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opularsentimentisthatthesmalltreesin thelowercanopywhenreleasedwillbecome thelargetreesoftomorrow.Thisassump-tionhasbeenperpetuatedinthediameter-limitharveststhathaveledtowhatwecallhigh-gradingtoday.Thelargestandbesttreesarerepeatedlyharvestedleavingthesmaller,inferiortreestoper-petuatethenextstand.Inreality,thetreesbeingreleasedareprobablyofsimilarageasthosebeingcut.Thesmaller,releasedtreesdidnothaveachancetoprosperincompetitionwiththefaster-growing,overstorytrees.Thesereleasedtreesareincapableofcontinuedgrowthwiththeirsmall,spindlycrowns.Theconsequenceofremovingonlyhighlyvaluedtreeswitheachharvestisahardwoodresourcewitheverlowerlevelsofeconomicallyvaluabletrees.
Degraded,lowqualityorproblemhardwoodstandsgenerallyresultfromthehistoricabsenceofmarketsforlow-valuetrees.Aftermanyyearsofonlyharvestingthemostvaluabletrees,millionsofacresofdegradedstandsintheeasternhardwoodregionhavelittlelefttomanage.Thesestandsneedsilvicul-turaltreatmenttoincreasetheirvalueandproductiv-ity.Recentimprovementinthemarketsforpallets,ties,chipsandpulpwoodincreasesthemanagementoptionsavailablefortreatingdegradedstands.
Forestpractitionersandlandownersshouldunderstandwhyandhowtheseproblemstandswerecreatedsothatfewerofthesestandsoccurinthe
Degraded stand with fire-scarred trees and trees with poor form.
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Treatments for Improving Degraded Hardwood Stands Wayne K. Clatterbuck, Associate Professor, Forest Management and Silviculture, University of Tennessee, Knoxville
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future.Thegoalofthispublicationistoexplainwhyhardwoodstandsbecomedegradedandtodescribecorrectivemeasuresforimprovingdegradedhard-woodstands.
Degraded Hardwood Stands
DefinitionTheterm“degraded”inthismanuscriptincludes
alllow-qualityandproblemhardwoodstands.Asaresultofpastpractices,degradedhardwoodstandsusuallycontaintreesthatarecrooked,rottenordiseased;areofundesirablespecies;arephysicallydamagedfrompreviousloggingoperationsandarenotgrowingatasatisfactoryrate.Degradedstandsalsocontainpatchesoftoomanyortoofewtreesandregenerationofdesirablespeciesislacking.Mostimportantly,degradedstandsusuallydonotcontainlargevolumesornumbersofdesirablegrowingstocktrees(HaymondandZahner1985).Thesedegradedstandspresentgreatopportunities,buttoughchal-lengesforforestmanagement(McGee1982).Theopportunityforimprovingthesestandsisconsider-able,asmanyacresnowproducejustafractionoftheirpotential.
Itisassumedthatusually,butnotalways,thesestandshavebeencutoverandonlythebesttrees
removed.Butdegradedstandsalsooccuronlow-qualitysitesorasaresultoffire,insectsordisease.Itisalwaysimportanttodetermine“why”astandisdegraded.Ifthedegradedstandoccursonapoorsite,carefulplanningoftreatmentisrecommendedbecausethereislittlethatcanimprovetreegrowthonpoorsites.
How Did These Stands Become Degraded? Acauseofdegradedhardwoodstandsisrepeated
cuttingsthroughpractices(commonlycalledhighgrading,diameter-limitcuttingorselectcutting),wherethebesttreesareharvestedandpreviouslydescribednon-marketableanddefectivetreesareleft.Cuttingonlythelargestandbesttreesremovesthosetreesthatarebestsuitedforthesiteandleavestreesforgrowingstockthatarelessadaptedtothesite.Yet,repeatedhighgradingwithnostandimprovementhasprogressivelyremovedthebesttimberandleftthestandinadegradedcondition.
