简介：Elevatedatmosphericnitrogen(N)depositionhasbeendetectedinmanyregionsofChina,butitseffectsonsoilNtransformationintemperateforestecosystemsarenotwellknown.WethereforesimulatedNdepositionwithfourlevelsofNadditionrate(N0,N30,N60,andN120)for6yearsinanold-growthtemperateforestinXiaoxing’anMountainsinNortheasternChina.WemeasuredgrossNtransformationratesinthelaboratoryusing15NtracingtechnologytoexploretheeffectsofNdepositiononsoilgrossNtransformationstakingadvantageofNdepositionsoils.NosignificantdifferencesingrosssoilNtransformationrateswereobservedafter6yearsofNdepositionwithvariouslevelsofNadditionrate.ForallNdepositionsoils,thegrossNH4+immobilizationrateswereconsistentlylowerthanthegrossNmineralizationrates,leadingtonetNmineralization.Nitrate(NO3-)wasprimarilyproducedviaoxidationofNH4+(i.e.,autotrophicnitrification),whereasoxidationoforganicN(i.e.,heterotrophicnitrification)wasnegligible.Differencesbetweenthequantityofammonia-oxidizingbacteriaandammonia-oxidizingarchaeawerenotsignificantforanytreatment,whichlikelyexplainsthelackofasignificanteffectongrossnitrificationrates.GrossnitrificationratesweremuchhigherthanthetotalNO3-consumptionrates,resultinginabuild-upofNO3-,whichhighlightsthehighriskofNlossesviaNO3-leachingorgaseousNemissionsfromsoils.ThisresponseisoppositethatoftypicalN-limitedtemperateforestssufferingfromNdeposition,suggestingthattheinvestigatedold-growthtemperateforestecosystemislikelytoapproachNsaturation.

简介：Background:Forestmanagementstrategiessuchasthinninghavelongbeenusedtoenhanceecosystemfunctions,especiallyinplantations.Thinninginplantationswithhighdeerdensity,however,maynotyieldadesiredincreaseinunderstoryvegetationbecausedeergrazeongerminatingplantsafterthinning.Here,weexaminethechangesinunderstoryvegetationafterthinninginplantationsthathavebeenovergrazedbysikadeertoprovideinsightintotheeffectsofthinningonecosystemfunctionssuchassoilconservationandbiologicaldiversity.Methods:WeconductedoursurveyintheTanzawaMountainsofeasternJapan.Wesurveyedthechangeinunderstoryvegetationwithinandoutsideofthreedeerexclosuresonasingleslopewiththreelevelsofunderstoryvegetationcover:sparse(1%,exclosure'US'),moderate(30%,exclosure'MM'),anddense(80%,exclosure'LD')over10yearsaftera30%thinningofanold-growthcedarandcypressplantationwhichwasovergrazedbysikadeer.Results:Understoryvegetationcover,biomassandspeciesrichnessincreasedwithinandoutsidethe'US'and'MM'exclosuresafterthinning,andbiomasswasgreaterwithinthanoutsidetheexclosuresat10yearsafterthinning.Unpalatablespeciesdominatedboth'US'and'MM'exclosuresbeforethinning,andtreesandshrubsdominatedwithintheexclosuresovertimeafterthinning.Incontrast,unpalatable,grazing-tolerant,perennial,andannualspeciesincreasedoutsidethe'US'and'MM'exclosures.Nonoticeablechangeswereobservedwithinandoutsidethe'LD'exclosurewhencomparedwiththe'US'and'MM'exclosures.Conclusions:Ourresultssuggestthatthinningastandby30%basedonvolumeresultedinanincreaseinunderstoryvegetationcovermainlycomposedofbothunpalatableandgrazing-tolerantspeciesinaplantationforestwhereunderstoryvegetationissparseormoderateandsikadeerdensityishigh.Weemphasizethatestablishingdeerexclosuresorcontrollingdeerisessentialtomaintainingsimilarunderstoryvegetationbothwit

