United StatesDepartment ofAgriculture

Forest Service

Southern Research Station

Research PaperSRS–43

Mechanical Removal of Chinese Privet

John Klepac, Robert B. Rummer,

James L. Hanula, and Scott Horn

John Klepac, General Engineer, and Robert B. Rummer, Research Engineer, U.S. Department of Agriculture Forest Service, G.W. Andrews Forestry Science Laboratory, Auburn University, AL 36849; and James L. Hanula, Research Entomologist, and Scott Horn, Entomologist, U.S. Department of Agriculture, Forest Service, Forestry Sciences Laboratory, Athens, GA 30602-2044.

The Authors

January 2007

Southern Research Station200 W.T. Weaver Blvd.Asheville, NC 28804

The use of trade or firm names in this publication is for reader information and does not imply endorsement of any product or service by the U.S. Department of Agriculture or other organizations represented here.

PESTICIDE PRECAUTIONARY STATEMENT

This publication reports research involving pesticides. It does not contain recommendations for their use, nor does it imply that the uses discussed here have been registered. All uses of pesticides must be registered by appropriate State and/or Federal agencies before they can be recommended.

CAUTION: Pesticides can be injurious to humans, domestic animals, desirable plants, and fish or other wildlife if they are not handled or applied properly. Use all pesticides selectively and carefully. Follow rec-ommended practices for the disposal of surplus pesticides and their containers.

Cover Photo: Small tracked machine with horizontal mulching head removing Chinese privet at the Botanical Gardens in Athens, GA, during October 2005.

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Mechanical Removal of Chinese Privet

John Klepac, Robert B. Rummer, James L. Hanula, and Scott Horn

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Contents

Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Study Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Machine Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Mechanical Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Chemical Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

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Mechanical Removal of Chinese Privet

John Klepac, Bob Rummer, Jim Hanula, and Scott Horn

Abstract

Ch�nesepr�vet(Ligustrum sinense Lour.),ah�ghly�nvas�venonnat�veplant,�sprevalent�ntheSouthernUn�tedStates .Ch�nesepr�vet�nfestat�onscanh�nderregenerat�onofdes�rablespec�es,reducestandproduct�v�ty,andhaveotherundes�rableconsequences .Acomb�nedmechan�cal(mulch�ng)andchem�cal(tr�clopyr)treatmentwasappl�edtoCh�nesepr�vet�nforeststands�nGeorg�aonanexper�mentalbas�s .Thecostofremov�ngCh�nesepr�vetwasest�matedtobe$737peracrewhenatracked110-horsepowermulch�ngmach�neandatwo-personherb�c�deappl�cat�oncrewareemployed .

Keywords:Chem�caltreatment,Ch�nesepr�vet,Georg�a,�nvas�venonnat�veplant,mechan�caltreatment,mulch�ngmach�ne,tr�clopyr .

Introduction

Ch�nesepr�vet(Ligustrum sinense Lour.)�soneofthemost�nvas�venonnat�veplants�ntheSouthernUn�tedStates .It�nfestsm�ll�onsofacresand�sextremelyd�fficulttocontroldueto�tsadaptab�l�tytovar�ouss�tecond�t�ons(http://www .gwf .org/vol14no2 .htm) .Introduced�ntotheUn�tedStates�nthe1800s,�tarr�vedw�thoutthenaturalcontrolsof�nsectsandd�seasesthatkeepplants�nthe�rnaturalbalance(M�ller1999) .Naturalregenerat�on�nstands�nfestedw�thCh�nesepr�vetcanbeadverselyaffected,result�ng�naloss�nstandproduct�v�ty .M�llersuggeststhat�nvas�veexot�cplants�mpedeforestproduct�v�ty,h�nderforest-useact�v�t�es,andl�m�td�vers�tyandw�ldl�fehab�tat(M�ller1997) .

