Subjectreview–Pregledni rad
Croat. j. for. eng. 33(2012)2 357
Life Cycle Assessment (LCA)
in Forestry – State and Perspectives
Hans Rudolf Heinimann
Abstract – Nacrtak
Environmentally sound technologies are a key to reduce resource use and environmental impact. The paper reviews the state of knowledge of an analysis tool, life cycle assessment (LCA), by addressing three issues: 1) methodological foundations of LCA, 2) lifecycle inventory modeling, and 3) environmental performance indicators for wood supply systems. The study results in the following findings: 1) LCA is still not widely used and accepted in the forest operations engineering. 2) Only a few studies are based on state-of-the-art life cycle inventory analysis. 3) The boundaries of the studied systems are often too narrow, limiting comparability with standard LCA studies. 4) Most forest-related studies are based on direct process energy input only and are neglecting environmental burdens of upstream processes. 5) »Truncated LCAs«, neglecting embodied burdens of road infrastructure and forest machines always result in an underestimation of environmental impacts or an overestimation of environmental performance, respectively. There is a need for LCA capacity building in the forest operations community, on the basis of which forest-related LCA studies should become more comprehensive and comparable with studies of the core LCA community.
Keywords: LCA, environmental performance, wood supply, eco-efficiency, industrial ecology
1. Introduction – UvodThereisabroadconsensusthatmankindhasto
exploreandimplementpathwaysofdevelopmentthatminimize resource use while reducing emissions,wasteandimpactstostructuresandfunctionsoftheenvironmentalsystemto»nearzero«.Environmen-tallysoundtechnologies(ESTs)wereidentifiedasakeytoachievethisbroad,long-termgoal.ESTsencom-passtechnologiesthathavethepotentialtosignifi-cantly improve environmental performance, com-paredwithothertechnologies(UNEP-IETC,online).Followingthequote»whatgetsmeasuredgetsdone«,whichisattributedtoPeterDrucker,thereisaneedtoapplyand improveenvironmentalanalysis tools toproducereliable,comprehensibleenvironmentalper-formanceindicators.Thedevelopmentsincetheearly1990sledtoawholesetoftools,suchas1)lifecycleas-sessment(LCA)forproductsystems(ISO2006b),2)regionalmaterialflowanalysisforgeographicalregions(Hendriksetal.2000),or3)carbonbudgetmodelsforlarge-scalegeographicalareas(Kurzetal.2009).Those
tools,designedfordifferentcontexts,aresomewhatembeddedintheumbrellaconceptof»industrialecol-ogy«,whichlooksatindustrialsystemsthesamewayasecologistshavebeenlookingatecosystems(Erkman1997).Thekeyissueistounderstand,modelandman-agethe»industrialmetabolism«,particularlytheflowofmaterialsandenergy,tocontinuouslyincreaseenvi-ronmentalperformance(forthehistoryoftheindus-trialmetabolismthinking,see(Fischer-Kowalski1998a,b)).TheideasgobacktopioneerssuchasRobertAyres(AyresandKneese1969);CharlesHall(Halletal.1979);andHowardT.Odum(Odumetal.1977),whosethoughtsstimulatedUlfSundberg,aforestoperationsengineeringscholar,toperformsomepreliminaryen-ergyanalysisstudiesofforestoperationssystems(Sun-dbergandSvanqvist1987).Forestryhasbeenatraditionalsupplierofrenew-
ablerawmaterialsforindustrialuse(sawmilling,pulpandpaper,particleboards,etc.),forhouseholdfuelwood,particularlyintheThirdWorld,andincreas-inglyforbiofuels.Fromaproductioncontextpointof
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358 Croat. j. for. eng. 33(2012)2
Table 1 Positioning of LCA within set of environmental assessment and policy tools. LCA addresses the level of product systems by model-ing the life cycle of a productTablica 1. Položaj analize životnoga ciklusa unutar grupe alata okolišne politike i alata analize utjecaja na okoliš. Analiza životnoga ciklusa odnosi se na razinu sustava proizvoda, određujući životni ciklus proizvoda
Level of Action
Razina djelovanjaDefinition – Definicija
Environmental Policy Tools
Alati okolišne politike
Environmental Analysis Tools
Alati analize učinka na okoliš
Policy
Politika
A defined course of action, for guiding present and future decisions, as a result of a political weighting of interest
Definirane smjernice aktivnosti za donošenje sadašnjih i budućih odluka, a rezultat su političkoga interesa Strategic Environmental
Assessment SEA
Strateška procjena okoliša
Sustainability Impact Assess-ment SIA
Procjena učinka na potrajnost
Program
Program
A portfolio of actions, directed to a sectorial policy and usually allocating financial resources
Područje aktivnosti usmjereno na politiku sektora i dodjelu financijskih sredstava
Plan
Plan
Localization and temporal definition how and with what priority public actions should be implemented
Lokaliziranje i privremeno definiranje aktivnosti koje će se i s kojim prioritetom provesti
Project (public)
Javni projektA set of activities that is 1) limited in time, 2) directed to create a clearly defined output, 3) considering financial
constraints, and 4) fulfilling quality requirements
Skup aktivnosti koji je 1) ograničen vremenom, 2) ima jasan zadatak, 3) ograničena financijska sredstva i 4) zadovoljava
uvjete kakvoće
Environmental Impact Assessment EIA
Procjena učinka na okoliš
Sustainability Impact Assess-ment SIA
Procjena učinka na potrajnost
Project (private)
Privatni projekt
Product System
Sustav proizvoda
Collection of materially and energetically connected unit processes which perform one or more defined functions (ISO
14050)
Skup materijalnih i energetskih postupaka kojima se izvršava točno zadana zadaća (ISO 14050)
Eco-Labeling
Ekoobilježavanje
Eco-Auditing
Ekoispitivanje
Life Cycle Assessment LCA
(E-LCA, S-LCA)
Procjena životnoga ciklusa
view,LCAisasuitabletooltoassesswoodsupplysystems,becauseitwasdesignedforproductsystems(ISO2006b).Recenteffortsfosteringthedevelopmentanddeploymentofenergysystemsthatarebasedontherenewableresourcesshouldfolloweco-efficientpathways,whoseperformancehas tobebasedoncomprehensiveassessmentmethods.Thepresentpa-peraimstocriticallyreviewenvironmentalperfor-manceassessmentfromaLCA-perspective.Thepa-perlooksatwood-basedrawmaterialpathwaysonly,andalsoneglectsproductionimpactsonforestsoils.AssumingthatLCAhasnotbeenwidelyappliedandacceptedwithintheforestoperationsengineering,thepaperfirstreviewsthemethodologicalfoundationofLCA, then looksat the stateof lifecycle inventorymodeling,andfinallysynthesizesthestateofknowl-edgeonenvironmentalperformanceindicatorsforwoodproduct, forest roadandbioenergyproductsystems.
