Disclaimer
ThispaperisoneofaseriesofFAOdocumentsonforestrelatedhealthandbiosecurityissues.The
purposeofthesepapersistoprovideearlyinformationaboutongoingactivitiesandprogrammes,
andtostimulatediscussion.
Thedesignationsemployedandthepresentationofmaterialinthisinformationproductdonotimply
theexpressionofanyopinionwhatsoeveronthepartoftheFoodandAgricultureOrganizationofthe
UnitedNations(FAO)concerningthelegalstatusofanycountry,territory,cityorareaorofits
authorities,orconcerningthedelimitationofitsfrontiersorboundaries.Thementionofspecific
companiesorproductsofmanufacturers,whetherornotthesehavebeenpatented,doesnotimply
thatthesehavebeenendorsedorrecommendedbyFAOinpreferencetoothersofasimilarnature
thatarenotmentioned.
Commentsandfeedbackarewelcome.
Forfurtherinformation,pleasecontact:
GillianAllard
ForestryOfficer(ForestProtectionandHealth)
ForestAssessment,ManagementandConservationDivision
ForestryDepartment
FAO
VialedelleTermediCaracalla
00153Rome,Italy
Tel:+390657053373
Email:[email protected]
Acknowledgements
TheauthorswouldliketothankFAOForestryDepartmentpersonnel,NoraBerrahmouni,JimCarle,
ThomasHofer,DougMcGuireandPietervanLierop,forreviewingthisdocumentandproviding
valuablecomments,andRobertoCenciarelliandTulliaBaldassarriHögervonHögersthalforthe
designandlayout.
Coverphotos:
Lightningstrikes,Canberra,Australia(flickr/PRESCOTT)
Deadvegetationindroughtstrickenarea,Senegal(FAO/CH.ERRATH/12787)
Chile’sLonquimayVolcanoerupting(FAO/R.GRISOLIA/21843)
Icecoverstreesandpowerlinesafteramajorstorm,Canada(B.MOORE)
Floodedforest,Hungary(FAO/M.KERESZTES/FO6082)
©FAO2011
ForestHealthandBiosecurityWorkingPapers
Abioticdisturbancesandtheirinfluenceonforesthealth
Areview
BeverlyA.MooreandGillianAllard
2011
ForestAssessment,Managementand
ConservationDivision
ForestryDepartment
WorkingPaperFBS/35EFAO,Rome,
Italy
Contents
Foreword...................................................................................................................................iv
EXECUTIVESUMMARY....................................................................................................................1
INTRODUCTION.............................................................................................................................3
METEOROLOGICALEVENTS..............................................................................................................6
Cyclones(synonymshurricanesandtyphoons)..................................................................6
Storms(wind,snow,ice,hail,dustandsand)...................................................................11
Tornadoes...........................................................................................................................14
Thunderstormsandlightning.............................................................................................16
CLIMATOLOGICALEVENTS.............................................................................................................1
Drought...............................................................................................................................17
HYDROLOGICALEVENTS................................................................................................................19
Floodsandflashfloods.......................................................................................................19
Avalanches..........................................................................................................................20
Landslidesandmudslides..................................................................................................22
GEOPHYSICALEVENTS..................................................................................................................24
Tsunamis.............................................................................................................................24
Earthquakes........................................................................................................................25
Volcaniceruptions..............................................................................................................26
ANTHROPOGENICEVENTS.............................................................................................................29
Fire......................................................................................................................................29
Oilspills...............................................................................................................................31
Airpollution........................................................................................................................32
Radioactivecontamination................................................................................................34
CONCLUSIONS.............................................................................................................................36
References...............................................................................................................................37
iii
Foreword
TheUnitedNationsdeclared2011tobetheInternationalYearofForestswhichaimstoincrease
publicawarenessofforests’importantecological,economicalandsocialfunctions.Forestsprovide
shelterforpeopleandhabitattobiodiversity.Theyareasourceoffood,medicineandcleanwater
andplayavitalroleinmaintainingastableglobalclimateandenvironment.Withsuchimmeasurable
values,protectingtheworld’sforestsfromdevastatingdisturbancesiscrucial.
Disturbancesareanaturalandintegralpartofforestecosystems.Whentheyexceedtheirnormal
rangeofvariation,however,theimpactsonforestscanbeextremeaffectingentirelandscapes,
causinglargescaletreemortalityandcompletedestructionofundergrowthandsoils.Globalclimate
changeisexacerbatingmanyoftheseimpactsbymakingforestsmorepronetodamagebyaltering
thefrequency,intensityandtimingofsomeeventssuchascyclones,landslides,insectanddisease
outbreaks,andheatwavesanddroughtswhichincreasetheriskoflargescalefires.
Muchmoreinformationisavailableontheimpactsofbioticdisturbances,suchaspestoutbreaks,on
foreststhanontheimpactsofabioticdisturbances,thosecausedbynonlivingfactorssuchasstorms,
droughtandtsunamis.FAO’sGlobalForestResourcesAssessment(FRA),carriedoutatfiveyear
intervals,providesthedataandinformationneededtosupportpolicies,decisionsandnegotiationsin
allmatterswhereforestsandforestryplayapart.Forthefirsttimeever,countrieswereaskedto
reportontheareaofforestdamagedbyabioticdisturbancesforFRA2010.Informationprovidedwas
sparse,mostlyqualitativeanddidnotallowforanytrendanalysis.Tosupplementtheinformationin
FRA2010,andinacknowledgementoftheincreasingimportanceofabioticinfluencesonforest
health,FAOpreparedthismoredetailedstudy.
Abioticdisturbancesareexpectedtoincreaseinintensity,quantityandfrequency.Adaptiveforest
managementisthereforeessentialtoprotecttheworld’sforestsresources.Effectivemanagement
practicesandpoliciesarebuiltuponrelevantandtimelyinformationandaccuratedataon
disturbancesandtheirimpactsonforests.Thispaperisafirststepinsynthesizingsuchinformationto
assistwiththemanagementandprotectionofforesthealth.Takingcareoftheworld’sforestsand
effectivelymanagingthemnotonlyensuresthattheymeettheirobjectivesbutalsoreducestherisk
ofdamagefromfutureabioticdisturbancesandaddressesglobalclimatechangeconcerns.
JoseAntonioPrado
Director,ForestAssessment,Management
andConservationDivision
FAOForestryDepartment
iv
EXECUTIVESUMMARY
Abioticdisturbances,disturbancescausedbynonlivingfactors,areanaturalandintegralpartof
forestecosystemsthathavemajorimpacts,positiveandnegative.Theyinfluenceforeststructure,
compositionandfunctioningandcanbeimportantformaintainingbiologicaldiversityandfacilitating
regeneration.Whendisturbancesexceedtheirnormalrangeofvariation,however,theimpactson
forestscanbeextremeaffectingentirelandscapes,causinglargescaletreemortalityandcomplete
destructionofundergrowthandsoils.Globalclimatechangeisexacerbatingmanyoftheseimpactsby
makingforestsmorepronetodamagebyalteringthefrequency,intensityandtimingofsomeevents
suchascyclones,storms,landslides,insectanddiseaseoutbreaks,andheatwavesanddroughts
whichincreasetheriskoflargescalefires.
Thispaperreviewsthecurrentknowledgeontheimpactsofabioticdisturbances.Eventsare
discussedwithinfivecategories:
x Meteorological–cyclones,storms(wind,snow,iceandhail,dustandsand),tornadoes,and
thunderstormsandlightning;
x Climatological–drought;
x Hydrological–floodsandflashfloods,avalanches,landslidesandmudslides;
x Geophysical–tsunamis,earthquakesandvolcaniceruptions;
x Anthropogenic1–fire,oilspills,airpollutionandradioactivecontamination.
Almost4000abioticdisturbanceeventsoccurredfrom2000to2009,killingoveronemillionpeople,
impactingover2.5billionpeopleandcostingalmostatrillionUSdollars(overUS$971billion)(IFRC
andRCS,2010).Whileconsiderableinformationmayexistonindividualevents,oftenlittle
informationisreadilyavailableonthespecificimpactsofaneventonforests.Globalreportingon
suchimpacts,particularlyquantitativeinformationonareasaffected,islowandsporadic.Thedata
thatisavailablehowever,indicatesthesignificance,magnitudeandseverityofabioticdisturbances.
x Forexample,abioticfactorsdamaged1.2millionhectaresofforestinSwedenin2005.The
majorityofthedamageoccurredasaresultofamajorstormthatcausedseverewindthrowinthe
southofthecountry.
x TropicalCycloneSidrhitBangladeshin2007affectingapproximately8.7millionpeople(FAO,2008)
anddamagednearly1.5millionhousesand4.1milliontrees.Approximately20000–25000
hectaresoftheSundarbanmangroveforests,aUNESCOWorldHeritageSite,incurredsevere
damagesandafurther60000hectareswerepartiallydamagedbythecyclone(FAO,2008).
x The2004IndianOceanTsunamikilledapproximately230000people,displacedmorethanone
millionpeople,andcausedbillionsofdollarsofpropertydamage.InIndonesia,thehardesthit
country,itwasestimatedthatalmost49000hectaresofcoastalforests(notincludingmangroves)
wereimpactedbythetsunamirepresentinganeconomiclossofUS$21.9millionand300750
hectaresofmangroveforestssufferedapproximately90percentdamagerepresentingalossof
US$2.5million(UNEP,2005).
x The2010earthquake,andsubsequenttsunami,incentralChilekilledmorethan700peopleand
causedwidespreaddamageinmanypartsofthecountry.Temporaryshutdownsatmanyofthe
country’spulpandpaperproducersoccurredraisingglobalpulpprices.LossestoChile’seconomy
wereestimatedatUS$1530billion(UNEP,2011).
x In2010,over32000firesintheRussianFederationburnedapproximately2.3millionhectaresof
coniferandmixedforests,withsomeareasofpeatbogs,killing62peopleanddestroyinghundreds
ofhomes(Williamsetal.,2011).
1
Theseanthropogenic,orhumancaused,disturbancesareincludedinthisreviewsincetheagentitself,i.e.fire
orpollutants,isabioticornonliving.
1
x The2010floodsinPakistanaffectedover18millionpeopleandkilledapproximately2000people,
ruinedcrops,anddamagedordestroyed1.7millionhomesaswellaslivestock,forestsandwildlife
(UNEP,2011).Thefloodseverelydamagedthenaturalforests,plantations,communityforests,
treesgrownforfuelwood,wildlifehabitatandconservationareas(Khanetal.,2010).
Theconditionofforeststhemselvescanhaveaninfluenceondisturbances.Forexample,
deforestationorpoormanagementpracticescanincreasefloodingandlandslidesduringcyclonesand
degradationofmangroveforestsmayincreasethedamagecausedbystormsurgesortsunamis.In
someareas,climatechangeisincreasingtheincidenceofdroughtandheatwavesresultinginan
increasedriskandincidenceofwildfireswhichinturncontributestoglobalwarmingthroughcarbon
emissions.
Abioticdisturbanceswillcontinuetoincreaseinintensity,quantityandfrequency.Adaptiveforest
managementisthereforeessentialtoprotecttheworld’sforestresources.Activitiessuchas
diversifyingspecies,usingwindbreaksandmixedcroppingpatternsforresilienceandnotplanting
susceptiblespeciesinareaspronetoabioticdisturbancescanallhelptoreduceordivertpotential
impacts.Reducingtheeffectsofdisturbancesonforestswillcontributetocountries’effortstoreduce
carbonemissionsfromdeforestationandforestdegradationthroughforestconservation,sustainable
forestmanagementandenhancementofforestcarbonstocks(REDD+)2.Takingcareoftheworld’s
forestsandeffectivelymanagingthemnotonlyensuresthattheymeettheirobjectivesbutalso
reducestheriskofdamagefromfutureabioticdisturbancesandaddressesglobalclimatechange
concerns.
2
ReducingEmissionsfromDeforestationandForestDegradation(REDD)isanefforttocreateafinancialvaluefor
thecarbonstoredinforests,offeringincentivesfordevelopingcountriestoreduceemissionsfromforestedlands
andinvestinlowcarbonpathstosustainabledevelopment.“REDD+”goesbeyonddeforestationandforest
degradation,andincludestheroleofconservation,sustainablemanagementofforestsandenhancementof
forestcarbonstocks(UNFCC,DECISION1/CP.16).
2
INTRODUCTION
Disturbancesareanaturalandintegralpartofforestecosystems.Theyinfluenceforeststructure,
compositionandfunctioningandcanbeimportantformaintainingbiologicaldiversityandfacilitating
regeneration.However,globalclimatechange,primarilytheresultofhumanactivities,isreportedly
makingforestsmorepronetodamagebyalteringthefrequency,intensityandtimingofsomeevents
suchasfires,cyclones,storms,landslides,andinsectanddiseaseoutbreaks.Whendisturbances
exceedtheirnormalrangeofvariation,theimpactsonforestscanbeextreme.Poormanagement
practicesandclimaterelatedshiftsintherangeofforestpestspeciescanfurtherexacerbateabiotic
impactsonforesthealth.
Abioticdisturbances,disturbancescausedbynonlivingfactors,differinduration,rangingfromhours
todaysforcyclonesorwindstorms,weekstomonthsforfires,anddaysorweeksforvolcanic
eruptions(Turner,2010).Thetimingofmanydisturbancesislargelycontrolledbyclimate.Tropical
cyclones,forexample,typicallyoccurfromApriltoDecemberintheNorthernHemisphereandfrom
NovembertoAprilintheSouthernHemisphere,tornadoesinspringandautumn,floodsduring
seasonsofprecipitationorsnowmelt,andfiresduringperiodsoflowfuelmoistureandhigh
temperatures(Foster,KnightandFranklin,1998).
Socioeconomicimpacts
Informationonthenumberofabioticdisturbances,someestimatesoftheirassociateddamage,and
thenumberofpeopleaffectedareavailablefromseveralsources.TheInternationalFederationofRed
Cross(IFRC)andRedCrescentSocieties(RCS),forexample,reportedintheir2010WorldDisasters
Reportthatalmost4000sucheventsoccurredfrom2000to2009(Table1;IFRCandRCS,2010).Asia
experiencedthemostnaturaldisturbancesduringthisperiod–1536eventsrepresentingover38
percentofallthosereported.TheAmericasexperienced943naturaldisturbances,Africa–716,
Europe–661andOceania–158.Windstormsandfloodstogetheraccountedforapproximately70
percentofthetotalabioticnaturaldisturbancesreportedand72percentofthetotaleconomicloss.
Estimateddamagefromwindstormsalonerepresentedover50percentofthetotalcostsforthe
decade.Earthquakesandtsunamiswerethethirdcostliestdisturbanceatover18percentofthetotal.
Itshouldbenotedthattheeconomicfigurescorrespondto thedamagevalueatthemomentofthe
eventandusuallyonlyrepresentdirectdamage.Thenumbersarethetotalforallreporteddamage
(i.e.damagetoinfrastructure,crops,housing,etc.);specificcostsforimpactsonforestsandtheforest
sectorarenotavailable.Estimatesalsovarydependingonacountry’seconomyandthefinancial
valuesplacedonitemsdamagedsuchasinfrastructure;valuesaremuchhigherindeveloped
countries.Alsodataoneconomicdamagesaremissingfor67percentofdisturbancesthereforethese
figuresshouldberegardedasindicative(IFRCandRCS,2010).Evenwithlargegapsinreportingof
economicimpacts,itisquiteclearthatnaturaldisturbanceshavesubstantialimpacts.
Table1.Totalnumberofreportednaturalabioticdisturbancesandtheassociatedimpacts,2000
2009
Disturbancetype
Number of Numberof
Numberofpeople
Estimateddamage
events
deaths
reportedaffected
(US$millions)
reported
reported
(thousands)
Droughts
273
230 181
1 025 446
26811
Earthquakes/tsunamis
290
453 553
82 612
183425
Extremetemperatures
237
90 743
85 651
39798
Floods,waves,surges
1739
53 795
949 112
186584
Forest/scrubfires
142
636
2 140
24651
Massmovement:dryand
201
7 905
1 574
1212
wet(landslides,avalanches)
Volcaniceruptions
61
230
1 556
193
Windstorms
1054
172 334
400 144
508717
Totalabioticdisturbance
3997
1 009 377
2 548 234
971391
(Source:adaptedfromIFRCandRCS,2010)
3
Themostdevastatingimpactsofabioticdisturbancesarethelossofhumanlives,andtheimpactson
thesurvivorsrelatedtothelossoffamilymembers,homes,livelihoodsandthebasicnecessitiesof
life.Peoplemaydieasadirectresultofadisturbanceormaysuccumbintheaftermath.Overone
millionpeoplediedasaresultofthereportedeventsfrom2000to2009(Table1;IFRCandRCS,
2010).Earthquakesandtsunamiswerethedeadliestevents,responsibleforapproximately45percent
ofallreporteddeaths;themajorityoftheseattributabletothe2004IndianOceandisaster.Droughts
resultedinthedeathsof23percentofallextremeweathereventsreportedandwindstormstookthe
livesofapproximately17percent.Thetotalnumberofpeopleaffectedbyabioticdisturbancesduring
thelastdecadeisimmense–over2.5billion–andillustratesthewidespreadimpactsoftheseevents.
Droughtimpactedthegreatestnumberofpeople,followedbyfloodsandwindstorms.
Impactsonforests
Seasonaltimingofextremeeventscontrolsthepotentialrangeofimpactinforestecosystems.Trees
withleavesaremuchmoresusceptibletoblowdownbycyclonesandtornadoeswhereaslateseason
storms,occurringafterleaffall,createdifferentimpacts(Foster,KnightandFranklin,1998).
Somedisturbancesmayoccurasindividualdiscreteeventsormayoccurconcurrentlyorinquick
successionwithotherevents.Forexample,floodingandtornadoesoftenaccompanytropical
cyclones,earthquakescantriggertsunamis,avalanchesorlandslides,andwinterstormscantrigger
avalanchesandalsoleadtofloodinglaterintheseason.Suchcombinationsofdisturbanceswillhave
animpactontheseverityandpatternoftheimpactsobservedinforests.
Eachdisturbanceeventaffectsforestsdifferently;somecauseextensivetreemortality,whereas
othersaffectcommunitystructureandorganizationwithlittlemortality.Theycanreduceleaf
function,deformtreestructure,causetreedeath,alterregenerationpatterns,disruptthephysical
environmentthroughsoilerosionornutrientloss,andincreaselandscapeheterogeneityofforest
communities(Daleetal.,2000).Thepotentialimpactsofadisturbancedependonitsseverityor
intensity,frequencyofoccurrence,duration,spatialscale,andpoint(s)ofinteractionwiththe
ecosystem(Lugo,2008).Theimpactsofdisturbancesareseenoverabroadspatialscale,fromaleaf
throughtotheentireforestecosystem.
