简介：因为他们说明大量陆上的碳存储和生产率，热带森林在减轻气候变化起一个关键作用。然而，有许多无常，与碳动力学的评价联系。我们沿着一个斜坡估计了森林结构和碳动力学(17.3跱<

简介：Background:Remotesensing-basedmappingofforestEcosystemService(ES)indicatorshasbecomeincreasinglypopular.TheresultingmapsmayenabletospatiallyassesstheprovisioningpotentialofESsandprioritizethelanduseinsubsequentdecisionanalyses.However,themappingisoftenbasedonreadilyavailabledata,suchaslandcovermapsandotherpubliclyavailabledatabases,andignoringtherelateduncertainties.Methods:Thisstudytestedthepotentialtoimprovetherobustnessofthedecisionsbymeansoflocalmodelfittinganduncertaintyanalysis.Thequalityofforestlanduseprioritizationwasevaluatedundertwodifferentdecisionsupportmodels:eitherusingthedevelopedmodelsdeterministicallyorincorporationwiththeuncertaintiesofthemodels.Results:PredictionmodelsbasedonAirborneLaserScanning(ALS)dataexplainedthevariationinproxiesofthesuitabilityofforestplotsformaintainingbiodiversity,producingtimber,storingcarbon,orprovidingrecreationaluses(berrypickingandvisualamenity)withRMSEsof15%–30%,dependingontheES.TheRMSEsoftheALS-basedpredictionswere47%–97%ofthosederivedfromforestresourcemapswithasimilarresolution.Duetoapplyingasimilarfieldcalibrationsteponbothofthedatasources,thedifferencecanbeattributedtothebetterabilityofALStoexplainthevariationintheESproxies.Conclusions:Despitethedifferentaccuracies,proxyvaluespredictedbyboththedatasourcescouldbeusedforapixel-basedprioritizationoflanduseataresolutionof250m~2,i.e.,inaconsiderablymoredetailedscalethanrequiredbycurrentoperationalforestmanagement.TheuncertaintyanalysisindicatedthatmapsoftheESprovisioningpotentialshouldbepreparedseparatelybasedonexpectedandextremeoutcomesoftheESproxymodelstofullydescribetheproductionpossibilitiesofthelandscapeundertheuncertaintiesinthemodels.

简介：Background:Forestmanagementdecisionsarebasedonexpectationsoffuturedevelopments.Forsounddecisionsitisessentialtoaccuratelypredicttheexpectedvaluesinfuturedevelopmentsandtoaccountfortheirinherentuncertainty,forexampletheimpactofclimatechangeonforests.Changingclimaticconditionsaffectforestproduaivityandaltertheriskprofileofforestsandforestenterprises.IntensifyingdroughtstressisseenasonemajorriskfactorthreateningforestmanagementinthenorthGermanlowlands.Droughtstressreducestreegrowthandvitalityandmighteventriggermortality.Butsofar,itisnotpossibletoquantifyeffectsofapersistentdryerclimateonforestproductivityatalevelsuitableforforestmanagement.Methods:Weapplyawell-establishedsingle-treeforestgrowthsimulatortoquantifytheeffectofpersistentdryerclimatesonfutureforestproductivity.WeanalysethegrowthofScotspine(PinussylvestrisL.);Europeanbeech{FagussylvoticoL.)andoak{QuercusroburL.andQuercuspetraeo(Matt.)Liebl.)intwoforestregionsinthenorthGermanlowlandsforatimeintervalof60yearsuntil2070.Thegrowthresponseunderthreedifferentclimateprojectionsiscomparedtoabaselinescenario.Results:Theresultsshowcleardifferencesinvolumeincrementtopersistentdryerclimatesbetweentreespecies.Thefindingsexhibitregionaldifferencesandtemporaltrends.WhilemeanannualincrementatbiologicalrotationageofScotspineandoakpredominantlybenefitsfromtheprojectedclimateconditionsuntil2070,beechmightsufferlossesofupto3m3-ha’-yr1dependingonclimatescenarioandregion.However,intheprojectionperiod2051to2070theuncertaintyrangescomprisepositiveaswellasnegativeclimaticeffectsforallspecies.Conclusions:Theprojectedchangesinforestgrowthserveasquantitativecontributionstoprovidedecisionsupportintheevaluationof,forexample,speciesfuturesitesuitabilityandtimbersupplyassessments.Theanalysiso