2. LCA Methodology – Metode analize životnoga ciklusa
AlthoughLCAwasstandardizedatthebeginningofthe1990s,theunderlyingmethodologyisnotwide-lyknownandacceptedwithintheforestsciencecom-munity.Therefore,itisusefultopositionLCAwithinthewholesetofenvironmentaltools,toexplaintheLCAframework,andtopresentthegenericapproachtomodellifecycleinventoriesinthefollowingpara-graphs.
2.1 Positioning of LCA within the set of environ-mental tools – Položaj analize životnoga ciklusa unutar grupe alata za procjenu utjecaja na okolišLifecycleassessment(LCA)isamethodtoquan-
tifyandimproveourunderstandingofpossibleim-pactsassociatedwithproductsaiming1)toidentify
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opportunities for environmental performance im-provement,2)toinformindustrialdecision-makersonthedevelopmentofproductsandonthedesignorre-designofmanufacturingprocesses,3)toselectandquantifyenvironmentalperformanceindicators,and4)toproveenvironmentalsoundnessforeco-labelsorenvironmentalclaims(ISO2006a).However,LCAisembeddedinawholesetofenvironmentaltools(Table1),andthereisstillsomeconfusionaboutthepurposeandscopeofdifferenttoolsandaboutwhichtoolismostappropriatetotackleaspecificproblem.Thesuccessofenvironmentalpolicies,aimingto
mitigateandlimitexhaustiveresourceuse,pollutionandwastedisposal,isonlyvisibleafteractionsaffect-ingtheenvironmenthavebeenimplementedontheground.Awholesetofenvironmentaltoolswasde-velopedtofosteraprocessofchange,leadingtoenvi-ronmentallymoresoundbehavior.Table1presentsanoverview,organizedalongtwodimensions.Thefirstdimensionrepresentsthelevelofaction,frompoliciestoprograms,projectsandproductsystems,whereastheseconddimensioncharacterizesthetypeoftools:1) analysis tools and2)policy tools (UdodeHaes1996a).Analysis toolsaddress thequantificationofeco-efficiencymetrics,aimingatansweringquestionslike»howdoesapackagesystemperformcomparedtoanew,alternativesystem«.Policytools,ontheoth-er hand, are »instruments throughwhich govern-mentsseektoinfluencecitizenbehaviorandachievepolicypurposes«(SchneiderandIngram1990).Strategicenvironmentalassessmentisapolicytool
toinfluenceenvironmentalsoundnessofpolicies,pro-gramsandplans,whereasenvironmentalimpactas-sessmentaimsatimprovingtheenvironmentalsound-nessofprojects(Anonymous2002,2009).Thepurposeofimpactassessmentistoensurethatenvironmentalconsiderationsareexplicitlyincorporatedintothede-velopment decision-making process (Anonymous1999,2002,2009);itthereforeaimstoinfluencethebe-haviorofmainlypublicdecision-makers,e.g.theau-thorities responsible to approveproject proposals.Sustainabilityimpactassessmenthasitsoriginsinthefamilyofenvironmentalassessmentprocesses(SEAandEIA)andreflectsthe»triplebottomline«approachtosustainabilitybyconcurrentlyassessingenviron-mental,economicandsocialimpactsofproposedin-terventions(Popeetal.2004).Eco-labelsandeco-au-ditingaretwopolicytoolsaddressingtochangethevaluesandperceptionsofconsumersandproducers,respectively.Eco-labelingisastatement,symbolorgraphicthatindicatesanenvironmentalaspectofaproduct, a component orpackaging,whereas eco-auditingisasystematicverificationprocesstodeter-
minewhereactivitiesormanagementsystemscomplywithnormativestandards(ISO2002).Lifecycleassessmentbegantoemargeattheendof
the1960swhentheMidwestResearchInstitutecon-ductedastudyonresourcerequirements,emissionsandwaste ofdifferent beverage containers for theCoca-ColaCompany(Guinéeetal.2010).Similarstud-iesfollowedintheUSandinSwitzerland,investigat-ing environmental burdens of containersmade ofPVC, glass, sheetmetal and cardboard.However,therewasalackofacommontheoreticalframeworkandofmethodologicalconsistency(differentnameswereinuse,suchas»eco-balance«or»resourceandenergyproductionanalysis«),affectingthecompara-bilityofresultsandpreventingLCAtobecomeanac-ceptedanalyticaltool(Guinéeetal.2010).Bytheendof the 1980s, SETAC, the societyof environmentaltoxicologyandchemistry,tookresponsibilityforthetheoretical foundation and the standardization ofLCA,whichresultedinacodeofpractice(Consolietal.1993).InEurope,thetwoguidelinesdevelopedbythecenterofenvironmentalscienceintheNetherlands(Heijungs1992a,b)hadaconsiderableimpactontheLCApracticebecausetheypresentedamathematicalframeworktohandleevenhugesetsofinterrelatedprocesses.Themathematicalformalismisbasedonformerworkof(AyresandNoble1978;Koopmans1951a,b).In1994,ISO–internationalstandardsorga-nization–startedtodeveloptheISO14000standardsseries(Marsmann1997),addressingallaspectsoflife-cyclemanagement(ISO2006a),particularlyLCAprin-ciplesandframework(ISO2006b),LCArequirementsand guidelines (ISO 2006c), LCA vocabulary (ISO2002), and environmental performance evaluation(ISO1999).In2002,SETACtogetherwithUNEP–UnitedNa-
tions environmentprogram– started the so-calledlifecycleinitiative(Guinéeetal.2010),aimingtofosterlifecyclethinkingandtointegratethe»triplebottomline«(economic,social,andenvironmental)philoso-phyforgoodsandservices.Lifecycleassessment,nowcalledenvironmentallifecycleassessment–E-LCAhasmainlybeenfocusingonimpactsonthenaturalenvi-ronment,whereaslifecyclecosting–LCCaddressesthedirectcostsandbenefitsforpeople,planetandprosperity(UNEPandSETAC2009).Atooltoassesstheimpactofaproductsystemonhumanwell-beingandcorporatesocialresponsibilitywasmissing,andthelifecycleinitiativeresultedinframingandconcep-tualizinganewtool,sociallifecycleassessment–S-LCAtofill thisgap(UNEPandSETAC2009).Thisbroader,moreholisticapproachcoversallaspectsofthetriplebottomline–people,planet,andprosperity
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360 Croat. j. for. eng. 33(2012)2
–andisalsocalledlifecyclesustainabilityanalysis–LCSA(Guinéeetal.2010).Thestandardizationeffortstriggeredtheintroduc-
tionofLCAintoforestryandforestindustries.OneofthefathersofLCA(UdodeHaes1996b)presentedthe»bottlenecks« thatprimaryproductionwas facing,particularly the definition of the upstream systemboundaryandco-production,whichrequirespecialallocationrules.AtthesametimeafirstconferencewasorganizedinGermany(Frühwald1995),andthemainLCAactivitiesrelatedtoforestsectoremergedinLCApioneeringcountries(Guinéeetal.2010),suchastheUS,Sweden,Switzerland,GermanyandFin-land.TheNordicpulpandpaperindustrystartedaninitiativetodevelopajointmethodologyforlifecycleinventories for forest industry in 1993 (Kärnä andEkvall1997),resultinginthedefinitionofparametersandunitsofmeasureandinapropositionofallocationrules.Atthesametime,thefirstLCAstudiesonforestoperationsandlong-distancetransportationoftimber(KarjalainenandAsikainen1996)andoneco-invento-ries of forest machines and processes (Berg 1995;Knechtle1997;ZimmerandWegener1996)appeared,yieldingoperationalperformanceindicators,particu-larlyrelatedtoenergyconsumptionandCO2emis-sion.HarmonizationeffortscontinuedwiththeEuro-peanCOST-action»lifecycleassessmentofforestandforestproducts«,whichpublishedthefindingsin2001(Karjalainenetal.2001).Lifecycleinventoriesoffor-estryandforestindustryprocessesstartedtobeinves-tigatedsystematicallyandenteredintolifecycle-inven-
tory databases, such as ecoinvent (ECOINVENT,online),orProBas(PROBAS,online).AnewwaveofLCA-typestudiesforforestoperationsappearedafter2005,e.g.(Valenteetal.2011a;Valenteetal.2011b),probablytriggeredbytheincreasinginterestinrenew-ableenergy.However,thestreamofresearchseemssomewhattobedelinkedfromtheLCAcommunity.
