Background:Tropicalforestsplayanimportantroleintheglobalcarbon(C)cycle.However,tropicalmontaneforestshavebeenstudiedlessthantropicallowlandforests,andtheirroleincarbonstorageisnotwellunderstood.Montaneforestsarehighlyendangeredduetologging,land-useandclimatechange.Ourobjectivewastoanalysehowthecarbonbalancechangesduringforestsuccession.Methods:Inthisstudy,weusedamethodtoestimatelocalcarbonbalancesthatcombinedforestinventorydatawithprocess-basedforestmodels.WeutilisedsuchaforestmodeltostudythecarbonbalanceofatropicalmontaneforestinSouthEcuador,comparingtwotopographicalslopepositions(ravinesandlowerslopesvsupperslopesandridges).Results:Thesimulationresultsshowedthattheforestactsasacarbonsinkwithamaximumnetecosystemexchange(NEE)of9.3MgC?(ha?yr)-1duringitsearlysuccessionalstage(0–100years).Inthelatesuccessionalstage,thesimulatedNEEfluctuatedaroundzeroandhadavariationof0.77MgC?(ha?yr)–1.ThesimulatedvariabilityoftheNEEwaswithintherangeofthefielddata.Wediscoveredseveralforestattributes(e.g.,basalareaortherelativeamountofpioneertrees)thatcanserveaspredictorsforNEEforyoungforeststands(0–100years)butnotforthoseinthelatesuccessionalstage(500–1,000years).Incaseofyoungforeststandsthesecorrelationsarehigh,especiallybetweenstandbasalareaandNEE.Conclusion:Inthisstudy,weusedanEcuadorianstudysiteasanexampleofhowtosuccessfullylinkaforestmodelwithforestinventorydata,forestimatingstem-diameterdistributions,biomassandabovegroundnetprimaryproductivity.Toconclude,thisstudyshowsthatprocess-basedforestmodelscanbeusedtoinvestigatethecarbonbalanceoftropicalmontaneforests.Withthismodelitispossibletofindhiddenrelationshipsbetweenforestattributesandforestcarbonfluxes.Theserelationshipspromoteabetterunderstandingoftheroleoftropicalmontaneforest
