简介:Plantationpoplarisoneofthemostimportantresourcesforwoodindustry,itsutilizationfieldisvast.ThewettabilityofPopulustomentosawithdifferentdryingmethodswasjudgedbymeasurementofcontactangleusingdistilledwaterinthispaper.Theresultsshowedthatthespecimensfromconventionaldryinghavethebiggestcontactangle,andtheairdriedhavethesmallestcontactangle,airdriedlumbershaveabetterwettabilitythanthekilndried.Thechangesofcontactangleinaperiodoftim...
简介:Structuralfinger-jointed(FJ)lumberwasusedmainlyinstructuralapplicationsincludingglue-laminatedbeamsandwoodenI-joistsandmorerecentlyinparallelchordwoodtrusses.ThepaperevaluatedstrengthpropertiesofstructuralFJlumberbythreenondestructivemethods(edge-wisebending,longitudinalandtransversalvibration)inordertofindanalternativetotraditionalevaluationmethods.LumberwassawnfromthelogsfollowingapatterntypicallyusedinChinatomaximizethevolumeofrecover...
简介:Background:Mostcurrentapproachesinforestscienceandpracticerequireinformationaboutstructureandgrowthofindividualtreesratherthan-orinadditionto-sumandmeanvaluesofgrowthandyieldatforeststandlevelasprovidedbyclassicexperimentaldesigns.Byinventingthewheeldesign,Nelderprovidedthepossibilitytoturntotheindividualtreeasbasicinformationunit.Suchtrialsprovidevaluableinsightsintothedependencyofgrowthonstanddensityatparticularsites.Methods:Here,wepresentanextensionoftheoriginaldesignandevaluationbyNelder.(i)WeestablishedNelderwheelsalonganenvironmentalgradientthroughEuropeinatlanticclimateinBelgiumandGermany,MediterraneanclimateinItaly,continentalclimateinHungaryaswellasonhighlandclimateinMexico.SuchdisjunctNelderwheelsalonganenvironmentalgradientcanberegardedandanalysedasatwo-factordesignwiththefactorsofsiteconditionandstanddensity.(ii)WepresentanadvancedstatisticalapproachtoevaluatedensitydependentgrowthdynamicsoftreesplantedinformoftheNelderdesign,whichconsidersspatio-temporalautocorrelation.(iii)Weprovetheusefulnessofthemethodsinimprovingecologicaltheoryconcerningdensityrelatedproductivity,trade-offsbetweenfacilitationandcompetition,andallometricrelationsbetweensizevariables.Results:FirstevaluationsbasedonremeasuredNelderwheelsinoak(QuercusroburL.)showasizegrowthdifferentiationduringthefirstobservationperiod.Inparticular,heightgrowthisacceleratedunderhighercompetitionindicatingfacilitationeffects.Wedetectfurthermoreahighvariabilityinallometricrelations.Conclusions:Theproposeddesign,methods,andresultsarediscussedregardingtheirimpactonforestpractice,modelbuilding,andecologicaltheory.WeconcludethattheextendedNelderapproachishighlyefficientinprovidingcurrentlylackingindividualtreelevelinformation.