditions,droughtorfreezingtemperatures.Intheurbanenvironment,theserootsarealsoverysusceptibletocompaction,over-watering,constructiondamage,waterpollutionandsoilcontamination.Treescanloseasmuchas95percentoftheirrootsysteminbeingtransplantedandthereforespendamajorityofenergyreservestore-establishthem.

Myth: Tree roots grow deep into the soil. Reality:Themajorityoftreerootsarefoundinthetop18”ofsoil,andtypicallyoverhalfofatree’srootsareinthetop6”ofsoil.Treerootsrequireoxygenforsurvival.Theywilloccupyandgrowinareasfavorableforsurvival,withgoodaerationandavailablemoistureandnutrients.Thesetypesofconditionsareeasilycreatedwithpropermulching.Whiletherearemanyinstanceswhereagivenspeciesmightsendrootsdeepintothesoil,thevastmajorityaretypicallyjustbelowthesoilsurface—deepenoughforreliablemoisture,yetshallowenoughforgoodoxygenlevels.Poorsoilaeration,typicalofcompactedsoils,isoneofthemostlimitingfactorsforrootgrowthintheurbanenvironment.Whencompactioniscoupledwithover-watering,thereisverylittleporespaceleftforoxygenand,asaresult,rootsslowlysuffocateanddie.

Myth: Tree roots exist only under the tree canopy. Reality:Treerootstypicallyhaveveryextensiverootsystemsgrowingwellbeyondthecanopyofthecrown.Inforestedornaturalenvironments,rootsmaybefoundgrowingtwotofourtimesbeyondthediameterofthetreecanopy,andwithdrought-tolerantspeciessuchasoak,thespreadcanbeuptosixtimesthecanopywidth.Rootsdonotmirrorwhatyouseeaboveground.Tovisualizethis,imagineatreerepresentedasawineglassconnectedtoawideflatplate.Theglassandstemrepresentthecanopyandtrunkandtheplaterepresentstherootsystemextendingwellbeyondthecanopyofthetree.Thisisveryimportanttoconsiderwhendealingwithpotentialconstructiondamageor

TheTruthaboutRootschemicalapplications.SoilsterilantsandmaterialscontainingDicambaforbroadleafcontrolshouldnotbeusedaroundtreesasthesechemicalsarepersistentandactiveinthesoilandwillseverelydamagetreerootsystemsovertime.

Healthyrootsystemsresultinhealthytrees,whetherthey’reinyourbackyard,inyourcommunityorinnaturalforestedareas.Bybetterunderstandingsomeofthebasicbiologicalrealitiesoftreeroots,youcanbettermaintainandprotectthem.Sothenexttimeyoudoconstructionwork,applyherbicideordriveacrossthatseeminglywideexpanseoffescue,stopandconsiderthetreesaroundyouandthefragilebutcriticalrootsbeneathyourfeet.

Top: The major portion of a tree’s root system is made up of small feeder roots. Because they are

fine-textured and close to the surface, they are easily damaged by compaction, construction dam-

age and chemical applications.Bottom: Circling and girdled roots are a common

problem in container-grown trees.(Photos courtesy of Eric Berg)

Justin Evertson

GrowingtreesinNebraskacanbeariskyproposition.Ifwind,hail,icestorms,tornadoes,droughts,hotsum-mersandcoldwintersdon’tkillatree,insects,diseasesandpeopleoftenseemreadytofinishthejob.Thankgoodnessforhackberry(Celtisoccidentalis).Thistough-as-nailscousintotheelmhasprovenitsworthinyards,parks,farm-steadsandshelterbeltsacrossthestateforgenerations. HackberrypossessesmanypositiveattributesthatmakeagoodtreefortheGreatPlains.Itsbroad,archinggrowthhabitmakesitanidealspeciesforstreetsideplantings;itstoughcharactermakesitveryusefulinparksandotherpublicspaces;itsdistinctivewartybarkandcleanbranchinggivesitauniquenaturalcharacter;itisnativetotheregionandthusuniquelyacclimatedtotheGreatPlainsenvironment;itsuffersfromfewdiseaseorinsectproblems;ittoleratesbothwetanddrysoils;anditsfruitsareprizedbycedarwaxwingsandothercolorfulbirds. Hackberryisnotperfect.Ithasbeenover-plantedinsomecommunitiesandittendstobreakupinwindandicestormswhennotproperlyprunedandcaredfor.Itcanalsobeveryopportunistic(nicewordfor“weedy”).Birdsareabletospreaditsseedsfarandwideandseed-lingsareoftenfoundgrowinginalleys,

AnOdetoHackberrywoodlotsandotherout-of-the-wayplaceswithinacommunity.Thisopportunisticnature,however,hasonegoodadvantage–freetreesareavailableforthosewillingtotransplantthem.Indeed,hackberryishardtofindinnurseries,sodiggingaseedlingissometimesthebestoption. Theimportantmessagehereisnottopromotethewidespreadplantingofmanymorehackberries.Rather,thepointistoencourageusalltoappreciatethemanyhackberrieswealreadyhave,workhardtomaintainthemproperly,andwhenpossible,assistintheirrenewalbyplantingafewhereandtheresothattheywillbeinourcommunitiesforyearstocome.AsIsitandwatchthecedarwax-wingsenjoyalatewintermealofhack-berryseeds,onthetreethatwillalmostfullyshademyneighbor’sbackyardinthecomingmonths,Ican’thelpbutfeelverythankfulforaspeciesthatgivessomuchwhileaskingforsolittleinreturn.