简介：Background:Treelinedynamicshaveinevitableimpactsontheforesttreelinestructureandcomposition.ThepresentresearchsoughttoestimatetreelinemovementandstructuralshiftsinresponsetorecentwarminginCehennemdere,Turkey.Afterimplementinganatmosphericcorrection,thegeo-shiftingofimageswasperformedtomatchimagestogetherforaperpixeltrendanalysis.WedevelopedanewapproachbasedontheNDVI,LST(landsurfacetemperature)data,airtemperaturedata,andforeststandmapsfora43-yearperiod.Theforesttreelineborderwasmappedontheforeststandmapsfor1970,1992,2002,and2013toidentifyshiftsinthetreelinealtitudes,andthenprofilestatisticswerecalculatedforeachperiod.Twentysampleplots(10×10pixels)wereselectedtoestimatetheNDVIandLSTshiftsacrosstheforesttimberlineusingper-pixeltrendanalysisandnon-parametricSpearman’scorrelationanalysis.Inaddition,thespatialandtemporalshiftsintreelinetreespecieswerecomputedwithintheselectedplotsforfourtimeperiodsontheforeststandmapstodeterminethepioneertreespecies.Results:Astatisticallysignificantincreasingtrendinallclimatevariableswasobserved,withthehighestslopeinthemonthlyaveragemeanJulytemperature(tau=0.62,ρ<0.00).Theresultantforeststandmapsshowedageographicalexpansionofthetreelineinboththehighestaltitudes(22m–45m)andthelowestaltitudes(20m–105m)from1970to2013.TheperpixeltrendanalysisindicatedanincreasingtrendintheNDVIandLSTvalueswithintheselectedplots.Moreover,increasesintheLSTwerehighlycorrelatedwithincreasesintheNDVIbetween1984and2017(r=0.75,ρ<0.05).CedruslibaniandJuniperuscommunisapp.weretwopioneertreespeciesthatexpandedandgrewconsistentlyonopenlands,primarilyonrocksandsoil-coveredareas,from1970to2013.Conclusion:Thepresentstudyilustratedthatforesttreelinedynamicsandtreelinestructuralchangescanbedetectedusingtwodata

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简介：Forestmanagementinseveralborealcountriesisstronglyfocusedonconifersbecausetheyaremoreproductive,thetechnicalqualityoftheirstemsisbetter,andtheirwoodfibersarelongerascomparedtobroadleaves.Favoringconifersinforestmanagementleadstosimpleforeststructureswithlowresilienceanddiversity.Suchforestsareriskyinthefaceofclimatechangeandfluctuatingtimberprices.ClimatechangeincreasesthevitalityofmanyforestpestsandpathogenssuchasHeterobasidionspp.andIpstypographusL.whichattackmainlyspruce.Winddamagesarealsoincreasingbecauseofashorterperiodoffrozensoiltoprovideafirmanchorageagainststorms.Wind-throwntreesserveasstartingpointsforbarkbeetleoutbreaks.Increasingtheproportionofbroadleavedspeciesmightalleviatesomeoftheseproblems.Thisstudypredictsthelong-term(150years)consequencesofcurrentconifer-orientedforestmanagementintwoforestareas,andcomparedthismanagementwithsilviculturalstrategiesthatpromotemixedforestsandbroadleavedspecies.Theresultsshowthat,intheabsenceofdamages,conifer-orientedforestrywouldleadto5-10%highertimberyieldsandcarbonsequestration.Thesomewhatlowercarbonsequestrationofbroadleavedforestswascounteractedbytheirhigheralbedo(reflectance).Mixedandbroadleafforestswerebetterprovidersofrecreationalamenities.Speciesdiversitywasmuchhigherinmixedstandandbroadleaf-orientedsilvicultureatstandandforestlevels.Theanalysisindicatesthatconifer-orientedforestmanagementproducesrathersmallanduncertaineconomicbenefitsatahighcostinresilienceanddiversity.