Mostoftheseharvestsareconductedforshort-termeconomicgain,withoutconsiderationforthegrowthandcompositionofthegrowingstockthatisleftandregenerationofthefutureforest.Histori-cally,theonlymarketsavailablewereforthebesttrees,whichpromoteshigh-grading.Thistypeofcuttingdoesnotmakeprovisionsfortheregenera-tionofmanydesirablespecies,especiallyoaksandhickories.Themostlyundesirable,shade-tolerantspecies(blackgum,redmaple,sugarberry,boxelder,hornbeam,sourwoodandbeech)inthemidstoryandunderstorypriortotheharvestremain,suppressingthegrowthanddevelopmentofdesirable,regenerat-ingspecies.However,withtheexpansionofmarketsforlow-qualityproducts,landownerswillhavemoreoptionsforaddressingdegradedstands.
Manyoftheseharvestsweredoneinthenameofgoodforestmanagement(Ezell1992).Landownersthoughtthatthelargetreesweretheoldertrees,sotheyremovedthemtogiveroomforyoungtreestodevelop.Wenowknowthatsmalltreesthatareleftarenotnecessarilyyoungtrees(Clatterbuck2004)andthatcuttingthebiggestandbesttreesoutofastandusuallyresultsindegradedstands.
Repeatedharvestingentriesintoastandusuallyresultindamagetosomeresidualtreesfromloggingwounds.Inadditiontopoorharvestingpractices,fire,insectsanddisease,wind,ice,grazingandgrapevineshavedegradedmanytreesinhardwoodstands.Whatwefindinmanydegradedstandstodayisamosaicofdegradedremnantsleftoverfrompreviousharvests,someregrowthofdesirablespecies
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Damaged trees usually do not improve with growth as shown by this fire-scarred yellow-poplar on a good site.
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andalargeproportionofshade-tolerantspeciesthatareundesirablefortimberproduction(Ezell1992).Often,standshaveapatchydistributionoftrees,includingcrowdedconditionsinsomeareas(over-stocked)andsizableopeningsorwidelyspacedtrees(understocked)inothers(Nyland2006).
Sitequalityisanothercauseofdegradedstands.Somesitesaresopoor,theyarenotcapableofgrowinggoodhardwoods.Thesesitesmightincludethethinsoilsanddroughtyconditionsfoundonexposedridgesandsteep,southslopes.Typicalspe-ciescompositionisblackjackoak,postoak,chestnutoak,easternredcedar,Virginiapineandvacciniums.However,manydegradedstandsoccuronmedium-tobetter-qualitysites.Better-qualitystandscanberegeneratedonthesesites(McGee1982).Inmostcases,ratherthanrepresentingthetruepotentialofstandsonthesesites,thetreespresentareoftenaresultofacombinationofharvestingpracticesandotherfactorssuchasburningorgrazing,andnotjustbecausethesiteispoor(Smalley1982,McGee1982,HaymondandZahner1985).Becauseofthepresenceofdegradedtreesonthesesites,manyland-
A degraded hardwood stand with oak decline.
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Causes of Stand Degradation
1.HighGradingorDiameterLimitLogging
• Reducesstemquality• Reducesmerchantablevolume• Maychangespeciescomposition• Promotescanopydiscontinuity• Changesdiameterdistribution
2.GrazingorFire---Increasesrotandcanreduceregeneration
3.RepeatedLoggingEntries---Loggingdamagetoresidualtreesand
regeneration
4.Insectsanddisease,wind,icestormsandotherfactors
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ownersandpractitionersinferthatthesesitesarepoor.However,withcarefulplanningandharvestofpoorertrees,thesebettersitescanproducebetterstandsofhardwoods.
Insummary,degradedstandsusuallyhavethefollowingfeatures(Nyland2006):
• fewtreesofdesirablespecies,goodvigororgoodformremainasgrowingstock,limitingthefuturepotentialforvolumeandvaluegrowth
• thestandoftenhasapatchydistributionofresid-ualtrees,resultinginincompletesiteutilizationandlittlecontroloverunderstorydevelopment
• limitedusablevolumeremains,makingfurthercuttingcommerciallymarginalorinfeasible
• fewlargeseedtreesremain,complicatingattemptstoestablishanewcohort
•understoryplantsmaydominatetheunderstory,particularlyinthemoreopenareas,furtherchal-lengingchancestoregeneratenewseedlingsacrossthestand
Why Does the Problem of Degraded Stands Persist?
Whilesomecausesofdegradedtreesarecon-trollable,themajorityofdegradedstandsarenotmanaged.Thesimpleansweristhatthelandownershavelittleeconomicincentivetoimprovethestand(McGee1982).Marketsfordegradedhardwoodsarenotgenerallyavailable,andwheretheydoexist,theincomeismarginalatbest.Moreoptionsareavail-abletorectifyadegradedsituationwhenmarketsexistforsmallandlow-valuematerial.
