简介：Background:InWesternNorthAmerica,increasingwildfireandoutbreaksofnativebarkbeetleshavebeenmediatedbywarmingclimateconditions.Bioclimaticmodelsforecastthelossofkeyhighelevationspeciesthroughouttheregion.Thisstudyusesretrospectivevegetationandfirehistorydatatoreconstructthedriversofpastdisturbanceandenvironmentalchange.Understandingtherelationshipamongclimate,antecedentdisturbances,andthelegacyeffectsofsettlement-eraloggingcanhelpidentifythepatternsandprocessesthatcreatelandscapessusceptibletobarkbeetleepidemics.Methods:Ouranalysisusesdatafromlakesedimentcores,standinventories,andhistoricalrecords.Sedimentcoresweredatedwithradiometrictechniques(~(14)Cand~(210)Pb/~(137)Cs)andsubsampledforpollenandcharcoaltomaximizethetemporalresolutionduringthehistoricalperiod(1800CEtopresent)andtoprovideenvironmentalbaselinedata(last10,500years).Pollendataforsprucewerecalibratedtocarbonbiomass(Ct/ha)usingstandardallometricequationsandatransferfunction.Charcoalsampleswereanalyzedwithstatisticalmodelstofacilitatepeakdetectionanddeterminefirerecurrenceintervals.Results:TheWasatchPlateauhasbeendominatedbyEngelmannspruceforestsforthelast~10,500years,withsubalpinefirbecomingmoreprominentsince6000yearsago.Thislandscapehasexperiencedadynamicfireregime,whereburningeventsaremorefrequentandofhighermagnitudeduringthelast3000years.TwoimportantdisturbanceshaveimpactedEngelmannspruceinthehistoricalperiod:1)high-gradeloggingduringthelate19~(th)century;and(2)ahighseveritysprucebeetleoutbreakinthelate20~(th)centurythatkilled>90%ofmaturespruce(>10cmdbh).Conclusions:Ourstudyshowsthatspruce-dominatedforestsinthisregionareresilienttoarangeofclimateanddisturbanceregimes.Severallinesofevidencesuggestthat19~(th)centuryloggingpromotedalegacyofsimplifiedstandstructureandcompositionsuchthat,whencli

简介：Background:Thispaperexploredthelong-term,ceteris-paribuseffectsofpotentialCO,fertilizationontheglobalforestsector.BasedonthefindingsofNorbyetal.(PNAS2005,102(50))aboutforestresponsetoelevated[CO_2].Methods:ForestproductivitywasincreasedintheGlobalForestProductsModel(GFPM)inproportiontotherising[CO.,]projectedintheIPCCscenarioA1B,A2,andB2.Projectionsoftheforestareaandforeststockandoftheproduction,consumption,prices,andtradeofproductsrangingfromfuelwoodtopaperandpaperboardwereobtainedwiththeGFPMforeachscenario,withandwithoutCO_2fertilizationbeginningin2011andupto2065.Results:C02fertilizationincreasedwoodsupply,leadingtolowerwoodpriceswhichinturninducedmodestlowerpricesofendproductsandhigherglobalconsumption.However,productionandvalueaddedinindustriesdecreasedinsomeregionsduetotherelativecompetitiveadvantagesandtothevaryingregionaleffectsofCO_2fertilization.Conclusion:ThemaineffectofCO,fertilizationwastoraisetheleveloftheworldforeststockin2065by9to10%forscenariosA2andB2andby20%forscenarioA1B.Theriseinforeststockinducedbyfertilizationwasinpartcounteractedbyitsstimulationofthewoodsupplywhichresultedinlowerwoodpricesandincreasedharvests.