简介：Relationshipsbetweendiameteratbreastheight(dbh)versusstanddensity,andtreeheightversusdbh(heightcurve)wereexploredwiththeaimtofindiftherewerefunctionallinksbetweencorrespondentparametersoftherelationships,exponentsandinterceptsoftheirpowerfunctions.Ageometricmodelofaforeststandusingaconicapproximationsuggestedthatthereshouldbeinterrelationsbetweencorrespondentexponentsandinterceptsoftherelationships.Itisequivalenttoatypeof‘relationshipbetweenrelationships’thatmightexistinaforeststandundergoingself-thinning,andmeansthatparametersofonerelationshipmaybepredictedfromparametersofanother.Thepredictionsofthemodelweretestedwithdataonforeststandstructurefrompublisheddatabasesthatinvolvedanumberoftreesspeciesandsitequalitylevels.Itwasfoundthatthecorrespondentexponentsandinterceptsmaybedirectlyrecalculatedfromoneanotherforthesimplestcasewhenthetotalstemsurfaceareawasindependentofstanddensity.Forcaseswheretotalstemsurfaceareachangeswiththedropofdensity,itispossibletodevelopageneralizationofthemodelinwhichtheinterrelationshipsbetweencorrespondentparameters(exponentsandintercepts)maybestillestablished.

简介：Determiningthephysicalandmechanicalpropertiesofsoilanditsbehaviorforengineeringprojectsisessentialforroadconstructionoperations.Oneofthemostimportantprinciplesinforestroadconstruction,whichisusuallyneglected,istoavoidmixingorganicmatterwithroadmaterialsduringexcavationandembankmentconstruction.Thecurrentstudyaimedtoassesstheinfluenceoforganicmatteronthephysicalpropertiesandmechanicalbehaviorsofforestsoilandtoanalyzetherelationbetweentheamountoforganicmatterandthebehaviorofforestsoilasroadmaterial.Atypicalsoilsamplefromthestudyareawascollectedbesideanewlyconstructedroadbed.Thesoilwasmixedwithdifferentpercentagesoforganicmatter(controltreatment,5,10,and15%bymass)anddifferenttestsincludingAtterberglimits,standardcompaction,andCaliforniabearingratio(CBR)testswereconductedonthesedifferentsoilmixtures.Theresultsshowedthatsoilplasticityincreasedlinearlywithincreasingorganicmatter.Increasingtheorganicmatterfrom0%(control)to15%resultedinanincreaseof11.64%oftheplasticlimitand15.22%oftheliquidlimitafterdryingat110℃.Also,increasingtheorganicmattercontentreducedthesoilmaximumdrydensityandincreasedtheoptimummoisturecontent.Increasingtheorganicmatterfrom0to15%resultedinanincreaseof11.0%oftheoptimummoisturecontentandadecreaseof0.29g/cm3ofthemaximumdrydensity.OrganicmatterdecreasedtheCBR,whichisusedastheindexofroadstrength.Adding15%organicmattertothesoilresultedinadecreaseoftheCBRfrom15.72to4.75%.Therewasasignificantdifferencebetweenthetwodryingtemperatures(60and110℃)forthesameorganicmattermixtureswithlowerwatercontentvaluesafterdryingat60℃.Theresultsrevealedtheadverseinfluenceoforganicmatteronsoilengineeringpropertiesandshowedtheimportanceoforganicmatterremovalbeforeexcavationandfillconstruction.

