简介:TenhealthytreespecieswithregularmanagementwereselectedonthecampusofBeijingForestryUniversity,andtheybelongtotalltree,shrubandliana,respectively.Waterpotentialandhydraulicarchitectureparametersofone-year-oldtwigsweremeasuredinsunnydayinthelasttendaysofMarchtothemiddletendaysofMayin2002.Theresultsshowthatthedailychangeinwaterpotentialoftreespeciesexaminedappearsconvex,i.e.thewaterpotentialishigherinthemorningandevening,and...
简介:Behaviorsofsikadeerinspringwerestudiedbyscansampling,adlibitumsampling,andall-occurrencerecordingmethodsduring1998.Theresultsshowedthatbehaviorsofsikadeerinspringcanbeclassifiedbysevencategories:grazing,ruminating,bedding,moving,standing,drinking,alert,agonisticandotherbehaviors.Variousbehavioralmodelsweremoreregular.Grazingbehaviorwasakindofmainlybehavioralmodel.
简介:Globalclimatechangehascausedphenologychangeofvegetation.Thisisespeciallyobviousinurbanarea.ThispaperrevealsresponsemechanismofspringphenologyofmaingymnosperminHarbinCitypropertoclimatechangebasedonrelationshipstudybetweentwotypicalphenophases(beginningofbudburstandbeginningofleafexpansion)ofKoreanpine(Pinuskoraiensis),Koyamaspruce(PiceakoraiensisNakai),needlefir(Abiesnephrolepis)andPinussylvestnisvar.mongolicaLitv.andthetemperatureofeveryten...
简介:Availablewaterandfertilizerhavebeenthemainlimitingfactorsforyieldsofspringwheat,whichoccupiesalargeareaoftheblacksoilzoneinnortheastChina;thus,theneedtosetupappropriatemodelsforscenarioanalysisofcroppingsystemmodelshasbeenincreasing.ThecapabilityofCropSyst,acroppingsystemsimulationmodel,tosimulatespringwheatgrowthofawidelygrownspringcultivar,'Longmai19',intheblacksoilzoneinnortheastChinaunderdifferentwaterandnitrogenregimeswasevaluated.Fielddatacollectedfromarotationexperimentofthreegrowingseasons(1992-1994)wereusedtocalibrateandvalidatethemodel.Themodelwasrunfor3yearsbyprovidinginitialconditionsatthebeginningoftherotationwithoutreinitializingthemodelinlateryearsintherotationsequence.CropinputparametersweresetbasedonmeasureddataortakenfromCropSystmanual.Afewcultivar-specificparameterswereadjustedwithinareasonablerangeoffluctuation.TheresultsdemonstratedtherobustnessofCropSystforsimulatingevapotranspiration,abovegroundbiomass,andgrainyieldof'Longmai19'springwheatwiththerootmeansquareerrorsbeing7%,13%and13%oftheobservedmeansforevapotranspiration(ET),grainyieldandabovegroundbiomass,respectively.AlthoughCropSystwasabletosimulatespringproductionreasonablywell,furtherevaluationandimprovementofthemodelwithamoredetailedfielddatabasewasdesirableforagriculturalsystemsinnortheastChina.
简介:ThetaigaconiferousforestsoftheSiberianregionarethemaincarbonsinksintheforestecosystems.Quantitatively,thesizeofthecarbonaccumulationisdeterminedbythephotosyntheticproductivity,whichisstronglyinfluencedbyenvironmentalfactors.Asaresult,anassessmentoftherelationshipbetweenenvironmentalfactorsandphotosyntheticproductivitymakesitpossibletocalculateandevenpredictcarbonsinksinconiferousforestsattheregionallevel.However,atvariousstagesofthevegetativeperiod,theforceoftheconnectionbetweenenvironmentalconditionsandtheproductivityofphotosynthesismaychange.Inthisresearch,correlationsbetweenthephotosyntheticactivityofScotspine(PinussylvestrisL.)withtheenvironmentalconditionswerecomparedinspringandinautumn.Inspring,closepositivecorrelationofthemaximumdailynetphotosynthesiswasidentifiedwithonlyoneenvironmentalfactor.Fordifferentyears,correlationswereforsoiltemperature(rs=0.655,p=0.00315)oravailablesoilwatersupply(rs=0.892,p=0.0068).Inautumnwithindifferentyears,significantcorrelationwasshownwithtwo(temperatureofairandsoil;rs=0.789and0.896,p=0.00045and0.000006,respectively)andfourfactors:temperatureofair(rs=0.749,p=0.00129)andsoil(rs=0.84,p=0.00000),availablesoilwatersupply(rs=0.846,p=0.00013)andirradiance(rs=0.826,p=0.000001).Photosyntheticactivityhasaweakerconnectionwithchangesinenvironmentalfactorsinthespring,ascomparedtoautumn.Thisisexplainedbythemultidirectionalinfluenceofenvironmentalconditionsonphotosynthesisinthisperiodandbythenecessityofearlierphotosynthesisonset,despitetheunfavorableconditions.Thisdatamaybeusefulforpredictingtheflowofcarbonindependenceonenvironmentalfactorsinthisregioninspringandinautumn.