“In the intimate and

humanized landscape,

trees become the

greatest single

element linking

us visually and

emotionally with our

surroundings. Other

manifestations

of nature—great

rocks, deserts,

moors, torrents,

hurricanes—stir

us, fill us with awe,

make us afraid or

humble, but a tree we

understand and can

allow to become part

of us. It’s no wonder

that when we first

think of a garden we

think of a tree.”

Thomas D. Church

4

Bob Henrickson

Evenaquicklookattreesgrowinginanurbanenvironmentmakesiteasytoseethestressestheyhavetoendure.Weplanttheminpits,parkingislands,compactedconstructionsitesandbasementsub-soilsandexpectthemtoperform.WeforgetthatNebraskaisaplainsstatewhereprairieonceruledandwheretreeswereoftenfoundonlyalongstreamsandrivers.Theplainsclimatehasalwaysbeentoughontrees,withdamagefromwind,ice,heat,drought,insectsanddiseases,tonamejustafew.Wearefamiliarwiththeseproblems,butweforgetthatthesestressesareevenmoremagnifiedintheurbanenvironment. Arboristsandothertreeprofessionalsoftenconsideronlythetopofthetree—leaves,branchesandtrunk—indiagnosingproblems.Therootstockorrootsystem,oftenthemostimportantpartofthetree,ismoredifficulttoexamine.Afterplantingandcaringfortreesovertheyears,I’mconstantlyremindedthat,forthehealthandperformanceofatree,“it’sallintheroots.”Ifrootsarestressedfrompoorlydrained,oxygen-deprivedsoilsorfromcompactedorcontaminatedsoil,thetreewillbemorevulnerabletoinsects,diseasesandotherproblems. Whilepoorsoilorplantingdepthisanobviouscauseofproblems,thereisanotherstressthatisrarelyconsidered.AccordingtoJohnBallofSouthDakotaStateUniversity,“manyofoururbantreessufferfromasplitpersonality…they’rereallytwotrees,thetrunkandcanopyisonespecies,therootsanother.”Namedcultivarsorclonesareagroupofcultivatedplantsdistinguishedfromotherplantsofthesamespeciesbya

TreeswithaSplitPersonalitycharacteristicretainedinpropagation. Manytreecultivarsarepropagatedbyagraftingtechniquecalledbudding,inwhichasinglebudtakenfromthedesiredcultivarisnestledwithinafoldmadeinthelowerstemofaseedlingtree.Theinitialsidewardgrowthfromthissinglebudiswhatcausestheslightcrookatthebaseofthestem.Thetopofthetree,referredtoasthescion,originatesfromthesinglebudtakenfromaspecifictreeorcultivar.Thebottom,calledtherootstockorunderstock,isbeneaththescionandconsistsofthelowerfewinchesofthestem(wherethebudisgrafted)andtheentirerootsystem. Inthepast,manyshadetreecultivarswereselectedfordesirablegrowthhabitorfallcolor,withlittleregardfordrought-orheat-toleranceoradaptabilitytovarioussoiltypes.Fortunately,today’scultivarsareselectednotonlyforshape,sizeandfallcolor,butalsoforhowwelltheytolerateurbangrowingconditions. TwocommoncultivarsintheurbanlandscapeincludeAutumnPurplewhiteash(Fraxinus Americana‘AutumnPurple’),selectedfromasinglespecimeninOhioknownforitsoutstandingdeeppurplefallcolorand‘OctoberGlory’redmaple(Acer rubrum‘OctoberGlory’)selectedfromatreewithcrimsonredfallcolor.Whenthescionwoodiscollectedfromthesetreesweknowwherethetreescomefrom,buttheoriginofthelowerportionofthetreeorrootstockisusuallyamystery.Veryrarelyareweawareoftheoriginoftherootstock(andyes,thatdoesmatterwhenyouconsiderthatredmaplesgrownaturallyfromnorthernMinnesotatoFlorida). Mostwhiteashcultivars,including‘AutumnPurple’,arebuddedontogreenashrootstock.Greenashiscommonly