2.2 LCA framework – Okosnica analize životnoga ciklusaTheproceduralLCAframework,consistingof1)
goalandscopedefinition,2)inventoryanalysis,3)im-pact assessment and 4) interpretationhas been thefoundationofLCA.Table2presentsthefourphasesofLCAandthedefinitionfollowingtheISO14,000stan-dards.Therearetwocriticalissuesinscopedefinition,1)thedeterminationofsystemboundariesand2)thedefinitionofthefunctionalunit.Aswewillshowlater,systemboundariesareoftennotclear,particularlyinthe»upstream«direction.Theenvironmentalsystemhastobepartoftheanalysis,characterizedbyinputflowssuchasCO2,solarenergy,mineralresourcesandland(occupiedandtransformed).Inventoryanalysesconsistsofmappingthestructureandfunctionsoftheproductsystem,usuallyintheformofaprocessflowdiagramthatisthebasisforthefollowingmodelingofmaterials,energy,emissionandwasteflows.Inventoryanalysis is theheartofLCA, takingaconsiderableamountoftimeandbeingextremelydataintensive.Lifecycleimpactassessmentassignstheresultof
inventoryanalysistospecificimpactcategories,such
Table 2 Definition and positioning of LCA phases as defined by the ISO standardTablica 2. Određivanje i pozicioniranje faza analize životnoga ciklusa, opisanih u normama ISO
Phase – Etapa Definition – OpisRequired knowledge
Potrebno znanje
Goal and scope definition
Cilj i značaj definicije
Goal definition, e.g. environmental performance comparison of alternative systems
Definicija cilja, npr. usporedba okolišne pogodnosti alternativnih sustava
Scope definition, particularly determination of 1) system boundaries, 2) functional unit.
Značaj definicije, poglavito određivanje 1) granica sustava, 2) funkcionalnih jedinica
Systems theory
Teorija sustava
Inventory analysis – LCI
Analiza zaliha – LCI
Inventory modeling of input/output flows for specified product system(s)
Modeliranje ulaznih i izlaznih tokova za određeni proizvodni sustav
Systems theory, process engineering
Teorija sustava, tehnike postupaka
Impact assessment – LCIA
Procjena učinaka – LCIA
Impact assessment: assignment of LCI results to specific impact categories
Procjena utjecaja: zadatak utjecaja životnoga ciklusa na određene kategorije
Environmental science, Eco toxicology
Znanost o okolišu, Ekotoksikologija
Interpretation
Tumačenje
Conclusions and recommendations for process improvement.
Zaključci i prijedlozi za poboljšanje postupka
Critical thinking – Kritičko promišljanje
Decision making – Odlučivanje
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asdepletionofnonrenewableandrenewableresourc-es,greenhouseeffect,ozonedepletion,humantoxicity,acidification,etc.(Heijungs1992b).Finally,lifecycleinterpretationformulatesconclusionsandrecommen-dationsastohowtheenvironmentalperformanceofproductsystemsmaybeimproved,orwhatalterna-tiveofdifferentproductsystemsperformsbest.
2.3 Life Cycle inventory modeling of a product system – Životni ciklus zaliha proizvodnoga sustavaInventoryanalysisconsistsofthreemajorsteps:
firsttheidentificationoffunctionsandflowsoftheproductsystem;second,thequantificationofflows;andthird,thequantitativemodelingofallflowscon-vertingintoaspecificsetofoutputflows.Thesimplestapproach,tabularbalancing,isverylimitedtohandlecomplex networks of flows, resulting in so-called
»truncated«systeminventories(Joshi1999)thatdonotfulfillthecradletograverequirement.Therefore,wewillpresent the formalmathematicalapproachbelow,whichtoourknowledgeisnotwellknownintheforestsciencecommunity,andillustrateitwithapracticalexample.Productioneconomicsprovidesaformalapproach
toinvestigateprocessnetworksoreveneconomicsec-tors,whichreliesontwofundamentalconcepts:1)com-modities,and2)activities(Koopmans1951b,1951c).Anactivity,alsocalledaprocess,consistsofaspecifictech-nology, which transforms specific input-flows intooutput-flowsaccording towell-definedprocedures.Themappingofprocessnetworksasflowsonagraphhasbecomeanimportantapproachtoanalyzeenviron-mentalimpacts(Koopmans1951b,1951c).Activitiesarerepresentedasnodes,whilearcs representflowsofgoods,resources,emissions,andwastes.Theresulting
Table 3 Flow of materials, equipment components and services into the functional unit – one productive machine hour PMH of a Stihl 026C chainsaw (Knechtle 1997). Source flows are positive, whereas sink flows are negativeTablica 3. Tok materijala, sastavni dijelovi i servis radne jedinice na temelju jednoga proizvodnoga sata Stihl 026C (Knechtle 1997). Ulazni su tokovi pozitivni, dok su izlazni negativni
X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11
Steel, high alloyed, kg
Visokolegirani čelik, kg1 0 0 0 0 0 –1.166 –1.06 –0.24 –0.35 0
Steel, non-alloyed, kg
Nelegirani čelik, kg0 1 0 0 0 0 –0.088 0 0 –0.026 0
Aluminum, kg
Aluminij, kg0 0 1 0 0 0 –2.268 0 0 –0.681 0
Plastic, kg
Plastika, kg0 0 0 1 0 0 –1.127 0 0 –0.338 0
Gasoline, kg
Gorivo, kg0 0 0 0 1 0 0 0 0 0 –1.245
Chainsaw oil, kg
Ulje za motornu pilu, kg0 0 0 0 0 1 0 0 0 0 –0.296
Manufacturing, unit
Proizvodnja, komada0 0 0 0 0 0 1 0 0 0 –8E-04
Guide bar, unit
Vodilica, komada0 0 0 0 0 0 0 1 0 0 –0.005
Chain, unit
Lanac, komada0 0 0 0 0 0 0 0 1 0 –0.017
Maintenance, unit
Održavanje, komada0 0 0 0 0 0 0 0 0 1 –8E-04
Chainsaw deployment, PMH
Rad motorne pile, radni sat0 0 0 0 0 0 0 0 0 0 1
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362 Croat. j. for. eng. 33(2012)2
graphisnon-cyclic,directed,andfinite.Additionally,severalsourcenodesandsinknodesmayexist,beinglocatedoutsideofthesystem’sboundaries.ThistypeofgraphhasalsobecomeknownasGOZINTO-graph,fol-lowing»thepartthatgoesinto«(Vazsonyi1954).Life-cycleassessmentbegantoemergeinthelate