简介：研究被进行在C在碱新陈代谢的变化上调查高温的效果。升起我们在福雷斯特植物生态学的关键实验室的幼苗，东北林地大学，Heilongiang，中国。60-day-oldC。玫瑰我们有34片叶子的幼苗与30°C的温度在房间被孵化；为短期的热的40°C震惊实验；20°C，25°C；为长期的实验的35°C。vindoline的内容，catharanthine，vinblastine；在C的长春新碱。玫瑰我们离开；根在短术语(16h)在不同温度被检查；长期(116d)。结果在短期的热吃惊下面显示出那，vindoline的内容，catharanthine；在幼苗的叶子的vinblastine在40°C是更高的与比在30°C，但是在6h处理以后，vindoline的内容；在二温度下面的catharanthine来到了一样的水平。Catharanthine只在C被散布。升起我们根；它的内容被40%在40°C在二小时孵化以后增加，当在30°C孵化慢慢地增加了时；在6h到达了最高的价值。在长期的实验，monomeric碱catharanthine的集中；vindoline比在25°C在20°C是更高的；在35°C的条件下面有锋利的增加。当时为二聚的碱，越高，看了那温度，vinblastine内容的山峰价值越earlier出现。长春新碱有连续改进；达到了0.027mg·g[1]在在比处于另外的条件的那些高的35°C状况下面的第16白天。高温能在C支持不同的碱的累积，这被结束。升起我们；累积特征是高度与处理时间有关。

简介：ＭｅｅｔｉｎｇｓａｎｄＳｈｏｒｔＴｒａｉｎｉｎｇＣｏｕｒｓｅｓＭｅｅｔｉｎｇｓａｎｄＳｈｏｒｔＴｒａｉｎｉｎｇＣｏｕｒｓｅｓＪｕｌｙ７－１０，１９９７．３ｒｄａｉｒｂｏｒｎｅｒｅｍｏｔｅｓｅｎｓｉｎｇｃｏｎｆｅｒｅｎｃｅａｎｄｅｘｈｉｂｉｔｉｏｎ...

简介：ＭｅｅｔｉｎｇｓａｎｄＳｈｏｒｔＴｒａｉｎｉｎｇＣｏｕｒｓｅｓＡｕｇｕｓｔ１２－Ｄｅｃ．１３，１９９６．Ｃｅｒｔｉｆｉｃａｔｅｃｏｕｒｓｅｉｎｃｏｍｍｕｎｉｔｙｆｏｒｅｓｔｒｙ．ＲＥＣＯＦＴＣ，Ｔｈａｉｌａｎｄ．Ｃｏｎｔａｃｔ：Ｄｉｒｅｃｔｏｒ，ＲＥ...

简介：ＭｅｅｔｉｎｇｓａｎｄＳｈｏｒｔＴｒａｉｎｉｎｇＣｏｕｒｓｅｓＤｅｃ４－８，１９９５．Ｒｅｇｉｏｎａｌｓｙｍｐｏｓｉｕｍａｇｒｏｆｏｒｅｓｔｒｙｒｅｓｅａｒｃｈａｎｄｄｅｖｅｌｏｐｍｅｎｔｉｎｔｈｅｈｕｍｉｄｌｏｗｌａｎｄｓｏｆｗｅｓｔａｎｄｃｅｎｔ...

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简介：Background:FrequentoutbreaksofinsectsanddiseaseshavebeenrecordedinthenativeforestsofwesternNorthAmericaduringthelastfewdecades,butthedistributionoftheseoutbreakshasbeenfarfromuniform.Insomecases,recentclimaticvariationsmayexplainsomeofthisspatialvariationalongwiththepresenceofexpansiveforestscomposedofdense,oldertrees.Forestmanagersandpolicymakerswouldbenefitifareasespeciallypronetodisturbancecouldberecognizedsothatmitigatingactionscouldbetaken.Methods:Weusetwoponderosapine-dominatedsitesinwesternMontana,U.S.A.toapplyamodelingapproachthatcouplesinformationacquiredviaremotesensing,soilsurveys,andlocalweatherstationstoassesswherebarkbeetleoutbreaksmightfirstoccurandwhy.Althoughtherewasageneraldownwardtrendinprecipitationforbothsitesovertheperiodbetween1998and2010(slope=-1.3,R2=0.08),interannualvariabilitywashigh.Someyearsshowedlargeincreasesfollowedbysharpdecreases.Bothsiteshadsimilartopographyandfirehistories,butbarkbeetleactivityoccurredearlier(circa2000to2001)andmoreseverelyononesitethanontheother.Theinitialcanopydensityofthetwositeswasalsosimilar,withleafareaindicesrangingbetween1.7-2.0m2?m-2.WewonderedifthedifferenceinbarkbeetleactivitywasrelatedtosoilsthatwerehigherinclaycontentatsiteIthanatsiteII.Toassessthispossibility,weappliedaprocess-basedstandgrowthmodel(3-PG)toanalyzethedataandevaluatethehypotheses.Results:Wefoundthatwhenwetyearswerefollowedbydrieryears,thesimulatedannualwoodproductionperunitofleafarea,ameasureoftreevigor,droppedbelowacriticalthresholdonsiteIbutnotonsiteII.Conclusion:Weconcludedthatthedifferenceinvulnerabilityofthetwostandstobeetleoutbreakscanbeexplainedlargelybydifferencesingrossphotosynthesisattributedtothefactthatanequivalentamountofstoredwaterintherootingzone(100m

