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:Multi-functionaldendrometerisakindofforestrytoolthatcanmeasuremultiplefactorsofforest.Bycombiningsensortechnologyandcomputertechnology,adigitalmulti-functiondendrometerhasbeendeveloped,whichintegratedthefunctionsofmeasuringheight,distance,azimuth,slope,elevation,formquotientofanypartsofthestemintoonebodyatthesametest.Thedendrometercanfitthecomplexforestenvironment,solvethedifficultproblemsinaspectsofplantheight,measuredistance,centraldiameterandformquotientofbreastheight.Theaccuracycanmeettherequirementsofgeneralforestsurvey.
简介:Thispaperproposesanautomaticmethodofporecombinationrecognition,whichisanimportantfeaturetohardwoodrecognition.Afterextractingedgefromwoodmicroscopiccross-section,basedonareahistogramofthesimilarcircleregions,themethodclassifiesallregionsintotwoclasseswithmaximumbetween-classvariance,soastodistinguishtheporefromothertextures,whicharesimilarinshapesbutdifferentinsizes.Meanwhile,secondobjectivefunctionaboutaverageareaofclosedregionsisusedtoimprovetheporesegmentationperformance.Atlast,themethodusesadjacencydegreeofporesettojudgeporecombination.Theexperimentsdemonstratethatthetaskofporesegmentationcanbecompletedsuccessfullyforallkindsofporedistributionandcombination,andalsothecorrectcombinationsofporesaregiven.
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:MetropolitanManila,thecapitalregionofthePhilippines,initiatedurbanforestryprojectstoshowcaseitsenvironmentalbenefits.MetroManilawasonceapartofatropicalmangroveforestdominatedbysmalltreeslocallycallednilad(Scyphiphorahydrophyllaceae).Thefast-pacedurbanizationtransformedtheoriginalecosystemintoabustlingmetropolissubjectedtoenvironmentaldecay.Theestablishmentofurbanforestryisoneoftheinterventionssoughtbythegovernmenttomitigatetheenvironmentalconditions.Thus,theconceptofparticipatoryurbanforestrywasformalizedin1988bythenationalgovernment.However,itwasduringtheearlyyearsofthe1970sthattheideaofexertingcollectiveeffortingreeningMetroManilastartedthroughtheGreenRevolution,withtheprimarymotiveofupliftingtheeconomicconditionofthepeopleratherthanonecologicalenhancement.Theprojectwasforcedonthepeopletoplantvegetablesandfruittreeswithlessemphasisonforesttreesspecies.Althoughtheprojectwasnotsuccessful,thegovernmentrealizedthatthecitizenrycouldbeagreatpartnerforacollectiveworthwhileundertaking.
简介:BasedonthepreviousstudyoncultivationnutritionofCunninghamialanceolataplantationsoffirstgeneration,thecultivationnutritionofC.lanceolataplantationswithmulti-generationwasstudied.Theresultsshowthattherearesignificantdifferencesinthegrowth,developmentandnutrientassimilationamongC.lanceolataplantationswithdifferentgenerationsandnutritionconditions.ThesedifferencesarecloselyrelatedtothelandfertilitydeclineofC.lanceolataplantations.Thispaperde...
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373%.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:TwoclonaltrialstandsofChineseFir(Cunninghamialanceolata)wereusedinthisstudy,onewas19-year-oldstandwhichincluded38clones,andtheotherwas17-year-oldstandincluding102clones.Thestatisticalanalysesshowedthattherewereverysignificantgeneticvariationsinheight,DBH,volumeandratioofheartwood(Rhw),woodbasicdensity(ρb)oftheclonesinthetwostands.Therepeatabilityofcloneswasinmediantohighlevel,andthegeneticCVwasdifferentovertheallfivetraits.Therewereverysignificantphenotypicandgeneticcorrelationsamongheight,DBHandvolume,andnegativecorrelationsamonggrowth,Rhwandρb.Theselectionmethodexperimentindicatedthatindexselectioncouldimprovevolume,Rhwandρb,showingsyntheticallysuperiorselectioneffectscomparedtoanyindividualtraitselectionmethods.
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
简介:Blacklocust(RobiniapseudoacaciaL.)wasthefirstNorth-AmericantreespeciesimportedtoEuropeatthebeginningoftheseventeenthcentury.Itiscommonlyplantedworldwidebecauseofitsadaptabilitytoenvironmentalstresses,itsvaluablewood,easypropagation,frequentandabundantseedproduction,excellentcoppicing,highseedlingsurvival,andrelativelyhighwoodyield.InEurope,RomaniaandHungaryhavethemosthighly-developedblacklocustgrowingtechniquesandexperiences.Asaresultofincreasinginterestinblacklocustinmanycountries,thisreviewaimstoprovideacomprehensiveoverviewofstate-of-the-artsiterequirements,propagation,improvementandmanagement(includinggrowthandyieldaswellasuseinenergyplantations).
简介:Globalclimatechangeposesnewopportunitiesandchallengesforforestrydevelopment,andthereforedevelopingmultiple-purposeforestryisanimportantmeasuretostrengthenforestryresponsetoclimatechange.Atpresent,plantationinChinarankstheworldfirstinarea,butwithrelativelylowproductivity.Constantlyexpandingforestareaandimprovingforestmanagementforenhancingmultiplefunctionsandpurposesofplantationsarethekeymeasurestoupgradeplantationcapacitytomitigateandadap...