1960’s,whenAyresandKneesepublishedapaperon»production,consumption,andexternalities«(AyresandKneese1969).Theystartedfromthepremisethatthecapacityoftheenvironmenttoprovideresourcesandassimilateemissionsandwastehasbecomescarce,andthatthereisastrongneedtorelieftheconceptof»freeeconomicgoods«,suchaswater,air,etc.Theirguidingideawasthatresourceextractionandenviron-mentalpollutionanditscontrolisa»materialsbalanceproblem«.Theyformulatedamathematicalapproachtomodelthematerialsbalanceproblemwithaninput-outputapproach,consideringtheproductsofphoto-synthesisandmineralresourcesasinputs,andCO2 andwasteasfinaloutputs.Flowsonagraphmayberepresentedbyasystemof
linearequations,anexampleofwhichispresentedinTable3foraStihl026Cchainsawfrom(Knechtle1997).Eachrowrepresentstheflowofacommodityfromthesourceprocess(positiveunitvalues)tosinkprocesses(negativeunitvalues).Thefirstrowrepresentstheflowofhighalloyedsteel,ofwhich–1.16kgareflowingintothemanufacturingprocess,–1.06intotheguidebar,–0.24intothechainand–0.35intomaintenance(spareparts).Rows2to11followthesamerepresentationallogic,andthewhole system is representedby11 commodities(rows)flowingbetween11processes(columns).Assum-ing that eachprocess canbe scaledbyavariablexi,whereasi=1...11thesystemof11equationscanbesolvedforX,whereasXisthevector(x1,...,x11),ifthetotalsystemoutputYisknown.ForTable3,theelementsoftheout-putvectorYare0,exceptforx11,whichisequaltooneunityofthefunctionalunit.The11×11matrixofTable3definesthechainsaw
technologyandiscalled»technologymatrix«A(Koop-mans1951b).Auniquesolutionrequires1)aquadratictechnologymatrixA,and2)aknownbalanceofinflowsandoutflowsforallcommodities.Inmatrixnotation,theequationsystem(1)ofTable3iswrittenas
A · X = Y (1)
Modelanalysisiscomplete,ifweknowthevectorX.Itcanbefoundbysolvingmatrixequation(1)forX(2).
X = A–1 · Y (2)
Equation(2)completelydescribestheflowofcom-moditiesforaspecificprocessnetwork.Assumingan
outputvectorYasbelow,equation(2)resultsinthefollowingsolutionforX.
Thescalingvector Xhasthefollowingmeaning:x5,gasolineconsumption,meansthat2.96kgofgasolineareusedforaproductivemachinehourPMH;x1,con-sumptionofhighalloysteel,meansthatabout10gofsteelareconsumedperPMH.However,themodeljustdescribesmaterialsandenergyflows,andithastobeenhancedtoanalyzetheflowsofenvironmentalbur-dens.Thereisawell-documentedapproach(Koop-mans1951b;1951c)thatassumestheflowofcommod-itiestobeproportionaltotheflowofenvironmentalburdens(linearityassumptions).Asingletypeofen-vironmentalburdenmayberepresentedbyavectorB,whichhasthesamelengthasthescalingvectorX.Table4presentseightenvironmentalburdenvectors,writtenasrows.Theburdensofmaterialsandenergycarriersweretakenfromecoinvent(ECOINVENT,on-line),whereastheburdenassociatedwithchainsawdeployment (x11) characterizes the engine-specificemissionprofileofatwo-strokeengine.Thex7tox10 processesdonothavedirectburdens,butareusedtologicallylinktheflows.ThefiguresinTable4definetheso-calledburden
matrixB,whichbymultiplicationwiththescalingvec-torXresultsintheburdenvectorbofthetotalsystem(3),resultinginthefollowingvaluesfortheStihl026Cexample.
b = B· X (3)
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TheuseofaproductivemachinehourPMHofachainsawconsumes65.8MJofprocessenergy,16.1MJofembodiedenergy,andemits4.79kgofCO2,0.29kgofCOand0.17kgofHC.Thischainsawspecificbur-denvectorBcanbereusedfortheanalysisofproduc-tionsystems,whichcontribute to comparabilityofresults.
3. State of Modeling Approaches – Pristupi modeliranja
3.1 Conceptual Models – Konceptualni modeliLifecycleinventoryanalysishastobebasedona
conceptualmodelthatdefinesthebuildingblocksofanalysisfrom»cradletograve«.TheauthorproposedaconceptualmodelthatispresentedinFig.1(Heini-mannetal.2006).Productsystemsarehierarchicallyorganized.Thehighest leveloforganization is theproductsystemlevel(Fig.1,level2,right),consistingofanetworkofhumans,machineryandfacilities.Theunderlyinglevelconsistsofmachines,madeofdiffer-entkindsofmaterialsduringthemanufacturingpro-cess.Combustionengineshavebeenthebackboneofforestmachineryandthequalityofthecombustionprocessiscrucialforallsubsequentresults.Machinesconsume resources through maintenance, whichshouldalsobeconsideredintheanalysisprocess.Thematerialsofwhichamachineismanufacturedem-
bodyenvironmentalburdensthathavetobeconsid-eredtofulfilltheir»cradletograve«requirement.En-vironmentalburdensofmaterialsaredocumentedindatabases,suchasecoinvent(ECOINVENT,online).Theecoinventdatabasecontainsinternationalin-
dustriallifecycleinventorydataonenergysupply,resourceextraction,materialsupply,chemicals,met-als, agriculture, waste management services, andtransportservices.Itisusedbyabout4’500usersinmorethan40countriesworldwideandisincludedintheleadingLCAsoftwaretoolsaswellasinvariouseco-designtoolsforbuildingandconstruction,wastemanagementorproductdesign(ECOINVENT,on-line).Similardatabasesarespine@cpm(SPINE@CPM,online),ELCD(ELCD,online),orProBas(PROBAS,online).Fig.2presentstheproductsystemforsolidwood
production,asrepresentedintheecoinventdatabase(Werneretal.2007).Thefirstfunction,biomassgrowth,consistsofthreeinputflowsfromtheenvironment,thecaptureofsolarenergy,thesequestrationofCO2,andlandoccupation.Thesecondfunction,forestman-agement,hasthreeinputflows,too,energyinput(die-selcombustion), theuseofgravelforroadmainte-nance, and the conversion of forest land intoindustrialland,whichiscausedbytheareaoccupiedbyforestroads.Thethirdfunction,harvesting,hastwoinputflows, energy input (diesel combustion) andchainsawuse(inPMH).
