简介：ChemicalanalyseswereconductedwithleaveoilsofEucalyptussmithii,E.bakeri,E.polybractea,E.dives,E.radiataandE.macarthuriivvhichwereintroducedtosouthwesternChinafromAustralia.ItwasfoundthattheleafoilsofE.smithii,E.bakeriandE.polybracteacontained81-90%of1,8-cineole,andE.divesandE.radiatacontainedhighera-phelandreneandpiperitone.Therevveresignificantinter-andintraspeciflcvariationsinleafoilyield,italsovariedwithseasonsinvvhichleaves...

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简介：Thepredictionofthedistributionofquantitativevariablesinaforeststandisofgreatinteresttoforestmanagers,fortheevaluationofforestresourcesandschedulingoffuturesilviculturaltreatments.TheaimofthisresearchwastomodelthedistributionofquantitativevariablesforQuercuspersicainopenforestsinIran.Toinvestigatetheprobabilitydistributionoftreesinnaturalstands,642treeswereselectedformeasurementusingasystematicrandomsamplingmethod.Selectedtreesweremeasuredanddatawereanalyzed.Gamma,beta,normal,lognormal,exponentialandWeibullprobabilitydistributionswerefittedtotheheightdistributionoftrees.Variablesofdistributionfunctionswereestimatedusingthemaximumlikelihoodestimationmethod.ActualprobabilityandprobabilitywhichderivedfromfunctionswascomparedusingKolmogorov–SmirnovandAnderson–Darlingtests.Beta,WeibullandWeibullprobabilitydistributionsexplainedthedistributionsoftreeheight,DBHandcrownarea.

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.