Considerableinformationmayexistonindividualeventsbutoftenlittleinformationisreadily
availableonthespecificimpactsofaneventonforests.Globalreportingonsuchimpacts,particularly
quantitativeinformationonareasaffected,islowandsporadic(Box1;FAO,2010).
Box1.Globalinformationonimpactsofabioticdisturbances
Toattempttoquantifytheimpactsofthemanyfactorsthat
affectthehealthandvitalityofaforest,FAO,throughtheGlobal
ForestResourcesAssessment(FRA)2010,askedcountriesto
reportontheimpactofinsectpestsanddiseases,fire,other
bioticfactors(suchaswildlifebrowsing,grazingandphysical
damagebyanimals),andabioticfactors(suchasairpollution,
wind,snow,ice,floods,landslides,tropicalstorms,droughtand
tsunami)ontheirforests.Countrieswereaskedtoprovidedata
(areaaffected)averagedoverfiveyears,sothatlarge
fluctuationsinasingleyeardidnotsignificantlyskewthe
figures.Datawerethuspresentedfor1990(anaverageofthe
period1988–1992),2000(averageof1998–2002)and2005
(averageof2003–2007).
Mostcountrieswerenotabletoprovidereliablequantitative
informationbecausetheydonotsystematicallymonitorthese
variablesformanyreasons.Verylittlequantitativedataexistfor
4
manyregions,andexistingdataareoftennotavailableinaneasilyaccessibleformat.Inadditionitis
oftendifficulttodeterminethecauseofforestdamageordecline.Dataareoftencollectedonlyafter
significantdamagehasbeencaused.Consistentdataontheimpactsofdisturbancesovertimeare
notavailableformostregions.
Forabioticdisturbances,reportingwasmoredetailedinFRA2010thaninFRA2005however,in
general,informationwashighlysporadic.Theremayonlybeoccasionalreportingafteramajorstorm
orothereventandmostoftenthevolumeofwoodthatisdamagedisreported(e.g.throughsalvage
fellingreports)butnottheareaaffected.
Datawereprovidedby45countriesontheareaofforestaffectedbyabioticfactorsotherthanfire
forallthreereportingperiods,togetheraccountingfor24percentofthetotalforestarea.Afurther
15countriesprovideddataforthe2005reportingperiodonly.
Sweden,forexample,recorded1.2millionhectaresaffectedbyabioticfactorsincludingamajor
storminJanuary2005whichcausedseverewindthrowinthesouthofthecountry,especially
affectingmiddleagedandoldsprucestands.TheRussianFederationreportedthatabioticfactors
affected1.3millionhectaresofforestsandItalyreportedsnow,stormanddroughtaffecting0.5
millionhectaresofforest.StormsandblizzardsinJanuary2008causedgreatdamageto18.6million
hectaresofforestineightprovincesinChinaincludingHunan;1781stateownedfarmsand1200
nurserieswereseverelydamaged,while760tonnesoftreeseedand10billionseedlingswerefrozen
(StateForestryAdministration,2008).
Mostinformationonforesthealthisdescriptive(i.e.qualitative)innatureandmanycountries
describedavarietyofabioticdisturbancesaffectingtheirforests.Storms(snow,wind,ice)werethe
mostreportedabioticeventespeciallyfromEuropeancountriesincludingBelgium,CzechRepublic,
Denmark,Estonia,France,Iceland,Ireland,theNetherlands,Slovakia,Slovenia,Sweden,Switzerland,
UkraineandtheUnitedKingdom.DamagefromstormswasalsoreportedfromcountriesinAfrica
(Sudan,Togo),AsiaandthePacific(NewZealand,RepublicofKorea)andtheNearEast(Lebanon).
HurricaneswerereportedfromcountriesinAfrica(Madagascar,Mauritius,Mayotte,Réunion),Asia
andthePacific(CookIslands)andLatinAmericaandtheCaribbean(Belize,Cuba,Jamaica,
Martinique).DroughtwasreportedfromcountriesinAfrica(theGambia,Togo),AsiaandthePacific
(Australia,SriLanka),Europe(Hungary,Slovakia)andtheNearEast(Yemen).Floodswerereported
fromcountriesinAsiaandthePacific(RepublicofKorea),Europe(Estonia)andLatinAmericaandthe
Caribbean(Panama).
InthePhilippines,anoilspillof2.1millionlitresofbunkeroildamagedmangroveforestsinthe
provincesofGuimarasandIloiloinAugust2006.Eruptionofthevolcano,PitondelaFournaise,in
Réuniondestroyedsectionsofoldnaturalforestbylavaflows;lavaflowsweresubsequently
colonizedbyintroducedplantspecies.TheMaldivesreportedconsiderabledestructionoftreesand
forestvegetationasaresultoftheIndianOceanTsunamiin2004.Avalancheswerereportedfrom
Slovenia,earthquakesinPanamaandairpollutioninSlovakiaandSlovenia.
Aboutthisreview
Thispaperreviewsthecurrentknowledgeontheimpactsofabioticdisturbances,suchasstorms,
drought,tsunamisandoilspills,onforests.Examplesprovidedarenotanexhaustivelistofeventsbut
aselectionofthoseoccurringmostrecentlyorthosehavingknownimpactsonforestsandtheforest
sector.Anthropogenic,orhumancaused,disturbancesareincludedinthisreviewsincetheagent
itself,i.e.fireorpollutants,isabioticornonliving.
5
HurricaneHugodamage,SouthCarolina,USA
6
Cyclones(synonymshurricanesandtyphoons)
Cyclones(asystemofwindsrotatinginwardstoanareaoflowbarometricpressure)cananddooccur
atanylatitudeandinanyclimate.Thoseoccurringwithin30degreesnorthorsouthoftheequator
arecalledtropicalcyclones;thosefoundabove60degreesnorthorsouthoftheequatorarearcticor
polarcyclones;andthosebetween30and60degreesarecalledextratropicalcyclones.
Whileextratropicalcyclonesarenotasstrongastropicalcyclones,theycanproduceveryintense
thunderstorms,powerfulwinds,hailandtornadoes.Suchcyclonesareimpactingforestsaroundthe
world.Forexample,theGreatStormof15–16October1987hitnorthernFranceandsouthernUnited
Kingdomresultinginthelossof19lives,thedeathof25milliontreesaswellaswidespreaddamage
tohomes,transportandinfrastructureandanestimatedeconomiccostofUS$2.3billionintheUK
alone(RMS,2007).ThestormwasfeltfromSpaintoNorwaythoughdamagewasmostsevereinthe
UKandFrance.TreesofgreatscientificandaestheticvaluewerewindblownordamagedintheUK
includingtreesincollectionsinKew,Wakehurst,VentnorandBedgebury.
Tropicalcyclonesareareasofverylowatmosphericpressureovertropicalandsubtropicalwaters
whichbuildupintoahuge,circulatingmassofwindandthunderstormsuptohundredsofkilometres
across(IHRC,2011;WMO,2011).Surfacewindscanreachspeedsof200km/hormore.Cycloneshave
averydifferentwindprofileanddistributionandsignificantlyhigherprecipitationlevelsthanstorms.
Theterms‘hurricane’and‘typhoon’areregionallyspecificnamesforastrongtropicalcyclone:inthe
westernNorthPacificOceanandSouthChinaSeathetermtyphoonisused;intheAtlanticOcean,
CaribbeanSea,andintheeasternNorthandcentralPacificOcean–hurricane;andintheIndian
OceanandSouthPacificregion–tropicalcyclone(NOAA,2011;WMO,2011).
Asatropicalcyclonemakeslandfallitsenergyistransferreddirectlytocoastalregionsoveralarge
areabyhighvelocitywinds,witheffectsextendinginlandforhundredsofkilometresduringsevere
events(Stanturf,GoodrickandOutcalt,2007).Threeprimaryfeaturesofcyclonesthatcausedamage
arerainfall,stormsurgesandwinds.
BUGWOOD.ORG/R.L.ANDERSON/3036081
METEOROLOGICAL
METEOROLOGICALEVENTS
7
METEOROLOGICAL
Torrentialrainsaccompanyingtropicalcyclonesfrequentlycauseextensiveflooding,leadingtotree
mortalityfromanoxia(absenceofoxygen).Floodingandrainfallsaturatessoil,whichmayincrease
susceptibilitytowindthrowinshallowsoils.Evenatsomedistancefromthecyclonecentreandwith
lowerwindvelocities,heavyrainswithmoderatewindsmaycausewindthrow(Stanturf,Goodrickand
Outcalt,2007).
Astormsurgeisalargedomeofwater,sometimesgreaterthanfivemetres,thatfloodsthecoastat
highspeedandwithimmenseforceasthestormmakeslandfall(IHRC,2011).Stormsurgescancause
extensivedamagetocoastalvegetationbybending,breakingoruprootingtrees.Scouringanderosion
mayexposerootsystemsleadingtodesiccation,anddepositionmayleadtorootsuffocation.Salinity
andinundationincreasedbythestormsurgecancauseplantandtreemortality(Stanturf,Goodrick
andOutcalt,2007).
Windisthefeaturethatislinkedtoavastmajorityofacyclone’sdamage,bothdirectlyandindirectly,
throughwavesandstormsurge.Thestrongestwindsoccurinasemicircletotherightofthestorm’s
pathashortdistancefromthecentre.Asthestormmovesinlandanditsoceanicenergysourceis
removed,itrapidlylosesenergyandweakens.Tornadoes(seefollowingsectiononTornadoes)
frequentlyoccurembeddedwithintherainbandsthatspiraloutfromtheeyeofthecyclonethough
theyaretypicallyshortlivedandlessintensethanordinarytornadoes(Stanturf,Goodrickand
Outcalt,2007).
Themostcommonimpactsofwindincludedefoliation,looseningandshreddingofbark,andabrasion
ofstemsurfaces(Stanturf,GoodrickandOutcalt,2007).Treescansway,twistandrock,andlarge
branchesmaybreakoffandcausedamagetounderstorytrees.Individualstemsmaybend,breakor
suffersomelevelofuprootingfromleaningtocompleteblowdownofthetree(Boose,Serranoand
Foster,2004;Lugo,2008;Stanturf,GoodrickandOutcalt,2007).
Treemortalitycanfollowasaresultofalmostanyoftheimpactsnotedabove.Estimatesofplantand
treemortalityfollowingacyclonevaryfromtwopercent(HurricaneDavid,1979inDominica)to95
percent(HurricaneBetsy,1956inPuertoRico)(Stanturf,GoodrickandOutcalt,2007).Injuriestothe
treesandlossofvigourcanalsoincreasetheirsusceptibilitytootherdisturbancessuchasinsectpests
andpathogens(Lugo,2008).SeeBox2forsomeexamplesoftropicalcyclonesandtheirimpactson
forests.
Predictingthedamagecausedbytropicalcyclonesisdifficultwithavarietyoffactorsinfluencing
forestsatalllevels.Attheindividualplantlevel,rootingconditions(soildepthandmoisture)and
growthforminfluenceatree’sresistancetowindthrow(Boose,SerranoandFoster,2004).Atthe
standlevel,theamountandtypeofdamageisrelatedtothecyclone’sintensityaswellastosite
specificconditionssuchas:treeheight,age,healthandotherfactorsaffectingsusceptibilitytohigh
winds;speciescomposition;standstructure,conditionanddisturbancehistory;andsoilconditions,
geologyandotherfactorsaffectingrootingstrength(Kupferetal.,2008).Attheregionalscale,
patternsofforestdamagearecontrolledbycyclonesize,intensity,andstormtrack;largetopographic
featuresthatweakenstormssuchascoastlinesandmountainranges;andregionalvariationin
vegetation(Foster,KnightandFranklin,1998).
Cycloneimpactscouldbeconsideredbeneficialecologically,atleastinnaturallyregeneratedforests.
Lugo(2008)suggestedthemainecologicalrolesofcyclonesinclude:alteringtheecologicalspace
availabletoorganisms;increasingtheheterogeneityofthelandscapeandthevariabilityinecosystem
processes;rejuvenatingthelandscapeanditsecosystemsandredirectingsuccession;shapingforest
structure,influencingspeciescompositionanddiversityandregulatingtheirfunction;andinducing
evolutionarychange.
TropicalCycloneNargis
CycloneNargismadelandfallinMyanmaron2May2008withwindspeedsofupto200km/handheavy
rain.ThedamagewasmostsevereintheDeltaregionwheretheeffectsoftheextremewindswere
compoundedbya3.6metrestormsurge.Thecyclonekilled84537peopleplus53836peoplemissingand
19359injured(TCG,2008).Morethan2.4millionpeoplewereestimatedtobesignificantlyaffectedbythe
storm.ThetotalamountofdamageandlossesintheaffectedareasofMyanmarwasestimatedatabout
US$4057million(TCG,2008).Todate,itisconsideredtheworstnaturaldisasterintherecordedhistoryof
Myanmar.
Some17000hectaresofnaturalforestand21000hectaresofforestplantationsweredamaged(TCG,
2008).Thelossofmangroveforestsandassociatedecosystemgoodsandserviceswillhaveasignificant
impactonlocalcommunitiesthatareheavilyorpartiallydependentonforestsfortheirlivelihood.Besides
cashemploymentfromtheforestsector,villagersobtainconstructionmaterialandfood(i.e.fish)fromthe
mangroveforests.
TropicalCycloneSidr
On15November2007TropicalCycloneSidrhitBangladeshwithwindspeedsofupto240km/hcausing
significantdamagetolife,livelihoodsandproductiveinfrastructure.Approximately8.7millionpeopleor
nearly2millionhouseholdswereaffected(FAO,2008).Nearly1.5millionhousesandsome4.1million
treesweredamaged.TheSundarbanmangroveforests,thelargestsuchforestintheworld(140000
hectares)andaUNESCOWorldHeritageSite,incurredseveredamages.Theyformanaturalbuffer
protectingmillionsofpeopleinBangladeshfromtheBayofBengal.Inadditiontosignificantenvironmental
andecologicalfunctions,theSundarbansalsoplaymajorsocialandeconomicfunctionsandmany
communitiesdependonthemfortheirlivelihoods.Theareaisalsoknownforitswiderangeoffauna,
including260birdspecies,theBengaltigerandotherthreatenedspeciessuchastheestuarinecrocodile
andtheIndianpython(UNESCO,2011).
flickrJOISEYSHOWAA
METEOROLOGICAL
Box2.Examplesofmajortropicalcyclonesandtheirimpactsonforests
DamagetotheSundarbanmangoveforestsinBangladeshafterTropicalCycloneSidr
IntheSundarbanssome45percent(20000–25000hectares)offorestareawereseverelydamagedand
nearly15percent(60000hectares)partiallydamagedbythecyclone(FAO,2008).Someintroduced
species,whichwereplantedinvariouspartsoftheSundarbans,wereuprootedwhileintheseverely
affectedareasalargenumberoftreeshadstembreakorwereuprooted.Inthepartiallydamagedareas
manybrancheswerebrokenbutthemaintrunksremainedintact.
8
flickrNASAGODDARDSPACEFLIGHTCENTER
ForestsdamagedfromHurricaneKatrinaarecurrentlybeinginvadedbyexoticspeciessuchasChinese
tallow(Triadicasebifera)(Chapmanetal.,2008).Thisspecies,whichwaspresentbeforethehurricanebut
witharestricteddistribution,nowthrivesinsomeareasinthelargecanopygapscreatedbythehurricane
winds.
TyphoonSudal
InApril2004,TyphoonSudalpassedoverthestateofYapintheFederatedStatesofMicronesiawith
impactsonmangroveforests.Practicallyalltreessufferedcanopydamage,andsignificantproportionsof
treesweresnappedoruprootedbutthisvariedbyspecies.Mortalityofmangrovespeciesrangedfromsix
to32percentamongstands(KauffmanandCole,2010).
TropicalCycloneGafilo
CycloneGafilostruckMadagascarinMarch2004causingdevastatingdamage,killingapproximately250
people,injuringmanymoreandleaving300000peoplehomeless.Justoveronehundredpeopledied
whentheferry'LeSamson'sankinheavyseasofftheComoros;onlytwosurvived.Heavyrainafterthe
(continues)
9
SatelliteimagesoftheNewOrleansarea,USA,beforeandafterHurricaneKatrina.Healthyvegetation
appearsbrightgreenbeforethestorm,indicatinggrowingtrees(left);brightreddepictsplantmortality
justweeksafterthestorm(right).
METEOROLOGICAL
HurricaneKatrina
HurricaneKatrinamadelandfallinLouisiana,UnitedStatesofAmericaon29August2005damagingcoastal
andinlandforestsofMississippi,Louisiana,andAlabama.Inadditiontostrongwinds,Katrinabrought
massiveamountsofrainoveraveryshorttime;astormsurgeofupto8.5metresacrosssouthern
LouisianaandMississippi;extensivewind,rainandtornadodamagethroughoutMississippi,western
TennesseeandwesternKentucky;andhurricaneassociatedprecipitationasfarnorthasNewYorkState
(OswaltandOswalt,2008).
HurricaneKatrinawasthecostliestnaturaldisaster,aswellasoneofthefivedeadliesthurricanes,inthe
historyoftheUnitedStates.Atleast1836peoplediedintheactualhurricaneandinthesubsequent
floods.TotalpropertydamagewasestimatedatUS$81billion.
ItwaspredictedthatHurricaneKatrinakilledorseverelydamaged320millionlargetreesinGulfCoast
forestsandtheresultinglossofcarbonrepresented50to140percentofthenetannualcarbonsinkofall
forestsintheUSA(Chambersetal.,2007).InitialestimatesinMississippiindicatedpotentialtimberlosses
ofupto84.9millioncubicmetresacross1.4millionhectaresofdamagedforestlandwhichcorresponded
toapproximately90percentofstandingtimberinseveredamagezones,andanaverageof37percentof
standingtimberacrossalldamagezones(OswaltandOswalt,2008).Hardwoodsexperiencedseverebole
damageandwindthrow.InLouisiana’sPearlRiverbasin,hurricanerelatedtreemortalitywasmorethan
fourtimesgreaterthanannualpreKatrinamortalityrates(Chapmanetal.,2008).Theestimatedeconomic
lossoftimberfromwinddamagewasbetweenUS$1.42.4billion(Stanturf,GoodrickandOutcalt,2007).
METEOROLOGICAL
cycloneresultedinwidespreadfloodinginthenorth,northwestand southwest ofthecountry.
Soonafterthecyclonestruck,theMinistryfortheEnvironment,WaterandForests(MINENVEF)issued
temporarypermitsforthecollectionofwoodthathadbeenwindthrownordamagedbythecyclone
outsideofprotectedareasonly.Withlittleenforcementandthepostdisastereconomicstress,thiscleared
thewayforillegalloggingoflargeamountsofpreciouswoodssuchasrosewood,palisandre,andebonies
andsubsequentexportas‘salvage’;theamountsofloggedwoodbeingmuchgreaterthantheactual
amountdamagedbythecyclone(Patel,2007).Hundredsoftonnesofrosewoodandebonywere
confiscated,mostofwhichwereloggedwithinthetwolargestprotectedareasintheregion.Suchselective
loggingthreatensthevaluableprotectedforestsandcanresultinincreasedincidenceoffireandspecies
invasions,alteredhabitats,andlossingeneticdiversity.