Table 4 Environmental burden matrix B for the Stihl 026C chainsaw. The figures for x1 to x6 were taken from the ecoinvent database (ECO-INVENT, online) (grey shaded), whereas the values for x11 characterize the combustion process in the 2-stroke engine (dark shaded)Tablica 4. B matrica okolišnoga opterećenja motorne pile Stihl 026C. Izvor je podataka x1 do x6 baza Ecoinvent, dok je vrijednost x11 rad dvo-taktnoga motora
X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11
Embodied energy, MJ
Ugrađena energija, MJ109.7 33.3 231.4 93.32 9.216 9.21 0 0 0 0 0
Process energy, MJ
Utrošak energ. pri radu0 0 0 0 42.7 42.7 0 0 0 0 0
CO2, kg 5.282 1.614 9.964 3.229 0.505 0.503 0 0 0 0 3.926
CO, kg 0.029 0.03 0.004 0.001 9E-04 9E-04 0 0 0 0 0.285
CH4, kg 0.016 0.009 0.022 0.008 0.004 0.004 0 0 0 0 2E-04
HC, kg 0.005 0.001 0.011 0.011 0.009 0.009 0 0 0 0 0.16
NOx, kg 0.01 0.003 0.02 0.007 0.003 0.003 0 0 0 0 0.004
SOx, kg 0.343 0.005 0.058 0.019 0.003 0.003 0 0 0 0 0.001
Imported from Ecoinvent (2012) – Izvor Ecoinvent (2012)No direct burden
Bez izravnoga opterećenja
Engine combustion
Sagorijevanje
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Fig. 1 Components of the framework of life cycle inventory analysis (Heinimann et al. 2006). Recycling of materials, such as steel is assumed to be included in raw material burdensSlika 1. Dijelovi okvira analize zaliha životnoga ciklusa. Recikliranje materijala, poput čelika, pretpostavlja se da ulazi u granice sirovih materijala
Fig. 2 Conceptual mapping of energy, material and area flow for wood product systems (Werner et al. 2007)Slika 2. Konceptualno kartiranje tokova energije, materijala i područja u proizvodnji drva (Werner i dr. 2007)
Theharvestingfunctionisatypicalcaseofco-pro-duction,whichisatermformultipleproductscomingoutofonefunction(ISO2002).Co-productionrequiresrulesastohowtoallocateupstreamenvironmentalburdenstoasetofproducts,whichisoftendonepro-portionallytotheeconomicvalueoftheoutputprod-ucts.Intheecoinventdatabase,theallocationfactorsare0.86forroundwood,0.09forindustrialwood,and0.05forresidualwood.Thenatureofallocationfactorsisnormative,andthereisnorightorwrongsolutiontothisproblem.There-presentationinecoinventdoesnotfullycomplywiththe»cradletograve«require-ment thatwouldrequest to includeenvironmentalburdensthatareembodiedinforestmachines,tools,
andinforestroads.Takingintoaccounttheseshort-comings,(Heinimannetal.2006;Knechtle1997)eco-inventoriesforforestmachinesandfortheconstruc-tionandmaintenanceofforestroadsweremodeled.
4. State of environmental performance knowledge – Stanje znanja o okolišnoj
učinkovitostiTheselectionandquantificationofoperationalper-
formanceindicators(OPIs)isamainpurposeofLCA(ISO2006a).OPIsareindicatorstomeasureandcom-pare eco-efficiency (Huppes and Ishikawa 2007),
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whichisarelationshipbetweenresourceconsump-tion,emittedpollutantsordeposedwasteperaunityofthefunctionalunit.Materials-relatedindicatorsarethemassofmaterials,orthequantityofwaterusedperproductunit,whichise.g.aperformanceindicatorforpulpproductsystems.Energy-relatedOPIsspeci-fythequantityofenergyusedperproductunit,andemission-relatedOPIsthemassofspecificemissionsperproductunit(ISO1999).Below,wepresenttwotypicalOPIs,energyconsumptionandCO2emissionperfunctionalunit,asreportedinthescientificlitera-ture.
4.1 OPIs for solid wood product systems – Poka-zatelji ekološke učinkovitosti za drvne proiz-vodeTable5presentsOPIsforthe»solidwoodproduct
system«.Afirstproblemthatweencounteredduringthe screeningof the literaturewas that the systemboundarieswereeithernotclearlyspecifiedordiffer-ingacrossstudies.Theupstreamboundaryshouldinclude the environmental system (Udo de Haes
1996b)asrepresentedintheecoinventmodel(Fig.2).However, someof the studies startwith the forestmanagement function (see Fig. 2),whereas othersseemtoconsidertheharvestingfunctiononly.IntheNordiccountries,thedownstreamboundaryisusu-allyat themillgate,whereas inCentralEuropeanstudies,theboundaryisattheforestroad.Consider-ingtheearlyfindingsof(KarjalainenandAsikainen1996)thatabouttwothirdoftheenvironmentalbur-denoftheforesttomillproductsystemarecausedbyroad construction and long distance transport, itwouldmakesensetoreporttwoseparateOPIs,oneforforestmanagementandharvesting,andtheotheroneforlongdistancetransportation,includingroadinfra-structure.Asecondproblemthatweencounteredwasthefactthatmostoftheforestrystudieswereoflevel2only(seeFig.1),consideringonlydirectmaterialsandenergyconsumptionsduringsystemdeploymentandneglectingembodiedenvironmentalburdensofupstreamfunctions.Accordingto(Knechtle1997),theembodiedenergyinmachineslikeharvestersandfor-wardersequalstoabout40to50%ofthedirectprocessenergy.Thehigheremissionvaluesfromtheeco-in-
Table 5 Energy input and CO2 output for harvesting operations. The underlying harvesting systems are of harvester-forwarder type, with a motor-manual system for ecoinventTablica 5. Utrošak energije i emisija CO2 pri pridobivanju drva sustavom harvester – forvarder, osim u slučaju »Ecoivent« gdje je u pitanju ručno-strojni rad
Source – IzvorCO2
(kg m–3 ub)
Energy – Energija
(MJ m–3 ub)
Level – Razina
2 1+2
Ecoinvent 2012 12.41 4.07 kg crude oil
4,07 kg sirove naftex
ProBas 2012 17.92 501 x
SPINE@COM 2012 57 x
Berg 1997 2.4 – x
González-García et al. 2009, Spain3,4 ~22 ~90 x
González-García et al. 2009, Sweden3,4 ~14 ~40 x
Karjalainen and Asikainen 19963 6.4 – x
Knechtle 19993 7.4 110 x
Lindholm 20063 5.9 63–66 x
Schwaiger and Zimmer 2001 2.4–4.3 36 x
Valente et al. 20113 4.4 52 x
1 road maintenance included – uključeno održavanje cesta2 functional unit: 1 kg, conversion with 0.007 m3 per kg – funkcionalna jedinica 1 kg, pretvorba s 0,007 m3 po kg3 without silvicultural operations – bez uzgojnih radova4 including transport to mill – uključujući prijevoz do pilane
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ventorydatabases (Table 5) (ECOINVENT, online,PROBAS,online)mayalsobeexplainedbytheem-bodiedburden.MedianvaluesofthestudiesreportedinTable2
areabout7.5kgCO2.m-3
ubandabout60MJ.m-3ub,both
withconsiderablevariabilityanduncertainty.Thereisaneedtoimprovethequalityandcomparabilityoffuturestudiesbystandardizingthedefinitionofsys-temboundariesforthesolidwoodproductionsystemandbydefiningandinvestigatingidenticalflows.Thishastobeachievedontheconceptuallevel,asillus-tratedinFig.2.
