简介：目前，关于防风林的保护的效果的大多数研究根据森林带和网络的二规模。与关于全球环境变化的进一步的研究，然而，更多的注意对防风林的地区性的气候效果被给予。在现在的学习，我们由使用陆地表面温度(LST)在地区性的规模分析了防风林的温度效果从在在到在2008的10月的从三月的中国的吉林省的Yushu，Nongan，Dehui，和Fuyu的中等决定成像分光辐射函数(MODIS)的数据。结果证明防风林能作为与没有防风林地区相比增加保护的农田的土壤温度，与0.57的增长吗？

简介：Thechangeofpinescale(HemiberlesiapitysophilaTakagi)populationdensityonpineforestinurbanparkbetweentreatment(tendingoperations)andCK(notendingoperations)wasresearchedinthispaper.Theresultswereshownasfollows:populationdensitydeclinedto0.63headperbundlefrom2.61headsperbundlewhencrowndensityofpineinurbanparkhadbecome0.5orsobymeansofcultivationactivitiessuchasfelling,pruningandthinningandsoon,anddropgotto75.86percent.Thepinewoodswouldsoongetrevivedonceusingthesecultivationactivities,sotendingoperationswasmainmeasurescontrollingoverharmofpinescaleinurbanpark;Atthesametime,populationdensityofpinescaleonpinewoodsinthesunnyslopewasmorethanthatinthesomberslopeandithadbecomelessandlessfromsunnyslopetosomberslope.Therefore,treespeciesmustbechosenintheplanninganddesignofurbanparkforpreventingharmandhappeningofpinescale.

简介：Background:Attentionhasrecentlybeendrawntotheissueoftransboundaryinvasions,wherespeciesintroducedandnaturalizedinonecountrycrossinternationalbordersandbecomeproblematicinneighbouringcountries.Robustmodellingframeworks,abletoidentifytheenvironmentaldriversofinvasionandforecastthecurrentandfuturepotentialdistributionofinvasivespecies,areneededtostudyandmanageinvasions.Limitationsduetothelackofspeciesdistributionandenvironmentaldata,orassumptionsofmodellingtools,oftenconstrainthereliabilityofmodelpredictions.Methods:Wepresentamultiscalespatialmodellingframeworkfortransboundaryinvasions,incorporatingrobustmodellingframeworks(MultimodelInferenceandEnsembleModelling)toovercomesomeofthelimitations.TheframeworkisillustratedusingHakeasericeaSchrad.(Proteaceae),ashruborsmalltreenativetoAustraliaandinvasiveinseveralregionsoftheworld,includingtheIberianPeninsula.Twostudyscaleswereconsidered:regionalscale(westernIberia,includingmainlandPortugalandGalicia)andlocalscale(northwestPortugal).Attheregionalscale,therelativeimportanceofenvironmentalpredictorssetswasevaluatedandrankedtodeterminethemaingeneraldriversforthespeciesdistribution,whiletheimportanceofeachenvironmentalpredictorwasassessedatthelocalscale.ThepotentialdistributionofH.sericeawasspatiallyprojectedforbothscaleareas.Results:ModelprojectionsforwesternIberiasuggestthatalargeareaisenvironmentallysuitableinbothPortugalandSpain.Climateandlandscapecompositionsetswerethemostimportantdeterminantsofthisregionaldistributionofthespecies.Conversely,ageologicalpredictor(schistlithology)wasmoreimportantinexplainingitslocal-scaledistribution.Conclusions:AfterbeingintroducedtoPortugal,H.sericeahasbecomeatransboundaryinvaderbyexpandinginpartsofGalicia(Spain).ThefactthatalargerareaispredictedasenvironmentallysuitableinSpainraisesconcern

简介：Background:Withthelossofspeciesworldwideduetoanthropogenicfactors,especiallyinforestedecosystems,ithasbecomemoreurgentthanevertounderstandthebiodiversity-ecosystemfunctioningrelationship(BEFR).BEFRresearchinforestedecosystemsisverylimitedandthusstudiesthatincorporategreatergeographiccoverageandstructuralcomplexityareneeded.Methods:Wecompiledground-measureddatafromapprox.onehalfmilionforestinventorysampleplotsacrossthecontiguousUnitedStates,Alaska,andnortheasternChinatomaptreespeciesrichness,foreststocking,andproductivityatacontinentalscale.Basedonthesedata,weinvestigatedtherelationshipbetweenforestproductivityandtreespeciesdiversity,usingamultipleregressionanalysisandanon-parametricapproachtoaccountforspatialautocorrelation.Results:Ingeneral,forestsintheeasternUnitedStatesconsistedofmoretreespeciesthananyotherregionsinthecountry.ThehighestforeststockingvaluesovertheentirestudyareawereconcentratedinthewesternUnitedStatesandCentralAppalachia.Overall,96.4%ofsampleplots(477,281)showedasignificantpositiveeffectofspeciesrichnessonsiteproductivity,andonly3.6%(17,349)hadaninsignificantornegativeeffect.Conclusions:Thelargenumberofground-measuredplots,aswellasthemagnitudeofgeographicscale,renderedoverwhelmingevidenceinsupportofapositiveBEFR.Thisempiricalevidenceprovidesinsightstoforestmanagementandbiologicalconservationacrossdifferenttypesofforestedecosystems.Foresttimberproductivitymaybeimpairedbythelossofspeciesinforests,andbiologicalconservation,duetoitspotentialbenefitsonmaintainingspeciesrichnessandproductivity,canhaveprofoundimpactsonthefunctioningandservicesofforestedecosystems.