TropicalCycloneWaka
On31December2001,TropicalCycloneWakapasseddirectlyovertheVava‘uislandgroup,Kingdomof
Tonga,withsustainedandmaximumwindspeedsof185km/hand230km/hrespectively.Cyclonerelated
treemortalityaveragedsixpercentandvarieddependingonspeciestype:0–7percentforlowlandlate
successionalspeciesand4–19percentforearlysuccessionalspecies(Franklinetal.,2004).Severedamage
(i.e.uprooting,snappedstems)affected25percentofstemsmeasured;thehighestfrequencyofsnapped
stemsoccurredinthesmallmediumdiametertrees(10–15cmdbh)whileuprootingwasmoreprevalent
amonglargertrees(>20cmdbh)(Franklinetal.,2004).
HurricaneMitch
HurricaneMitchisconsideredtheworstdisasterofthe20thcenturyinCentralAmerica.Thehurricanehit
Hondurasandthenfrom29Octoberto3November1998,theslowmovinghurricaneandthentropical
stormdroppedhugeamountsofraininHonduras,Guatemala,NicaraguaandBelize,resultinginmassive
floodingandmudslides.Anestimated11000peopledied,withthousandsmoreunaccountedforand
approximately2.7millionlefthomeless.Thefloodingandmudslidesdamagedordestroyedtensof
thousandsofhomes,withtotaldamageamountingtooverUS$5billion,mostofwhichwasinHonduras
andNicaragua.
Thehurricanecauseddamage,deforestationanddisruptionoftheforestsectoringeneral.Mangrove
forestsinthecoastalzonesoftheAtlanticandPacificcoastswereseverelyimpactedbothdirectlyand
indirectlybythestorm(Doyleetal.,2002;HenselandProffitt,2002).Windscausednearcomplete
defoliationofthevegetationontheBayIslandofGuanaja,Honduras,includingmangroveforests,and
tallertreeswereeitherbrokenoruprooted(HenselandProffitt,2002).Damagetomangroveswasalso
causedbywavesandsedimentburial(HenselandProffitt,2002).
InthefiveyearsfollowingHurricaneMitch,over100000hectaresofpineforestinCentralAmericawere
infestedwiththesouthernpinebeetle,Dendroctonusfrontalis,inassociationwithotherspeciesof
DendroctonusandIpsspp.Theresultingextensivetreemortalityseverelyincreasedtheriskofwildfiresand
negativelyaffectedwildlifeandrecreationcausingwidespreadandsignificanteconomicimpacts.
HurricaneHugo
InSeptember1989,HurricaneHugostruckGuadeloupe,Montserrat,St.Croix,PuertoRico,Antiguaand
SouthCarolina,USA.InGuadeloupe,tallmixedmangrovesexperienceda78percentdecreaseinaverage
treedensityand71percentreductioninaveragebasalareaafterthestorm’spassage(Lugo,2008).The
hurricanepassedoverthenortheastcornerofPuertoRicowithsustainedwindsofover166km/hresulting
indefoliation,windthrowandlandslides(Turner,DaleandEverham,1997).Thestormalsoresultedin
populationoutbreaksof15speciesofLepidoptera(mothsandbutterflies)inthesamecountry,including
larvaeofSpodopteraeridania(Noctuidae)whichwerefeedingonearlysuccessionalplantspecies(Lugo,
2008).Theoutbreakoftheseinsectsendedwiththedeclineofthehostplants.Thisstormalsoimpacted
forestsinSouthCarolina,UnitedStateswhereitcausedextensivedamagefor325kilometresinland
(Stanturf,GoodrickandOutcalt,2007).
10
FAO/V.CABOUN/FO6095
11
Stormdamage,Slovakia
METEOROLOGICAL
Storms(wind,snow,ice,hail,dustandsand)
Stormsbringingwind,snow,iceorhailoracombinationofthesefactorshavealwaysimpactedthe
healthofforestsandthusarearegularconsiderationinforestmanagementplans.Theycanoccuras
catastrophiceventsaffectingentirelandscapes,thequalityofwildlifehabitats,andforeststand
structure,whichcanleadtomajordisruptionsinmanagementgoals.Alternativelytheymayoccuras
smallscaledisturbancesthataffectindividualtreesorgroupsoftreeswithinastandincreasingthe
amountofdeadwoodanddiversifyingstandstructure,whichcanhavepositivebenefitsforbiological
diversity.
Damagingwindsvaryfromshortlivedgusts,tostrongprevailingwinds,topowerfulhurricanes,to
briefbutintensedowndraftsfromthunderstorms(LauranceandCurran,2008).Theimpactofwindon
forestsisdeterminedbyacomplexofmanybioticandabioticfactorsandissimilartothose
experiencedduringcyclones(Seeprevioussection).Stormdamagecanincludeinitialmechanical
damagefromthestorm,subsequentdamagefromotherbioticorabioticfactors(i.e.insects,fire,sun,
snow,ice,etc.),andlossofproduction.Theseverityandextentofwindstormdamageinforestsarea
functionof:thedamagepotential(i.e.theamountofgrowingstockexposedtostrongwinds);the
susceptibilitytowind,whichisdeterminedbytreeandstandcharacteristics(i.e.treespecies,
tree/standheight,slendernessoftrees,crownandrootingcharacteristics,standdensity)andsite
characteristics(i.e.soiltype,soilmoisturecontent,topography);andtheextentandseverityofthe
eventitself(i.e.stormextent,windspeedandgusts)(MartinandOgden,2006;Seidletal.,2011;
Usbecketal.,2010).Whethertreesareuprootedorbrokenisdeterminedprimarilybyitsposition
withinthecanopyandbyitsrootingdepth(MartinandOgden,2006).
Insomeareas,stormshavebeencausingincreaseddamagetoforestsinrecentdecades(Schelhaas,
NabuursandSchuck,2003).InEurope,forexample,stormscausemorethan50percentofalldamage
toforestsandthustheyhavebecomesuchamajorconcerntotheforestsectorthattheDirectorate
GeneralfortheEnvironmentoftheEuropeanCommissioncommissionedastudyintotheproblem.
METEOROLOGICAL
Thisstudyidentified130separatewindstormsthatcausedconsiderabledamagetoforestswithinthe
last60years(Gardineretal.,2010).Byanalysinginformationonthesestorms,theauthorsnotedthat
gustpeakwindspeedisstronglycorrelatedtothemaximumpotentiallevelsofdamage,treeheight
hasanimportantimpactonitsvulnerability,andrecentthinning,particularlyinolderstands,isoften
associatedwithincreaseddamage.
Spruceandpoplarappeartobeamongthemostvulnerablespeciesandsilverfirandoakamongthe
leastvulnerableoftheconifersandbroadleavesrespectivelyalthoughsuchfindings,andthegenerally
highersusceptibilityofconiferstodamage,arepossiblyrelatedmoretovariationsinmanagement
andsite.Soilconditionhadalargeinfluenceontheextentofdamage.Rootanchoragestrengthis
increasedbysoilfreezingandreducedbywaterlogging,heavyrainandbypoordrainagethatallows
soilsaturationduringstorms.Withclimatechange,increasedtemperatureswilldecreasetheperiod
oftimeinwhichsoilsarefrozen,particularlyinnortherncountries,potentiallyincreasingthedamage
fromwind.Stormswillalsobeaccompaniedbyheavierprecipitationresultinginmoresaturatedsoils
andincreasedriskofdamage.
Snowmostcommonlyimpactstreesbybreakingstemsbuttreescanalsobebentoruprooted
(Nykänenetal.,1997).Theseverityofsnowdamageisrelatedtotreecharacteristics;factors
controllingthestabilityoftreessuchasstemtaperandcrowncharacteristicsarethemostimportant
(Nykänenetal.,1997).Conifersareparticularlydamagedbyheavysnowfall,whilebroadleavedtrees
aregenerallymoreresistanttostormsandsnowinthelateautumnandwinterduetobetterroot
systemsandlackoffoliage(FAO/ECE/ILO,1995).
Icestormsresultwhenliquidprecipitationfallsthroughalayerofcoldair.Ifthislayerofcoldairis
thickenoughandtheairtemperatureisbelowfreezing,theprecipitationfreezesoncontactwith
groundlevelobjects,formingacoatofice.Theleveloficeaccumulationvarieswithtopography,
elevation,aspect,andtheamountofareaintheregioninwhichconditionsfavouriceaccumulation
(Irland,2000).
Inamatterofminutesanicestormcandepositalayeroficeheavyenoughtobringdownpowerand
telephonelinesandsnapbranchesfromtrees(WMO,2011).Impactsofindividualstormsarehighly
patchyandvariable,anddependonthenatureofthestorm,itsseverity,frequency,timingand
extent.Icestormdamagetoforestcanopiesisrelatedtocanopyarchitecture,treesize,age,health
andthemechanicalpropertiesofthewooditself(Irland,1998).
Iceaccumulationontreescancauseminorbranchbreakage;majorbranchloss,uptototalcrown
loss;temporarilyorpermanentlybendingoverofcrowns;rootdamage(whensoilisnotfrozen);
breakageoftrunkswithinorbelowthecrown;andforsomehardwoods,splittrunks(Irland,2000).
Freezingrainimmediatelyfollowingheavysnowfallscanbeverydamagingtovegetationbecauseof
theincreasedloadingonbranches(Irland,2000).Softwoodsseemtosufferlessdamagethan
hardwoods.Recentlythinnedstandscanbehighlyvulnerable,ascrownshavespreadintonewly
openedspacebutbranchstrengthmaynotbefullydeveloped.Treesdamagedbyicestormsor
windthrowcanbemoresusceptibletootherdisturbancessuchasinsectpestsorfire.
Icestorms,likeotherdisturbances,caninfluencestandcomposition,structureandconditionover
wideareas(Irland,2000).Asarecurringeventtheyplayaroleindeterminingforestsuccessionand
areimportantfactorsinfluencingthedynamicsoftheforestsinaffectedregions(Hooper,Ariiand
Lechowicz,2001).Icestormsredistributelivinganddeadbiomassinforests,reducecanopyheight
andstratification,increaseorganicinputstothesoilandexposemineralsoil(Hooper,Ariiand
Lechowicz,2001).
InJanuary1998,amajoricestormoccurredaffectinglargeportionsofNewEnglandintheUSAand
theCanadianprovincesofNewBrunswick,OntarioandQuebec.Millionsoftreesfell,andmore
continuedtobreakandfallthroughouttherestofthewinterseason.Nonnativespeciesandtrees
12
B.MOORE
plantedoutsidetheirnaturalranges,suchasRobiniaandSalixspp.,sufferedseverely,whilenearby
nativespeciessufferedfarlessdamage(Irland,1998).InanoldgrowthhardwoodforestatMontSt.
Hilaire,Quebecthestormbroughtdown19.9metrictonnesor33.6cubicmetresofwoodydebrisper
hectarewhichrepresentedabout7–10percentofthetotalabovegroundbiomassinthisforestbefore
thestorm(Hooper,AriiandLechowicz,2001).
AFebruary1994icestorminnorthernMississippihadmajorimpacts,includingdamageto1500000
hectaresofforestsandheavylossestourbantreesandpecanorchards(Irland,1998).Astormin
November1996ineasternWashingtonandIdaho,USAcausedwidespreadtreedamageandheavy
lossestogardenandstreettrees(Irland,1998).
Largehailstonesthatcanreachdiametersofover10centimetresandcanfallatspeedsofover150
km/h(WMO,2011)canalsocauseconsiderabledamagetoforests.
Atopicrelatedtotheimpactsoficeandsnowontreesistheimpactofdeicingsalts,suchassodium
chloride,usedliberallyonroadstomaintainsafewinterdrivingconditionsinmanycoldregionsofthe
world.Sodiumchloridecandamageroadsidevegetationandaffectsurfacewaterandgroundwater
quality(Muncketal.,2010).Conifersaremoresusceptibletodamagefromsaltspraycomparedto
hardwoodsbecausetheyretaintheirfoliagethroughthewintermonthswhensaltisappliedtoroads.
Tipdiebackandleafscorcharethetypicalsymptomsassociatedwithsaltdamageonconifers.Salt
ionscauseosmoticandionicstressinplantsandsoilsalinityinterfereswithbothwaterandnutrient
uptakebyroots(Muncketal.,2010).
Duststormsandsandstormsarenaturaleventsthatoccurthroughouttheworld,especiallyin
drylandareaswhichcoverapproximately41percentoftheearth’slandsurface(morethan6billion
hectares)(MEA,2005).DrylandsoccurintheMediterraneanregion,SaharaandsubSaharanAfrica,
CentralandSouthAsia,AustralianOutback,SouthAmericanPatagoniaandtheNorthAmericanGreat
Plains.
Duststormsandsandstormsarearesultofwinderosionandaredrivenbypoorlandmanagement
anddegradationofthedrylandvegetationcover.Strongwindsandfavourablesurfaceatmospheric
conditions(i.e.turbulencelevel,stability,soilmoisture)canallowforlargeamountsofsandanddust
tobeliftedfrombare,drysoilsintotheatmosphere.Everyyearoneandahalftonnesofsandand
13
METEOROLOGICAL
Icecoverstreesandpowerlinesafteramajorstorm,Canada
Flickr/DABAYU
METEOROLOGICAL
DuststorminNewSouthWales,Australia,2009
dustareemittedfromdrylandsintotheatmospherewhereitcanbetransporteddownwindaffecting
regionshundredstothousandsofkilometresawaydependingonmeteorologicalconditions(WMO,
2011).DustfromtheGobiDesert,forexample,iscarriedtothePacificcoastsofNorthAmericaand
dustfromtheSaharaDesertiscarriedtotheCaribbeanislandsandtheAmazonbasin(MEA,2005).
Dustcanhavenumerousimpactsonhumanandveterinaryhealth,theenvironment,agriculture,
marineecosystems,fisheries,transport,visibility,aviation,andweatherandclimateatlargerscales
(WMO,2011).AmajorsandduststorminnorthwestChinaon5May1993illustratesthedevastation
andseriouseconomiclossthatsuchstormscanproduce.Atotalof85peopledied,31peoplewere
lostand264peoplewereinjured.Approximately373000hectaresofcropsweredestroyed,120000
animalsdiedorwerelost,16300hectaresoffruittreesweredamaged,90000individualtreeswere
blowndownandthousandsofgreenhousesandplasticmulchingshedswerebroken(UNCCD,2002).
Insomecases,however,thedepositionofdustcanproducepositiveresults.Forexample,mineral
richSaharandusttransportedacrosstheAtlanticOceantotheAmazonrainforestinSouthAmerica
providesironandphosphorustothenutrientpoorrainforestsoilsactingasfertilizer(WMO,2011).
Measurestocombattheoccurrenceandimpactsofsandandduststormsincludetheuseof
windbreaksorshelterbeltstoreducetheimpactofwindspeedsanddecreasesoilerosion(Sivakumar,
MothaandDas,2005).
Tornadoes
Tornadoesareshortlived,relativelysmall,complex,violentandunpredictablestormsthatcancause
severedamagethoughusuallyinlimitedareas(Foster,KnightandFranklin,1998;Fujita,1971).They
aremostcommoninspringinlateafternoonandareconcentratedininteriorcontinentalregions,
particularlyinTornadoAlleyoftheGreatPlainsofNorthAmerica,buttheycananddooccur
anywhere,especiallyintemperatelatitudes(WMO,2011).Tornadowindsgreatlysurpasstropical
cyclonewindsinintensity,reachinganestimatedmaximumexceeding400km/h(Foster,Knightand
Franklin,1998).
14
BUGWOOD.ORG/J.O’BRIEN/5059075
Theydevelopunderthreemeteorologicalconditions:longlivedsupercell3thunderstorms,which
generatethelargestandmostdamagingtornadoes;ordinarythunderstorms;andincyclonesafter
theymakelandfall(Foster,KnightandFranklin,1998).Thoseassociatedwithcyclonestendtobe
moreshortlivedandlessintensethanothertornadoes(Stanturf,GoodrickandOutcalt,2007).
Tornadoescancreatecomplexdamagepatternsowingtotheirextremevariabilityinintensity,path
length,width,andcontinuity;thepotentialformultipletouchdowns;andthehighfrequencyof
multiplestormsinclusters(Foster,KnightandFranklin,1998).Damagetotreesandforestscanrange
frombranchbreakandsingletreegapstoextensiveareasofcompleteblowdown.Peterson(2007)
notedanincreaseintheprobabilityofwindrelateddamagewithincreasingtreediameterinastudy
oftornadodamageacrosseasternNorthAmerica.Someofthedamagecausedbytornadoesmaybe
positive.Thelossofcanopycanallowforotherspeciestoflourishtherebyincreasingbiodiversityand
theconsequentincreasesinsoiltemperaturemayincreasemicrobialactivityandtherebyenhance
nutrientcyclinginthesoil(Peterson,2000).
TornadoescausemorehumanmortalityintheUnitedStatesthananyotherweathereventexcept
lightning(Peterson,2000)anddespitetheirsmallsize,theyhavemassiveeconomiccosts.Asingle
NorthCarolinatornadocausedanestimatedUS$100millionindamageinNovember1988,asdidthe
Catoosa,OklahomatornadoofApril1993(Peterson,2000).OtherexamplesincludeaNovember1992
tornadooutbreakthatcausedapproximatelyUS$291millionindamage,asystemoftornadoesin
Mississippi,Alabama,GeorgiaandTennesseeon8April1998(US$300million),theOklahomaKansas
tornadoesofMay1999(US$1billion),theArkansasTennesseetornadoesofJanuary1999(US$1.3
billion),andthecombinedfloodingandtornadoesofMarch1997intheMississippiandOhiovalleys
(US$1billion)(Peterson,2000).
The2011tornadoseasonintheUnitedStatesiscurrentlyonrecordpaceandprovinglikelytobethe
mostdamagingyet.Asof04July2011,1583tornadoeswerereported(someoftheseareyettobe
confirmed)(NOAA/NWS,2011).Sincethebeginningoftheyear,537peoplehavedied,approximately
346fromtheoutbreaksoftornadoesinAprilalone.
Asupercellisathunderstormwithadeeprotatingupdraftormesocyclone.