4.2 OPIs for the construction and maintenance of forest roads – Pokazatelji ekološke učinkovitosti pri gradnji i održavanju šumskih cestaTakingtheevidencethatabout60%oftheoverall
environmental burdens of forest production arecausedbyroadnetworkinfrastructureandlong-dis-tancetransport(KarjalainenandAsikainen1996;Win-kler1997;Heinimann1999)asastartingpoint,Heini-mann andMaeda-Inaba (2004) presented an LCAstudythatfollowedtheconceptualapproachpresent-edinFig.1,performingbothlevel1andlevel2analy-sisandusingeco-inventoriesformaterialsandenergycarriersfromecoinvent(ECOINVENT,online).Table6presentsasummaryoftheresults.Onmoderateslopesupto40percent,construction
ofoneunitlength(m)offorestroadconsumesabout350MJofenergywhileemittingabout20kgofgreen-housegases.Thisamountofenergyconsumptionisequivalenttotheheatingvalueofabout10lofdieselfuel,andabout10kgofwoodmass thathas tobegrowntosequestratetheamountemittedgreenhousegas.Transportdistanceofbasecoursematerialsisthemostsensitivefactorofinfluence.Comparedtoon-site
preparationofaggregates,a50-kilometertransportincreasesenergyconsumptionbya factorofaboutfive.Slopedemonstratedtobethesecondimportantfactorthatshowsanonlinearinfluenceonenergycon-sumptionandgreenhousegasemissions.Increasingslopetoabout50percent,doublesenergyconsump-tionandgreenhousegasemissions,whileaslopeof70percentalmost triples them.Roadbedwidth is thethirdfactorofinfluence.Energyconsumptiondoublesbyincreasingitfrom4.2mto6.2m.Assumingalifecycleofaforestroadof40years,
a road density of 25 m ha–1, an average yield of10m3ha–1a—1,andallocatingtheOPIsofTable6tothefunctionalunit(m3
ub)ofthewoodproductsys-tem results inanamountof embodiedenergyof20–40MJ m–3,whichisconsiderable,comparedtotheenergyinputofharvestingoperations(Table5).Iftheannualyieldisloweredtoabout5m3ha–1a–1,theroad-inducedembodiedenergyreachesthesameorderofmagnitudeastheimpactoftheproductsystemitself.Thesefindingsillustratethatneglectingtheforestroadinfrastructureresultsinaconsiderableoverestimationofenvironmenttalperformance,particularlyforlow-yieldforestsandfordifficultterrain.
4.3 OPIs for truck transport systems – Pokaza-telji ekološke učinkovitosti pri prijevozu drva kamionimaRoadtransportationwithtruckshasbeenthemain
modeforlong-distancehauling.Allowablegrossve-hiclemass(GVM)wasstandardizedwithintheEuro-peanUnion,definingthefollowinglimitsfortrucks:2-axle18tons,3-axle26tons,4-axle32tons,and5-axle38tons.Typicalconfigurationsfortimbertransportarea3-axlemotorvehicleplus2-or3-axletrailerwithaGVMof40tons,anda3-axlemotorvehicleplus4-axletrailerwithaGVMof60tonsintheNordiccountries.
Table 6 Energy input and CO2 output for the construction and maintenance of forest roads. Functional unit: 1 m of road length. Assumptions: (1) roadbed width of 4.2 m, (2) cut slope angle of 1:1, (3) fill slope angle of 4:5, (4) base course thickness of 0.3 m, (5) surface course thick-ness of 0.08 m, and (6) base course materials transport distance of 10 kilometers, (6) increasing rock excavation on slopes steeper than 50%Tablica 6. Utrošak energije i emisija CO2 prilikom gradnje 1 m šumske ceste širine planuma od 4,2 m, nagiba usjeka 1 : 1, nagiba nasipa 4 : 5, debljine donjega stroja 0,3 m, debljine gornjega stroja 0,08 m, s prijevozom građevnoga materijala na udaljenost od 10 km i povećan iskop materijala na nagibima > 50 %
Terrain conditions – Terenski uvjetiCO2
(kg m–1)
Energy – Energija
(MJ m–1)
Level 2
Razina 2
Level 1+2
Razina 1+2
Slope >10% – Nagib >10 % 19 315 x –
Slope ~ 40% – Nagib ~ 40 % 25 405 x –
Slope ~60% – Nagib ~ 60 % 47 735 x –
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Table7givesanoverviewofenergyinputandCO2 emissionsforthesetwoconfigurations.TheGermanProBasdatabase(PROBAS,online)
providesthemostup-to-dateeco-inventoriesfortrucktransportation,consideringeuro-5emissionstandards,however,withoutfiguresfor60tonconfigurations.TheSwedishSpinedatabase(SPINE@CPM)providesfig-ures for 60 ton configurations,which are based onanalysisworkdoneinthelate1990s.Forest-specificfig-uresareonlyavailableforSweden(LindholmandBerg2005)andforFinland(KarjalainenandAsikainen1996),whereassomeresults,e.g.(Valenteetal.2011b),arenotcomparable.TheProBasdataillustratethatenviron-mentalperformancedependsonthetrafficmode(high-way,overland,inthecity),yieldinganincreasinggradi-ent from highway to in the city transport. TheSwedishdata(LindholmandBerg2005)giveapre-liminaryhintthattimberhaulagehasitsown,forest-specifictrafficmode(intheforest,overland,high-way)thatisnotwellunderstood,butprobablyresultsinburdensthatareclosetothe»inthecity«mode.Assuminga40tonconfiguration,overlandmode,andatimberloadof28m3yieldsanenergyconsump-tionofabout0.55MJ m–3
ub.Comparedtoanaverageenergyinputof60MJ m–3
ub(Table5),aroadtransportdistanceofabout100kmresultsinanenvironmentalburdenofthesameorderofmagnitudeasfromtheharvestingprocess,however,neglectingtheembodiedenergyoftheforestroadinfrastructure(seeTable6),whichaddsbetween20and40MJ m–3
ub(see4.2).
