简介：Theeffectsofsucroseconcentration,pHvalueandstorageconditionsongerminationandpollentubegrowthofinvitroculturedsprucewerestudiedandtheingredientsofculturemediumwereoptimized.TheresultsshowedthattheeffectofsucroseconcentrationandpHvalueonsprucepollen’sgerminationwassignificant,andaclearthresholdeffectexisted.Loworhighconcentrationofsucrosewasnotconducivetothepollen’sgermination,itwasfoundthat10%ofwhichwasmoresuitabletotheinvitrocultureofsprucepollen;differentsprucespeciesrequireddifferentconcentrationsofsucrosemedium,7.5%ofsucroseconcentrationmediumwasbettertopollentubegerminationofPiceaasperata,but10%ofwhichwasthebestmediumtothatofPiceaabies.BothpH4.5and6.5hadrestrainedactiononpollengerminatingrateofspruce,andthegrowthofpollentubes.Underdarkcultureconditions,P.abiesbegantogerminatein6h,butP.asperatagerminatedin8h,themassgerminatingpowerofP.abieswashigherthanthatofP.asperata;thegrowthprocessofP.abieswas20-22h,andthatofP.asperatawasabout16h;ThepollentubesofP.abieswasover10?mlongerinlengththanthatofP.asperata.Thereweresignificantdifferencesofgerminatingpowerandlengthofpollentubesbetweengenotypesoftwodifferentindividualsofbothspruces.Thestoragemethodshadgreatinfluenceontheviabilityofpollen.Intheprocessofpollenpreservation,temperaturewasthekeyfactor.Cryopreservationwasbetterthancoldstorageandroomtemperaturepreservationwasunfavorable.

简介：Vegetationdegradationisrelatedtothestabilityandsuccessionprocessofecologicalsystems.Thispapercombedandscreenedtherecentnationalandinternationalresearchonvegetationdegradation,anddiscussedvegetationdegradationresearchintermsofselectionofreferenceecosystemforevaluation,selectionofevaluationindexsystemandtheselectionofevaluationmethods.Atlast,thedirectionofvegetationdegradationresearchwaspredictedandprospected.

简介：Thepaperanalyzedthebottlenecksofinternationalforestfinancingdevelopmentfromtheperspectiveofthedevelopmentstateofforestfinancingmechanism.Italsoanalyzedthedevelopmentpossibilitiesofemergingfinancingchannelswhileintroducingofficialdevelopmentassistanceandnon-financialdevelopmentassistanceintheframeworkofinternationalforestfinancingmechanism,andpooledthevariousexistingforest-involvedfundstoproposeafeasiblearchitecturedirectionforpossiblefuturedevelopment.

简介：Thepatternofprecipitation,includingprecipitationamount,frequencyandintensity,maychangeinthefutureaccordingtothepredictionofclimatechange.Inaridzones,thesoildynamics,plantgrowthandvegetationchange,desertificationandhydrologymightbeaffectedbyprecipitationchange.Ingeneral,theprecipitationinextremearidzoneandaridzoneshowedanincreasetendencywhereastheprecipitationinsomeareainsemi-aridzoneandsub-humidaridzoneshowedadecreasetendency.Theincreaseofprecipitationcouldenhancethegrowthofbiologicalsoilcrust,improvesoilwaterstatus,promoteplantgrowth,increasevegetationcoverage,facilitatethechangefromdesertvegetationtograsslandvegetation,anditisbenefittothereversionoflanddesertification.Inaddition,theincreaseofprecipitationcouldalsoincreasetheriverrunoff,lakestorageandpromotetheoccurrenceofflood,whilethedecreaseofprecipitationhastheadverseeffect.Thesestudieswillbenefitthepredictionofthepossibleresponseofecosystemprocessestothepotentialchangeofprecipitationpatterninaridzonesinthefuture,anditisimportanttotheconservationofnaturalvegetationandthecontrolofdesertification.Morefieldexperimentsandstudiesshouldbeconductedinthefuture,includingtheeffectofincreasedprecipitationortemperature,nitrogendepositionandCO2onsoil,vegetation,desertificationandhydrologyofaridzones,soasthemorepersuasiveresultscouldbeobtainedfromtheseexperimentsandstudies.

简介：Theprocessthattreeconeacquisitionrobotgetsconeshasbeensimulatedwiththeprocessthathumanbendsorstretcheshisarmsinsomeload.Andthentheshaftdrivingforcesimulationoftreeconeacquisitionrobotinthewordingprocesswasanalyzedaccordingtobiomechanicslawsbysystemmodelingsimulationanalysissoftwarethatisusedincurrentpopular.Theforcesoftheshaftsatshoulderjointandelbowjointoftherobotwereanalyzed,meanwhile,werecalculatedanddrewupthefiguresbyusingMaplesoftware.Finally,theanalyticalresultsverifiedthecorrectnessofthetheoryanalysiswithSolidDynamicssoftware.Andfromthestudy,thefindingsprovideimportanttheoryandparametersforimprovingthetreesconesacquisitionrobot.

简介：Theroleandpositionofforestryinresponsetotheissueofclimatechangehavebeenincreasinglyconcernedbymoreandmorecountriesandtheinternationalcommunity.Thecostincurredinforestcarbonsequestrationislowerthanotheroptionstomitigateclimatechange.However,thefund’sgapbecomesthemainbarriertoreducingcarbonemissionscausedbydeforestationandforestdegradation(REDD)andenhancingcarbonstorageinforests(REDD+)andalsobecomestheconcernsofgovernments,academiccommunityandenterprises.Basedonthecomparativeanalysisofoverseasforestcarbonfinancingmodels,thepaperpinpointedtheirdevelopmenttrendandproposedsolutionstofinancingforforestcarbonsinkinChina.

简介：Nonlinearmixedeffectsmodel(NLMEM)isbuiltontherelationshipofthefixedandrandomeffectsintheregressionfunction.TheNLMEMhasanobviouscomparativeadvantageinanalyzingthelongitudinaldata,repeatedmeasuresdataandmultileveldata.Two-levelNLMEMisusedtoanalyzethedominantheightforChinesefir(Cunninghamialanceolata).Theauthorsoutlinethetwo-levelNLMEMandintroducetheparametersestimationmethodofthemodel.BasedonfivecommonRichardandLogisticmodels,themixedmodelisbuilt.Themodelingdataareusedtocalculateandcomparewith19modelsderivedfromeachbasedmodel,and5optimalmixedmodelsarebuilt.Comparedthe5optimalmixedmodelswithtraditionalregressionmodels,itisshowedthatthetwo-levelNLMEMhasabetterfittingeffectthantheregressionmodel.