Recommendedcontrolmeasures(M�ller2003)�ncludevar�ousappl�cat�onsofherb�c�de .Controlbygroundspray�ngcanbeverylabor�ntens�ve,wh�leaer�alappl�ca-t�oncanbeextremelyexpens�ve .Inmanys�tuat�onsplantsaretootallforeffect�vetreatmentus�nggroundappl�ca-t�onmethods,mak�ng�tessent�alto�ncorporatealternat�vetreatmenttechn�ques .Forexample,�nject�ngherb�c�dearoundthetrunk�ntothecamb�umlayer�sonealternat�vebut�slabor�ntens�veandt�meconsum�ng .Us�ngacomb�-nat�onofmechan�calandchem�caltreatmentstocontrolth�s�nvas�vespec�esmayreducebothlaborrequ�rementsandtreatmentcosts .Although�neffect�vebythemselves,bothmechan�calandburn�ngtreatmentscang�veadd�-t�onalk�llofherb�c�de-weakenedplantsandmayhaveaplace�nan�ntegratedpestmanagementprogram(M�ller1999) .

Study Overview

Th�sstudywas�n�t�atedbytheInsectsandD�seasesofSouthernForestsResearchWorkUn�toftheUSDAForestServ�ce,SouthernResearchStat�on .Atotaloffours�tesweretreated,eachmeasur�ng3to5acresandcons�st�ngofbothbottomlandhardwoodandm�xedp�ne-hardwoodstands .S�teswerealllocatedw�th�nthefloodpla�noftheOconee,NorthOconee,orM�ddleOconeeR�vers .Theobject�vewastotreatallCh�nesepr�vethav�ngad�ameter>1�nch1footabovethegroundus�ngamulch�ngmach�ne .Somepr�vetexceeded6�nches�nd�ameteratthes�tes .Noothertreesw�thad�ameter4�nchesorlargerat4 .5feetabovegroundwerecut .Allpreex�st�ngcoarsewoodydebr�sontheground>6�nches�nd�ameterwasavo�ded,�fposs�ble .Aftermulch�ng,athree-personcrewtreatedcutstumpsw�tha30-percentm�xtureofatr�clopyrherb�c�de .Theefficacyoftheherb�c�detreatmentw�llbereported�nfuturepubl�cat�ons .

Product�ondatawerecollectedontwoofthes�tes—theSandyCreekNatureCenter(s�te1)andtheGeorg�aStateBotan�calGardens(s�te2) .Boths�tesarelocated�nAthens,GA .S�te1wasabottomlandhardwoodstandcompr�sedma�nlyofsweetgum(Liquidambar styraciflua),yellow-poplar(Liriodendron tulipifera),maple(Acerspp .),andelm(Ulmus spp .) .S�te1wasflatovermostof�tsarea,w�thabruptslopesof12to15percentalongapprox�matelyhalfof�tsper�meter .S�te2wasalsoabottomlandhardwoodstandw�thboxelder(Acer negundo),sweetgum,r�verb�rch(Betula nigra),sycamore(Platanus occidentalis),andp�ne(Pinusspp .)asthepredom�nantspec�es .S�te2wasflatover�tsent�rearea .However,th�ss�ted�dconta�nabeaverpondwh�chmeasuredapprox�mately1 .65acres .Thepondwastotallydrydur�ngdatacollect�onandnopr�vetwaspresent�nth�sarea,butgroundcond�t�onsweretoosofttoperm�tmach�neoperat�ononthedrypondbottom�nanycase .

Machine Overview

Themulch�ngmach�neusedhasa110-horsepowereng�neand�smountedon8-foot-longrubbertracks .Ithasalowgroundpressure(4 .2poundspersquare�nch)andwasappropr�ateforuse�ntheselowareas .Theheadhasahor�-zontalshaftand24fla�l-typeteeth,wh�chrotateat2,200

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revolut�onsperm�nute .Teethareattachedtotheheadw�thp�ns .Toothl�fe�saround150hours,wh�lep�nl�fe�sabout450hours(Personalcommun�cat�on .2005 .DonPenn�ngton,Contractor,GFALandClear�ng,1224DevonStreet,SE,PalmBay,FL32907) .Themach�nemakesa5 .5-footswathas�tworksthroughanarea .Thecontractorest�matedfuelconsumpt�onat6gallonsperhour .