usedasanunderstockformanyashspeciesandforthisreasonhasbeendubbed“theuniversaldonor.”Thoughgraftinghasenabledustoselectcultivarswithsuperiorornamentalqualities,thesetreeslackthefullgeneticrepresentationofaspecies,includingitsabilitytoovercomeawidevarietyofstressfactors.Oneofthequestionsweneedtoaskis“Willthesetreesbepronetofailurebeforetheyreachmaturity?” Therearewell-documentedcasesofgraftincompatibility,evenwhenthescionandtherootstockareofthesamespecies.Inthe1970s,manyredmaplesgrownfrombuddedtreesbegantodeclinefornoapparentreason.Researchersdeterminedthattheproblemwasdelayedgraftincompatibility,i.e.thefailureofthegraftdoesnotoccuruntilfiveto10yearsafterbudding,whenthetreeisalreadyestablishedinthelandscape.Mapleswereshowingprematurefallcolor,diebackandsheddingbark;manyweredying.Becauseofthis,nurserygrowersbegandevelopingmaplecultivarsontheirownrootsviacuttingsortissuecultureratherthangrafting. Ornamentaltreesendurealotofunique,stressfulsituationsintheurbanlandscape.Their“splitpersonality”maynotbetheprimarystresstheyhavetoovercome,butitisaproblemnotsharedbytheirforestcousins.Totrulydiversifytheurbancommunityforest,weneedtoconsiderplantingmoretreesthatareproducedfromseed.Bysimplyplantingoneseed-grownredoakorKentuckycoffeetreeforevery‘AutumnBlaze’mapleor‘Skyline’honeylocust,wecanmakeagoodstarttowarddiversityandsustainabilityinourcommunitylandscapes.

Justin Evertson

PinewiltdiseaseandthepotentialthreatofemeraldashborerhavemanyNebraskansconcernedaboutthefutureofsomeofthestate’smostpopulartrees.Herearesomefastfactsaboutthesethreats.Formoreinformation,goto:http://www.nfs.unl.edu/program-foresthealth.asp

PineWilt PinewilthasalreadykilledthousandsofotherwisehealthyScotchpineinsoutheastNebraskaandalso

PineWiltDiseaseandEmeraldAshBorerhasbeguntokillAustrianpines.Thediseaseisadvancingnorthandwestacrossstateandshowsnosignsofslowingdown.ScotchpineandAustrianpinehavebeenthetwomostcommonpinesplantedinthestate,especiallyinshelterbelts,overthelast50years.Thepotentiallossfromthispestissignificantandcouldeventuallytotalmillionsoftrees.Assuch,Scotchpineisnolongerrecommendedforplantingthroughoutmostofthestate.

Susceptibletrees:ScotchpineishighlysusceptibleandAustrianpinesomewhatsusceptible.

Symptoms:Faded,gray-greenneedleseventuallyturnbrown.Treesdierapidly,sometimesbranch-by-branch,usuallybetweenlatesummerandearlyspring.

Cause:Pinewoodnematodeattackstissuesinthewood,decreasingwaterflowandeventuallykillingthetree.Thenematodesarecarriedtoothertreesbypinesawyerbeetles,whichtunnelinthewoodofdyingpines(includingthosedyingfrompinewilt).Emergingbeetlescancarrythousandsofnematodesontheirbodies.Astheyfeedonnewshootsofhealthypines,theycreatewoundsthroughwhichnematodesinfectthetree.

Control:Diseasedtreescannotbesavedandshouldbedestroyed(burned,buriedorchippedbeforebeetlesemergefromthewood)topreventspreadtohealthytrees.Highlyvaluabletreescanbeprotectedwithatrunkinjectionofabamectin,availablefromcertifiedarborists.

EmeraldAshBorer Overthelastfewyears,theemeraldashborer(EAB)haskilledmillionsofnativeashtreesinMichigan,OhioandIndianaandithasthepotentialtokillmostoftheashtreesintheeasternU.S.ManyexpertsbelieveitislikelythattheinsectwillreachNebraska(probablyonfirewood)withinthenextseveralyears. Thepotentialimpactisenormoussincegreenashisoneofthemostcom-montreesfoundthroughoutNebraskaincommunities,onfarmsandinnativewoodlands.BecauseofthethreatofEAB,nativeashspeciesincludinggreenash(Fraxinus pennsylvanica),whiteash(F. pennsylvanica),blueash(F. quad-rangulata)andblackash(F. nigra)arenolongerrecommendedforplantingintheeasternhalfofNebraska,andshouldbeusedonlywithcautionandinlimitednumbersinthewesternpartofthestate.Thisrecommendationincludesallofthecommonnativeashcultivarssuchas‘Patmore’and‘Marshall’sSeedless’greenashaswellas‘AutumnPurple’whiteash.

Susceptibletrees:AllNorthAmericanash(Fraxinus)speciesandcultivarsaresusceptible(notmountain-ashorSorbus,whichisnotatrueash).

Symptoms:Exitholesinashbarkabout1/8”indiameterand“D-shaped”;zigzagtunnelsunderthebark;tunnelspackedwithsawdust;diebackfromtopoftree.

Cause:Emeraldashborer—slender,emerald-greenbeetleabout½”long.

Control:Noneatpresent.Treesusuallydiewithinthreeyearsofinfestation.