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简介：Exploringtheresponsedifferencesofleafphysiologyparameterstoenhancednitrogendepositionbetweensaplingsandtreesisvitalforpredictingthevariationsofterrestrialecosystemstructureandfunctionunderfutureglobalclimatechange.Inthisstudy,theecophysiologicalparametersofsaplingsandtreesofFraxinusmandshuricaRupr.weremeasuredatdifferentlevelsofnitrogenadditioninatemperateforest.Theresultsshowthatecophysiologicalparametersmaximumnetphotosyntheticrate(Pmax),apparentquantumefficiency(a),darkrespiration(Rd),lightsaturationpoint(Lsp),photosyntheticnitrogenuseefficiency(PNUE),specificleafarea(SLA)andstomatalconductanceundersaturatedlightintensity(Gsmax)werehigherinsaplingsthanintrees.ThesephysiologicalparametersandnotNleaf(leafnitrogencontent)ledtorelativelylowerPmaxandRdintrees.Forbothsaplingsandtrees,lowandmediannitrogenaddition(23and46kgha-1a-1)resultedinsignificantincreasesinPmax,Rd,Lsp,Chl,PNUE,SLAandGsmax.Theseparameterstendedtodeclineunderhighadditionsofnitrogen(69kgha-1a-1),whereasNleafwasalwaysenhancedwithincreasingnitrogen.VariationsinPmaxandRdwithincreasingnitrogenwereattributedtovariationsinthestronglyrelatedparametersof,Lsp,Chl,PNUE,SLAandGsmax.Overall,theresponsesensitivityofphysiologicalparameterstoenhancednitrogenlevelswaslowerintreescomparedwithsaplings.

简介：Thecircumborealforestencompassesdiverselandscapestructures,dynamicsandforestagedistributionsdeterminedbytheirphysicalsetting,andhistoricalandcurrentdisturbanceregimes.However,duetointensifyingforestutilisation,andincertainareasduetoincreasingnaturaldisturbances,borealforestage-classstructureshavechangedrapidly,sothattheproportionofoldforesthassubstantiallydeclined,whilethatofyoungpost-harvestandpost-natural-disturbanceforestproportionshaveincreased.Inthefuture,withawarmingclimateincertainborealregions,thistrendmayfurtherbeenhancedduetoanincreaseinnaturaldisturbancesandlarge-scaleuseofforestbiomasstoreplacefossil-basedfuelsandproducts.Themajordriversofchangeofforestageclassdistributionsandstructuresincludetheuseofclearcutshortrotationharvesting,morefrequentandseverenaturaldisturbancesduetoclimatewarmingincertainregions.Thedeclineinoldforestarea,andincreaseinmanagedyoungforestlackingnaturalpost-disturbancestructurallegacies,representamajortransformationintheecologicalconditionsoftheborealforestbeyondhistoricallimitsofvariability.Thismayintroduceathreattobiodiversity,ecosystemresilienceandlong-termadaptivecapacityoftheforestecosystem.Tosafeguardborealforestbiodiversityandecosystemfunctioning,andtomaintainthemultipleservicesprovidedtosocietiesbythisforestbiome,itispivotaltomaintainanadequateshareandtheecologicalqualitiesofyoungpost?disturbancestages,alongwithmatureforeststageswithold-growthcharacteristics.Thisrequiresmanagementfornaturalpost-disturbancelegacystructures,andinnovativeuseofdiverseuneven-agedandcontinuouscovermanagementapproachestomaintaincriticallate-successionalforeststructuresinlandscapes.