Improvementofsomeseverelydegradedstandsmayrequireacashoutlayandthecostofremovingpoortreesmayexceedthevalueofthestumpage.Manyownersarereluctantorunwillingtoinvestinthesestands.Oftentheyfeelthatotherinvestmentsmayyieldmorecertainresults.Moreover,timbermaybeviewedasaone-timewindfallratherthanalong-terminvestment.Someowners,awareofthelengthoftimeandassociatedriskofforestinvest-ments,choosenottospendfundsonthesestands.Often,becausetheycannotproperlyevaluatethesitepotentialandlackknowledgeofstandmanagementandmarkets,ownerscannotproperlyevaluatethepossiblereturnontheirinvestment(McGee1982).
Withdegradedstands,threeoptionsformanage-
mentaregenerallyavailable:(1)rehabilitatethestand,(2)regeneratethestand,or(3)postponeactionorleavethestandalone.
Unfortunately,leavingthestandaloneistheoptionusedtoooften,evenonsitescapableofgrow-ingqualitytimber.Rehabilitationofadegradedstandrequiresthemeasureofacceptablegrowingstock.Ifthereisnotenoughgrowingstocktopro-duceanewstand,thenregenerationofthestandisnecessary.Regeneratingthestandoftenhasthepotentialtocreateabetterqualitystandthanwhatiscurrentlyonthesite.
Corrective Measures for Degraded Hardwood Stands
Standdegradationcanoccurquickly,butusuallydevelopsoveralongperiodfollowingsuccessivehar-vestsandwildfire.Acceptablegrowingstock(AGS)referstotreesofcommercialanddesirablespeciesthatarecapableofincreasinginvalueandvolume,andareorcanbecomeviablecroptrees.Standsarenotconsideredseriouslydegradediftheycontainatleast50ft2ofbasalareaofAGSperacre.Degradedstandsusuallylacktreesinthesawtimbersizeclass.Thinningisusuallynoteconomicallyfeasiblein
Assessing Degraded Stands(Adapted from: Ezell 1992)
1.Performaforestinventory
2.Determinesitequality
3.Determinestockinganddistributionofdesirabletrees(AGS)
4.Considerspeciescomposition(desiredvs.unwantedtrees)
5.Estimatetreequalitybyconsideringtreeform,potentialtreegradeandtreecrownsofresiduals
6.Evaluateregenerationpotentialthrougharegenerationsurvey,bothdesirablespeciesandcontrolofinterferingvegetation
7. Estimateageofthestand
8.Determineobjectivesofmanagementandmarkets
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degradedstandsbecauseofthelackofgrowingstock.Thustoaddressdegradation,treatmentsshouldincreasegrowingstockeitherbyrehabilitationoftheexistingdegradedstandorbyregeneration. The major key to deciding to rehabilitate or to regenerate is the measure of adequate growing stock.Therec-ognitionandclassificationofAGSwilloftenrequireprofessionalassistance.
Determining a Course of Action
Degradedstandsmustbeevaluatedtodeter-minethecauseandtheleveloftheproblem,aswellastheirpotentialforvalueincreaseswithtreat-ment.McGee(1982)providesausefulchecklistforevaluatingandprescribingtreatmentsfordegradedandproblemhardwoodstands.Ezell(1992)andMcGee(1982)basestandevaluationonsixcrite-ria:sitequality,manageabilityoftrees,cullingoftrees,desirabilityofthespecies,advanceregenera-tionandstandage.Highlyproductivesitesbringahigherreturnoninvestment,sincethesite qualityisgreater.Themanageability of treesisdeterminedbyspecies,stemformandtheabilitytorespondtosil-viculturaltreatmentbasedoncrownposition(dom-
inant,codominant,intermediate,overtopped)andcondition.Crownconditionisevaluatedonthefull-nessorsizerelativetoexpectedsizeofatreeofthatheightanddiameter.Theestimatedbasalarea(measureofstanddensity)ofdesirabletreesfeasi-bleforfuturemanagementis30to50squarefeetperacreorabout40to50smallsawlog-sizetreesperacre.