Thousands of Scotch pines have died of Pine Wilt Disease (top photo taken in Auburn). Though not yet sighted in Nebraska, Emerald Ash Borer has killed millions of trees in more eastern states and

is moving westward toward Nebraska, often by means of transported firewood.

Top: Most white ash cultivars, including ‘Autumn Purple’, are budded onto

green ash rootstock.Bottom: Red maple cultivars are often prone

to bark sloughing, due in part to delayed graft incompatibility.

5

anironicthoughpredictabletwistoffate,aninsectcalledtheemeraldashborer(seearticleonpage4)isadvancingtowardNebraska.Emeraldashborerhastheveryreal,andlikely,potentialtowipeoutmostashtrees,includingthegreenashwhichisthemostcommonshadetreefoundinmanyNebraskacommunities. Sowhyhavewenotdoneabetterjobofplantingandcaringforlarge-growingtrees?Althoughthereasonscanvaryfromplacetoplace,somecommonconsiderationsinclude:

Ourdisconnectfromnature. Inourmodernworld,manypeopleliveinairconditionedhomesandtraveltoairconditionedofficesinairconditionedvehicles.OurleisuretimeisoftenspentindoorswatchingTVorgoingtomovies,restaurantsandshoppingplaces.Wejustdon’tconnecttotheoutdoorslikeweusedto.Perhapswehavecollectivelyforgotten(orneverexperienced)thevalueofshadetrees.

Impactsfromlawncare. Lush,greenlawnshavecometodominateplantedlandscapesacrossNebraskaandthroughoutmuchofthecountry.Unfortunately,manyoftheinputsandactivitiesneededtomaintainsuchlawnscanhavenegativeconsequencesfortrees.Over-watering,herbicidedamage,compactedrootzonesandtrunkinjuriesfrommowersandtrimmersareallverycommontotreesinturf-dominatedlandscapes.

Constructionandcommunitydevelopment. Inanycommunity,treesareofteninthewayofconstructionactivities,utilityworkandnormalmaintenanceofthebuiltenvironment.Treetrunksandbranchesinconstructionzonesarerarelyorinadequatelyprotectedandarefrequentlydamagedfromcarelessequipmentoperators.Anevenbiggerproblemisthedamagedonetotreerootsbytrenchingandsoilcompactionfromheavyequipment.

Poorchoiceofspecies. Manyoftheshadetreesplantedtodayareselectedprimarilyforsuchthingsasuniformshapeandhabit,acertainfallleafcolorandadesirefortreestonotbe“messy”(oftenmeaningfruitless).Assuch,graftedmaleclonesfromjustafewspecies,includinggreenash,whiteashandredmaple,havecometodominatethemarket.Manyofthebetter-adaptedandlonger-livedspeciesarenotnearlyaspopular.

Poorplantingpractices. Somehowwehaveforgotten,ormorelikelyneverlearned,howtoproperlyplanttrees(seearticleonbackcover).Forvariousreasons,manytreesplantedtodayareplantedtoodeepandoftenwithsignificantrootproblems.Othercommonmistakesincludethefailuretoremoveballingtwineandburlap,poorstakingandpoormulching.

Poornurserystock. Amass-marketsocietyseekingthelowestcostalternativehasledtothepurchaseandplantingofmanylow-qualitytrees.Questionablehardinessandpot-boundrootsareverysignificantproblems—especiallyfrombig-boxstoresandotherretailersthatsetuptemporarynurseriesintheirparkinglotseachspring.Itisimportanttopurchasetreesfromreputable,localnurseriesthathavetheexperienceandknowledgetostockonlythehighestqualitytrees,andthatwillstandbytheirproducts.

Poorcare. Whetherthroughignoranceoroutrightneglect,manycommunitytreesdonotgetthecaretheydeserve.Over-watering,under-watering,mowerblight,poorpruning,dogschainedtothetrunks,etc.areallcommonacrossacommunity.Althoughitmaybenaivetothinkthateverytreecanhaveperfectcare,itshouldbeaneasymattertoraiseoverallcareofcommunitytreesthroughbetterpromotionandeducation.

Fearofbigtrees. Manypeoplefearthatbigtreeswillcausebigproblems—suchaslarge,fallinglimbs,highermaintenancecostsandhigherremovalcostswhentheyneedtobetakenout.Itistruethatbiggertreescanlosebiggerlimbsandtheydohavehighermaintenancecosts.However,well-caredfortreesrarelyhavesignificantlimbfailuresandthebenefitsoflargetreescanexceedmaintenancecostsbyan8to1margin*.

From top: Large-growing trees are important even in very urban settings, such as this plaza in downtown Kansas City.Trees shade a bench in Atchison, KS.Kentucky coffeetree is one of the most beautiful and adaptable large-growing trees for Nebraska. Here they grace pathways at Harmon Park in Kearney.