Methods

T�mestudydatawerecollectedtodeterm�nemach�neproduct�v�ty�ntermsofacresperhour .Astopwatchwasusedtot�methemach�nedur�ngoperat�on .Observat�onsofthemach�nework�ngweretakenthroughouttheday .Aftert�m�ngwascompletedforanobservat�on,aglobalpos�-t�on�ngsystemun�twasusedtodeterm�nethes�zeofthetreatedarea .Fourobservat�onswerecollectedons�te1andthreeons�te2 .Inadd�t�ontot�mestudydata,travelspeedswerealsoest�mated .Forth�s,thetracklengthwasmeasuredtothenearest0 .1footus�ngalogger’stapeandthemach�newast�medasthelengthofthetrackwastraversed .

Wh�lethemach�neprogressedthroughastand,athree-personcrewfollowedupthemechan�caltreatmentbyapply�nga30-percentm�xtureofthetr�clopyrherb�c�detotheexposedcamb�umofseveredstumpsus�ngahandheldpressur�zedchem�calsprayer .

Table 1—Summary of elementary statistics for time study

Var�able S�te1 S�te2 S�te1 S�te2acres/pmh hours/acre

Mean 0 .18 0 .22 6 .97 5 .72Standarddev�at�on 0 .070 0 .120 4 .511 3 .166M�n�mum 0 .07 0 .11 4 .58 2 .88Max�mum 0 .22 0 .35 13 .73 9 .13

pmh=product�vemach�nehour .

Results

T�mestudydataareprov�ded�ntable1 .Themulch�ngmach�neaveraged0 .19acresperproduct�vemach�nehour(pmh)overall .T�mespenttreat�ng1acreaveraged6 .43hoursforthetwos�tes .Totalproduct�vet�mefors�te1was11 .5hours .Totalareatreatedwasabout2 .85acres,wh�chresulted�nagrossproduct�v�tyof0 .25acresperpmh .T�mestudydataest�matedaproduct�v�tyof0 .18acresperpmhfors�te1 .Fors�te2,totaltreatedareawasaround3 .20acres .Totalmach�net�mefors�te2was20 .5hours,wh�chgaveagrossproduct�onrateof0 .16acresperpmh .Aproduct�v�tyof0 .22acresperpmhwasest�matedfromthet�mestudydata .F�gures1and2�llustratepre-andpost-treatmentcond�t�onsofabottomlandhardwoods�te�nfestedw�thCh�nesepr�vet .

F�gure1—S�te1:Pretreatment .

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Mechanical Costs

Own�ngandoperat�ngcostsforthemulch�ngmach�newereest�matedus�ngamach�nerateanalys�s(M�yata1980)andaresummar�zed�ntable2 .Salvagevaluewasest�matedtobe20percentofthepurchasepr�ce(Br�nkerandothers2002) .An�nterestrateof10percentandan�nsurancerateof4 .5percent(Br�nkerandothers2002)ofthepurchasepr�cewereassumed .Fuelcostwascalculatedus�ng$2 .15pergallonford�eselfuelandafuelconsumpt�onrateof0 .0545gallonsperhorsepowerhour .Arateof36 .8percentoffuelcostwasusedtoest�matelubecost(Br�nkerand

others2002) .Arepa�randma�ntenancerateof100percentofannualdeprec�at�onwasassumed(Br�nkerandothers2002) .Costsforteethandp�nswerecalculatedus�ngfiguresobta�nedfromtalk�ngw�ththeowner .Foraforestryheavyequ�pmentoperator(occupat�oncode8160),arateof$15perscheduledmach�nehourwasused,plus30percentforbenefits .Mach�neut�l�zat�onwasassumedtobe75percent .

