简介:<正>Since1980s,participatoryapproach,asatoolandmajortechnology,hasbeenreceivedbymanycountriesandinternationalorgans,andhasbeenusedextensivelyintheprojectsofsurvey,povertyrelief,resourcedevelopmentandresourceprotection.Indeed,thesedevelopmentactions,supportedby
简介:Inrecentyears,thequantityandqualityofglobalforestresourcesaredecliningcontinually.Contrarily,thebothinChinaareincreasing,whichisdeeplyrelatedtothesustainableforestmanagementandeco-systemmanagementinChina.Withthetrendthatworldcommunityknowsmoreabouttheimportantroleofforest,moreandmorefunctionsofforestarerecognized.TheimpactandfunctionsofChina'sforestrydeservemoreconcern.Basedonsomeexperiencesinthefieldofforestryresearch,theauthors...
简介:Inthispaper,tenwoodyplantsgrewonthecampusoftheBeijingForestryUniversitywereselectedformeasuringhydraulicarchitectureparametersandwaterpotentialofone-year-oldtwigs.Theresultsshowthatdayandnightchangeofwaterpotentialandhydraulicarchitectureparametersappeartobeobviouslyconvextrend.Therelationshipmodelsbetweenwaterpotentialandhydraulicconductivity,specialconductivityandleafspecialconductivitywererespectivelyestablished,whichweresimulatedb...
简介:Thisarticle,bycomparingthebasicconceptsofsubstrateandsoil,theircompositionofsubstanceandmethodsofmeasuringtheindexesofphysicalandchemicalproperties,analyzesandresearcheswaysofchoosingsubstrateforcultivationwithfacilities.Itindicatesthatthenormalphysicalandchemicalindexesofevaluatingasubstratearebulkdensity,totalporosity,non-capillaryporosity,ratioofbigporositytosmallporosity,thepHandtheelectricalconductivity(EC)valueofthesubstrate.By...
简介:Inthepaper,thehydraulicarchitectureparametersofPinustabulaeformisseedlings(4yearsold)weremeasuredbyimprovedflushingmethodundernormalwaterconditioninthegreenhouseandthebasictheoryofhydraulicarchitectureisusedtodiscusstherationalityofthepipemodel.Theresultsoftheexperimentandsimulationshowthatthedifferencesofhydraulicconductivity,specificconductivityandleafspecificconductivityisgreatindifferentstemsandbranchesofPinustabulaeformisseedlings.Thehydraulicconductivityofnon-constrictionareaishigherthanthatofconstrictionarea.Thedevotionoffunctionalxylemofstemtounitleafgrowthisnotaconstant,namely,theHubervalueisdiverse.Eventhoughthepipemodelhasbeenacceptedinsomeareas,itspreconditionisnotperfect,anditishelplessincorrectlyunderstandingtheessenceofwatertransportinseedlingsfromtheprospectiveofwaterphysiology.
简介:AccordingtotheunificationprincipleofsystemstructureandsystemfunctionoftheWaterResourceConservationForests,sevenfactorswereselectedfromstandspatialstructure,treesstructureandhealthyofwoods,themultifunctionmanagementoptimizationmodeltargetwasconfirmedbyusingnonlinearitymulti-objectiveprogrammingapproach,andthetargetfunction-standspatialstructurehomogeneityindexwasdefinedtoestablishspatialoptimizationmodelswithrestrainingconditionssetupindiversityofstandstructureandspatialstructure.ThespatialstructureofavailabletypicalstandinthewetlandareainsouthernDontingLakewasoptimizedbymeansofselectivecuttingandreinforcementplanting.Theresultsshowedthatthespatialstructurewasimprovedobviouslyandtreesdiversityandstandhealthwerenotweakened.It’ssuggestedthattheestablishedoptimizationmodelcaneffectivelyguidemultifunctionmanagement,standstructureoptimizationandthesteadinessofecologicalecosystemanditisconvenientandoperableinpractice,andit’sveryimportanttoprotectandrecoverecosystemofWaterResourceConservationForests.
简介:我国DHI(奶牛生产性能测定)取得了很多成绩,但也存在测定有效数据比例不高等一些问题,本文就DHI测定有效数据低的可能原因及改进措施进行了阐述。