“A single great tree can make a kind of garden, an entirely new place on the

land, and in my mind I was already visiting the place my maple made, resting

in its shade. I knew it wouldn’t happen overnight, probably not even in my

lifetime, but wasn’t that precisely the point? To embark on a project that

would outlast me, to plant a tree whose crown would never shade me but my

children or, more likely, the children of strangers? Tree planting is always a

utopian enterprise, it seems to me, a wager on a future the planter doesn’t

necessarily expect to witness.”

Michael Pollan, Second Nature

TheSimpleActofPlantingBetterTrees

The Value of Large Trees continued from cover

Justin Evertson

Thewritingonthewallisclear:large-growingtreesareveryimportanttoindividualsaswellascommunitiesastheyreturnbenefitsvaluedatupto$65/tree/year(whichismorethanfourtimeshigherthanthevalueforsmalltrees*).Andyet,formostcommunities,thenumberoflarge-growingtreesbeingplantedisnotkeepingpacewithremovals.Infactthetreecoverformosttownshasdeclinedsignificantlyfromjustafewdecadesago. NowisthetimetobeginthesignificanteffortofreforestingNebraskacommunitiesandtoprepareforthepotentiallossofpineandashtrees(seearticleonpage4)byplantingtreesatamuchfasterpaceandincludingamuchwidervarietyoflarger-growingspecies.Acooperativeeffortmustbeundertakentoretakethestreets,parksandbackyardsfromthetimidtree-plantingactivitiesoftherecentpastandonceagainrestoreourcommunitiestothetree-filledgloriestheyoncewere.Suchaneffortwon’tbeeasyanditwon’tbewithoutcost,butitwillmostdefinitelybeawonderfulgifttoourselvesandfuturegenerations. *EstimatefromtheCenterforUrbanForestResearch,USDAForestService.Additionalbenefitsoflarge-growingtreescanbefoundat:http://www.fs.fed.us/psw/programs/cufr/

6

Ten Elms To Try‘ValleyForge’AmericanElmUlmus americana ‘ValleyForge’ SeverallargeAmericanelmssurvivedtheravagesofDutchelmdiseaseandhavebeenusedtodevelopdiseaseresistant,clonedcultivarsincluding‘ValleyForge’,‘NewHarmony’,and‘Independence’.‘ValleyForge’isrecognizedasbeingthemostdiseaseresistant.Thetreeisadaptabletoawidevarietyofsoilconditionsandtoleratesdeicingsalts,airpollution,drought,andarangeofsoilpH.Americanelmhasanupright,archinghabitmakingitanidealstreettree.Itcangrow50’-70’tallandequallyaswide.

Accolade™ElmUlmus japonica × wilsoniana ‘Morton’ AccoladeelmhasquicklybecomeoneofthemostpromisingandpopularelmcultivarsforuseacrossmuchoftheU.S.Thetreehasanupright,archinghabitthatisreminiscentofAmericanelm.ThishybridelmoriginatesfromatreethathasbeengrowingattheMortonArboretumnearChicagosince1924.Thetreecangrow50-70’talland40-60’wide.

Justin Evertson

Untilthe1970s,elmtreeswereperhapsthemostcommontreesplantedincommunitiesacrossNebraska.Americanelm(Ulmus americana)wasespeciallypopularasitstall,archinghabitmadeitanidealshadetreeforplantingalongstreets,inparksandinbackyards.InmanycommunitiestheAmericanelmcomprisedmorethanhalfthetotalspeciesplantedinpublicspaces.Unfortunately,Dutchelmdiseasespreadrapidlyacrossthestateinthe1960sand70s,killingmostAmericanelmsalongthewayandlayingbaretheleafycanopiesthatoncegracedsomanyofourstreets. Duringandafterthedustbowlyearsofthe1930s,Siberianelm(Ulmus pumila)alsobecameapopulartreeacrossmuchofNebraska.Thetreewasabletogrowwithalmostnocareandcouldsurviveextremedrought

Return of the Elmconditions,makingitquitecommoninwesternNebraska.TothisdayitremainstheprimaryshadeandwindbreaktreeforourfamilyfarminKimballCounty.Unfortunately,Siberianelmhasalsoproventobeaweak-woodedand“messy”treewithaweedy,invasivehabit,makingitatreethatisscornedbymanypeople. Withthosestarkvisionscloudingourmindsitisunderstandablewhyelmsfelloutoffavorandarerarelyplantedincommunitiestoday.Fortunately,someforwardlookingpeoplehaveworkedhardformanyyearstodevelopnewelmvarietiesthatshouldbeplantedmore.Newspecieshavebeendiscovered,uniqueformshavebeenhybridizedanddisease-resistantvarietiesoftheoldAmericanelmhavebeendeveloped. Therearemanybenefitstothesenewelms:

The most prominent new elms are resistant to Dutch elm disease.Inaddition,manyarealsoresistanttoelmleafbeetle,thusretainingamuchgreenerappearancethroughoutthegrowingseason.

Several of the elms are able to tolerate a wide range of growing conditionsincludingthepoorsoilsandtheextremeclimateoftheGreatPlains.