Trees to be culledmayormaynotbeanassettothestand.Althoughtheymayhavelittletimbervalue,theymaybedesirabletowildlifeandtopoten-tialregenerationthroughsproutingorseedingiftheyareofapreferredspecies.Undesirable speciessuchasredmaple,beech,hickories,dogwoodandothersareusuallyshade-tolerant,takinggrowingspacefrommorevaluablespecies,orinhibitingregenera-tion,sotheyshouldbecontrolled.Theamountanddistributionofadvanced regenerationandtheseedingandsproutingofdesirablespeciesmustbeassessedtodetermineregenerationpotential.Theabilityofresidualtreestorespondtosilviculturaltreatmentsisrelatedtoage:young,vigoroustreeswithbalancedcrownshaveagreatercapacitytorespondtoreleasethanoldertreesapproachingmaturity.
Degraded stand with a few acceptable growing stock (AGS) trees.
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The Decision to RegenerateIfasufficientnumberofAGStreesarenot
presentinthedegradedstand,thenthestandshouldberegenerated,becauseanewyoungstandgenerallyhasthepotentialtocreateabetter-qualitystand.Methodsofregenerationincludeclearcut-ting,patchclearcut,shelterwoodandgroupselec-tion.Mosthardwoodspeciescanberegeneratedbyone,twoorallthreeofthesemethods.Thespecieslikelytobepresentfollowingtheregenerationhar-vestwillvaryforeachstandandwilldependuponmanyfactorsincludingadvanceregeneration,seedandsproutsources.
Obviously,desirablespeciesshouldbefavoredthroughpre-andpost-harvestsitepreparation.Equallyimportantisthedeterminationoftheunwantedspeciesthatmightneedtobecontrolled;simplyharvestingdegradedstandsandallowingnaturetotakeitscoursemaynotimprovethestandcomposition.Midstoryspeciessuchasmaple,black-
gum,dogwoodandbeechsproutprolifically,canbeaproblemandwillneedtobecontrolled(probablybyherbicides).
Mostspecieshavespecificpathwaysthatpromotesuccessfulregeneration.Yellow-poplar,sweetgum,blackcherryandashreproducefromseed;oaksandwalnutfromadvanceregeneration;andalmostallsmallhardwoodstumpswillsprouttosomedegree.Recognizingtheregenerationsources,regenerationmethods,siteproductivityandthegrowthhabitofeachspeciesandhowtheyallinter-actintheirassociatedcompetitiveenvironmentswillassistinyourassessmentofsitepreparationneedsforsuccessfulregenerationofthefavoredspecies.
Whilemosthardwoodsregeneratequicklyandreadilyfollowingsomeformofclearfelling,oneofourmostfavoredgroups,theoaks,presentsspecialregenerationproblems(LoftisandMcGee1993).Fortheoaks,advanceregeneration(pre-existingseedlingsfrom1to4feettall)mustbepresentor
A diameter-limit harvest leaving white oak trees with little potential to increase in value. The second photo is of the same tree 15 years after the harvest. Note that the tree still retains surface defects (knots and branches) that degrades the stem. The tree grew 1.5 inches in diameter in fifteen years after release.
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developedpriortothefinalharvest.Establishedadvanceregenerationgivesoaksaninitialadvan-tageoverfaster-growingspecies.Withoutadvanceregeneration,oakwillprobablynotbeacomponentofthenewstand.Seriousmistakesareoftenmadeassumingthatsmall(lessthan1foot)oakseedlingswillcompetewithfaster-growingyellow-poplar,birch,ashandlocustwhenreleased.Onhigher-qual-itysites,oakadvanceregenerationofsufficientsize(greaterthan4feet)andnumber(60to80peracre)mustbeculturedatleastthreetofiveyearsormoretoincreasetheprobabilitythatoakswillbecomeanoverstoryspecies(Stringer2005).Onpoorersites,oaksaremuchmorereadilyregenerated,oftenfromsmallstumps.
Regenerationofmostdegradedstandsrequiresremovalofoverstoryandmidstorytrees,usuallythroughclearcutting.Otherwise,thesetreeswillinfluencethegrowthanddevelopmentoftheregeneration.Ideally,theclearcutisachievedbyacommercialharvestandnocashoutlayisrequiredofthelandowner.However,manydegradedstandsmaynotcontainenoughtimbervaluefortheharvesttobeprofitable.Regardless,clearcuttingisanefficientregenerationmethodtoquicklyremedydegradedhardwoodstands.Fortunately,mostdegradedstandsregeneratereadilyfollowingclearcutting.
