简介：Woodpropertiesfrom28trees(Populuseuramericana)selectedfromhealthyandacidraindamagedforestweremeasuredtoevaluatethepossibleimpactsonwoodqualityandutilization.Ontheheavilydamagedlocation,thepHvalueofprecipitationrangedfrom3.7-5.0,andsulfateloadingrangedfrom20-40kg·ha-2.y-1.Quantitativeandqualitativestudiesonringwidth,physicalpropertiesandmechanicalpropertiesindicatedthatchangesofwoodpropertiesbetweendiseasedandhealthypoplaroccurred.Aci...

简介：ThispaperestablishedanintegratedstandgrowthmodelofMongolianoak(ISGM_oak)usingthedatafrom61permanentsampleplotsmeasuredin1997and2007.ISGM_oakisagroupofnonlinearsimultaneousequations.Themethodofnonlinearerror-in-variablesimultaneousequationsisusedtoestimatetheparametersofISGMoakwiththestatisticalsoftwareForstat2.0,sotheparameterestimationofthegroupofcorrelatedequationsinISGMoakisunbiasedandtheequationsarecompatible.Modelvalidationusingbootstrapmethodshowedthatboththeaveragerelativeerrorandsquareerrorarelessthan15percent.TheISGM_oakmodelcanbeusedtosimulatethestandgrowthwithdifferentvaluesofsiteindex,standdensityandtodrawstanddensitymanagementdiagramfordecision-making.

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简介：Thebiodiversityofarbuscularmycorrhizalfungi(AMF)wassurveyedintheKolmregionofIraninthreeadjacentsites,anaturalstand,a10-year-oldanda15-yearoldplantationofAmygdalusscoparia.Todate,therehavebeenfewstudiesofAMFbiodiversityinIran,especiallyinthewesternforestsofthecountry.Forthisstudy,soilandrootsamplesweretakenfromA.scopariarhizospheresoilinspringandautumn.AlmosthalfoftherootlengthwascolonizedbyAMF.Weidentified13AMFspeciesbelongingtoGlomeraceae,ClaroideoglomeraceaeorDiversisporaceae.Thethreeplantationsdifferedintermsofsoilelectricalconductivity,organicCandP.SporedensitywassignificantcorrelatedwithPconcentration.RootlengthcolonizationwascorrelatedonlywithsoilCa.SpeciesdiversityandrichnessweresignificantlycorrelatedwithsoilN,P,organicCandsporedensity.AMFdiversityin15-year-oldplantationswasmoresimilartothatinthenaturalstandthaninthe10-year-oldplantation.Weconfirmedthata15-year-oldplantationisnotsimilarintermsofAMFcolonizationtonaturalstands.Weconcludethatmorethan15yearsarerequiredforAMFcolonizationofplantationstoresemblethatofnaturalstands.

简介：Eucalyptusisthemostvaluablecultivatedforestgenusinthetropicalandsubtropicalareasnowadays.Ithasbeenachallengeforforesterstomodelgrowthduetothegeneticvariations,managementregimes,andmultipleproductsgeneratedfromtheplantations.Inthispaper,LogisticequationwasusedtostudythestockgrowthprocessofE.urophylla×E.grandisplantationatageof14with6spacingtreatments.AndthebiologicalinterpretationoftheparametersofLogisticequationwasanalyzed.There...

简介：BambooforestisanimportantlanduseinthetraditionalvillageofPenglipuran,BaliIndonesia.BamboogrowingintheruralareascanbeagoodchoiceforcapturingCO2.Iharvestedselectedculmstodeterminebiomasscontent,and50%ofdryweightbiomasswascalculatedascarboncontent.ThePenglipuranbambooforestsupportedsixbamboospeciesinaonehectaresamplingplot,allofthegenusGigantochloa.Theclumpandculmdensitieswere339and7190ha-1,respectively.Totalabove-plusbelow-groundbiomasswas87.35Mgha-1,andcarbonstoragewas43.67Mgha-1.CarbonstorageestimatedinthebambooforestatPenglipuranoffersinsightintotheopportunityforPES（paymentforecosystemservices）throughemissiontradingmechanisms.

简介：Background:ThefloodplainforestsofAraguaiaRiver,aclear-waterriverinthesoutheasternAmazon(TocantinsState,Brazil),arecharacterizedbyseasonalfloodingupto3.5mheight,lownutrientlevelsinthewater,andseasonaldroughtperiodsof4–5months.Methods:Westudiedtheforestdynamics(treediametergrowth,treemortalityandrecruitment)ofthisuniqueforestecosystemovera5-yearperiodbyrepeatedcensusesin12permanentplotsestablishedalongafloodinggradient.Results:Thecumulativebasalareaintheplotsincreasedby0.84(±0.45)m2?ha~(–1)?yr~(–1)(mean±SD)intheannualy-flooded(AF)plotsinlowerterrainandby0.69(±1.00)m2?ha~(–1)?yr~(–1)inthehighernon-annualyflooded(NAF)plots,correspondingtoanabovegroundbiomassincreaseof0.81(±0.57)and0.69(±1.58)Mg?ha~(–1)?yr~(–1)intheAFandNAFplots,indicatingarecentcarbonsinkinthebiomass.Meandiametergrowthratewas1.8(±0.44)mm?yr~(–1)intheAFand2.0(±0.56)mm?yr~(–1)intheNAFplots(correspondingtoacoarsewoodproductionof1.53(±1.29)and2.02(±0.52)Mg?ha~(–1)?yr~(–1)),indicatingnofloodingeffectonradialgrowth.Meanmortalityratesinthe5-yearperiodwere1.9(±0.37)%?yr~(–1)intheAFplotsand1.8(±0.87)%?yr~(–1)intheNAFplotswithnodifferencesalongthefloodinggradient.HighestmortalitieswereregisteredintheAFplotsforthe10–20cmdbhclass(2.4%?yr~(–1)),likelyasaconsequenceofflooding,andintheNAFplotsforthe40–50cmdbhclass(3.0%?yr~(–1)),probablymainlycausedbyENSO-relateddroughts.Conclusions:Weconcludethatthesedrought-affectedtropicalfloodplainforestshavealowerstandingbiomassandabovegroundproductivitythancentralAmazonianfloodplainforestsinmorehumidclimates,andtheimprintofthefloodinggradientonstanddynamicsisrelativelyweak,whichmayresultfromthelowerfloodingheightandtheinteractionoffloodingwithlownutrientsupplyandperiodicdrought.