15
METEOROLOGICAL
Tornadodamage,HoosierNationalForest,Indiana,USA
Talltreestendtobethemostvulnerabletolightningstrikes,especiallythosegrowingsinglyinopen
areassuchasonhills,infields,nearwaterorinurbanenvironments.Thelikelihoodofastrikeis
greatestonexposedridges,summits,slopesandotherconvexsurfaces(Päätalo,1998).Lightningcan
impactatree’sbiologicalfunctionsandstructuralintegrity.Alongthepathofthestrike,sapboils,
steamisgeneratedandcellsexplodeinthewood,resultinginstripsofwoodandbarkpeelingor
beingblownoffthetree(Clatterbuck,VandergriffandCoder,2011).Treesmaysurviveifonlyoneside
ofthetreeshowsevidenceofalightningstrike;howeverwhenthestrikecompletelypassesthrough
thetrunk,treesareusuallykilled.Manytreescansuffersevereinternalorbelowgroundinjury
despitetheabsenceofvisible,externalsymptomswhenthelightningpassesthroughthetreeand
dissipatesintheground(Clatterbuck,VandergriffandCoder,2011).Majorrootdamagemaycause
thetreetodeclineanddie.Lightninginducedmortalitycancreategapsinforestcanopies
(Magnusson,LimaanddeLima,1996).
Flickr/PRESCOTT
METEOROLOGICAL
Thunderstormsandlightning
Severethunderstormsgiverisetosuddenelectricaldischargesintheformoflightningandthunder.
Theyoftenbringheavyrainorhail,strongwindsandoccasionallysnowandinsomepartsofthe
worldtheytriggertornadoes(WMO,2011).Inareaswherelightningisnotaccompaniedbyrain,so
calleddrylightning,itmayalsobeasourceofignitionforforestfires(Päätalo,1998)asnotedinsome
remoteareasofCanadaandtheRussianFederation(FAO,2007).Howeveritisgenerallyrecognized
thatthemajorityofforestfiresarecausedbyhumansandnotbylightning(SeesectiononFireunder
Anthropogenicevents).
Lightningstrikes,Canberra,Australia
16
CLIMATOLOGICALEVENTS
FAO/CH.ERRATH/12787
CLIMATOLOGICAL
Drought
Droughtsarecausedbyadeficiencyofprecipitationovertimeandassuchcandevelopslowly,
sometimesoveryears.OftenassociatedwiththearidregionsofAfrica,particularlytheSahel,in
recentyears,droughtshavealsostruckIndiaandpartsofChina,theNearEast,theMediterranean,
Australia,partsofNorthAmerica,SouthAmericaandEurope(WMO,2011).Increasesinthe
frequency,duration,and/orseverityofdroughtandheatstressassociatedwithclimatechangecould
fundamentallyalterthecomposition,structureandbiogeographyofforestsinmanyregions.Of
particularconcernareincreasesintreemortalityassociatedwithclimateinducedphysiologicalstress
andinteractionswithotherdisturbancessuchaspestoutbreaksandfire(Allenetal.,2010).
Allenetal.(2010)identified88welldocumentedepisodesofincreasedmortalityduetodroughtand
heatthroughoutavarietyofforesttypes,frommonsoonalsavannaswithmeanprecipitation<400
mm/year,tosubalpineconiferforestswithaMediterraneanclimate,totropicalrainforestswithmean
precipitation>3000mm/year,illustratingthatdroughtinducedmortalityisnotrestrictedtoforests
normallyconsideredwaterlimited.Theynotedacomplexsetofmortalitypatternsrangingfrom
small,shortlivedlocalincreasesinbackgroundmortalityratestoepisodesofacute,regionalscale
forestdieoff,whichmayinvolvebioticdisturbancessuchasdiseaseorinsectoutbreaks.Regional
scalemortalityofoverstorytreesisofparticularconcernasitrapidlyaltersecosystemtype,
associatedecosystemproperties,andlandsurfaceconditionsfordecades(Breshearsetal.,2005).
Quakingaspen(Populustremuloides)inWesternCanadaexhibitedsteepproductivitydeclinesand
diebackafteraparticularlyseveredroughtin20012003,witheffectscontinuingforyears(Hogg,
BrandtandMichaelian,2008).Impactswereexacerbatedbyattacksofdefoliatingandwoodboring
insectsandpathogens(HoggandBernier,2005;Hogg,BrandtandMichaelian,2008).Steepgrowth
declinesandstandreplacementofEuropeanbeech(Fagussylvatica)attheloweredgeofitsrange
hasbeenobservedinSpainandothersouthernEuropeancountriesinresponsetodrought(Jump,
HuntandPeñuelas,2006).InItaly,SpainandPortugalnativeoaksaredecliningduetowarming,
Deadvegetationindroughtstrickenarea,Senegal
17
CLIMATOLOGICAL
droughtorPhytophthoraspeciesandinSpain,Pinusuncinata,P.pinaster,andP.pineahavebeen
exhibitingdeclineanddieback(RescodeDios,FischerandColinas,2007).Carniceretal.(2011)
reportedageneralizedincreaseincrowndefoliationinsouthernEuropeanforestsfrom1987to2007
inresponsetodroughtconditions.
ParkWilliamsetal.(2010)concludedthatprojectedrisesintemperatureandaridityinthe
southwesternUnitedStateswillsubstantiallyreducetreegrowthandlikelyincreasemortalityrates.
Breshearsetal.(2005)reportedaregionalscalevegetationdieoffacrosswoodlandsinthesame
regionin2002–2003inresponsetodroughtandassociatedbarkbeetleinfestations.Otherexamples
ofrecentdieoffscausedbyelevatedtemperaturesand/orwaterstresshavebeenwelldocumented
forsouthernpartsofEurope(Bigleretal.,2006;Bredaetal.,2006;Peñuelas,LloretandMontoya,
2001)andfortemperateandborealforestsofwesternNorthAmerica,wherebackgroundmortality
rateshaveincreasedrapidlyinrecentdecades(vanMantgemetal.,2009)andwidespreaddeathof
manytreespeciesinavarietyofforesttypeshasaffectedwellover10millionhectaressince1997
(Raffaetal.,2008).InsemiaridandMediterraneansystems,severalstudieshaverecentlyreported
increasedplantmortalityratesanddieoffevents,reducedseedlingrecruitment,longtermshiftsin
vegetationcomposition,reducedradialgrowth,andincreasedcrowndefoliationresponses(Carnicer
etal.,2011).
Aprimaryresponseofforeststofuturedroughtwillbeareductioninnetprimaryproduction(NPP)
andstandwateruse(HansonandWeltzin,2000).DroughtshavebeenreportedtoreduceNPPin:
NorthAmericaandChina(2000);NorthAmericaandAustralia(2002);Europe(2003);Amazonregion,
AfricaandAustralia(2005);andlargepartsofAustralia(20072009)(ZhaoandRunning,2010).
Forestdroughtusuallyresultsinreducedshootgrowth,reducednitrogenandwaterfoliar
concentrations,andincreasedallocationtosecondarydefensivecompounds,suchastannins
(Carniceretal.,2011).Droughtinducedreductionsindecompositionratesmaycauseabuildupof
organicmaterialontheforestfloorwhichcouldinfluencenutrientcyclingandincreasesusceptibility
tofire(HansonandWeltzin,2000).
Susceptibilityofforestecosystemstodroughtismainlydeterminedbysite(i.e.soiltexture,soildepth,
waterholdingcapacity)andstand(i.e.leafarea,speciescomposition,androotingdepth)
characteristics(Seidletal.,2011),standmanagementaswellashumanpressure.Youngplantssuch
asseedlingsandsaplingsareparticularlysusceptibletodroughtwhereaslargetreeswithamore
developedrootingsystemandgreaterstoresofnutrientsandcarbohydratestendtobelesssensitive,
thoughtheyareaffectedbymoresevereconditions(HansonandWeltzin,2000).Shallowrooted
treesandplantsaswellasspeciesgrowinginshallowsoilsaremoresusceptibletowaterdeficits.
Deeprootedtreescanabsorbwaterfromgreaterdepthsandthereforearenotaspronetowater
stress.
Strategiesforforestmanagerstoadapttofuturedroughteventsmightincludethinningstandsto
reducecompetitionorselectingappropriategenotypes,suchasthosewithimproveddrought
resistance.
AseveredroughthasbeenaffectingthecountriesofDjibouti,Ethiopia,KenyaandSomaliasinceearly
2011,theworstonetohittheregionforsixdecades.Theregionhasexperiencedtwoconsecutive
seasonsofsignificantlybelowaveragerainfall,resultinginfailedcropproduction,depletionofgrazing
resourcesandsignificantlivestockmortality.AsofJune2011,highlevelsofacutemalnutritionwere
widespreadandmorethan8millionpeoplewereinneedofemergencyassistance.Impactshave
beenworsenedbyhighfoodpricesandinsomeareas,conflict.Attimeofprint,theimpactson
forestswerenotknown.
18
HYDROLOGICALEVENTS
FAO/M.KERESZTES/FO6082
HYDROLOGICAL
Floodsandflashfloods
Floodsoccurwhentherateofwatersupplyexceedsthecapacityofstreamchanneldrainagesuchas
duringperiodsofheavyrainsandrapidlymeltingsnowandice.Theycanbetriggeredbycyclones,
severethunderstorms,tornadoesandmonsoonsorcanresultfromthebuildingofdams(i.e.by
beavers)orbydambreakscausedbygeneralfailure,icejams,landslides,orbytectonicandother
geologicalprocesses(Foster,KnightandFranklin,1998).Excessiverainfallonsaturatedsoilsinflat
areascanalsocreatefloods.Incoastalareas,stormsurgescausedbytropicalcyclonesandtsunamis,
orbyacombinationofhighriverflowsandbackwatereffectsasaresultofhightides,canalsocause
flooding.
Theecologicaldamageofregularfloodingmaybeminorasfloodplainplantsandanimalsarewell
adaptedtosuchconditions(Foster,KnightandFranklin,1998).Inaddition,themechanicalforceof
floodwaterisnottypicallyadequatetoincreaseplantmortalityrates,especiallywhenfloodingoccurs
inspringbeforebudbreakofdeciduoustrees.Oxbowformation,icescouring,andbankerosionmay
causethedeathofsometreesandchangesinthelandscapemosaic,butimpactsaregenerally
affectedonlyoverlimitedareas(Foster,KnightandFranklin,1998).Floodscausedbywaterloggingof
large,flatareas,however,canpersistforseveraldaysandcausedamagetotreesandforests.Some
examplesofrecentfloodeventscanbefoundinBox3.
Flashfloodscanoccurafterheavystormsorafteraperiodofdroughtwhenheavyrainfallsontovery
dry,hardgroundthatthewatercannotpenetrate(WMO,2011).Sucheventsmayhavemuchmore
impactonforests,especiallyinareasnotaccustomedtohighwaters.
Floodedforest,Hungary
19
HYDROLOGICAL
Box3.Somerecentfloodevents
BeginninginJuly2010,aheavierthannormalmonsoonseasonresultedindevastatingfloodsin
Pakistanthatkilledapproximately2000people,ruinedcrops,anddamagedordestroyed1.7million
homesaswellaslivestock,forestsandwildlife(UNEP,2011).Over18millionpeoplehavebeen
affected.Thefloodseverelydamagednaturalforests,plantations,communityforests,treesgrownfor
fuelwood,wildlifehabitatandconservationareas(Khanetal.,2010).Theremainingintactforestsare
atriskoffurtherdegradationaslocalcommunitiesextracttimbertorebuildhomesandforfuelwood
andfodder,andsellforestproductsandwildlifetoearncash(Khanetal.,2010).
SignificantfloodingoccurredinmanyareasofQueensland,AustraliaduringlateDecember2010and
earlyJanuary2011.Threequartersofthestatewasdeclaredadisasterzoneandcleanupeffortsare
expectedtocostbillionsofdollars.Thousandsofpeoplewereevacuatedfromtheirhomesandmore
than200000peoplehavebeenaffected.Theimpactsonforestsremaintobeseen.
UnusuallyheavyrainfallsinceJanuary2011hascausedwidespreadfloodinginsouthernAfrica,
particularlyinAngola,Botswana,Lesotho,Madagascar,Malawi,Mozambique,Namibia,SouthAfrica,
ZambiaandZimbabwe.Theaffectedcountriesreportdeaths,displacements,evacuationsaswellas
damagetocrops,housesandinfrastructure(OCHA,2011).InNamibia,thehardesthitcountry,flood
watersaresubsiding,howeverthenumberofpeopleaffectedbythefloodscontinuestoriseasnew
informationisreceived;itisestimatedthatthetotalnumberofpeopleaffectedis500000with65
relateddeathsandapproximately60000displacedand19000inrelocationcamps(asof02July
2011).InMalawi,14peoplehavedied,over61000peopleareaffectedandover3800hectaresof
cropsdamaged(asof29April2011).Atleast234peoplediedinAngolawithapproximately254000
peopledirectlyaffected(asof02June2011).Impactsonforestsarenotyetknown.
TheMississippiRiverfloodsof2011areamongthelargestandmostdamagingalongthefloodprone
USriverinthepastcentury.ComparisonsarebeingdrawntothemajorMississippiRiverfloodsin
1927and1993,thelatterinwhichmorethan10millionacresoflandwereflooded.InApril2011,
twomajorstormsystems,alsoresponsibleforlargetornadooutbreaks,producedlargeamountsof
rainfallacrossmuchofthevastMississippiRiverwatershed.Combinedwithspringtimesnowmelt,
theriverbegantorisetorecordlevelsbyearlyMay.StatesexperiencingfloodingincludeIllinois,
Missouri,Kentucky,Tennessee,Arkansas,MississippiandLouisiana.Theimpactsonforestsremainto
beseen.
Avalanches
Avalanchesarerapid,gravitydrivenmassflowsofsnow,airanddebris(Bebi,KulakowskiandRixen,
2009).Theycangenerallybeclassifiedintoloosesnowavalanches(startingatasingleareaorpoint)
andslabavalanches(releaseofacohesivesnowlayerinitiatedbyafailureatdepthinthesnow
cover).Theycanbehighlydestructive,movingatspeedsinexcessof150km/h(WMO,2011).
Avalanchesclaimapproximately150livesperyearandthatnumbercontinuestoriseasmorepeople
participateinwintersportstherebyspendingmoretimeinvulnerableareas.On17February2010,for
example,anavalanchefuelledbyheavysnowfallsstruckseveraltownsinNorthWestFrontier
ProvinceofPakistankillingover100people.
Avalanchedisturbanceregimesaretwowayinteractionsinwhichforeststructureandcomposition
affectavalanches,andavalanches,inturn,affectforeststructureandcomposition(Bebi,Kulakowski
andRixen,2009).Avalanchesprimarilyaffectsubalpineforests(thoseforestsclosesttouppertree
line).Theycandamageorkillindividualtreesovertenstohundredsofhectaresinforeststhatare
locatedinvulnerableareas.Atastandscale,avalanchestypicallyresultinforestcommunitiesthatare
characterizedbysmallerandshortertrees,shadeintolerantspecies,lowerstemdensities,and
20
FAO/T.HOFER/FO0346
Damagecausedbyalargeavalanche,Switzerland
21
HYDROLOGICAL
greaterstructuraldiversity.Suchcommunitiesprovidevaluedhabitatforvariousanimalandplant
speciesandcancontributetooverallhigherbiodiversity.Atabroaderscale,avalanchetracksprovide
increasedlandscapeheterogeneityandedgedensityandcanserveasfirebreaks.
Theimpactsofavalanchesontreesarecloselyrelatedtothesizeandflexibilityofthetreeandwhere
theavalancheoccursinrelationtothetree.Intreeswithlargerdiameters,thestressesexertedby
avalanchescanexceedthebreakingstrengthofthetree,resultinginbolebreakageoruprootingof
thetreeifthepressureishighenough.Ifatreeisflexibleenough,itmaybedeflectedandbelargely
undamaged.Smalltrees(height<5metres)cantoleratesnowpressurebybendingandleaninginthe
snowpack(Kajimotoetal.,2004).Criticaltreediametersforbreakagerangeforcommonsubalpine
treespeciesfrom6to14centimetres,andarehigherforbroadleaved,relativelyshortlivedtreeswith
flexiblestemssuchasBetula,Alnus,AcerorSalixspecies(Bebi,KulakowskiandRixen,2009).
Whenavalancheseverityand/orfrequencyarehigh,theycanbethedominantfactorthatcontrols
survival,growthratesandgrowthformsoftrees.Withdecreasedseverityandincreasingintervals
betweenavalancheevents,thegrowthoftreespeciesshiftsfromshrubstoerecttrees(Bebi,
KulakowskiandRixen,2009).Standsthatarefrequentlydisturbedbyavalanchesaretypically
dominatedbytreeswithsmallerdiameters,shorterstature,andslowannualgrowthratesin
comparisontoundisturbedstands(Bebi,KulakowskiandRixen,2009).Disturbedstandsalsotendto
becharacterizedbyadominanceofshadeintolerantspeciesandlowertreedensities(Butler,1979;
Johnson,1987;Bebi,KienastandSchönenberger,2001).Forestrecoveryafteravalanchesisnormally
bywayofsurvivingvegetationasopposedtonewspeciesestablishment.
Oneofthemostimportantecologicaleffectsofavalanchesisincreasedstructuralandcompositional
diversity(Bebi,KulakowskiandRixen,2009).Inmontaneandsubalpineareas,coniferousforests
composedofrelativelylargetreesusuallydominate;avalanchedisturbanceallowsforsmaller
individualstodominateplantcommunities.Avalanchescreateopenhabitatinotherwiseclosed
forestswhichcontributestothecomplexityanddiversityoftheecosystem.Bebi,Kulakowskiand
Rixen(2009)notedthatthenumberofvascularplantspecieswasgreatestinareasofhighest
disturbanceintensityandfrequencyasopposedtoareasthatexperiencedavalancheslessfrequently.
HYDROLOGICAL
Landslidesandmudslides
Landslidesandmudslidesoccurwhenheavyrain,rapidsnoworicemeltoranoverflowingcraterlake
sendslargeamountsofearth,rock,sandormudflowingswiftlydownhillandmountainslopes
(WMO,2011).Earthquakes,volcaniceruptions,heavyrainstorms,andcyclonescantriggerlandslides.
Landuseintensificationandclimatechangeareincreasinglandslidinginmountainousregions
(Restrepoetal.2009).Infact,moreinformationisavailableontheimpactsofforestactivitieson
landslidesthanontheimpactsoflandslidesonforests.Forestharvesting,particularlyclearcutting,
androadbuildingcanresultinincreasedsurfaceerosion,changesinhydrology,andincreasesin
landslidesanddebrisflows(Guthrie,2005;Imaizumi,SidleandKamei,2008;Sidle,2005).
Shallowlandslidestypicallyhavelittleimpactontrees.Deeplandslides,triggeredbymajor
earthquakesorvolcanicactivity,howevercandenudehundredsoreventhousandsofsquare
kilometresofland(SchusterandHighland,2004).Insuchmajorlandslides,allofthesoildownto
bedrockiscarrieddownslope,takingallofthetreesandothervegetationwithit.Becausenosoilis
leftfornewplantstogrowon,thebaretracksoflandslidescanremainvisibleforhundredsofyears.