The Decision to Rehabilitate Standrehabilitationinvolvesimprovingthe
existingdegradedstandby(1)harvestinglessdesir-abletreesandretainingdesirablegrowingstock,and(2)securingandprotectingdesirableregenerationintheopenspaces.Nyland(2006)listsfourstepsthatoccurduringtherecoveryofdegradedstandswhenadequategrowingstockispresent.
•protectdesirableresidualtreesorgroupsoftreesbyremovingthepoorandundesirabletrees
•growthisconcentratedonresidualtreesofAGS
• regenerationfillsthespacesbetweenthewidely-spacedtrees
•enhancedesirableseedlingregenerationanddevel-opmentsuccessbycontrolling,withherbicides,interferingunderstoryandmidstoryvegetation
Theremovaloflessdesirabletreesprovidesmoregrowingspacefortheresidualtrees.McGee(1982)
callsthis“sparsetreeretention”anditleadsbrieflytotwo-agedstandstructure(Stringer2002)withasparse,olderageclassandaregeneratingageclass.Fromastandproductivitypointofview,thegrowthofthesparsetreescanproduceaquickreturnin10to20years(Milleretal.2004).However,whensparsetreesareharvested,damageislikelytooccurtothe10to20yearregenerationhardwoods.
Anadvantageofrehabilitatedstandswithtwo-agestructureisthatregenerationofthestandoccurswithoutclearcutting.Additionally,somefutureshort-termincomeisgeneratedfromreten-tiontreesthatotherwisewouldnotbeavailableifthesetreeswereharvested.Developmentofhigher-gradebuttlogsispossiblethroughadditionalgrowthwhenretentiontreesareselectedwiththepotentialtoincreaseingrade.Also,byleavingsomelargertreesonthesite,sexualreproductioncanstilltakeplace,providingseedforregenerationaswellasmastforwildlife.
Ontheotherhand,rehabilitatingstandsdoeshaveseveralpotentialproblems(McGee1982).Treesselectedforretentionmusthavetheabilitytogrowquicklyintohighersizeandvaluecategories.Epicor-micbranchingmayreducethegradeoftheseretained
Silvicultural Treatments for Rehabilitation of Degraded Stands
1. Two-agemanagementordefermentcuttingorsparsetreeretention
2.Sitepreparationtechniques(eitherpre-orpost-harvest)ofclearcutsanddefermentcutstofavorregenerationofdesiredspecies
3.Enrichmentplantings(ifprescribed)andcontrolofundesirablespeciesinthemidstoryandunderstory
4.Croptreereleaseofacceptablegrowingstock(AGS)
5.Adjustingharvestopeningsizetotargetadvantageousconditionsbasedonregenerationpresent,site-qualityconditionsandAGS
6.Considermixedpine-hardwoodstandsonlower-qualitysites
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trees.Inaddition,treesmustbeloggedandcullscontrolledwithoutphysicallydamagingtheretentiontrees.Manysmallertreesmustbecut,loppedandinjected,whichisusuallydoneasanexpense.Oncethesesmallertreesarecontrolled,thentheregenera-tionwillhaveanopportunitytogrowunhindered.Asretentiontreesreachharvestablesize,theremustbeameanstoharvestthesetreeswithminimaldam-agetothedevelopingregeneration.
Rehabilitatingdegradedstandsisnotapanacea.Itisastop-gaptreatmentthatprovidessomebenefitwhileshapingthestandtobemoreproductiveinthefuture.Manydegradedstandsdonothaveenoughdesirabletreestomaketheeffortworthwhile.Thedecisiontorehabilitateratherthanregenerateshouldbebasedonanobjectiveevaluationofavailablegrow-ingstock.Iftherehabilitatedstandcanprovidesomeincomeandlogsinthefuture,thestandcanbereha-bilitated;otherwise,thestandshouldberegenerated.Regardless,rehabilitatedstandswillprobablyneedtoberegeneratedin10to30years.