The tall, arching habit of some elms makes them especially usefulforplantingalongstreetsandinparkswheremanytreelessgapsstillexist.

The new elms help greatly expand the diversity oflarge-staturetreesavailableforplantinginNebraska.

These elms add a variety of interest andbeautytothelandscapethroughuniqueleaf,barkandbranchingcharacteristics.

Soplantanelm!

JapaneseElmUlmus davidiana var. japonica JapaneseelmhasprovenhardyasfarnorthasNorthDakotaandManitoba,Canada.ThespecieshasbeendisbursedbyNSAfortestinginNebraskaandearlyreportsarepromising,especiallyforeasternNebraska.Thetreeisalsoaparenttomanyofthemorepromisinghybridelms.Japaneseelmhasglossygreenleaves,relativelytightbranchingandaroundedhabitwiththepotentialofgrowingupto40-50’tallby30-40’wide.

‘Cathedral’ElmUlmus davidiana var.japonica × pumila CathedralelmwasdevelopedattheUniversityofWisconsinbycrossingSiberianelmwithJapaneseelm.Itisafastgrower,istolerantofclaysoils,andhasayellowtoorangefallcolor.Thetreehasabroad,vaseshapeandgrows40-50’tallby40-50’wide.

‘Frontier’ElmUlmus parvifoliaxcarpinifolia Thisveryattractivehybridsharesmanycharacteristicsoflacebarkelm(oneofitsparents)includingsmall,glossyleavesthatturnadustypurpleinthefall,andmottledbarkonmaturingtrunks.AlthoughsomereportsindicatewinterdiebackintheGreatPlains,ithasperformedwellinsoutheastNebraskaforseveralyears.Cangrow30-40’tallby25-30’wide.

‘Pioneer’ElmUlmus glabra× carpinifolia PioneerelmhasbeenplantedinseverallocationsinNebraskaandhasperformedwellinCreighton,Pierce,WaverlyandAlliance,amongothercommunities.Itisafastgrowerwithdarkgreenleavesandanupright,pyramidalhabitwhenyoung.Pioneerelmwilleventuallybearoundedtreegrowing40-50’tallby40-50’wide.

Triumph™ElmUlmus x ‘MortonGlossy’ TriumphelmwasdevelopedattheMortonArboretumbycrossingVanguard™elmwithAccolade™elm.Ithasavigorous,uprighthabit

withstrongbranchesbearingglossy,deep-greenfoliage.Thetreeappearstobeveryadaptabletoawiderangeofgrowingconditionsandwillgrow50-60’tallby30-40’wide.

Vanguard™ElmUlmus japonica × pumila ‘MortonPlainsman’ VanguardelmisanotherSiberianelm/JapaneseelmhybridwhichwasdevelopedattheMortonArboretum.Thetreeisconsideredtobeverytolerantofhighheatanddrought,thusmakingitapromisingselectionforthewesternGreatPlains.Thetreehasdarkgreenfoliage,aroundedvaseshapeandwillgrow40-50’tallby40-50’wide.

RockElmUlmus thomasii RockelmisnativetotheeasternU.S.,includingeasternNebraska.Itsrelativelynarrowanduprighthabitisreminiscentofpinoak.Averydistinctivefeatureofthistreeisthecorkyridgesfoundonstemsandyoungbranchesthateventuallydevelopintoadeeplyfissuredbark.SeveralRockelmshavegrowntallandoldinCheyenne,WY,givingtestamenttoitshardinessandadaptability.Rockelmcangrow50-60’highby30-40’wide.

LacebarkElmUlmus parvifolia Thecommonnameofthiselmreferstotheveryattractivemottled,lacybarkthatdevelopsonolderstems.LacebarkelmissometimescalledChineseelminreferencetoitsnativerangeofChina,JapanandKorea.Theleavesaresmallerthanmostelmsandaredeepgreenandveryglossy.Floweringoccursinlatesummerwithseeddevelopmentinearlyfall.Theyellowishseedsarequiteattractiveagainsttheshinygreenleaves.Manytreesalsodevelopanicereddishfallcolor.ThistreeisbestadaptedtothesouthernhalfofNebraska.‘EmeraldPrairie’isanexcitingnewcultivardevelopedinKansasthatmayhavebettercoldhardiness.Lacebarkelmisamedium-sizedtreegrowingto25-40’tallby20-35’wide.

From top: Accolade™ elm; leaf of American elm.Japanese elm is a graceful tree that has good

potential for the Great Plains. Rock elms growing along a street in Cheyenne,

WY attest to the tree’s toughness.Lacebark elm with emerging seeds.

7

Justin Evertson

EveninaprairiestatelikeNebraska,therearemanytreesthatwillgrowwellifgivenachance.Thefollowing50speciesoflarge-staturetreesaresuitableforplantinginmuchofNebraska.Allwillgrowatleast30’tall.AnEindicatestreesprimarilysuitedtotheeasternhalfofthestate.Thesizelistedistheaveragerangeofheightandspreadatmaturity.