Shallowlandslidescanbepreventedbytreecoverwhereasdeeplandslidescannotbeprevented,
evenwithhighforestcover.
Widespreadstrippingofforestsbymassmovementshasbeennotedinmanypartsoftheworld,
particularlyinearthquakepronetropicalareas(SchusterandHighland,2001;2004).
x InSeptember1935,twoshallowearthquakesintheTorricelliRange,PapuaNewGuinea,caused
hillsidestoslideaway,carryingwiththemmillionsoftonnesofearthandtimberandrevealingbare
rock.Approximately130squarekilometres(eightpercentoftheregionaffected)wasdenudedby
thelandslides.
x InNovember1970,anearthquaketriggeredlandslidesalongthenorthcoastofPapuaNewGuinea.
Theyremovedshallowsoilsandstrippedtropicalforestvegetationfromabout25percentofthe
240squarekilometresareaaffected.
x In1976twoshallowearthquakesoccurredinPanama,causinghugeareasoflandslidingand
removinganestimated54squarekilometresofforestcoveror12percentoftheaffectedregion.
x Similarsubtropicalforestdevastationduetoearthquakeinducedlandslidesoccurredinthe1987
Reventadorand1994PaezeventsinEcuadorandColombia,respectively.Inbothcases,the
earthquakesoccurredafterlongperiodsofrainfall,andthesaturatedsoilsrapidlygaveway.The
Reventadorlandslidesremovedthesubtropicalforestsfrommorethan75percentofthe
southwesternslopesofthevolcano.Itwasestimatedthat230squarekilometresofnaturalforest
werelostintheregion.ThePaezlandslidesstrippedsoilandvegetationfrom250square
kilometresofsteepvalleywalls.
x IntheLuquilloMountainsofPuertoRico,whichareespeciallyhardhitbylandslides,itwas
reportedthatlandslidesdenudebetween0.08and1.1percentoftheforestareapercentury.
Thedestructionoftemperateforestsbylandslideshasalsobeenobserved(SchusterandHighland,
2001;2004).
x ManyforestareasinNewZealandhavebeendamagedbylandslides.Studiesofforestlossesinthe
upperdrainagebasinofthePohanginaRiverontheNorthIslandnotedthatin1946theerosion
surfaceexposedbymassmovementsinaredbeechforestwas1.7percentofthedrainagearea.By
1963,thedenudedareawas2.7percent,anincreaseof60percentin17years.
x Duringthe1960Chileanearthquake,morethan250squarekilometresoftemperateforestslopes
weredenuded.
x NumerousstudieshaveinvestigatedlandslidedamageinsouthwesternCanadaandthe
northwesternUnitedStates.Especiallynoteworthyhavebeenstudiesoflandslidecausedforest
damageontheQueenCharlotteIslandsoffthecoastofBritishColumbia,whichincludevast
expansesofvaluablecommercialtimber.
22
FAO/M.KASHIO/FO6749
Morerecently,anumberofeventshavecausedconsiderabledamagethoughtheimpactsonforests
remaintobeseen.InJanuary2011,heavyrainsresultedinfloodingandmassivemudslidesinthree
townsofBrazilNovaFriburgo,PetrópolisandTeresópolis.Hundredsofpeoplehavediedandsome
14000peoplewerelefthomeless.Thiseventwasthedeadliestsinglenaturaldisastertooccurinthe
country.
InHaitiin2004,mudslidestriggeredbytheheavyrainsbroughtbyHurricaneJeanneresultedinmore
than3000deathsandanother2600injured.ThecoastalcityofGonaïveswasespeciallyhardhit;
80000ofthecity's100000residentswereaffected.
On13November1985,thelongdormantvolcanoNevadodelRuizinColombiacamealiveandwithin
hoursitleftapproximately23000peopleburiedinamilewideavalancheofmudandashand
destroyedmorethanUS$339millioninproperty(Piersonetal.,1990;SchusterandHighland,2001).
ThehardesthittownwasArmerowheremorethan20000peoplediedand5000morewereinjured
(SchusterandHighland,2001).Nolavawasproduced;ratherthemagmawithintheconemeltedthe
overlyingsnowandicewhichcreatedcatastrophiclahars(volcanicflowscomposedofhotorcold
waterandrockfragments)thateventuallycametumblingdown.Specificimpactsonforestsarenot
known.
23
HYDROLOGICAL
Depositionofsandanddebrisafteralandslideandflashflood,Thailand
GEOPHYSICALEVENTS
FAO/H.HIRAOKE/FO6354
GEOPHYSICAL
Tsunamis
Atsunamiisaseriesofenormoustravelingoceanwavesofextremelylonglengthgeneratedprimarily
byearthquakesoccurringbeloworneartheoceanfloor.Theymayalsobegeneratedbyunderwater
landslidesandvolcaniceruptions,ormeteorites.Tsunamiwavesaredistinguishedfromordinary
oceanwavesbytheirgreatlengthbetweenwavecrests,oftenexceeding100kilometresormorein
thedeepocean,andbythetimebetweenthesecrests,rangingfrom10minutestoanhour(ITIC,
2011).Inthedeepocean,thetsunamiwavestravelatover800kilometresperhour,withashort
waveheightofonlyafewtensofcentimetresorless.Astheyreachshallowcoastalwaters,thewaves
slowdownandthewatercanpileupintoawallofdestructiondozensofmetresormoreinheight.
Largetsunamishavebeenknowntoriseover30metresandevenatsunami36metreshighcanbe
verydestructiveandcausemanydeathsandinjuries(ITIC,2011).Although60percentofalltsunamis
occurinthePacificOcean,theycanalsothreatencoastlinesofcountriesinotherregions,including
theIndianOcean,MediterraneanandCaribbeanSeas,andtheAtlanticOcean(ITIC,2011).
ThemostdevastatingeventoccurredinDecember2004,whenanearthquakeoffnorthwestern
Sumatra,IndonesiaproducedadestructivetsunamithatstruckcoaststhroughouttheIndianOcean,
killingapproximately230000people,displacingmorethanonemillionpeople,andcausingbillionsof
dollarsofpropertydamage.Mangroves,coastalforests,homegardens,agroforestrysystemsand
treesincoastallandscapesweredamagedbythetsunami(FAO,2011).Treesweresnappedand
uprootedbywavesandstrongcurrents.Observedchangesintopography,soilsalinityandfreshwater
inputmayalsoadverselyaffectthemangroves,coastalforestsandothertreesinthelongerterm.
InIndonesia,thehardesthitcountry,thedegradationandconversionofmangrovesintoshrimpfarms
exacerbatedthedamagecausedbythetsunami(Adgeretal.,2005;SrinivasaandNakagawa,2008;
UNEP,2005).Itwasestimatedthatalmost49000hectaresofcoastalforests(notincluding
mangroves)wereimpactedbythetsunamirepresentinganeconomiclossofUS$21.9million(UNEP,
2005).Approximately90percentdamageto300750hectaresofmangroveforestswasalsonoted
representingalossofUS$2.5million(UNEP,2005).Onlyabout306hectaresofmangroveforests
wereimpactedbythetsunamiinThailandrepresentinglessthan0.2percentoftheirtotalarea
(SrinivasaandNakagawa,2008;UNEP,2005).InsomeareasinSriLanka,largemangrovetreeswere
uprootedandfoundfarfromthebeach(UNEP,2005).Thetsunamialsocausedwidespreadimpactsto
mangrovesandcoastalvegetationintheSeychellesandtheMaldives.Directimpactstothe
mangroveswerecausedbyinputsofsandandsiltthatcoveredthepneumatophores(breathing
roots).
Soilerosionanddebrisresultingfromthe2004IndianOceanTsunami,Indonesia
24
flickr /F.GRAHAM
Damagecausedbythe2011earthquakeinChristchurch,NewZealand
25
GEOPHYSICAL
GEOPHYSICAL
Areaswithhealthy,matureandextensivemangrovesweregenerallyprotectedfromtheforceofthe
tsunamiandsufferedlessdamage(SrinivasaandNakagawa,2008).ObservationsfromtheMaldives
showedthatcoastalforestsweremostresilienttothetsunamiimpactswhenleftasanundisturbed,
mixedspeciescommunity(UNEP,2005).Althoughmaturemangrovesarequiteresistanttowater
surges,therearelimitstothisresilience.Sanddunes,mangroveforestsandcoralreefsallhelpto
reducetheenergyoftsunamiwaves.Considerableinternationalinterestintheroleofcoastalforests
inthemitigationoftsunamiimpactsaroseaftertheIndianOceanTsunamiin2004.
Morerecently,on11March2011,amassiveearthquakeoffthenortheasterncoastofJapan,the
strongesteverrecordedinthecountry,triggeredadevastatingtsunamiofupto30metresinheight
thatpusheduptofivekilometresinland,resultinginmassivelossoflife,environmentaldevastation
andinfrastructuraldamage.Aftershockspersistedforsometimeafter.Thetsunamialsodamagedthe
Fukushimanuclearpowerplant,leadingtoseriousconcernsoverradiationcontamination(see
Radiationcontaminationsection).
Whileeventsarestillunfolding,thescaleofthedisasterisalltooapparent:asof01May2011,14704
peoplewereconfirmeddead,5278injuredand10969weremissing.Withapreliminaryestimated
costofUS$309billion,itisalsobelievedtobethemostcostlydisastertodateworldwide.The
estimatecoversdestructiontoinfrastructureinsevenprefecturesaffectedbythedisaster,including
damagestonuclearpowerfacilitiesnorthofTokyo.Widerimplicationsontheeconomy,including
howradiationwillaffectfoodandwatersupply,arenotincludedintheestimate.
Earthquakes
Intectonicallyactiveregionsoftheworld,largeearthquakesdisturbforestsoverextensiveareasand
assuchareimportantdeterminantsofforeststructureandfunction(Allen,BellinghamandWiser,
1999;Vittoz,StewartandDuncan,2001).Theintensityofdamagetoforestsvariesstronglywith
distancefromtheearthquake’sepicentre.
Earthquakescantriggerlandslideswhilethoseoccurringunderwatercanproducetsunamis.Itis
generallyconsideredthattheprimarycauseoftreemortalityduringearthquakesisasaresultofthe
landslidestheycreate(Allen,BellinghamandWiser,1999);forestsareoftencompletelyremovedor
submergedbysuchlandslides.Howevermuchoftheimmediateimpactofanearthquakeis
widespread,lowintensitytreemortalityandinjury(Allen,BellinghamandWiser,1999).
Damageiscausedbytheshakingorshearingoftreeroots,theupliftofthegroundsurface,orchanges
inthewatertable(Allen,BellinghamandWiser,1999;Vittoz,StewartandDuncan,2001).The
movementofsoilorbouldersdownslopecanalsodamagetrees.Damagedtreesmaysurvivebutthey
willexhibitsignsofthedisturbancesuchasfracturesinthewood,growthsuppressionorthe
productionofreactionwood(Vittoz,StewartandDuncan,2001).Thediversityofearthquakeimpacts
isamajorsourceofheterogeneityinforeststructureandregeneration.Someexamplesofrecent
earthquakesandtheirimpactsonforestscanbefoundinBox4.
GEOPHYSICAL
Box4.Recentearthquakesandtheirimpactsonforests
A6.3magnitudeearthquakestruckChristchurch,NewZealandon22February2011killingatleast
160peopleandcausingbillionsofdollarsindamage.Manytreesinurbanareasandparkswere
damagedandneededtoberemovedtoensurepublicsafety.
Thedevastating7.0magnitudeearthquakeof12January2010inHaitiresultedinmorethan230000
deaths,left1.5millionhomelessintheregionaroundHaiti’scapital,PortauPrinceanddelivereda
severeblowtothecountry'salreadyshakyeconomyandinfrastructure(UNEP,2011).Forestdamage
asaresultoftheearthquakewasunknownattimeofprint.
Anearthquakeof8.8magnitudehitcentralChileon27February2010killingmorethan700people
andcausingwidespreaddamageinmanypartsofthecountry,particularlynearConcepción,the
secondlargestmetropolitanarea.Followingtheearthquakeatsunamihitthecoastlineseverely
impactingcoastalcommunities.Approximatelyhalfamillionhomeswereseriouslydamaged.The
impactedregionishometoimportantindustriesincludingfishing,shipping,powergeneration,
petroleumrefining,andforestproducts.LossestoChile’seconomywereestimatedatUS$1530
billion(UNEP,2011).Thecountry’spulpandpaperproducers,suchasArauco,EmpresasCMPC,
PapeleraConcepcionandNorskeSkog,wereamongthehardesthitwithseverelydamaged
productionfacilitiesforcingatemporaryshutdownofallplants.Globalpricesforpulprose
significantlyasaresult.
Inadditiontoacatastrophiclossofhumanlifeanddestructionoftownsandvillages,theearthquake
inWenchaun,SichuanProvince,Chinain2008causedforestfragmentationandseverelydamaged
ecosystemsthatsupportsomeofthelastremaininggiantpanda(Ailuropodamelanoleuca)
populationsinthewild(Xuetal.,2009).
On08October2005amagnitude7.6quakestruckKashmirinnorthernPakistankillingapproximately
30000peopleinjusthours.Bytheonsetofwinter,morethan87000peopleweredeadandsome
threemillionwerehomeless.Theearthquakemagnifiedtheimpactofenvironmentaldegradation,
causingsignificantlanddestabilizationanddamage.Severalmajorlandslidesandthousandsofminor
landslipsoccurred,affectingabouttenpercentofhillsidearableland,forestsandrangelands(FAO,
2009).Manytreeswerealsodamagedbyrockfallsandinsomeareastheearthquaketruncatedtrees
abouttwometresabovetheground(IUCN,2006).Theinnercoreofmanytreeswerelikelydamaged
whichwaspredictedtoaffecttheirfutureuseandvalue(IUCN,2006).Flashfloodsandmudslides
destroyedagriculturallandandfruittreeplantations,andalteredrunoffroutesonhillsidesandin
valleylowlands.Thetotalcostofdamageandlossesintheagriculturalandlivestocksectorswas
estimatedatUS$409million(FAO,2009).
Volcaniceruptions
Thereareapproximately1500potentiallyactivevolcanoesworldwide,plushundredsmoreonthe
oceanfloor.About500ofthesehaveeruptedinhistoricaltime.Manyofthesearelocatedalongthe
PacificRiminwhatisknownasthe"RingofFire".
Ofthevariousdisturbancesdiscussedhere,volcaniceruptionshavetheleastpotentialofleaving
residualmaterialsbehind.Theintenseforceoftheblast,andthelargeamountofearththatiseither
movedorcoveredwithvariouskindsofdebris,makesitadisturbancethatismoreseverethanthe
hottestfireorthemostintensewindstorm(Foster,KnightandFranklin,1998).Impactsdiminishas
distancefromthevolcanoincreases.
Volcanohazardsthatmayimpactforestsinclude:
x gases,suchassulphurdioxide,carbondioxideandhydrogenfluoride;
x lahars–volcanicflowscomposedofhotorcoldwaterandrockfragments;
x landslides;
26
x lavaflows;
x pyroclasticflows–fastmovingcurrentsofhotrockandgasthattraveldownhillalongslope
depressions(Grishin,2009);
x tephra–fragmentsofvolcanicrockandlavathatbecomeairbornethroughexplosionsortherise
ofhotgases(USGS,2011).Thesmallestfragmentsarevolcanicash.
Youngforestsaremostatriskfromashfall;standsoftreeslessthantwoyearsoldarelikelytobe
destroyedbyashdepositsthickerthan100millimetres(USGS,2011).Maturetreesareunlikelyto
succumbfromashfalldepositionalone,buttheaccumulatedweightofashcanbreaklargebranches
incasesofheavyashfall(>500mm).Defoliationoftreesmayalsooccur.
Oneofthemostdocumentedvolcaniceruptionsanditssubsequentimpactsonforestsandnatural
environmentsisMountSt.HelensinWashington,USA.On18May1980thevolcanoeruptedkilling
some57people,impactingmorethan700squarekilometresoflandandcreatingseveraldistinct
disturbancesincluding:a0.25squarekilometrepyroclasticflow;a550squarekilometreareaofblown
downtreesborderedby96squarekilometresofscorchedtrees;a60squarekilometredebris
avalancheorlandslide;andmassivemudflows(Turner,DaleandEverham,1997).
NoplantssurvivedonthepyroclasticflowsatMountSt.Helens,andtherecoveryoftheseareashas
beenslow,beingcolonizedbyherbaceousandforbspecieswithwinddispersedseeds(Turner,Dale
andEverham,1997).Theforceoftheeruptionintheblowdownzonewasstrongenoughtoknock
overtrees,althoughherbsandunderstoryvegetationsurvived(Halpernetal.,1990).Inthescorch
perimeteraroundtheblowdownzone,temperatureswerehotenoughtoburnleaves,butthewinds
werenotstrongenoughtofellthetrees.Coniferoustreesinthisareadied,butsomedeciduoustrees
survived(Turner,DaleandEverham,1997).
Noviableseedssurvivedthedebrisavalancheorlandslidesandtheveryfewsurvivingplants
developedfromrootstocksorstemsthatweremovedbythelandslideandcametorestnearthe
surface(Turner,DaleandEverham,1997).By1994,vegetationcoveronthedebrisavalanchehad
graduallyincreasedfromzeroto35percentandwascomposedofearlysuccessionalspecieswith
winddispersedseeds,afewconifersandredalder(Alnusrubra)(Turner,DaleandEverham,1997).
Mudflowswashedawaymostoftheunderstoryvegetationandsmalltrees;largetrees,thosetaller
FAO/R.GRISOLIA/21843
GEOPHYSICAL
Chile’sLonquimayVolcanoerupting
27
thanthesurfaceoftheflow,survived.Theproximityofsurvivingvegetationandseedingbyhumans
resultedinalmost100percentcoveronthemudflowswithinafewyears(HalpernandHarmon,
1983).FurtherexamplesofvolcaniceruptionscanbefoundinBox5.
Box5.Examplesofvolcaniceruptionsandtheirimpactsonforests4
OneoftheoldestwellknowneventsisthatofMountVesuviusinItalywhicheruptedinA.D.79
andcompletelyburiedthecitiesofPompeiiandHerculaneum,preservingtheancientlifethere.
Morerecenteruptionsoccurredin1906,whichkilledover100people,andin1944,which
destroyedthevillagesofSanSebastianoalVesuvio,MassadiSomma,OttavianoandpartofSan
GiorgioaCremano.Thevolcanoremainsoneofthemostthreateningactivevolcanoeswiththe
greatestdeadlypotentialasitislocatednearlargepopulations;over11millionpeopleliveclose
byinNaplesandothertowns.