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简介：Chinesefir(Cunninghamialanceolata)andpoplar(Populusspp.)woodmealwerephenolatedinthepresenceofsulfuricacidusedasacatalyst.Theeffectsofreactiontimeandreactiontemperatureonthewoodliquefactionwereinvestigated.Theresultsshowedthatthereactiontemperaturehadthegreaterinfluenceontheresiduecontentthanreactiontime.Additionally,theliquefactioncurvefortheChinesefirandPoplarweresimilaringeneral.

简介：ThenitrogendepositionexperimentsonCinnamomumcamphoraplantationofHunanprovincialbotanicalgardenweresimulatedfromJunethe7thtoOctoberthe7th,2010,thenitrogendepositionlevelswasrespectivelyascontrol(CK,0g·m-2a-1),lownitrogen(LN,5g·m-2a-1),mediumnitrogen(MN,15g·m-2a-1)andhighnitrogen(HN,30g·m-2a-1).ThesoilrespirationspeedandsoilsurfacetemperatureandthesurfacewatercontentofthesoilweredeterminedbyLI-8100measuringinstrument.TheresultsshowthattheaveragevaluesofsoilrespirationspeedwereCK(4.09±0.66μmol·m-2s-1),LN(2.39±029μmol·m-2s-1),MN(2.18±0.19μmol·m-2s-1),HN(2.28±0.25μmol·m-2s-1),andthetreatmentoftheCKwasobviouslyhigherthantheotherthreetreatments（P<0.01）.Withdifferentnitrogenconcentrationsdepositiontreatments,theQ10（temperaturesensitivitycoefficients）forsoilrespirationofCK,LN,MNandHNtreatmentswere1.84,1.71,1.83and1.56.Itwaspositivecorrelationbetweentherespirationspeedandthesurface（≤10cm）temperatureoftestedsoil.Itwasnegativecorrelationbetweentherespirationspeedandthesurface（≤5cm）watercontentoftestedsoil（P>0.05）.Volumetricwatercontentof5-cmsoilwasbetween0.2666-0.2944(m3·m-3),andthemonthlycontentdidnotvarytoomuchduringtheresearchperiod（1.8%-9.4%）.ThefindingssuggestthattheinitialstageofnitrogendepositionobviouslyinfluencedthesoilrespirationofC.camphoraplantation.

简介：Thecircumborealforestencompassesdiverselandscapestructures,dynamicsandforestagedistributionsdeterminedbytheirphysicalsetting,andhistoricalandcurrentdisturbanceregimes.However,duetointensifyingforestutilisation,andincertainareasduetoincreasingnaturaldisturbances,borealforestage-classstructureshavechangedrapidly,sothattheproportionofoldforesthassubstantiallydeclined,whilethatofyoungpost-harvestandpost-natural-disturbanceforestproportionshaveincreased.Inthefuture,withawarmingclimateincertainborealregions,thistrendmayfurtherbeenhancedduetoanincreaseinnaturaldisturbancesandlarge-scaleuseofforestbiomasstoreplacefossil-basedfuelsandproducts.Themajordriversofchangeofforestageclassdistributionsandstructuresincludetheuseofclearcutshortrotationharvesting,morefrequentandseverenaturaldisturbancesduetoclimatewarmingincertainregions.Thedeclineinoldforestarea,andincreaseinmanagedyoungforestlackingnaturalpost-disturbancestructurallegacies,representamajortransformationintheecologicalconditionsoftheborealforestbeyondhistoricallimitsofvariability.Thismayintroduceathreattobiodiversity,ecosystemresilienceandlong-termadaptivecapacityoftheforestecosystem.Tosafeguardborealforestbiodiversityandecosystemfunctioning,andtomaintainthemultipleservicesprovidedtosocietiesbythisforestbiome,itispivotaltomaintainanadequateshareandtheecologicalqualitiesofyoungpost?disturbancestages,alongwithmatureforeststageswithold-growthcharacteristics.Thisrequiresmanagementfornaturalpost-disturbancelegacystructures,andinnovativeuseofdiverseuneven-agedandcontinuouscovermanagementapproachestomaintaincriticallate-successionalforeststructuresinlandscapes.