There’s lots to love if you’re looking for large shade trees for Nebraska. From top: Bur oaks on the campus of Peru State College (“Campus of a Thousand Oaks”).Fall foliage of white oak.Creamy, mottled bark of London planetree.Concolor fir (Abies concolor) is one of the most graceful evergreens for Nebraska. Many large specimens, including the state champion, can be found at the CABG Patch Arboretum–an NSA affiliate site just north of Omaha.

Fifty Large-Growing Trees for Nebraska

Buckeye,Ohio,Aesculus glabra,30’x30’

Catalpa,Northern,Catalpa speciosa,50’x35’

Cherry,Black,Prunus serotina,35’x20’

Coffeetree,Kentucky,Gymnocladus dioicus,50’x40’

Corktree,Amur,Phellodendron amurense,35’x40’

Cottonwood,Eastern,Populus deltoids,80’x70’

Elm,miscellaneous,Ulmusspp.(seearticleonpage6)

Filbert,Turkish,Corylus colurna,E40’x25’

Ginkgo,Ginkgo biloba,E50’x40’

GoldenrainTree,Koelreuteria paniculata,E35’x25’

Hackberry,Celtis occidentalis,60’x50’

Hickory,Shagbark,Carya ovata,E50’x40’

Honeylocust,Thornless,Gleditsia triacanthos var. inermis,60’x50’

Horsechestnut,Aesculus hippocastanum,E40’x30’

Linden,American,Tilia americana,60’x40’

Linden,Littleleaf,Tilia cordata,45’x30’

Linden,Silver,Tilia tomentosa,E50’x40’

Locust,Black,Robinia pseudoacacia,35’x25’

Maple,Miyabe,Acer miyabei,30’x25’

Maple,Sugar,Acer saccharum,50’x50’

Oak,Bur,Quercus macrocarpa,60’x70’

Oak,Chinkapin,Quercus muehlenbergii,45’x40’

Oak,English,Quercus robur,60’x50’

Oak,Red,Quercus rubra,60’x50’

Oak,Sawtooth,Quercus acutissima,E60’x40’

Oak,Shumard,Quercus shumardii,E50’x40’

Oak,SwampWhite,Quercus bicolor,60’x50’

Oak,White,Quercus alba,E60’x50’

Pagodatree,Japanese,Sophora japonica,E40’x30’

Pear,Callery,Pyrus calleryana,35’x25’

Pecan,Carya illinoinensis,E60’x50’

Planetree,London,Platanusxacerifolia,E75’x50’

Poplar,Silver,Populus alba,75’x60’

Sycamore,Platanus occidentalis,80’x50’

TulipTree,Liriodendron tulipifera,E50’x40’

Walnut,Black,Juglans nigra,60’x45’

Yellowwood,Cladrastis kentukea,E35’x25’

Evergreen Trees

Douglasfir,Pseudotsuga menziesii,50’x30’

Fir,Concolor,Abies concolor,50’x25’

Juniper,RockyMountain,Juniperus scopulorum,35’x20’

Pine,Austrian,Pinus nigra,60’x35’

Pine,Bosnian,Pinus heldreichii var.leucodermis,45’x30’

Pine,EasternWhite,Pinus strobus,E70’x40’

Pine,Jack,Pinus banksiana,40’x25’

Pine,Limber,Pinus flexilis,50’x30’

Pine,Ponderosa,Pinus ponderosa,65’x30’

Redcedar,Eastern,Juniperus virginiana,40’x30’

Spruce,BlackHills,Picea glauca var.densata,50’x30’

Spruce,Colorado,Picea pungens,65’x35’

Spruce,Norway,Picea abies,70’x40’

Justin Evertson

Properplantingiscriticaltotheestablishmentofhealthy,thrivingtrees.Thefollowingplantingguidelineshavebeendevelopedtohelpnewtreesgetofftoasuccessfulstart.TherecommendationsarebasedonnationallyrecognizedstandardsaswellasexperiencecompiledbytheNebraskaStatewideArboretumandtheNebraskaForestService.Therecommendationsassumethatanappropriatetreehasbeenselectedfortheplantingsiteandthatthesiteissuitableforplanting.

DIGGING Digasaucer-shapedholewiderthantherootsystembutnodeeperthantherootmass.Mostholesdonotneedtobedeeperthanaboutoneshovel’sdepth(10-14”).Thebottomoftheholeshouldbefirmenoughtopreventthetreefromsettlingdeeperafterplanting.Note:Us-inganaugerisnotrecommendedsincetreesoftensettletoodeepandthesidesoftheholesbecomeglazed.Ifusinganauger,don’tdrilldeeperthanneededandloosenthesidesofthehole.