ThemostpowerfulmoderneruptionisthatoftheKrakatauvolcanointheKrakatauIslands,
Indonesiain1883whichkilled40000people.Itcreatedcatastrophictsunamisintheregionand
emittedsomuchashintothestratospherethatglobaltemperatureswereloweredforabouta
yearafter.Eachofthethreeislands(Krakatau,Panjang,Sertung)wereentirelystrippedofall
vegetationbyathicklayerofash,lavaandpumice(Whittaker,BushandRichards,1989;Zabka
andNentwig,2002).
TheeruptionofMountPinatubointhePhilippinesin1991killedapproximately300people,
injuredhundredsmoreanddisplacedmillions.Theeruptionproducedhighspeedavalanchesof
hotashandgas,giantmudflows,andacloudofvolcanicashhundredsofmilesacross(UGSG,
2005).Thetoxicashcloudreducedglobaltemperatures0.5°Cbelownormalfortwoyearsafter
theeruption(Hansenetal.,1996)
TheSoufrièreHillsvolcanoinMontserratbeganeruptingin1995andcontinuesatthetimeof
writing.Bylate1997,pyroclasticflowshadalmostcompletelydestroyedthetropicalforestinthe
southernhillrangesoftheisland(Dalsgaardetal.,2007).Theremainingforestedhillrange,the
CentreHills,havebeenimpactedbyfrequentandheavyperiodsofashfallandacidrain,
interspersedwithperiodsofrecovery.Fieldstudiesintheareahavenotedthatpopulationsof
canopyinsectsandbirdspecieswereoftenreducedaftermajorashfalls,buttheimpactwasshort
livedandrecoveryfollowedinsubsequentyears(Dalsgaardetal.,2007;Marske,IvieandHilton,
2007).
PitondelaFournaiseinRéunionisoneoftheworld’smostactivevolcanoes;ithaseruptedmore
than150timessince1640.Recenteruptionsinclude2002andtwicein2010.The2002eruption
resultedinthecolonizationoflavabyexoticplantspeciesandthedestructionofnaturalforests
bylavaflows(FAO,2010).
TheeruptionofIceland’svolcano,Eyjafjallajökull,inApril2010createdamassivecloudofashthat
shutdownairtravelinEuropeformorethanaweek,inconveniencingmillions.Coststotheglobal
airtravelsectorwereestimatedatUS$200millionperday.ThegroundingofEuropeanflights
avoidedanestimated344109tonnesofcarbondioxide(CO2)emissionsperdaywhilethevolcano
emittedabout150000tonnesofCO2perday(UNEP,2011).
GEOPHYSICAL
TheeruptionofChile’sPuyehuevolcanoinJune2011wreakedsimilarhavoc.Theashcloudcircled
theworlddisruptingflightsinArgentina,Brazil,Chile,Uruguay,AustraliaandNewZealand.
Littleinformationisavailableonthedirectimpactsofvolcanoesonforests;manyoftheseexampleshavebeen
includedtoillustratetheimpactsofashandcarbonemissions.
28
ANTHROPOGENICEVENTS
Bushfireduringthedryseason,Thailand
29
ANTHROPOGENIC
FAO/M.KASHIO/FO6479
Fire
Theimpactoffireonforestsismentionedonlybrieflyhere.Considerablymoreinformationonthis
topiccanbefoundatFAO’sForestsandfireWebsiteat:www.fao.org/forestry/firemanagement/
Firehasamajorinfluenceonthedevelopmentandmanagementofmanyoftheworld'sforests.Some
forestecosystemshaveevolvedinresponsetofrequentfiresfromnatural(Seesectionon
ThunderstormsandlightningunderMeteorologicalevents)aswellashumancauses,butmostothers
arenegativelyaffectedbywildfire.Everyyearmillionsofhectaresoftheworld'sforestsareconsumed
byfire,whichresultsinsignificantlossoflifeandlivelihoodsandenormouseconomiclossesfrom
destroyedtimberandinfrastructure,thehighcostsoffiresuppression,andlossofenvironmental,
recreationalandamenityvalues.FAO’sGlobalForestResourcesAssessment2010notedthat,on
average,onepercentofallforests,or19.8millionhectares,werereportedtobesignificantlyaffected
eachyearbyforestfires(FAO,2010).However,theareaofforestaffectedbyfireswasseverely
underreportedandthusthenumbersareconsideredanunderestimateofthetrueareaaffected.In
additiontodirectlosses,theassociatedsoilerosion,sitedeteriorationandsubsequentdifficultiesin
reestablishingtheforestduetothedryclimateandpoorsoilconditionshavemajorimpactsonthe
forestsector(FAO,ECEandILO,1995).
Foreststructuremaybeabruptlychangedbyintensecanopyfires,whichburnleavesandsmall
branchesandwhichareaccompaniedbysurfacefiresthatconsumeforestfloorandunderstory
vegetation(Foster,KnightandFranklin,1998).Notably,mostofthelargertreebolesarenotburned,
evenifkilled,andtheyoftenremainstandingfor10–50yearsafterafire.Suchresiduallivingand
deadorganicmatterareimportantforwildlifehabitat,nutrientdynamics,ecosystemfunctionand
forestrecovery(Harmonetal.,1986),thoughitmayprovideabreedingsubstrateforinsectpeststhus
possiblyleadingtodevastatingoutbreaks.
Firescanbetriggeredduringandafterperiodsofdrought,byheatwaves,drylightning,humanaction
oracombinationofthesefactorsinalmostallpartsoftheworld.Peoplearetheoverwhelmingcause
offireshowever,throughsuchactivitiesaslandclearingandotheragriculturalactivities,maintenance
ofgrasslandsforlivestockmanagement,extractionofnonwoodforestproducts,industrial
development,resettlement,hunting,negligenceandarson(FAO,2007).
Susceptibilitytofiredependsonthepropertiesoflivinganddeadvegetationasfuel,i.e.itsamount
andspatialdistribution,whicharerelatedtoforestcompositionandstructure(Seidletal.,2011).Dry
conditionsareaprerequisiteforsignificantfireevents.However,generallydryclimateconditionsalso
reduceproductivityandthusfuelavailability,exertinganegativefeedbackonfires(Seidletal.,2011).
Fireriskandincidencecanalsoincreaseasaresultofotherdisasters,suchaspestanddisease
outbreaksandstorms,whichincreasetheamountofdrydeadbiomass,orbyalackofsilvicultural
treatmentsforeconomicalreasonsoroutoffear(presenceoflandmines).
Inmanyforests,lowtomediumintensitysurfacefiresburninginregularintervalshelptoreducefuel
loadswithoutdamagingthetimber.InseveralcountriesliketheUSA,decadesoffiresuppressionhas
drasticallyalteredthecompositionandstructureofvegetationandhasresultedinforestswithhigh
treedensitiesandunnaturallyhighfuelloadsthatincreasetheriskofmorefrequentandhigher
intensityfires(Allenetal.,2010).Thesefireshavequitedifferentimpactsfromlowintensityfiresand
resultinsignificanteconomicandecologicallossessuchasstanddestruction,habitatlossand
susceptibilitytosecondarydisturbances.Therearemanyexamplesfromaroundtheworld,suchas
Australia,NorthAmericaandtheMediterraneanarea,ofsuchproblemsassociatedwithremovingfire
fromfireadaptedecosystems.
Inrecentdecadesanotableincreaseoflargewildfiresormegafireshasbeennotedinallregionsof
theworld.Megafiresarethemostcostly,mostdestructiveandmostdamagingofallwildfires.Not
alwaysasinglewildfire,theyaresometimesagroupofmultiplefiresacrossalargegeographicarea.
Theriskoftheiroccurrencelikelyincreasesasdroughtsdeepen,fuelsaccumulate,andlandscapes
becomemorehomogeneous.Megafiresareoftenextraordinaryfortheirsize,buttheyaremore
accuratelydefinedbytheircomplex,deepandlonglastingsocial,economicandenvironmental
impacts(Williamsetal.,2011).Theyseverelyimpactlocalcommunitiesandalsohaveseriousregional
orglobalconsequences.Environmentalimpactsincludeinterruptingoradverselyalteringenergy,
water,nutrientandcarboncycles,declinesinbiodiversity,increasedcarbonemissions,andweed
invasion(Williamsetal.,2011).ExamplesofsomenotablemegafirescanbefoundinBox6.
Box6.Recentexamplesofmegafiresfromaroundtheworld
PerhapsthefirstknownmegafirewasChina’s1987GreatBlackDragonFirewhichclaimedthelives
ofover200peopleandburnedapproximately1.2millionhectares(Salisbury,1989).
InIndonesia,asuccessionofextraordinarywildfiresin1982/83,1994,and1997/98resultedin
significantecologicaldamage.Biodiversitylossesandgreenhousegasemissionswerenearly
incalculableonaglobalscale.
ANTHROPOGENIC
SimilareffectsinBrazil’sAmazonregionwerewitnessedoveraperiodofyears,endingwiththe
Roraimafiresin1998whichburnedforover30daysandcoveredapproximately11000hectares.
Since1998,atleastninestatesintheUnitedStates,havesufferedtheirworstwildfiresonrecord.In
California,forexample,multiplelargefiresclaimeddozensoflivesanddestroyedthousandsof
homesin2003.
InAustralia,aseriesofdisastrousbushfiresinearly2003,January2005,and20062007were
exceededbytheFebruary2009BlackSaturdayFires,whichfolloweda13yearperiodofdrought.The
2009eventisconsideredthedeadliestcivildisasterinthatcountry’shistory,killing173peopleand
incineratingentiretowns(Teague,McCleadandPascoe,2009).
30
InBotswana,aseverewildfirein2008spread ontothesecondlargestgamereserveintheworld,
disruptingafragilelocaleconomytiedtoindigenousgrazingandtheregion’simportantecotourism
sector.
In2007,severewildfireshitGreece,killing84peopleandburning270000hectaresofland.Thefires
occurredafteradeepdroughtandatleasttwoheatwaves.
Morerecently,recordsettingwildfiresoccurredintheRussianFederationandIsraelin2010.Across
alloftheRussianFederation,approximately2.3millionhectaresburnedasaresultofover32000
fires.Sixtytwopeoplediedandhundredsofhomeswerelost.Thefirescreatedatoxiccloudofsmog
thathoveredoverMoscowandothercitiesforweeksparticularlyaffectingpeoplewithrespiratory
diseases,theveryyoungandtheelderly.InIsrael,ontheoutskirtsofHaifa,42peoplewerekilledby
fireandmuchofatreasuredforestwaslost.
Overthepastseveralyears,similarcatastrophicwildfireshaveoccurredinCanada,SouthAfrica,
Portugal,SpainandTurkeyamongothers.
(Source:Williamsetal.,2011,unlessotherwisenoted)
31
ANTHROPOGENIC
Oilspills
Oilspillscanhavedevastatingimpactsoncoastalforestsandmangroves.Mangrovesarehighly
susceptibletooilexposureandcanbeaffectedintwomainways:fromthephysicaleffectsofoiling
andfromthetoxicologicaleffectsoftheoil(NOAA,2010).Thephysicaleffectsofoiling(e.g.covering
orblockingspecializedtissuesneededforrespirationorsaltmanagement)mayincludeeither
disruptionorcompletepreventionnormalbiologicalprocessesofexchangewiththeenvironment.
Whenoilphysicallycoversplants,animalsandbirds,theymaydiefromsuffocation,starvation,or
otherphysicalinterferencewithnormalphysiologicalfunction.
Acuteeffectsofoil(mortality)occurwithinsixmonthsofexposureandusuallywithinamuchshorter
timeframe(afewweeks).Visiblesignsofmangrovestress,includingchlorosis,defoliationanddeath,
oftenshowwithinthefirsttwoweeksofaspillevent.Thetreemaysurviveforatimeonlytosuccumb
weeksormonthslater,or,dependingontheseverityofthedamage,itmayrecovertoproducenew
leafgrowth.Seedlingsandsaplings,inparticular,aresusceptibletooilexposure(NOAA,2010).More
subtleresponsesincludebranchingofpneumatophores(breathingroots),germinationfailure,
decreasedcanopycover,increasedrateofmutation,andincreasedsensitivitytootherstressors
(NOAA,2010).
Chronicoilimpactsonmangrovesincludealteredgrowthratesandreproductivetimingorstrategy
andcanbemeasuredoverlongtimeperiods,potentiallyadecadeordecades.Theymayalsoexhibit
morphologicaladaptationsinordertosurvivetheoilingasillustratedbythedevelopmentof
branchedsecondarypneumatophoresinmangrovesasaresponsetoimpairmentofnormal
respirationafterthe1991GulfWarspill(Böer,1993).
Rootsurvival,canopyconditionandgrowthratesofmangroveseedlingsinoildeforestedgapsare
adverselyaffectedbyoilremaininginmangrovesediments.Sixyearsafterthe1986BahíalasMinas
(Galeta)oilspillinPanama,survivingforestssurroundingdeforestedareasexhibitedcanopy
deterioration(Burns,GarrityandLevings,1993).Alackofrecoveryinaffectedmangroveareaswas
alsonotedfouryearsafterthe1992EraspillinAustralia(NOAA,2010).Suchlongtermimpactshave
alsobeenreportedfromanexperimentalstudy,theTROPICSspillinPanamain1984,wherebynearly
halfoftheaffectedtreesweredeadtenyearsaftertheoilingcomparedwith17percentmortalityat
sevenmonthspostoiling(NOAA,2010).
flickr/NASAGODDARDSPACEFLIGHTCENTER
OilspillintheGulfofMexicoaftertheexplosionoftheDeepwaterHorizonoilrig,2010
ANTHROPOGENIC
Theseverityoftheimpactsofoilspillsonmangrovesaredependantontheamountofoilspilled,the
typeofoilspilled(includingadditives),theamountoftimetheoilremainsnearthemangroves,and
theweatheringtimeoftheoilitself(NOAA,2010).Lighteroilsaremoreacutelytoxictomangroves
thanheavieroilsandincreasedweatheringgenerallylowersoiltoxicity.
Aninitialdamageassessmentsurveyconductedinthefirstmonthafterthe1999RooseveltRoads
NavalAirStation(PuertoRico)spillofjetfuel,determinedthat46percentofmangrovetrees,
saplings,andseedlingsalongatransectinthemostimpactedbasinareawereexhibitingobvioussigns
ofstress(NOAA,2010).Withinthreemonthsofthe1992AustralianEraspill,extensivedefoliationof
mangrovetreeshadbegunandmanyappearedtobedead(NOAA,2010).Fivemonthsafterthe1986
BahíalasMinasspill,abandofdeadanddyingtreeswasnotedandayearandahalfafterthespill,
deadmangroveswerefoundalong27kilometresofthecoast(NOAA,2010).
Oneofthemostpublicizedandstudiedenvironmentaldisasterinhistoryisthe1989ExxonValdezoil
spillinPrinceWilliamSound,Alaska,USA.Approximately11milliongallonsor257000barrelsofoil
spilledfromthegroundedtankerimpactingover2000kilometresofcoastline(ExxonValdezOilSpill
TrusteeCouncil,2011).Itiswidelyconsideredthemostdamagingoilspilleverprimarilybecauseof
themagnitudeofthespill,extentofshorelinecontamination,andhighmortalityofwildlifeincluding
algae,benthicmacroinvertebrates,seabirds,baldeagles,seaotters,sealsandwhales.Thetimingof
thespill,theremotelocation,thethousandsofkilometresofwildshoreline,andtheabundanceof
wildlifeintheregioncombinedtomakeitsonotable.
On20April2010,theoilrigDeepwaterHorizonexplodedintheGulfofMexico,resultinginthe
largestaccidentalmarineoilspillinthepetroleumindustry’shistoryandcausingdamagetowildlife
andmarinehabitats,andtothefishingandtourismindustries(UNEP,2011).Almostfivemillion
barrelsflowedintotheGulfbeforethewellwaspermanentlysealedon19September2010.
Hundredsofkilometresofcoastalvegetationwereimpactedandrecoverymaytakemanyyears.
Airpollution
Airpollutionhaslongbeenrecognizedasadetrimenttotheworld’sflora.Pollutantssuchasnitrogen,
sulphurdioxide,heavymetalsandozonecanbeconveyedintheatmosphereovergreatdistancesas
32
AirpollutiondamagetoEuropeanlarch(Larixdecidua),CzechRepublic
33
ANTHROPOGENIC
BUGWOOD.ORG/P.KAPITOLA/3040065
gasesormicroscopicparticles(MCPFE,2007).Treecanopiesareveryefficientatcapturingdeposition
of,orfiltering,atmosphericpollutantsofallkindsresultinginhighinputstoforests.Depositionof
pollutantscanimpactecosystemsdirectlyorthroughsoilacidificationandeutrophication.
Theenvironmentalimpactsofairpollutantshavebeenofgreatconcern,particularlyinEurope,
resultingintheadoptionoftheUnitedNationsEconomicCommissionforEurope(UNECE)Convention
onLongrangeTransboundaryAirPollution(CLRTAP)in1979.TheConventionaddressessomeofthe
majorenvironmentalproblemsoftheUNECEregionthroughscientificcollaborationandpolicy
negotiationandhasbeenextendedbyeightprotocolsthatidentifyspecificmeasurestobetakenby
Partiestocuttheiremissionsofairpollutantssuchaspersistentorganicpollutants(POPs),sulphur
andnitrogenoxides.
TheInternationalCooperativeProgrammeonAssessmentandMonitoringofAirPollutionEffectson
Forests(ICPForests)waslaunchedin1985undertheConventionduetothegrowingpublic
awarenessofpossibleadverseeffectsofairpollutiononforests.TheProgrammemonitorsforest
conditioninEuropetoprovideanoverviewofthestatusofforestecosystemswithrespecttoair
pollutionandcontributetotheunderstandingoftherelationshipbetweenpollutionandforest
health.Crownconditionparameters,suchasdefoliationanddiscolouration,areusedastheprincipal
indicatorsofforestcondition.
Groundlevelozone(O3),themostimportantairpollutantaffectingforestsworldwide,isknownto
reducephotosynthesis,growth,andotherplantfunctions(Bytnerowiczetal.,2008;Felzeretal.,
2007;Karnoskyetal.,2005).Italsoenhancessusceptibilitytopathogens(Karnoskyetal.,2002)and
resultsinleafchlorosisorsenescenceandforestdecline(Emberson,2003).
Thedepositionofatmosphericnitrogenouspollutantsemittedfromindustrial,urbanandagricultural
sourcesisalsoofgreatimportanceinthattheyaffectgrowth,biodiversityandbiogeochemicalcycles
inforestecosystemsinmanyareas(Bytnerowiczetal.,2008).Nitrogenoxides(NOx)resultinaltered
plantgrowth,enhancedsensitivitytosecondarystresses,andeutrophication(Emberson,2003).At
lowlevelsandinnitrogenlimitedecosystems,suchasborealforests,nitrogenmayenhancegrowth.
NOx,ammonia(NH3)andnitricacid(HNO3)vapourmayhavedirectphytotoxiceffectsbutonlyathigh
concentrations(Bytnerowicz,OmasaandPaoletti,2007).