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简介：Disturbancesthatcreategapscanshapethestructureandfunctionofforests.However,suchdisturbanceregimesinAsiantropicalmontanerainforestsremainlargelyunquantified.Leaststudiedaretyphoondisturbancesthatareattributabletoclimatechange.Weinvestigatedgapcharacteristicsintermsofsize,age,andgapmakertoquantifythegapdisturbanceregimesinanintactold-growthtropicalmontanerainforestonHainanIsland,China.Theintensityoftyphoonshasincreasedsince1949,andtyphoonwindsblowmostly(45.5%)fromthenortheastcornerofHainanIsland,resultinginahigherfrequencyofgapsinthenortheast.Atotalof221gap-makers(treesthatfelltocreatecanopygaps)and53gapswereobservedina3.16haold-growthrainforest.Mostcanopygaps(85%)were\200m2.Theaveragesizeofcanopygapswassmallerintherainforestthaninothertropicalforests,whiletheaveragesizeofexpandedgapswassimilartothoseinothertropicalforests.Themaximumageofgapswas23.5yearsindicatingthatgapshadmorerapidturnoverthanotherpartsoftropicalforests.Thefrequencydistributionofgap-makersfollowedalognormaldistributionwithadistinctivepeakatthreegap-makers,whichwasdifferentfromtheinverseJ-shapedcurvetypicalofothertropicalforests.Gapswererecordedmainlyonslopesbetween20_and35_andwooddensityofgap-makerswasbetween0.6and0.7gcm-3.Ourresultssuggestthatsmall-scaledisturbancewasthedominantagentofgapformationinthisold-growthrainforestthatissubjecttoincreasingtyphoondisturbances.

简介：木质的种类的差异和新生在二生态的壁龛viz被调查。在旧生长的季节联盟者的差距和未经触动的植被弄干Shorea柔韧一(Gaertn。f.)在尼泊尔的森林。我们也联系了差异措施和新生属性的变化到差距特征。树和灌木部件的茎密度比在未经触动的植被在差距是更高的。S的幼苗密度。柔韧andTerminaliaalata(B。Heyne前Roth)比在未经触动的植被在差距是更高的，当矛盾的结果为T被观察时。bellirica(Gaertn。前Roxb)并且Syzigium枯茗i(L。Skeels)以幼苗密度。在幼苗层的Simpson索引，平均索引，和种类个人比率的补充比未经触动的植被在差距是更低的。差距尺寸能解释种类丰富和种类建立率。在不同的年里到多重树下降创造的差距有S的更高的幼苗密度。柔韧a比单个或多重的树创造的差距掉在一样的年里。在结论，差距由增加柳安森林的幼苗密度，和帮助新生维持种类差异。除了差距尺寸，另外的差距属性也影响种类差异和新生。

简介：Microbecommunitiesinrhizosphereecosystemsareimportantforplanthealthbutthereislimitedknowledgeofthemintherhizospheresofgeneticallymodified(GM)plants,especialfortreespecies.WeusedtheamplitudesequencingmethodtoanalyzetheV4regionsofthe16SrRNAgenetoidentifychangesinbacterialdiversityandcommunitystructureintwoGMlines(D520andD521),onenon-geneticallymodified(nonGM)lineandinuncultivatedsoil.Afterchimerafiltering,468.133sequencesinthedomainBacteriaremained.Thereweretendominanttaxonomicgroups(with[1%ofallsequences)acrossthesamples.241of551genera(representingaratioof97.33%)werecommontoallsamples.AVenndiagramshowedthat1.926operationaltaxonomicunits(OTUs)weresharedbyallsamples.Wefoundaspecificchange,areductioninChloroflexi,inthemicroorganismsintherhizospheresoilplantedwithpoplars.Takentogether,theresultsshowedfewstatisticaldifferencesinthebacterialdiversityandcommunitystructurebetweentheGMlineandnon-GMline,thissuggeststhattherewasnoorverylimitedimpactofthisgeneticmodificationonthebacterialcommunitiesintherhizosphere.