Choosing Other OptionsSitesonupperslopes,ridgesanderodedsoils
haveinherentlypoorproductivityandtendtoslowlygrowshort-bodiedhardwoodtrees.Manyofthesetreeshavebeensubjectedtofireandoccasionalcutting,whichhasfurtherdegradedstandquality.Thesesitesmaybebettermanagedforotherusessuchaswildlifehabitat.Anotherpossibilityismixedhardwood-pinestandswherepineisplantedatawidespacing(perhaps100ormorepinesperacre)andnaturalhardwoodsareallowedtogrowbetweenthepines(Mullinsetal.1998).Pinesarewell-adaptedtoandgrowatafasterratethanhardwoodsonthesepooreranddriersites.Theattractivenessofthistwo-stagemethodisthatthepinecanprovideanearlierincome,whilehardwoodsgrowforalon-gertime.
Manydegradedhardwoodstandsonlowproduc-tivitysitescanalsobeconvertedtopine.However,controlofhardwoodcompetitioncanbecostly.Marketsfordegradedhardwoodscansubstantiallyreducesitepreparationneeds.
Forked and poor quality trees remaining after repeated high-grading.
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Actionispostponedormanydegradedhardwoodstandsareleftalonewithsomehopethattheymayimprove.Degradedstandsarenotlikelytoimprovemuchwithouttreatment.Afewtreesperacremayincreaseinvalue,buttheculls,damaged,poorlyformedandundesirabletreeswillalsocontinuetogrow.Adegradedstandtodaywill,withoutsometypeoftreatment,remainadegradedstand.Ownersshouldcarefullyassesstheirpropertyanddeterminethepriorityofdegradedstandswithintheirmanage-mentgoals.
Enrichmentplantingisalow-costcompromisebetweendoingnothingandspendingthetimeandmoneytocompletelyharvestandregeneratethestand(HaymondandZahner1985).Whereacertainspeciesissparseorabsent,enrichmentplant-ingwouldallowtheintroductionofoneormoredesirablespecieswithoutcompletelyregeneratingthestand.Competingvegetationinthevicinityoftheplantedseedlingmustbecontrolledtogivetheplantedseedlingachancetoprosper.Anothermethodistoplantseedlingsaftercompletevegeta-tionremoval(clearcutting)toenhanceaspeciesthatmaynotbepartofthenaturalregenerationpool.Enrichmentplantinghasbeendiscussedbypractitionersandresearchers,butfewtrialshavebeenconducted,especiallyinplantinghardwoodseedlingsinaresidualhardwoodstand.Althoughrecommendationscannotbemadebasedonresearchdata,introducingpinesinhardwoodstandstocreateadiversified,mixedstandhasbeensuccessfulonmedium-tolow-qualitysites(Mullinset.al1998).
Anotheralternativemightbetoadjustmanage-mentsoonlyportionsofthestandaretreatedwithaprescriptionratherthantreatingtheentirestand.Thisalternativeisappropriateintargetedareaswherestocking(AGS)isfavorableoronbetter-qual-itysites.Inthesecircumstances,methodstoenhanceindividualtreedevelopmentmaybemorepositivethanstandleveltreatments.Managingthesizeofopeningsisameansofprovidingregenerationtotar-getedareaswithinstands(LeDoux1999).Crop-treerelease(Mercker2004;Stringeretal.1988)canbeparticularlyusefulwhenfocusingonindividualtrees.
SummaryDegradedhardwoodsilvicultureiscomplex,due
totherangeofspecies,sitesandlevelofdegradation.Degradedstandsoftenresultfrommistreatmentandneglect,butsomepoorstandsresultfromnaturalcauses.Mostanysetoftreatmentsthatcanbeprescribedthatwillimprovethestandwill
Factors That May Affect Degraded Stands
1.Standswithmorethan50squarefeetofbasalareaperacreofacceptablegrowingstock(AGS)aregenerallynotconsidereddegraded.
2.Normalthinningisgenerallynotpracticalindegradedstands,buttimberstandimprove-ment(TSI)toremoveunwantedtreesmaybe.ThereisnotenoughAGStojustifyathinning.Regenerationharvestingandthinningareseparateoperationswithdifferentpurposes.Thinningisanintermediateoperationtopro-moteresidualtrees.Regenerationharvestingistoinitiateanddevelopregeneration.