Theest�matedtotalcostof$71 .40perscheduledhour�ncludesown�ng,operat�ng,pluslaborandbenefits,and20percentforprofitandoverhead .Costperacre�stherat�ooftotalcostonapmhbas�stoaproduct�v�tyof0 .18acresper

F�gure2—S�te1:Post-treatment .

Table 2—Cost summary for the mulching machine

Var�able Cost Own�ng Operat�ng Totalcost $/acre

Purchasepr�ce($) 110,000Salvagevalue($) 22,000Deprec�at�on($/yr) 17,600Averageyearly�nvestment($/yr) 74,800Interest($/yr) 7,480 14 .22 25 .78 71 .40 529Insurance($/yr) 3,366Fuelandlube($/pmh) 17 .63Repa�randma�ntenance($/pmh) 11 .73Teethandp�ns($/pmh 5 .01Laborandbenefits($/smh) 19 .50

pmh=product�vemach�nehour;smh=scheduledmach�nehour .

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pmh .Thesemach�necostsreflecttheaveragecostsoverthel�feofthemach�neanddonotaccountfortaxes .

F�gure3�llustratesthesens�t�v�tyofcostperacretoproduct�v�ty,espec�ally�ntherangefrom0 .1to0 .5acresperpmh .An�ncrease�nproduct�v�tyfrom0 .2acresperpmhto0 .3acresperpmhresults�na33-percentreduct�on�ncostperacre .Alternat�vely,go�ngfrom0 .9acresperpmhto1acreperpmhresults�na10-percentreduct�on�ncost .

Chemical Costs

About6 .75gallonsoftheherb�c�dewereappl�edtocutstumpsateachs�te .Themarketpr�ceforth�stypeofherb�-c�de�saround$89pergallon .Th�sresults�natotalchem-�calcostofapprox�mately$200peracre .Toeffect�velytreatfreshlycutstumps,thechem�calappl�cat�onneedstobeconcurrentw�ththemechan�caltreatment .Inth�sstudy,athree-personcrewfollowedthemach�neandsprayedcutstumps .However,atwo-personcrewseemsadequateforth�ss�zemach�ne .U .S .DepartmentofLaborwageratesforbrushth�nners(occupat�oncode8010)�nGeorg�aare$11 .53perhour .W�th30percentbenefitsthelaborcostforatwo-personcrewwouldbearound$30perhour .Iftheoperat�on�sproceed�ngat0 .2acresperhour,thetotalcostofchem�calandlaborwouldbe$350peracre .Assum�ng20percentforprofitandoverheadresults�natotalchem�calandlaborcostof$420peracre .

Discussion

Themulch�ngmach�neused�ssmallandmaneuverable,andmaneuverab�l�ty�san�mportantfactorwhenoperat�ng

�nares�dualstand .However,thesmalls�zeofthemach�nealsoresulted�nlowproduct�v�ty�ntermsofacresperhourtreatedand,thus,h�ghertotaltreatmentcosts .Itseemsunl�kelythemach�neusedwouldbecapableoftreat�ngmorethan0 .3acresperpmhunderthecond�t�onsobserved�nth�sstudy .Atth�sproduct�onrate,mechan�caltreatmentcostwouldbearound$317peracre .Therefore,chem�calandmanuallaborcostsforchem�calappl�cat�onareanadd�t�onal$420peracreforatotaltreatmentcostof$737peracre .Alargermach�newouldbemoreproduct�ve,althoughh�gherown�ngandoperat�ngcostswouldalsobe�ncurred .Forexample,oneava�lablemach�newouldl�kelybeabletotreatatleast0 .75acresperpmh .W�thamach�nepr�ceof$300,000mechan�caltreatmentcostwouldbearound$292peracre .Aproduct�onrateof1 .25acresperpmhwouldresult�namechan�calcostof$175peracre,wh�ch�salsoposs�bleforthelargers�zemach�ne .