简介：Endophyticfungiarewidelyfoundinalmostallkindsofplants.Manyendophyticfungicanproducesomephysiologicalactivecompounds,whicharesametooranalogtothoseisolatedfromtheirhosts.Producingphysiologicalactivecompoundsthroughmicrobialfermentationcangiveanewwaytoresolveresourcelimitationandtofindoutalternativesource.Throughthemethodsoforganicsolventextraction,thinlayerchromatography(TLC)andcolumnchromatography,compoundIwasisolated,purifiedfromtheliquidfermentationmetabolitesofthetaxoids-producedendophyticfungi(Alternaria.alternatavar.taxi1011Y.XiangetLUAn-guo)thatwasscreenedfromthebarkofTaxus.cuspidataSieb.etZucc..CompoundIwasidentifiedasonekindoftaxoidstypeIII,basedontheanalyzingresultsbyusingthemethodsofultravioletspectroscopy(UV),infraredspectroscopy(IR),massspectrometry(MS)andnuclearmagneticresonancespectroscopy(NMR).Thisstudyprovidesacompletedmethodforseparationandpurificationoftheendophyticfungiaswellasstructureidentificationofitsfermentationmetabolite

简介：Background:Couplingbiomassmodelswithnutrientconcentrationscanprovidesoundestimationsofcarbonandnutrientcontents,enablingtheimprovementofcarbonandnutrientbalanceinforestecosystems.Althoughnutrientconcentrationsareoftenassumedtobeconstantforsomespeciesandspecifictreecomponents,atleastinmaturestands,theconcentrationsusuallyvarywithage,siteindexandevenwithtreedensity.Themainobjectiveofthisstudywastoevaluatethesourcesofvariationinnutrientconcentrationsinbiomasscompartmentsusuallyremovedduringharvestingoperations,coveringarangeofspeciesandmanagementconditions:semi-naturalforest,conventionalforestplantationsandshortrotationforestry(SRF).Fivespecies(Betulapubescens,Quercusrobur,Eucalyptusglobulus,EucalyptusnitensandPopulusspp.)and14genotypeswereconsidered.Atotalof430treesweresampledin61plotstoobtain6biomasscomponents:leaves,twigs,thinbranches,thickbranches,barkandwood.AbovegroundleaflessbiomassWaspooledtogetherforpoplar.TheconcentrationsofC,N,K,P,Ca,Mg,S,Fe,Mn,Cu,ZnandBweremeasuredandtheto:[albiomassofeachsampledtreeandplotweredetermined.Thedatawereanalysedusingboostedregressiontreesandconventionaltechniques.Results:Themainsourcesofvariationinnutrientconcentrationswerebiomasscomponent>>genotype(species)≈age>treediameter.TheconcentrationsofCa,MgandKweremoststronglyaffectedbygenotypeandage.TheconcentrationsofP,K,Ca,Mg,SandCuinthewoodcomponentdecreasedwithage,whereasCconcentrationsincreased,withatrendtoreach50%intheoldertrees.IntheSRF,interamericanpoplarandP.trichocarpogenotypeswerecomparativelymoreefficientintermsofCaandKnutrientassimilationindex(NAI)(+65-85%)thaneucalypts,,mainlybecauseleaflessbiomasscanberemoved.Intheconventionaleucalyptplantations(rotation15years),debarkingthewoodatlogging(savingsof225%ofCaand254%ofMgforE.globulus)ortheuseofselectedgenotype

简介：Treegrowthtraits(treeheight,DBHandstemvolume)andsurvivalfromtwo9-year-old,open-pollinatedprogenytestsofChinesefirwereinvestigatedforheritability,genotype9environmentinteraction,age-agegeneticcorrelationandselectionefficiency.The97and79familiesplantedattwositeswerecollectedfromthethirdcycleseedorchard.Individualheritabilitywasestimatedbetween0.05and0.21fortreeheight,DBH,andvolumeandbetween0.45and1.0forsurvival.Fa