4.4 Environmental performance of bioenergy product systems – Okolišna učinkovitost sustava za proizvodnju bioenergije
IEA(2011,2012),assumedthatlow-carbontech-nologieswouldcontributetothereductionofgreen-housegasemission.Thereareseveralbioenergypath-ways(Fig.3),1)biomassinunprocessedformsuchasfirewood,forestresidues;2)biomassintermediates,suchaspelletsorbiomethanefrommanureorlandfill;3)first-generationbiofuels,madeofseed,grain,orsugar;4)second-generationbiofuels,manufacturedfromlignocellulosicbiomass,and5)third-generationbiofuels,manufacturedfromalgaeorseaweeds(IEA2011,IEA2012,NigamandSingh2011).Environmen-talperformance,particularlyCO2-andenergy-effi-ciency,isadecisivecriteriontochoosethebestcourseofactionforfuturebiomass-basedenergysupply.Comparabilityofresultsofenvironmentalperfor-
manceassessmentrequiresfirstacleardefinitionofsystemboundaries,andsecond,anagreementonthefunctionalunit,whichisusedtonormalizetheresults.Systemboundariesshouldbeofa»welltoplant«forwoodchips,»welltostove«forpellets,and»welltowheel«typeforbiofuels.Asaconsequence,functionalunitsshouldbedefinedasaunitofenergyproducedinaplantorstove(MJ),oraunitoftransportationserviceproduced(t.km,person.km).ThescreeningoftheLCAliteratureforforestfuelsupplyindicatesthatsystemboundariesarefartoonarrow,particularlyinthedown-streamdirection,andthefunctionalunit is, inmostcases,definedintraditionalforestryunits,suchasbulkvolume,bulkmass,solidtimbervolume,etc.Thekeyquestionstilliswhattechnologyrouteout
ofthepossibilitiesoutlinedinFig.3ismostcost-effec-tiveandmostenvironmentallyperforming.TheEIAtechnologyroadmaphypothesizesthatthefollowing
Table 7 Energy input and CO2 output for long-distance truck transportationTablica 7. Utrošak energije i emisija CO2 pri daljinskom transport drva kamionima
Source – IzvorGross vehicle
mass, t
Masa vozila, t
Load capacity, t
Masa tovara, t
Emission standard
Standardi emisije
CO2
(kg· t–3 · km–1)
Energy
(MJ· t–3· km–1)
ProBas 2012 (over land, no highway – izvan autoceste)
40 24 Euro 5 0.057 0.67
ProBas 2012 (highway – autocesta) 40 24 Euro 5 0.050 0.59
ProBas 2012 (in the city – gradska vožnja)
40 24 Euro 5 0.084 0.99
SPINE@COM 2012 40 26 Euro 2 0.050 0.68
SPINE@COM 2012 60 40 Euro 2 0.041 0.57
Karjalainen and Asikainen 1996 60 40 ? 0.038 –
Lindholm and Berg 2005 60 40 ? – 0.99
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bioenergysystemsarethemostpromising:1)there-placementof traditionalbiomassbyadvancedbio-masscookstovesandhouseholdbiogassystems,2)cogeneratingheat-powerplantsCHP(IEA2012).EIAhypothesizesthatadvancedbiofuels,suchascellu-losicethanol,advancedbiodiesel,bio-syntacticgasBSGfromlignocellulosicbiomassoralgaearemorecost-andeco-efficient thanfirstgenerationbiofuelsmadeofsugarandstarch(Cherubinietal.2009).Areviewpaper(Cherubinietal.2009)assessesthestateofknowledgeofdifferenttechnologypathways.Theauthorsconcludethattheavailablestudiesindicatethatelectricityorheatgenerationofbiomasshaveabetterenvironmentalperformancethanbiofuels,andthatbioenergychainsbasedonthewasteandresiduerawmaterialsoutperformchainsbasedondedicatedcrops.Theyalsomentionedthatthe»cascading«useofbiomass(e.g.firstuseasbuildingmaterial,followedbyuseforfiber,followedbyenergeticuse)havethepotentialtofurtherenhancegreenhousegassavings.ArecentLCA-study(StuckiandJungbluth2012)onsecond-generationbiofuelspresentsevidencethatsys-temsbasedonmolasse,wasteoilglycerineandpuri-fiedbiogasperformedbestwithanamountofCO2-emissionsofabout120gpkm–1,whereasoil-baseddiesel and gasoline emit about 180 g pkm–1 and200gpkm–1,respectively.However,therearestillcon-siderablechallenges(Cherubinietal.2011),particu-larlymethodologicalinconsistenciesduetotheselec-tion of different system boundaries, alternativeapproachestoestimategreenhousegasemissions,or
alternativeallocationrules.TheauthorsalsostressthatanincreasingnumberofLCA-studiesonlignocellu-losic biomass, sugarcane, or palm oil is available,whereascontributionsonpromisingfeedstocks,suchas algae, or advanced biomass processing are stillscarce.Therearestill interestingforestryshortrotation
crops,usuallybasedonwilloworpoplar(Björeson2006;Göranson2009;Gyuriczaetal.2011).Acom-parisonof alternative bioenergy cropping systems(Adleretal.2007)showedthatsystemsbasedoncorn,soybean,andalfalfaoutperformedapoplar-basedsys-temintermsofCO2emissionsbyafactorofabout1.5.Astudycomparingtwopelletproductionsystems
(sawdust,chips)(Heinimannetal.2007)resultedinthefindingthatchip-basedsupplysystemsoutper-formsawdust-basedsystemsintermsofenergyeffi-ciency,carbondioxideemission,eco-toxicity,andpar-ticle emissions (PM10) caused by highermoisturecontentofsawdust.Thepelletmanufacturingprocess,consistingofrawmaterialssupply,pelletmanufactur-ing,andpelletdistribution,causedabout60to80%ofthetotalenergyinput.Thedryingprocessisthemostimportantstepofpelletmanufacturingwithashareof60to80%,andthereforeofferingpotentialforefficien-cy improvement by using e.g. superheated steamdryertechnology.IEA technology roadmaps (IEA2011, IEA2012)
stressthatalternativebioenergypathwaysrequirerawmaterialsupplychainsthataretailoredtotheenduseandoptimizedforbotheconomicandeco-efficiency.