简介：密云水库集水区水源保护林在北京地区饮用水源保护中起着非常重要的作用．本文给出了该区小流域对比实验的初步研究结果，有林小流域和无林小流域对１９９６年７月３０日降雨过程较为一致的径流响应表明，土壤前期含水量对流域产流有较大的影响，在降雨较多土壤含水量较大的情况下该区产流方式可以表现为饱和地表径流．尽管该区以霍顿超渗产流为主，但对于１９９７年７月３１日至８月１日降雨过程，森林流域产流总量为１３９３．８０ｍ３，无林流域为２２０２．４３ｍ３，森林流域减少洪水总量３６．７％，消减洪峰流量达３７３％．然而，１９９７年７月１９日降雨过程森林流域径流洪峰量与洪水泥沙含量均较无林流域高，这表明预处理措施对径流泥沙过程有极为显著的影响

简介：在考虑地表流边界条件情况下，森林对降雨径流和泥沙的影响是一个非常复杂的过程．本文给出了水源保护林在自然坡面尺度上对径流泥沙影响的初步试验研究结果，森林在自然坡面尺度上对１９９７年７月３１日至８月１日降雨过程的洪峰流量消减率达４５５９％，洪水总量的消减率为６．８％，森林坡面径流总量为９８０．７８ｍ３，荒草坡为１０５２２３ｍ３．森林对１９９６年７月３０日降雨过程的洪峰流量消减率为１７．９５％，森林坡面的径流总量为１５．０８ｍ３，荒草坡为１８．３８ｍ３．从１９９６年森林对降雨径流较低的消减率看，降雨量与降雨强度对径流泥沙有很大的影响．

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简介：Background:Theimportanceofstructurallydiverseforestsfortheconservationofbiodiversityandprovisionofawiderangeofecosystemserviceshasbeenwidelyrecognised.However,toolstoquantifystructuraldiversityofforestsinanobjectiveandquantitativewayacrossmanyforesttypesandsitesarestillneeded,forexampletosupportbiodiversitymonitoring.Theexistingapproachestoquantifyforeststructuraldiversityarebasedonsmallgeographicalregionsorsingleforesttypes,typicallyusingonlysmalldatasets.Results:HerewedevelopedanindexofstructuraldiversitybasedonNationalForestInventory(NFI)dataofBadenWurttemberg,Germany,astatewith1.3millionhaofdiverseforesttypesindifferentownerships.Basedonaliteraturereview,11aspectsofstructuraldiversitywereidentifiedaprioriascruciallyimportanttodescribestructuraldiversity.Aninitialcomprehensivelistof52variablesderivedfromNationalForestInventory(NFI)datarelatedtostructuraldiversitywasreducedbyapplyingfiveselectioncriteriatoarriveatonevariableforeachaspectofstructuraldiversity.Thesevariablescomprise1)quadraticmeandiameteratbreastheight(DBH),2)standarddeviationofDBH,3)standarddeviationofstandheight,4)numberofdecayclasses,5)bark-diversityindex,6)treeswithDBH>40cm,7)diversityoffloweringandfructification,8)averagemeandiameterofdowneddeadwood,9)meanDBHofstandingdeadwood,10)treespeciesrichnessand11)treespeciesrichnessintheregenerationlayer.Thesevariableswerecombinedintoasimple,additiveindextoquantifythelevelofstructuraldiversity,whichassumesvaluesbetween0and1.Weappliedthisindexinanexemplarywaytobroadforestcategoriesandownershipstoassessitsfeasibilitytoanalysestructuraldiversityinlarge-scaleforestinventories.Conclusions:Theforeststructureindexpresentedherecanbederivedinasimilarwayfromstandardinventoryvariablesformostotherlarge-scaleforestin