Theimportanceofsomeindustrialairpollutants,suchassulphurdioxide(SO2)andheavymetals,has
riseninrecentyearsasaresultoftherapidindustrializationofsomecountrieswhichoftenlack
adequateenvironmentalconsiderationsandcontrols(Bytnerowiczetal.,2008).Themajorsourceof
SO2isfromthecombustionoffossilfuelscontainingsulphur.Impactsonvegetationincludeleaf
chlorosis,reducedplantgrowthandvitality,andforestdecline(Emberson,2003;MCPFE,2007).
Radioactivecontamination
Accidentsatnuclearpowerplantscreateobviousconcernsaboutexposureofthehumanpopulation
tocontaminationintheimmediatevicinity,andtherearepotentiallylongertermproblemsduetothe
ecologicalimpactfromcontaminationwithradionuclides.Radionuclidesareradioactiveatomsthat
areeithermanmadeornaturallyoccuringbutonlyafewareconsideredtopresentseriousrisksto
human,wildlifeandecosystemhealth(FAO/IAEA,2011).
Althoughmanydifferentkindsofradionuclidescanbedischargedfollowingamajornuclearaccident,
someareveryshortlivedandothersdonotreadilytransferintofoodandecosystems.Thosethat
couldbesignificantforthefoodchainincluderadioactivehydrogen(3H),carbon(14C),technetium
(99Tc),sulphur(35S),cobalt(60Co),strontium(89Srand90Sr),ruthenium(103Ruand106Ru),iodine(131I
and129I),uranium(235U),plutonium(238Pu,239Puand240Pu),caesium(134Csand137Cs),cerium(103Ce),
iridium(192Ir),andamericium(241Am)(INFOSAN,2011).
Caesium137istheprimaryradionuclideofconcernregardingthelongtermcontaminationofforests
andforestproducts,owingtoits30yearhalflife(IAEA,2006;Riesen,2002).Thetransferof
radionuclidesintheenvironmentdependsontheparticularecosystem.Forestswithsoilsrichin
organicmatterandgenerallylowinclaycontentleadstoahighertransferofradiocaesiumtomost
forestproducts,suchasberriesormushrooms(Riesen,2002;FAO/IAEA,2011).
Overtime,radioactivitycanbuildupwithinfood,asradionuclidesaretransferredthroughsoilinto
cropsoranimals,orintorivers,lakesandtheseawherefishandotherseafoodcouldtakeupthe
radionuclides.Foodcollectedfromthewild,suchasmushrooms,berriesandgamemeat,may
continuetobearadiologicalproblemforalongtime(INFOSAN,2011).
Afteranuclearaccident,monitoringtheagricultural,forestryandfisheriesenvironmentand
restrictingthemovementandexportofpossiblycontaminatedproductsisanimportantfactor.
Implementationofsuchmonitoringcanbecomplex,expensiveandtechnicallydemandingand
requiresadvancetrainingandqualityassuranceoflaboratoryperformance.
OneofthemostwellknownandwellstudiedincidentsoccurredattheChernobylnuclearpower
plantintheUkraineon26April1986.Asuddenpowersurgeduringasystemstestcausedareactor
vesseltorupture,leadingtoaseriesofblasts.Anintensefireburnedfortendays.Substantial
radioactivecontaminationofforestsoccurredinBelarus,theRussianFederationandUkraine,but
radionuclidesfromChernobylwerecarriedintheatmosphereintoothercountriesinEuropeincluding
Austria,Bulgaria,Croatia,CzechRepublic,Finland,Germany,Greece,Hungary,Italy,Moldova,
Norway,Poland,Romania,Slovenia,Sweden,SwitzerlandandtheUnitedKingdom(FAO/IAEA,2011;
IAEA,2002;IAEA,2006).OtheraffectedareasincludedAsia(includingChina,Armenia,Georgia,
Turkey,UnitedArabEmirates),northernAfrica,andNorthAmerica(FAO/IAEA,2011).
ANTHROPOGENIC
TheExclusionZoneisa30kilometreareaofheavycontaminationaroundthesiteoftheChernobyl
nuclearreactordisaster.Wildlifeinthisareawereexposedtohighlevelsofradionuclidesviafood,
waterandair;levelsinsomeindividualsweremanyhundredtimeshigherthaninunaffected
populations(FAO/IAEA,2011).Manyindividualsthatremainedinthiszonediedfromradiation
inducedillnessesandtoday,mammals,birds,fishandamphibiansstillexhibitmorphological
deformitiesandgeneticdisorders(FAO/IAEA,2011).Veryhighlevelsofcontaminationonthe
canopiesofpinetreeswerenotedwithinasevenkilometreradiusofthereactor;thesetreesreceived
lethaldosesofradiation.ThissmallareaofforestbecameknownastheRedForest,asthetreesdied
andbecamereddishbrownincolour,themostobservableeffectofradiationdamageonorganismsin
thearea(IAEA,2006).
34
Inaffectedforests,therewasaninitialfilteringofcontaminantsbythetreecanopythoughcanopy
contaminationwasreducedrapidlyoveraperiodofweekstomonthsfromrainrunoffandleafor
needlefall(FAO/IAEA,2011;IAEA,2006).Thesoiloftheforestfloorbecamethemainrepositoryfor
radionuclidesandtreesandplantscontinuedtobecomecontaminatedthroughrootuptake.
Radiocaesiumcanberecycledintreesthroughrootuptakeandregularleaforneedlefall,andstored
longterminthetrunksofthetree(FAO/IAEA,2011).Forestfruitsandfungibecamecontaminated
withveryhighlevelsofCaesium137,whichledtoincreasedcontaminationofforestanimalssuchas
deerandmoose(FAO/IAEA,2011).SincetheChernobylaccidentithasbecomeapparentthatthe
naturaldecontaminationofforestsisproceedingextremelyslowly(IAEA,2006).Preventingwildfires
withintheExclusionZoneremainsahighprioritysincetheycouldreleasecloudsofradioactive
particlesthatstillpersistinthetrees.Smokefromfirescanspreadthousandsofkilometreswhich
couldsubstantiallyincreasetheareaofimpacttohumansandtheenvironment.
RadioactivecontaminationofforestsintheExclusionZoneatChernobyl,Ukraine.Thisforestbecameknownas
theRedForestasthetreesdiedandturnedreddishbrownincolour.
35
ANTHROPOGENIC
flickr/TIMMSUESS
Morerecently,on11March2011inJapan,amagnitude9.0earthquakeandassociatedtsunami
damagedthepowersystemsoftheFukushimaDaiichinuclearpowerplantcausingcoolingsystemsto
fail.Aseriesofgasexplosionsfollowed.ReportsfromtheGovernmentofJapanindicatedthatseveral
radionuclidesofconsequencetohumanhealth,includingIodine131andCaesium137,werefoundin
thesoil,vegetationandinanimals,ortheirproducts;someofwhichexceededacceptablelevels
(FAO/IAEA,2011).Whilenodatawereavailableattimeofprintontheimpactsofcontaminationon
forestsintheregion,lessonslearnedandprecautionarymeasuresleadtorecommendationsthat
peoplerefrainfromhunting,gatheringforestproductsandburningfuelwood.ThesituationinJapan
illustratestheseverityoftheimpactsofgeophysicaleventsoninfrastructurewherebyasophisticated
andwellpreparedsocietycanquicklyexperiencesituationsnormallyassociatedwithdeveloping
countries,suchaslargescalefoodshortages,waterandsheltercrises,logisticscollapseandthe
displacementofhundredsofthousandsofpeople.
CONCLUSIONS
Abioticdisturbancesarehavingmajorimpactsontreesandforestsandtherearemanysimilaritiesin
thetypesofimpactstheyhave,bothpositiveandnegative.Theyinfluenceforeststructure,
compositionandfunctioningandcanbeimportantformaintainingbiologicaldiversityandfacilitating
regeneration.Theymayhowever,occurascatastrophiceventsaffectingentirelandscapes,causing
largescaletreemortalityandcompletedestructionofundergrowthandsoils.Globalclimatechange
isexacerbatingmanyoftheseimpactsandthereisstillmajoruncertaintyabouttheinteractions
betweendisturbance,climatechangeandforests.InNovember2011,theIntergovernmentalPanelon
ClimateChange(IPCC)willreleaseaSpecialReportonmanagingtherisksofextremeeventsand
disasterstoadvanceclimatechangeadaptation.Thereportaimstobecomearesourcefordecision
makerstopreparemoreeffectivelyformanagingtherisksoftheseevents.
Whilethedamagecanbedevastatingintheshortterm,recoveryoftheforestsispossible.Forestsare
quiteresilientandwilleventuallyreturntoastablestate,thoughnotnecessarilytothesamestateas
predisturbance,overaperiodoftime.Whilethisisgoodnewsfromanecologicalpointofview,the
shorttermdamageisofconsiderableconcernforforestmanagerswhoaremaintainingforestsfora
specificpurpose,beitprotectiveorproductive.Inmanagedforests,damageresultsineconomic
losses.Inareaswheresuchdisturbancesareknownorpossibletooccur,managersmustincorporate
themintotheirmanagementplans.Sincesuchdisturbancesdonotrespectborders,regionalor
internationalcooperationisoftenrequired.
Abioticdisturbancesareexpectedtoincreaseinintensity,quantityandfrequency.Adaptiveforest
managementusingalandscapelevelapproachinvolvingallsectorsandstakeholdersistherefore
essentialtoprotecttheworld’sforestresources.Activitiessuchasdiversifyingspecies,using
windbreaksandmixedcroppingpatternsforresilienceandnotplantingsusceptiblespeciesinareas
pronetosuchdisturbanceswillhelpinthisregard.Moredataisneededandtheimpactsofabiotic
disturbancesonforestsmustberecordedandreportedsothatappropriateactionsmaybetakento
mitigatefuturedamage.Reducingtheimpactsofdisturbancesonforestswillcontributetocountries’
effortstoreducecarbonemissionsfromdeforestationandforestdegradationthroughforest
conservation,sustainableforestmanagementandenhancementofforestcarbonstocks(REDD+5).
Anotheritemofnoteforforestmanagersisthefactthattheconditionofforeststhemselvescanhave
aninfluenceondisturbances.Forexample,deforestationorpoormanagementpracticescanincrease
floodingandlandslidesduringcyclonesanddegradationofmangroveforestsmayincreasethe
damagethatstormsurgesortsunamiscause.Insomeareas,climatechangeisincreasingthe
incidenceofdroughtandheatwavesresultinginanincreasedriskandincidenceofwildfireswhichin
turn,contributestoglobalwarmingthroughcarbonemissions.Assuch,takingcareoftheworld’s
forestsandeffectivelymanagingthemnotonlyensuresthattheymeettheirobjectivesbutalso
reducestheriskofdamagefromfutureabioticdisturbancesandaddressesglobalclimatechange
concerns.
5
ReducingEmissionsfromDeforestationandForestDegradation(REDD)isanefforttocreateafinancialvaluefor
thecarbonstoredinforests,offeringincentivesfordevelopingcountriestoreduceemissionsfromforestedlands
andinvestinlowcarbonpathstosustainabledevelopment.“REDD+”goesbeyonddeforestationandforest
degradation,andincludestheroleofconservation,sustainablemanagementofforestsandenhancementof
forestcarbonstocks(UNFCC,DECISION1/CP.16).
36
REFERENCES
Adger,W.N.,Hughes,T.P.,Folke,C.,Carpenter,S.R.&Rockström,J.2005.Social–ecological
resiliencetocoastaldisasters.Science,309:1036–1039.
Allen,C.D.,Macalady,A.K.,Chenchouni,H.,Bachelet,D.,McDowell,N.,Vennetier,M.,Kitzberger,
T.,Rigling,A.,Breshears,D.D.,Hogg,E.H.,Gonzalez,P.,Fensham,R.,Zhang,Z.,Castro,J.,Demidova,
N.,Lim,JH.,Allard,G.,Running,S.W.,Semerci,A.&Cobb,N.2010.Aglobaloverviewofdrought
andheatinducedtreemortalityrevealsemergingclimatechangerisksforforests.ForestEcologyand
Management,259(4):660–684.
Allen,R.B.,Bellingham,P.J.&Wiser,S.K.1999.Immediatedamagebyanearthquaketoatemperate
montaneforest.Ecology,80(2):708–714.
Ayres,M.P.&Lombardero,M.J.2000.Assessingtheconsequencesofglobalchangeforforest
disturbancefromherbivoresandpathogens.ScienceofTheTotalEnvironment,262(3):263286.
Bebi,P.,Kienast,F.&Schönenberger,W.2001.Assessingstructuresinmountainforestsasabasisfor
investigatingtheforests’dynamicsandprotectivefunction.ForestEcologyandManagement,145:3–
14.
Bebi,P.,Kulakowski,D.&Rixen,C.2009.Snowavalanchedisturbancesinforestecosystems–State
ofresearchandimplicationsformanagement.ForestEcologyandManagement,257:1883–1892.
Bigler,C.,Braker,O.U.,Bugmann,H.,Dobbertin,M.&Rigling,A.2006.Droughtasaninciting
mortalityfactorinScotspinestandsoftheValais,Switzerland.Ecosystems,9:330–343.
Böer,B.1993.AnomalouspneumatophoresandadventitiousrootsofAvicenniamarina(Forssk.)
Vierh.mangrovestwoyearsafterthe1991GulfWaroilspillinSaudiArabia.MarinePollutionBulletin,
27:207–211.
Boose,E.R.,Serrano,M.I.&Foster,D.R.2004.LandscapeandregionalimpactsofhurricanesIn
PuertoRico.EcologicalMonographs,74(2):335–352.
Breda,N.,Huc,R.,Granier,A.&Dreyer,E.2006.Temperateforesttreesandstandsundersevere
drought:areviewofecophysiologicalresponses,adaptationprocessesandlongtermconsequences.
AnnalsofForestScience,63:625–644.
Breshears,D.D.,Cobb,N.S.,Rich,P.M.,Price,K.P.,Allen,C.D.,Balice,R.G.,Romme,W.H.,Kastens,
J.H.,Floyd,M.L.,Belnap,J.,Anderson,J.J.,Myers,O.B.&Meyer,C.W.2005.Regionalvegetationdie
offinresponsetoglobalchangetypedrought.ProceedingsoftheNationalAcademyofScienceUSA,
102:15144–48.
Burns,K.A.,Garrity,S.D.&Levings,S.C.1993.Howmanyyearsuntilmangroveecosystemsrecover
fromcatastrophicspills?MarinePollutionBulletin,26(5):239–248.
Butler,D.R.1979.Snowavalanchepathterrainandvegetationglaciernationalpark,Montana.Arctic,
Antarctic,andAlpineResearch,11:17–32.
Bytnerowicz,A.,Arbaugh,M.,Fenn,M.,SanchezGimeno,B.&Paoletti,E.2008.Introduction:
ForestsunderanthropogenicpressureEffectsofairpollution,climatechangeandurban
development.EnvironmentalPollution,155:389–390.
Bytnerowicz,A.,Omasa,K.&Paoletti,E.2007.Integratedeffectsofairpollutionandclimatechange
onforests:Anorthernhemisphereperspective.EnvironmentalPollution,147:438–445.
Carnicer,J.,Coll,M.,Ninyerola,M.,Pons,X.,Sánchez,G.&Peñuelas,J.2011.Widespreadcrown
conditiondecline,foodwebdisruption,andamplifiedtreemortalitywithincreasedclimatechange
typedrought.PNAS,108(4):1474–1478.
Chambers,J.Q.,Fisher,J.I.,Zeng,H.,Chapman,E.L.,Baker,D.B.&Hurtt,G.C.2007.Hurricane
Katrina'sCarbonFootprintonU.S.GulfCoastForests.Science,318(5853):1107.
37
Chapman,E.L.,Chambers,J.Q.,Ribbeck,K.F.,Baker,D.B.,Tobler,M.A.,Zeng,H.&White,D.A.2008.
HurricaneKatrinaimpactsonforesttreesofLouisiana'sPearlRiverbasin.ForestEcologyand
Management,256(5):883–889.
Clatterbuck,W.K.,Vandergriff,D.S.&Coder,K.D.2011.Treedamageandhazardassessment
Understandinglightningandassociatedtreedamage.Availableat:
essmextension.tamu.edu/treecarekit/index.php/afterthestorm/treedamageandhazard
assessment/understandinglightningandassociatedtreedamage/
Dale,V.H.,Joyce,L.A.,McNultyS.&Neilson,R.P.2000.Theinterplaybetweenclimatechange,
forests,anddisturbances.ScienceofTheTotalEnvironment,262(3):201–204.
Dalsgaard,B.,Hilton,G.M.,Gray,G.A.L.,Aymer,L.,Boatswain,J.,Daley,J.,Fenton,C.,Martin,J.,
Martin,L.,Murrain,P.,Arendt,W.J.,Gibbons,D.W.&Olesen,J.M.2007.Impactsofavolcanic
eruptionontheforestbirdcommunityofMontserrat,LesserAntilles.Ibis,149:298–312.
Doyle,T.W.,Michot,T.C.,Roetker,F.,Sullivan,J.,Melder,M.,Handley,B.&Balmat,J.2002.
HurricaneMitch:LandscapeAnalysisofDamagedForestResourcesoftheBayIslandsandCaribbean
CoastofHonduras.USGSOpenFileReport03175.
Emberson,L.2003.Chapter1:AirPollutionImpactsonCropsandForests:AnIntroduction.In:
Emberson,L.,Ashmore,M.&Murray,F.(eds),AirPollutionImpactsonCropsAndForests.AGlobal
Assessment.AirPollutionReviews,Vol.4.ImperialCollegePress,London.
ExxonValdezOilSpillTrusteeCouncil.2011.ExxonValdezOilSpillTrusteeCouncilWebsite.
Availableat:www.evostc.state.ak.us
Felzer,B.S.,Cronin,T.,Reilly,J.M.,Melillo,J.M.&Wang,X.2007.Impactsofozoneontreesand
crops,C.R.Geoscience.,339:784–798.
FAO.2007.FiremanagementGlobalassessment2006.Athematicstudypreparedintheframework
oftheGlobalForestResourcesAssessment2005.Rome.
FAO.2008.BangladeshEmergencylivelihoodprotectionandrehabilitation.Programmeappraisal
document.CycloneSIDR,November2007,DisasterNeedsAssessment.
FAO.2009.EvaluationoftheFAOResponsetothePakistanEarthquake,MayJuly2008FinalReport.
PreparedbyWatt,J.,Cossee,O.,Ahmed,J.,Khalid,N.,Riaz,M.&Shah,P.
FAO.2010.GlobalForestResourcesAssessment2010.Mainreport.FAOForestryPaperNo.163.
Rome.