Fig. 3 Classification of Biofuels (Nigam and Singh 2011), modifiedSlika 3. Podjela biogoriva (modificirano prema Nigam i Singh 2011)
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However,toourknowledge,therearenocomprehen-siveLCA-studies available that investigate supplychainstailoredtospecificbioenergypathwaysasil-lustratedinFig.3.Availablestudiesonsupplychainsarelimitedinscope,astheyinvestigatetheprocessenergyuseonly,andcalculatetheemissionsduetoenginecombustionwithrulesofthumb.Therefore,thereisastrongneedtodofurtherresearchonbio-masssupplychainsfordifferentbioenergypathways(Valenteetal.2011a;Valenteetal.2011b).
5. Conclusions – ZaključciTheguidingideaofLCAistoimproveourunder-
standingoftheimpactsofalternativeproductsystemsontheenvironmentandtoquantifyenvironmentalperformanceindicators,characterizingthecontribu-tionofproductstothemainenvironmentalrisks.ThepresentcontributionreviewedthestateofLCA-relat-edresearchforproductsystemswithforestbiomassasrawmaterial.The study resulted in the followingfindings. 1)
WhereasLCA-methodologyislookingbackonaboutthirtyyearsofexperience,itisstillnotwidelyusedandacceptedwithintheforestoperationsengineeringre-searchcommunity.2)Onlyafewforest-relatedLCA-studiesarebasedonaquantitative,mathematicalstrin-gentmethodologythatusessystemsoflinearequationstocharacterizeandmodelcommodity,energy,andsub-stanceflowsfrom»cradletograve«.3)AlthoughLCAisfollowinga»welltouse«philosophy,manyforestrelatedLCA-studiesarebasedonquitenarrowsystemboundaries,andonforest-specificfunctionalunits,thuslimitingthecomparabilitywithstate-of-the-artLCA-studies.4)Mostoftheforest-relatedLCA-studiesarebasedondirectprocessenergyconsumption,measuredasfuelconsumption,andemissionfiguresthatarecal-culatedfromfuelconsumptionbygeneralassumptions.5)»TruncatedLCAs«,neglectingembeddedenviron-mentalburdensofmachinesandforestroadinfrastruc-ture,resultsinanunderestimationofenvironmentalimpactsofforestproductsystems.Whereasenvironmentalanalysistoolsseemtocon-
verge,forexamplebybringingexergyanalysis,whichisatraditionalfieldinprocessengineering,togetherwithLCA-methodology(Hau2002;HauandBakshi2004),anew,forest-specificresearchstreamhasbeenemerging,sustainabilityimpactassessmentofwoodsupplychains,forwhichaspecific,made-to-purposesoftware toolwasdeveloped,ToSIA (Lindner et al.2012).Thisnewinitiativeseemsnottobewelllinkedtosustainabilityimpactassessment(SIA)thatemergedoutofthestrategicimpactassessment(SIA)andenvi-
ronmentalimpactassessment(EIA)traditions,beingdesignedaspolicy,andnotasanalysistools.Addition-ally,itisonlyweaklylinkedtotheongoinglifecyclemanagementinitiative,whichaddressesthe»triplebot-tomline«withthreetools:environmentallifecycleas-sessment(E-LCA),sociallifecycleassessment(S-LCA),andlifecyclecosting(LCC)(UNEPandSETAC2009).Thestudyhasseveralimplicationsfortheforest
operationsresearchcommunity.First,ithastoinvestincapacitybuildingtobetterunderstandmainstreamlife-cycleassessmentmethodology.Second,thereisastrongneedtodevelopstandardsforsystemboundariesandfunctionalunitsoftypicalbioenergypathways(seeforexampleFig.3),whichisthebasistoimprovethecom-parabilityoffuturestudies.Third,lifecycleinventoriesfor road construction, roadmaintenance and roadtransportationneedtobeupdatedbecausepreviousstudiesdemonstratedthatlong-distancetransportationandforestroadinfrastructureaccountforabouttwothirdofthetotalimpactfortypicalforestproductivitysystems(HeinimannandMaeda-Inaba2004;Karjalain-enandAsikainen1996).Andforth,futurelifecyclein-ventorieshavetobelinkedtoLCIdatabases,suchasEcoinvent (ECOINVENT,online),ProBas(PROBAS,online),etc.,toaccountformaterialsandenergysys-temsofveryupstreamprocesseslikethemanufacturingofmachines.Andfifth,futurestudiesshouldprovideinformationon the standards for theassessmentofcomplianceofmachineengines,e.g.Tier1toTier4stan-dardsintheUS(DIESELNET,online-b),StageItoIVfortheEuropeanUnion(DIESELNET,online-a),be-cause there isaconsiderabledecreaseofallowableemissionwithincreasingTierandStage.
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Sažetak
Analiza životnoga ciklusa u šumarstvu – stanje i perspektivaOkolišno prihvatljive tehnologije ključne su za smanjenje potrošnje ograničenih resursa i smanjenje utjecaja na
okoliš. U radu je opisano stanje poznavanja analitičkoga alata i analize životnoga ciklusa uz razradu triju problema: 1) metodološke postavke analize životnoga ciklusa, 2) modeliranja zaliha životnoga ciklusa i 3) pokazatelja okolišne učinkovitosti pri proizvodnji drva. Rezultati istraživanja ogledaju se u sljedećim nalazima: 1) Analiza životnoga ciklusa nema široku primjenu u šumarskoj zajednici. 2) Samo je nekoliko istraživanja napravljeno temeljem najsuvremenijih analiza zaliha životnoga ciklusa. 3) Postavljene granice istraživanja često su preuske, što smanjuje mogućnost usporedbe s uobičajenim istraživanjima životnoga ciklusa. 4) Većina se istraživanja analize životnoga ciklusa u šumarstvu zasniva samo na izravnom utrošku energije te time zanemaruje opterećenje okoliša daljinjim postupcima. 5) Takva »skraćena« analiza životnoga ciklusa zanemarivanjem opterećenja koja nastaju gradnjom šumskih cesta i uporabom šumskih vozila podcjenjuje učinak na okoliš ili precjenjuje okolišnu učinkovitost. U šumarstvu je potrebno dodatno razviti analizu životnoga ciklusa kako bi buduća istraživanja bila što obuhvatnija i kako bi se što lakše mogla usporediti s osnovnim istraživanjima analize životnoga ciklusa.
Ključne riječi: analiza životnoga ciklusa, okolišna učinkovitost, proizvodnja drva, ekološka učinkovitost, industrijska ekologija
Received(Primljeno):July14,2012Accepted(Prihvaćeno):September14,2012
Author’saddress–Autorova adresa:
Prof.HansRudolfHeinimann,PhD.e-mail:hans.heinimann@env.ethz.chInstituteofTerrestrialEcosystemsDepartmentofEnvironmentalSystemsETHZürichUniversitätsstrasse228092ZurichSWITZERLAND
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