简介：Background:Inthecontextofecosystemmanagement,thepresentstudyaimstocomparethenaturalandthepresent-dayforestedlandscapesofalargeterritoryinQuebec(Canada).Usingcontemporaryandlong-termfirecycles,eachnaturalforestlandscapeisdefinedaccordingtothevariabilityofitsstructureandcomposition,andcomparedtothepresent-daylandscape.Thisanalysiswasconductedtoaddressthequestionofwhetherhumanactivitieshavemovedtheseecosystemsoutsidetherangeofnaturallandscapevariability.Methods:Thestudyencompassedaforestedareaof17.5000km^2dividedinto14landscapes.Usingaframeworkthatintegratesfirecycles,agestructureandforestdynamics,wecharacterizedtheforestcompositionandagestructuresthatresultedfromthreehistoricalfirecycles(110,140,and180years)representativeoftheborealforestof.easternCanada.Themodelednaturallandscapeswerecomparedwithpresent-daylandscapesinregardtotheproportionofold-growthforests(landscapelevel)andtheproportionoflate-successionalforeststands(landscapelevelandpotentialvegetationtype).Results:Fourlandscapes(39%)remainwithintheirnaturalrangeofvariability.Incontrast,ninelandscapes(54%)showalargegapbetweennaturalandpresent-daylandscapes.Theseninearelocatedinthesouthernportionofthestudyarea,andaremainlyassociatedwithAbies-BetulavegetationwherehumanactivitieshavecontributedtoastrongincreaseintheproportionofPopulustremuloidesstands(early-successionalstages)andadecreaseofoldgrowthforeststands(morethan100yearsold).Asinglelandscape(7%),substantiallychangedfromitspotentialnaturalstate,isacandidateforadaptive-basedmanagement.Conclusion:Comparisonofcorrespondingnatural(referenceconditions)andpresent-daylandscapesshowedthattenlandscapesreflectinganimportantshiftinforestcompositionandagestructurecouldbeconsideredbeyondtherangeoftheirnaturalvariability.Thedescriptionofalandscape'snaturalvariabili

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简介：碳水池在全球气候变化，和森林生态系统的复杂现象以内组成一个重要元素是重要的全球碳水池。生来的福雷斯特保护节目(NFPP)是在在在1998的在这个国家的灾难的泛滥以后被建立的中国的一个生态的节目。NFPP的目标是限制生态的环境的恶化，加强产地的保护和恢复增加生物多样性，并且恢复在森林区域支持持续开发的自然森林。这研究在NFPP的开始以后在东北中国的一个forested区域在碳隐遁看了变化。节目把瓷器自然森林划分成三classescommercial，noneconomicforeststhat的二种类型服从于规定木材收获，造林，和重新造林的变化层次的管理政体。在从1998～2015的18年的时期期间，碳隐遁的全部的数量以0.04的平均的年度率增加了?MT?C。在导致了的NFPP的实现禁止了或限制了记载以后，这个趋势反映森林管理惯例的转变，许可的收获的更紧密的规定为特定的区域铺平。在记录这个趋势，为象在在未来的另外的国家的NFPP那样的林地节目的更多的有效实现的指南也被建议。

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简介：Prescribedfireisacommoneconomicalandeffectiveforestrypractice,andthereforeitisimportanttounderstandtheeffectsoffireonsoilpropertiesforbettersoilmanagement.Weinvestigatedtheimpactsoflow-intensityprescribedfireonthemicrobialandchemicalpropertiesofthetopsoilinaHungarianoak(QuercusfrainettoTen.)forest.Theresearchfocusedonmicrobialsoilparameters(microbialsoilrespiration(RSM),soilmicrobialbiomasscarbon(Cmic)andmetabolicquotient(qCO2)andchemicaltopsoilproperties(soilacidity(pH),electricalconductivity(EC),carbon(C),nitrogen(N),C/Nratioandexchangeablecations).Meanannualcomparisonsshowsignificantdifferencesinfourparameters(C/Nratio,soilpH,CmicandqCO2)whilemonthlycomparisonsdonotrevealanysignificantdifferences.SoilpHincreasedslightlyintheburnedplotsandhadasignificantlypositivecorrelationwithexchangeablecationsMg,Ca,MnandK.ThemeanannualC/Nratiowassignificantlyhigherintheburnedplots(28.5:1)thaninthecontrolplots(27.0:1).ThemeanannualCmic(0.6mgg-1)wassignificantlyloweralthoughqCO2(2.5lgCO2–CmgCmich-1)wassignificantlyhigher,likelyresultingfromthemicrobialresponsetofire-inducedenvironmentalstress.Low-intensityprescribedfirecausedveryshort-livedchanges.TheannualmeanvaluesofC/Nratio,pH,CmicandqCO2showedsignificantdifferences.

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