简介：Background:Treelinedynamicshaveinevitableimpactsontheforesttreelinestructureandcomposition.ThepresentresearchsoughttoestimatetreelinemovementandstructuralshiftsinresponsetorecentwarminginCehennemdere,Turkey.Afterimplementinganatmosphericcorrection,thegeo-shiftingofimageswasperformedtomatchimagestogetherforaperpixeltrendanalysis.WedevelopedanewapproachbasedontheNDVI,LST(landsurfacetemperature)data,airtemperaturedata,andforeststandmapsfora43-yearperiod.Theforesttreelineborderwasmappedontheforeststandmapsfor1970,1992,2002,and2013toidentifyshiftsinthetreelinealtitudes,andthenprofilestatisticswerecalculatedforeachperiod.Twentysampleplots(10×10pixels)wereselectedtoestimatetheNDVIandLSTshiftsacrosstheforesttimberlineusingper-pixeltrendanalysisandnon-parametricSpearman’scorrelationanalysis.Inaddition,thespatialandtemporalshiftsintreelinetreespecieswerecomputedwithintheselectedplotsforfourtimeperiodsontheforeststandmapstodeterminethepioneertreespecies.Results:Astatisticallysignificantincreasingtrendinallclimatevariableswasobserved,withthehighestslopeinthemonthlyaveragemeanJulytemperature(tau=0.62,ρ<0.00).Theresultantforeststandmapsshowedageographicalexpansionofthetreelineinboththehighestaltitudes(22m–45m)andthelowestaltitudes(20m–105m)from1970to2013.TheperpixeltrendanalysisindicatedanincreasingtrendintheNDVIandLSTvalueswithintheselectedplots.Moreover,increasesintheLSTwerehighlycorrelatedwithincreasesintheNDVIbetween1984and2017(r=0.75,ρ<0.05).CedruslibaniandJuniperuscommunisapp.weretwopioneertreespeciesthatexpandedandgrewconsistentlyonopenlands,primarilyonrocksandsoil-coveredareas,from1970to2013.Conclusion:Thepresentstudyilustratedthatforesttreelinedynamicsandtreelinestructuralchangescanbedetectedusingtwodata

简介：本文研究了长江三峡花岗岩地区林地土壤流失特性．结果表明由鳞片状面蚀导致的土壤流失量月分布与月降雨量的分布趋势基本一致，二者呈现出较为明显的线性相关关系．植物盖度≥０．７０的林地土壤流失多集中发生在６～９月份，土壤流失量在５０００ｔ·ｋｍ－２·ａ－１以下．盖度＜０．７的林地土壤流失年内分布时间多在３～１０月份，土壤流失量为５００～６０００ｔ·ｋｍ－２·ａ－１．

简介：Naturalspruce-firmixedstandisoneofthemainforesttypesintheworld,andalsohashugeecological,economicandsocialbenefits.Accordingtothestructuralcharacteristicsandsuccessionlawsofnaturalspruce-firforest,itisurgentandsignificanttodevelopscientificmanagementmeasuresfornaturalspruce-firmixedstandinlinewithlocalconditions.Thearticleoutlinedthecharacteristicsofthedistributionandstructure,regenerationandsuccessionlawsofnaturalspruce-firforest,andanalyzedthecurrentsituationandexistingproblemsofnaturalspruce-firforestmanagement.Thefollowingrecommendationswereeventuallymade:1)Innocuttingarea,allloggingactivitiesshouldbebanned.Inarestrictedcuttingarea,thecuttingintensityshouldbegenerallycontrolledwithin15%ofthestockvolumebeforecutting.Onthecommodityforestmanagementarea,theappropriatecuttingintensityshouldbedeterminedaccordingtothevolumeperhectare,determineandclassificationmanagementshouldbeimplementedinaccordancewiththecharacteristicsofforest,toensurethescientificselectivecutting.2)Closureforafforestation,plantingandrepairplantingshouldbeadoptedonvegetation-intensiveland,sparseshrubscoveredlandandharvestingslash,inordertoacceleratenaturalregeneration.3)Theinsituconservationshouldbeconductedinnaturereservesandscientificexperimentstationsofrareandendangeredspecies,suchasAbieschensiensis,Piceaneoveitchii,Abiesvuanbaoshanensis,toreducehumandestruction.4)Itissupposedtocollectseedsintime,establishnursery,activelyestablishforest,expandartificialpopulationandpromotenaturalregeneration.

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.