It�s�mportanttorecogn�zethatmechan�caltreatmentofpr�vet,by�tself,�snotacompletetool .Effect�veherb�c�deappl�cat�on�srequ�redtocontrolsprout�ng .Thecomb�nedoperat�onalcostsmeasured�nth�sstudyareabout$700peracrew�thoverhalfassoc�atedw�ththechem�calappl�ca-t�on .However,themulch�ngmach�negroundthestumpsdowntotheleveloftheso�landd�str�butedmulchedpr�vetovertheent�res�te .Th�smadefind�ngandtreat�ngstumpsd�fficult .Postpon�ngherb�c�detreatmentunt�lstumpsproutsappearandthenapply�ngfol�arherb�c�detok�llres�dualpr�vetwouldreducecostsbecauseafollow-upfol�arappl�-cat�onw�llberequ�redtok�llseedl�ngsandstumpsthatwerem�ssed .Alatefallorearlyw�nterfol�arappl�cat�onshouldeffect�velyk�llthepr�vetw�thm�n�mal�mpactonthenat�veplantcommun�ty(Harr�ngtonandM�ller2005) .

F�gure3—Effectofproduct�v�tyoncostperacreforthemulch�ngmach�neused .pmh=product�onmach�nehour .

Cost curve for the mulching machine used.

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Acknowledgments

Fund�ngfortheCh�nesepr�vetremovalstudywasprov�dedthroughtheUSDAForestServ�ce,StateandPr�vateForestry,ForestHealthProtect�on,Spec�alTechnologyDevelopmentGrantR8–2005–01 .Fund�ngfortheproduc-t�onstudyprov�dedbytheUSDAForestServ�ce,SouthernResearchStat�on,ForestOperat�onsResearchWorkUn�t .

Literature CitedGeorg�aW�ldl�feFederat�on .http://www .gwf .org/vol14no2 .htm/ .[Date

accessed:December2006] .

Harr�ngton,T .;M�ller,J .H .2005 .Effectsofappl�cat�onrate,t�m�ng,andformulat�onofglyphosateandtr�clopyrforcontrolofCh�nesepr�vet(Ligustrum sinense) .WeedTechnology .19:47-54 .

M�ller,J .H .1997 .Exot�cplantsare�nvad�ngsoutheasternforests .AlabamaW�ldl�fe .Spr�ng/Summer:36-39 .

M�ller,J .H .2003 .Nonnat�ve�nvas�veplantsofsouthernforests .Gen .Tech .Rep .GTR–SRS–62 .Ashev�lle,NC:U .S .DepartmentofAgr�cultureForestServ�ce,SouthernResearchStat�on .93p .

M�yata,E .S .1980 .Determ�n�ngfixedandoperat�ngcostsoflogg�ngequ�pment .Gen .Tech .Rep .NC–55 .St .Paul,MN:U .S .DepartmentofAgr�cultureForestServ�ce,NorthCentralResearchStat�on .16p .

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Klepac, John; Rummer, Robert B.; Hanula, James L.; Horn, Scott. 2007. Mechanical removal of Chinese privet. U.S. Department of Agriculture Forest Service. Res. Pap. SRS–43. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 5 p.

Chinese privet (Ligustrum sinense Lour.), a highly invasive nonnative plant, is prevalent in the Southern United States. Chinese privet infestations can hinder regeneration of desirable species, reduce stand productivity, and have other undesirable consequences. A combined mechanical (mulching) and chemical (triclopyr) treatment was applied to Chinese privet in forest stands in Georgia on an experimental basis. The cost of removing Chinese privet was estimated to be $737 per acre when a tracked 110-horsepower mulching machine and a two-person herbicide application crew are employed.

Keywords: Chemical treatment, Chinese privet, Georgia, invasive nonnative plant, mechanical treatment, mulching machine, triclopyr.

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