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.