PLANTING Plantsothatthebaseofthetrunkisatoriginalgroundlevelorslightlyhigher.The first lateral roots should end up just under the soil surface(1-2”deep)andthetrunk should flare visibly at ground level.n Alwayslocatethefirstmainlateralrootsandremoveanyexcesssoilabovethembeforesettingtheplantinthehole.Thefirstmainrootsareoftenseveralinchesbelowthetopofthecontainerorrootball.

Tree-planting for Successn Allgraftunionsshouldbevisibleabovethesoilline.n Removeallpotsandcontainersbeforeplanting.n Forballedandburlap(B&B)stock,trytoremovethewirebasketandburlapbeforeplacingthetreeinthehole.Ifmaintainingtheintegrityofthesoilballisimportant,thenremovethebottompartoftheburlapandwirebasketbeforesettingtheplantintheholeandthenremovetheremainingburlapandwirebasketafterstabilizingthetreeinthehole.Remembertocheckforandremoveanyexcesssoilatthetopoftherootballbeforeplanting.n Loosen and spread circling roots before backfilling(especiallyimportantforpottedtrees).Itmaybenecessarytocutlargerrootsthatcannotbestraightenedtopreventgirdling,butthisshouldbedonewithcaution.Rejectplantswithseverelycircledorgirdledrootsystems.n Forpottedtrees,trytoremoveasmuchoftheoriginalgrowingmediumaspossiblebeforeplantingtohelpachievegoodsoil-rootcontact.Dunkinginwaterorsprayingwithahosewillhelpinthiseffort.

BACKFILLING Backfillwiththeoriginalsoildugfromthehole.Largeclodsandsoilchunksshouldbebrokenupasmuchaspossible.Addingwaterduringbackfillingcanhelpremoveairpocketsandbettermoistentheroots.

MULCHING Mulchindividualtreeswitha2-4”layerofwoodmulchextendingfromthetrunktoatleastthedriplineofthetree.Wherepossible,mulchtreesandotherplantingstogetherenmassetohelpseparatefromsurroundingturf. Don’tpilethemulchdeeplyoverrootsoragainstthebaseofthetrunkanddon’tmulchwithrockoruseplasticweedbarriersunderthemulch.

STAKINGANDBRACING Bracethetreeifitmightdislodgeorblowoverinthewind(mosttreestypicallybenefitfromstaking).Someswayshouldbeallowedinthetreeafterstaking.Useonlybroad,belt-likematerialstoattachthebracingtothetrunktohelppreventrubbinginjuries. Do notbracewithwire,ropeorwirethroughhose.Removestakingwithinoneyear.

WATERING Afterplanting,keeptherootzonemoistbutnotwaterlogged.Ingeneral,anewlyplantedtreeshouldreceiveabout1”ofmoistureperweek,includingrainwater,duringthefirstgrowingseason.Checktherootzonefrequentlyformoistness—don’tjustguess.Manytreesarelosttoeitherunder-orover-watering.Containerizedtreesoftenneedmorewateringthanbare-rootorB&Bstock,becausetheporousgrowingmediumtheyarepottedindriesoutfaster.

FERTILIZING Iftherighttreewasselectedfortheplantingsite,fertilizerisgenerallynotneeded.Iffertilizerisdesired,useonlyaslow-release,low-nitrogenfertilizerappliedtothesoilsurfaceafterplanting.n Neveraddfertilizertotheplantingholesinceitcandamagenewlytransplantedroots.Inaddition,excessnitrogeninthesoilcancausenewlyplantedtreestoaddtopgrowthattheexpenseofproperrootdevelopment.

Post-plantingCareandOtherInformationn Addressmajorsoilproblemsbeforeplanting. Addingorganicmattertotheplantingsitebeforeplantingcanbeverybeneficialforpoor,inorganicand/orcompactedsoils.

PRUNING Atplantingtime, pruneonlytoremovedeadordamagedbranchesandtocorrectstructuraldefects.Nevercutbackhealthybranchesortrimthetreetotryand“balance”thetopwiththeroots.Thetreewillbenefitfromhavingasmanyfood-producingleavesleftonaspossible.Also,trytoleavelowerbranchesonatreeforasalongaspossibleafterplanting.Lowerbrancheshelpprotectthetrunkfromcracking,sunscaldandanimaldamageandtheyaidindevelopinggoodtrunktaper.Ifneeded,limbthetreeupgraduallyoveramatterofseveralyearsafterplanting.Monitorthetreewhenyoungandprune,sparinglybutproperly,topreventstructuraldefects.

Before planting a container-grown tree, examine the root system carefully and remove any excess potting soil and/or root massing above the trunk flare.For container-grown trees, it is important to try to straighten any roots found growing in a circle. If the roots cannot be carefully pulled straight, the root mass will likely need to be vertically scored (cut) in three or four places around the root mass.Nebraska tree enthusiasts and a properly planted tree in Cheyenne, Wyoming. From left: Dave Mooter (Kennard), Lyle Minshull (North Platte), Justin Evertson (Waverly), Chip Murrow (Lincoln), George and Gayla Probasco (Arapahoe), Deb Henderson (Hemingford).