3.Capitalisusuallylimitedforimprovingdegradedstands.Thecostsandbenefitsofpracticesshouldbecarefullyconsidered.Dividingstandsmaybenecessarybecausedegradedstandsoftenhaveareasthatshouldberegeneratedandareaswhereresidualtreescanbemanaged.Itmightbeacceptabletocultureportionsofthestandratherthanimplementingtreatmentsacrosstheentirestand.
4.Generallytreathigh-qualitysitesfirst.
5.StandregenerationisthebetteralternativethanstandrehabilitationwhenAGSisnotadequate.
6.Two-agemethodsaresuggestedfortreat-mentofdegradedstandsinestablishingviableanddesirableregenerationaswellassomepotentialincreaseinvalueoftrees.Favoredresidualtreesorgroupsoftreesshouldbewidelyspacedwithregenera-tionbeingpromotedintheopenspacesbetweentrees.
7.Treatmentofatolerant,undesirablemidstoryandunderstoryisusuallynecessary.Pre-harvestsitepreparationcostsmaybelowerinhardwoodstandsthanpost-harvestactivities.
8.Onlower-qualitysites,considermixedpine-hardwoodstands.
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resultinbetterconditionsandincreasedproductivity,butcomeatacostthatmaybeaseriousdeterrent.Judgingwhetherenoughacceptablegrowingstockispresentiskeyindeterminingwhethertorehabilitateortoregeneratedegradedstands.Thereisnoperfect,one-size-fits-allmethodforsuccess.Individualstandconditionsmustbeassessedandtechniquesappliedthatwouldbringthestandclosertoconditionsfavor-ableforproducingdesirabletrees,whilekeepingcostsataminimum.Mostlandownersareinterestedandprefertodosomethingenvironmentallypositivetoreturndegradedstandstomoredesirableconditions.Standrehabilitation,whereappropriate,andregenera-tion,wherenecessary,willsetthestageforagradualstandrecovery.
ReferencesClatterbuck,W.K.2004.Bigtrees,littletrees
–Istherealwaysacorrelationwithage?ForestLandowner63(1):26-27.
Ezell,A.W.1992.Evaluatinghigh-gradedhardwoodstands.Publication1834.MississippiState,MS:MississippiStateUniversity,CooperativeExtensionService.6p.
Haymond,J.L.,R.Zahner.1985.Forestryacrebyacre:Improvinglow-qualityoak-pinewoodlands.Bulletin131,Clemson,SC:CooperativeExtensionService,ClemsonUniversity.37p.
LeDoux,C.B.1999.Anintegratedapproachfordeterminingsizeofhardwoodgroup-selectionopenings.ForestProductsJournal49(3):34-37.
Loftis,D.L.,C.E.McGee,eds.1993.Oakregeneration:Seriousproblems,practicalrecommendations.GeneralTechnicalReportSE-84.Asheville,NC:U.S.DepartmentofAgriculture,ForestService,SoutheasternForestExperimentStation.319p.
McGee,C.E,1982.Low-qualityhardwoodstands.OpportunitiesformanagementintheInteriorUplands.GeneralTechnicalReportSO-40.NewOrleans,LA:U.S.Dept.ofAgriculture,ForestService,SouthernForestExperimentStation.22p.
Mercker,D.C.2004.Croptreereleaseinprecommercialhardwoodstands.PublicationSP559.Knoxville,TN:UniversityofTennessee,Extension.8p.
Miller,G.W.,J.N.Kochenderfer,D.Fekedulegn.2004.Compositionanddevelopmentofreproductionintwo-ageAppalachianhardwoodstands:20-yearresults.In:Silvicultureinspecialplaces:ProceedingsoftheNationalSilvicultureWorkshop.RMRS-P-34.FortCollins,CO:U.S.DepartmentofAgriculture,ForestService,RockyMountainResearchStation.p.171-181.
Mullins,J.A.,E.R.Buckner.T.A.Waldrop,R.M.Evans.1998.Sitepreparationtechniquesforestablishingmixedpine-hardwoodstandsinthesouthernAppalachians.GeneralTechnicalReportSRS-20.Proc.,9thBiennialSouthernSilviculturalResearchConference(T.A.Waldrop,ed.).Asheville,NC:U.S.DepartmentofAgriculture,ForestService,SouthernResearchStation.p,22-25.
