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简介：高考词汇matterv．countv．

简介：Background:Ineconomicallyoptimalmanagement,treesthatareremovedinathinningtreatmentshouldbeselectedonthebasisoftheirvalue,relativevalueincrementandtheeffectofremovalonthegrowthofremainingtrees.Largevaluabletreeswithdecreasedvalueincrementshouldberemoved,especiallywhentheyovertopsmallertrees.Methods:Thisstudyoptimizedthetreeselectionruleinthethinningtreatmentsofcontinuouscovermanagementwhentheaimistomaximizetheprofitabilityofforestmanagement.Theweightsofthreecriteria(stemvalue,relativevalueincrementandeffectofremovalonthecompetitionofremainingtrees)wereoptimizedtogetherwiththinningintervals.Resultsandconclusions:Theresultsconfirmedthehypothesisthatoptimalthinninginvolvesremovingpredominantlylargetrees.Increasingstumpagevalue,decreasingrelativevalueincrement,andincreasingcompetitiveinfluenceincreasedthelikelihoodthatremovalisoptimaldecision.However,ifthespatialdistributionoftreesisirregular,itisoptimaltoleavelargetreesinsparseplacesandremovesomewhatsmallertreesfromdenseplaces.However,thebenefitofoptimalthinning,ascomparedtodiameterlimitcuttingisnotusuallylargeinpureone-speciesstands.Onthecontrary,removingthesmallesttreesfromthestandmayleadtosignificant(30-40%)reductionsinthenetpresentvalueofharvestincomes.

简介：Background:Forestecosystemsareincreasinglyseenasmulti-functionalproductionsystems,whichshouldprovide,besidestimberandeconomicbenefits,alsootherecosystemservicesrelatedtobiologicaldiversity,recreationalusesandenvironmentalfunctionsofforests.Thisstudyanalyzedtheperformanceofeven-agedrotationforestmanagement(RFM)continuouscoverforestry(CCF)andany-agedforestry(AAF)intheproductionofecosystemservices.AAFalowsbotheven-agedanduneven-agedmanagementschedules.Theecosystemservicesincludedintheanalyseswerenetpresentvalue,volumeofharvestedtimber,cowberryandbilberryyields,scenicvalueoftheforest,carbonbalanceandsuitabilityoftheforesttoSiberianjay.Methods:Dataenvelopmentanalysiswasusedtoderivenumericalefficiencyratiosforthethreemanagementsystems.Efficiencyratioisthesumofweightedoutputs(ecosystemservices)dividedbythesumofweightedinputs.ThelinearprogramingmodelproposedbyCharnes,CooperandRhodeswasusedtoderivetheweightsforcalculatingefficiencyscoresforthesilviculturalsystems.Resultsandconclusions:CCFprovidedmoreecosystemservicesthanRFM,andCCFwasmoreefficientthanRFMandAAFintheproductionofecosystemservices.Multi-objectivemanagementprovidedmoreecosystemservices(exceptharvestedtimber)thansingle-objectivemanagementthatmaximizedeconomicprofitability.Theuseoflowdiscountrate(resultinginlowcuttinglevelandhighgrowingstockvolume)ledtobettersupplyofmostecosystemsservicesthantheuseofhighdiscountrate.RFMwhereNPVwasmaximizedwithhighdiscountrateledtoparticularlypoorprovisionofmostecosystemservices.InCCFtheprovisionofecosystemserviceswaslesssensitivetochangesindiscountrateandmanagementobjectivethaninRFM.

简介：Inthispaper,thesharpdistortiontheoremsoftheFr′echet-derivativetypeforasubclassofbiholomorphicmappingswhichhaveaparametricrepresentationontheunitballofcomplexBanachspacesareestablished,andthecorrespondingresultsoftheabovegeneralizedmappingsontheunitpolydiskinC~narealsogiven.Meanwhile,thesharpdistortiontheoremsoftheJacobideterminanttypeforasubclassofbiholomorphicmappingswhichhaveaparametricrepresentationontheunitballwithanarbitrarynorminC~nareobtained,andthecorrespondingresultsoftheabovegeneralizedmappingsontheunitpolydiskinC~naregotaswell.Thus,someknownresultsinpriorliteraturesaregeneralized.

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