Nyland,R.D.2006.Rehabilitatingcutoverstands:Someideastoponder.GeneralTechnicalReportNE-342.Proc.,ConferenceonDiameter-LimitCuttinginNortheasternForests(L.S.KeneficandR.D.Nyland,eds.).NewtownSquare,PA:U.S.DepartmentofAgriculture,ForestService,NortheasternResearchStation.p.47-51.
Smalley,G.L.1982.ClassificationandevaluationofforestsitesontheMid-CumberlandPlateau.GeneralTechnicalReportSO-38.NewOrleans,LA:U.S.Dept.ofAgriculture,ForestService,SouthernForestExperimentStation.58p.
Stringer,J.2005.Oakshelterwood:Howtoapplythesystemtostimulateoakregeneration.ForestLandowner64(3):27-29.
Stringer,J.W.2002.Oakregenerationusingthetwo-agedsystem.GeneralTechnicalReportSRS-48.Proc.,11thBiennialSouthernSilviculturalResearchConference(K.W.Outcalt,ed.).Asheville,NC:U.S.DepartmentofAgriculture,ForestService,SouthernResearchStation.p.379-382.
Stringer,J.W.,G.W.Miller,R.F.Wittwer.1988. Applyingacrop-treereleaseinsmall-sawtimber
whiteoakstandsResearchPaperNE-620.Broomall,PA:U.S.DepartmentofAgriculture,ForestService,NortheasternForestExperimentStation.5p..
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Regeneration Potential Recommendations for Degraded Stands
Species Acceptable Unacceptable
Stem Quality Good Poor Good/Poor
Vigor/Age Vigorous/Young Poor/Old Vigorous/Young Poor/Old Vigorous/Young Poor/Old
RegenerationPotential
AdequatePresent
CompleteregenerationpossibleConcentratesitepreparationforregenerationonunwantedoverstoryandmidstorytreesOR
Culturesparseoverstorytrees
Completeregenerationrequiredinnearfuture
Concentratesitepreparationonoverstoryandmidstorytrees
Completeregenerationrequired
Concentratesitepreparationforregenerationonunwantedoverstoryandmidstorytrees
Completeregenerationrequired
Concentratesitepreparationforregenerationonunwantedoverstoryandmidstorytrees
RegenerationPotentialCurrently
InadequatePresent,butinneedofculturing
tobecomeadequate
Postponeharvest
Usemidstoryremoval.
Ifharvestisrequired,leavegroupsofoverstorytreesConcentratesitepreparationforregenerationoncompetingunderstoryvegetation
Postponeharvest
Usemidstoryremoval
Ifharvestisrequired,leavegroupsofoverstorytrees
Concentratesitepreparationoncompetingoverstoryandmidstorytrees
Postponeharvest
Usemidstoryremoval
Ifharvestisrequired,concentratesitepreparationonoverstoryandmidstorytrees
Postponeharvest.Usemidstoryremovaltocultureregeneration
Ifharvestisrequired,concentratesitepreparationforregenerationonoverstoryandmidstory
RegenerationPotential
InadequateNotpresent
Postponeharvest
Culturespareoverstoryuntiladequateregenerationisestablished
Ifharvestisrequired,considerleavinggroupsofoverstorytrees
Completeregenerationrequired
Considercompleteorpartialartificialregeneration(speciesenrichment,mixedpine/hardwood,orcompletepineconversion)
Postponeharvest
Retainpoor-formedoverstoryasaseedsourceforregeneration
Ifharvestisrequired,considerleavinggroupsofoverstorytrees
Completeregenerationrequired
Considercompleteorpartialartificialregeneration(speciesenrichment,mixedpine/hardwood,orcompletepineconversion)
Completeregenerationrequired
Considercompleteorpartialartificialregeneration(speciesenrichment,mixedpine/hardwood,orcompletepineconversion)
Source: Adapted from Dr. Jeff Stringer, Dept. of Forestry, University of Kentucky
11
R12-4910-026-002-06SP680-1.5M-6/0606-0335
A Regional Peer-Reviewed Technology Extension Publication
ProfessionalHardwoodNote#6forTennesseeandKentucky
PublishedasUniversityofKentucky’sCooperativeExtensionpublicationFOR-104
PublishedasSouthernRegionalExtensionForestrypublicationSREF-FM-009
PartialfundingofthispublicationprovidedbyTennesseeDepartmentofAgriculture,DivisionofForestry
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