FAO.2011.FAOTsunamireconstruction–forestryWebsite.Availableat:
www.fao.org/forestry/tsunami(Accessed06/03/11)
FAO/ECE/ILO.1995.Acuteforestdamagemanual:Managingtheimpactofsuddenandsevereforest
damage.DiscussionPaperNo.7.Geneva,FoodandAgricultureOrganization(FAO)/Economic
CommissionforEurope(ECE)&InternationalLabourOrganization(ILO).
FAO/IAEA.2011.JointFAO/IAEAProgrammeWebsite.Nucleartechniquesinfoodandagriculture
Availableat:wwwnaweb.iaea.org/nafa/index.html(Accessedon01/05/11)
Foster,D.R.,Knight,D.H.&Franklin,J.F.1998.Landscapepatternsandlegaciesresultingfromlarge,
infrequentforestdisturbances.Ecosystems,1(6):497–510.
Franklin,J.,Drake,D.R.,McConkey,K.R.,Tonga,F.&Smith,L.B.2004.TheeffectsofCycloneWaka
onthestructureoflowlandtropicalrainforestinVava‘u,Tonga.JournalofTropicalEcology,20:409–
420.
Fujita,T.T.1971.Proposedcharacterizationoftornadoesandhurricanesbyareaandintensity.
SatelliteandMesometeorologyResearchPaper91.DepartmentofGeophysicalSciences,Universityof
Chicago,Chicago,IL.
38
Gardiner,B.,Blennow,K.,Carnus,JM.,Fleischer,P.,Ingemarson,F.,Landmann,G.,Lindner,M.,
Marzano,M.,Nicoll,B.,Orazio,C.,Peyron,JL.,Reviron,MP.,Schelhaas,MJ.,Schuck,A.,
Spielmann,M.&Usbeck,T.2010.DestructiveStormsinEuropeanForests:PastandForthcoming
Impacts.FinalreporttoEuropeanCommissionDGEnvironment.
Guthrie,R.H.2002.Theeffectsofloggingonfrequencyanddistributionoflandslidesinthree
watershedsonVancouverIsland,BritishColumbia.Geomorphology,43:273–292.
Grishin,S.Y.2009.ForestdieoffundertheimpactofburningpyroclasticsurgeontheShiveluch
Volcano(Kamchatka,2005).RussianJournalofEcology,40(2):146–148.
Halpern,C.B.&Harmon,M.E.1983.EarlyplantsuccessionontheMuddyRivermudflow,MountSt.
Helens.AmericanMidlandNaturalist,110:97–106.
Halpern,C.B.,Frenzen,P.M.,Means,J.E.,Franklin,J.F.1990.Plantsuccessioninareasofscorched
andblowndownforestafterthe1980eruptionofMountSt.Helens,Washington.Journalof
VegetationScience,1:181–194.
Hansen,J.,Sato,M.,Ruedy,R.,Lacis,A.,Asamoah,K.,Borenstein,S.,Brown,E.,Cairns,B.,Caliri,G.,
Campbell,M.,Curran,B.,deCastro,S.,Druyan,L.,Fox,M.,Johnson,C.,Lerner,J.,McCormick,M.P.,
Miller,R.L.,Minnis,P.,Morrison,A.,Pandolfo,L.,Ramberran,I.,Zaucker,F.,Robinson,M.,Russell,
P.,Shah,K.,Stone,P.,Tegen,I.,Thomason,L.,Wilder,J.&Wilson,H.1996.APinatuboclimate
modelinginvestigation.In:Fiocco,G.,Fua,D.&Visconti,G.,eds.,TheMountPinatuboEruption:
EffectsontheAtmosphereandClimate,pp.233272.NATOASISeriesVol.42,SpringerVerlag.
Hanson,P.J.&Weltzin,J.F.2000.Droughtdisturbancefromclimatechange:responseofUnited
Statesforests.ScienceofTheTotalEnvironment,262(3):205–220.
Hensel,P.&Proffitt,C.E.2002.HurricaneMitch:acuteimpactsonmangroveforeststructureandan
evaluationofrecoverytrajectories:executivesummary:USGSOpenFileReport03182.
Hogg,E.H.&Bernier,P.Y.2005.ClimatechangeimpactsondroughtproneforestsinwesternCanada.
For.Chron.,81:675–682.
Hogg,E.H.,Brandt,J.P.&Michaelian,M.2008.Impactsofaregionaldroughtontheproductivity,
diebackandbiomassofwesternCanadianaspenforests.Can.J.For.Res.,38(6):1373–1384.
Hooper,M.C.,Arii,K.&Lechowicz,M.J.2001.Impactofamajoricestormonanoldgrowth
hardwoodforest.CanadianJournalofBotany,79:70–75.
Imaizumi,F.,Sidle,R.C.&Kamei,R.2008.Effectsofforestharvestingontheoccurrenceoflandslides
anddebrisflowsinsteepterrainofcentralJapan.EarthSurfaceProcessesandLandforms,33:827–
840.
InternationalAtomicEnergyAgency(IAEA).2002.Modellingthemigrationandaccumulationof
radionuclidesinforestecosystems.ReportoftheForestWorkingGroupoftheBiosphereModelling
andAssessment(BIOMASS)Programme,Theme3.Vienna.Availableat:www
pub.iaea.org/MTCD/publications/PDF/Biomass1_web.pdf
IAEA.2006.EnvironmentalConsequencesoftheChernobylAccidentandtheirRemediation:Twenty
YearsofExperience.ReportoftheChernobylForumExpertGroup‘Environment’.Vienna.
InternationalFederationofRedCrossandRedCrescentSocieties(IFRC&RCS).2010.World
DisastersReport–Focusonurbanrisk.Geneva.
InternationalFoodSafetyAuthoritiesNetwork(INFOSAN).2011.Informationonnuclearaccidents
andradioactivecontaminationoffoods.InformationNote30March2011.WorldHealthOrganization
andFAO.
InternationalHurricaneResearchCenter(IHRC).2011.IHRCWebsite.Availableat:
www.ihc.fiu.edu/index.htm(Accessed07/03/11)
InternationalTsunamiInformationCenter(ITIC).2011.ITICWebsite.Availableat:http://itic.ioc
unesco.org(Accessed07/03/11)
39
InternationalUnionforConservationofNature(IUCN).2006.EarthquakeinPakistan:AnAssessment
ofEnvironmentalRisksandNeeds.BasedonIUCNFieldMissionstoNWFPandAJK,November19–26
andDecember4–7,2005.Pakistan.
Irland,L.C.2000.Icestormsandforestimpacts.ScienceofTheTotalEnvironment,262(3):231–242.
Johnson,E.A.1987.Therelativeimportanceofsnowavalanchedisturbanceandthinningoncanopy
plantpopulations.Ecology,68,43–53.
Jump,A.S.,Mátyás,C.&Peñuelas,J.2009.Thealtitudeforlatitudedisparityintherangeretractions
ofwoodyspecies.TrendsinEcologyandEvolution,24:694–701.
Kajimoto,T.,Daimaru,H.,Okamoto,T.,Otani,T.&Onodera,H.2004.Effectsofsnowavalanche
disturbanceonregenerationofsubalpineAbiesmariesiiforest,northernJapan.Arctic,Antarctic,and
AlpineResearch,36,436–445.
Karnosky,D.F.,Percy,K.E.,Xiang,B.,Callan,B.,Noormets,A.,Mankovska,B.,Hopkin,A.,Sober,J.,
Jones,W.,DicksonR.E.&Isebrands,J.G.2002.InteractingelevatedCO2andtroposphericO3
predisposesaspen(PopulustremuloidesMichx.)toinfectionbyrust(Melampsoramedusaef.sp.
tremuloidae).GlobalChangeBiology,8:329–338.
Karnosky,D.F.,Pregitzer,K.S.,Zak,D.R.,Kubiske,M.E.,Hendrey,G.R.,Weinstein,D.,Nosal,M.&
Percy,K.E.2005.Scalingozoneresponsesofforesttreestotheecosystemlevelinachangingclimate.
Plant,CellandEnvironment,28:965–981.
Kauffman,J.B.&Cole,T.G.2010.Micronesianmangroveforeststructureandtreeresponsestoa
severetyphoon.Wetlands,30:1077–1084.
Khan,A.,Khan,M.A.,Said,A.,Ali,Z.,Khan,H.,Ahmad,N.&Garstang,R.2010.Rapidassessmentof
floodimpactontheenvironmentinselectedaffectedareasofPakistan.PakistanWetlands
ProgrammeandUNDPPakistan.
Kupfer,J.A.,Myers,A.T.,McLane,S.E.&Melton,G.N.2008.Patternsofforestdamageinasouthern
MississippilandscapecausedbyHurricaneKatrina.Ecosystems,11:45–60.
Laurance,W.F.&Curran,T.J.2008.Impactsofwinddisturbanceonfragmentedtropicalforests:A
reviewandsynthesis.AustralEcology,33:399–408.
Lugo,A.E.2008.Visibleandinvisibleeffectsofhurricanesonforestecosystems:aninternational
review.AustralEcology,33,368–398.
Magnusson,W.E.,Lima,A.P.&deLima,O.1996.GrouplightningmortalityoftreesinaNeotropical
forest.JournalofTropicalEcology,12:899–903.
Marske,K.A.,Ivie,M.A.&Hilton,G.M.2007.Effectsofvolcanicashontheforestcanopyinsectsof
Montserrat,WestIndies.EnvironmentalEntomology,36(4):817–25.
Martin,T.J.&Ogden,J.2006.WinddamageandresponseinNewZealandforests:areview.New
ZealandJournalofEcology,30(3):295–310.
MillenniumEcosystemAssessment(MEA).2005.Ecosystemsandhumanwellbeing:Currentstate
andtrends.MillenniumEcosystemAssessmentSeriesVol.1.IslandPress,WashingtonDC.
MinisterialConferenceontheProtectionofForestsinEurope(MCPFE).2007.StateofEurope's
Forests2007:theMCPFEreportonsustainableforestmanagementinEurope.Jointlypreparedby
(MCPFE)LiaisonUnitWarsaw,UnitedNationsEconomicCommissionforEurope(UNECE),andFood
andAgricultureOrganizationoftheUnitedNations(FAO).Warsaw.
Munck,I.A.,Bennett,C.M.,Camilli,K.S.&Nowak,R.S.2010.Longtermimpactofdeicingsaltson
treehealthintheLakeTahoeBasin:Environmentalinfluencesandinteractionswithinsectsand
diseases.ForestEcologyandManagement,260(7):1218–1229.
NationalOceanicandAtmosphericAdministration(NOAA).2010.Oilspillsinmangroves:planning
andresponseconsiderations.Hoff,R.(ed).Washington,DC.Availableat:
response.restoration.noaa.gov/book_shelf/34_mangrove_complete.pdf
40
NOAA.2011.HurricaneResearchDivision.Availableat:www.aoml.noaa.gov/hrd/tcfaq/A1.html
(Accessed05/03/11)
NOAA/NationalWeatherService(NWS).2011.StormPredictionCentreMonthlyandAnnualU.S.
TornadoSummaries.Availableat:www.spc.noaa.gov/climo/online/monthly/newm.html
Nykänen,ML.,Peltola,H.,Quine,C.,Kellomäki,S.&Broadgate,M.1997.Factorsaffectingsnow
damageoftreeswithparticularreferencetoEuropeanconditions.SilvaFennica,31(2):193–213.
OfficefortheCoordinationofHumanitarianAffairs(OCHA).2011.SouthernAfricaFloodandCyclone
SituationUpdate#13.IssuedbytheRegionalOfficeforSouthern&EasternAfrica(ROSEA).Available
at:reliefweb.int/sites/reliefweb.int/files/reliefweb_pdf/node400015.pdf
Oswalt,S.N.&Oswalt,C.M.2008.Relationshipsbetweencommonforestmetricsandrealized
impactsofHurricaneKatrinaonforestresourcesinMississippi.ForestEcologyandManagement,255:
1692–1700.
Päätalo,ML.1998.FactorsinfluencingoccurrenceandimpactsoffiresinnorthernEuropeanforests.
SilvaFennica,32(2):185–202.
ParkWilliams,A.,Allen,C.D.,Millar,C.I.,Swetnam,T.W.,Michaelsen,J.,Still,C.J.&Leavitt,S.W.
2010.ForestresponsestoincreasingaridityandwarmthinthesouthwesternUnitedStates.PNAS,
107(50):21289–21294.
Patel,E.R.2007.Loggingofrarerosewoodandpalisandre(Dalbergiaspp.)withinMarojejyNational
Park,Madagascar.MadagascarConservation&Development,2(1):103–112.
Peñuelas,J.,Lloret,F.&Montoya,R.2001.SeveredroughteffectsonMediterraneanwoodyflorain
Spain.ForestScience,47:214–218.
Peterson,C.J.2000.CatastrophicwinddamagetoNorthAmericanforestsandthepotentialimpactof
climatechange.ScienceofTheTotalEnvironment,262(3):287–311.
Peterson,C.J.2007.Consistentinfluenceoftreediameterandspeciesondamageinnineeastern
NorthAmericatornadoblowdowns.ForestEcologyandManagement,250:96–108.
Pierson,T.C.,Janda,R.J.,Thouret,JC.,&Borrero,C.A.1990.Perturbationandmeltingofsnowand
icebythe13November1985eruptionofNevadodelRuiz,Colombia,andconsequentmobilization,
flow,anddepositionoflahars.JournalofVolcanologyandGeothermalResearch,41:17–66.
Raffa,K.F.,Aukema,B.H.,Bentz,B.J.,Carroll,A.L.,Hicke,J.A.,Turner,M.G.&Romme,W.H.2008.
Crossscaledriversofnaturaldisturbancespronetoanthropogenicamplification:thedynamicsof
barkbeetleeruptions.Bioscience,58:501–517.
RescodeDios,V.,Fischer,C.&Colinas,C.2007.ClimatechangeeffectsonMediterraneanforestsand
preventivemeasures.NewForests,33:29–40.
Restrepo,C.,Walker,L.R.,Shiels,A.B.,Bussmann,R.,Claessens,L.,Fisch,S.,Lozano,P.,Negi,G.,
Paolini,L.,Poveda,G.,RamosScharrón,C.,Richter,M.&Velázquez,E.2009.Landslidingandits
multiscaleinfluenceonmountainscapes.BioScience,59:685–698.
Riesen,T.K.2002.Radiocaesiuminforests:Areviewonmostrecentresearch.EnvironmentalReview,
10:79–90.
RiskManagementSolutions(RMS).2007.TheGreatStormof1987.Availableat:
www.rms.com/Publications/Great_Storm_of_1987.pdf
Salisbury,H.E.1989.TheGreatBlackDragonFire:AChineseInferno.Little,BrownandCompany,
BostonMA,USA.
Schelhaas,M.J.,Nabuurs,G.J.&Schuck,A.2003.NaturaldisturbancesintheEuropeanforestsinthe
19thand20thcenturies.GlobalChangeBiology,9(11):1620–1633.
Schuster,R.L.&Highland,L.M.2001.Socioeconomicandenvironmentalimpactsoflandslidesinthe
WesternHemisphere.U.S.GeologicalSurveyOpenFileReport010276.
41
Schuster,R.L.&Highland,L.M.2004.Impactoflandslidesandinnovativelandslidemitigation
measuresonthenaturalenvironment.InternationalConferenceonSlopeEngineering,HongKong,
China,810December2003.Keynoteaddress,Proceedings29.Availableat:
pubs.usgs.gov/op/HongKongJuly/HongKongJuly21sm.pdf
Seidl,R.,Fernandes,P.M.,Fonseca,T.F.,Gillet,F.,Jöhnsson,A.M.,Merganiová,K.,Netherer,S.,
Arpaci,A.,Bontemps,J.D.,Bugmann,H.,GonzálezOlabarria,J.R.,Lasch,P.,Meredieu,C.,Moreira,
F.,Schelhaas,M.&Mohren,G.M.J.2011.Modellingnaturaldisturbancesinforestecosystems:a
review.EcologicalModelling,222(4):903–924.
Sidle,R.2005.Influenceofforestharvestingactivitiesondebrisavalanchesandflows.In:Jakob,M.&
Hungr,O.eds.Debrisflowhazardsandrelatedphenomena,pp.387409.Praxis,SpringerBerlin
Heidelberg.
Sivakumar,M.V.K.,Motha,R.P.&Das,H.P.(eds.)2005.Naturaldisastersandextremeeventsin
agriculture:impactsandmitigation.SpringerVerlagBerlinHeidelberg,NewYork.
Srinivasa,H.&Nakagawa,Y.2008.Environmentalimplicationsfordisasterpreparedness:Lessons
learntfromtheIndianOceanTsunami.JournalofEnvironmentalManagement,89:4–13.
Stanturf,J.A.,Goodrick,S.L.&Outcalt,K.W.2007.Disturbanceandcoastalforests:Astrategic
approachtoforestmanagementinhurricaneimpactzones.ForestEcologyandManagement,250:
119–135.
StateForestryAdministration.2008.BlizzarddamageonforestryinChina.Translationofreport
preparedbyStateForestryAdministration,China.
Teague,B.,McClead,R.&Pascoe,S.2009.2009VictorianBushfireRoyalCommissionInterimReport.
Australia:GovernmentPrinterfortheStateofVictoria.
TripartiteCoreGroup(TCG).2008.PostNargisJointAssessment.AreportpreparedbytheTripartite
CoreGroupcomprisedofrepresentativesoftheGovernmentoftheUnionofMyanmar,theUnited
NationsandAssociationofSoutheastAsianNations(ASEAN)withsupportofthehumanitarianand
developmentcommunity.
Turner,M.G.2010.Disturbanceandlandscapedynamicsinachangingworld.Ecology,91(10):2833–
2849.
Turner,M.G.,Dale,V.H.&Everham,III,E.H.1997.Fires,hurricanes,andvolcanoes:comparinglarge
disturbances.BioScience,47(11):758–768.
UnitedNationsConventiontoCombatDesertification(UNCCD).2002.GlobalAlarm:Dustand
sandstormsfromtheworld’sdrylands.Editedby:Youlin,Y.,Squires,V.andQi,L.Availableat:
www.unccd.int/publicinfo/duststorms/globalAlarmeng.pdf
UnitedNationsEducational,ScientificandCulturalOrganization(UNESCO).2011.WorldHeritage
ConventionWebsite.Availableat:whc.unesco.org/en/list/798(Accessed31/05/11)
UnitedNationsEnvironmentProgramme(UNEP).2005.Afterthetsunami:rapidenvironmental
assessmentreport.Availableat:www.unep.org/tsunami/reports/TSUNAMI_report_complete.pdf
UNEP.2011.UNEPYearBook2011:Emergingissuesinourglobalenvironment.UnitedNations
EnvironmentProgramme,Nairobi.Availableat:www.unep.org/yearbook/2011
UnitedStatesGeologicalSurvey(USGS).2005.Thecataclysmic1991eruptionofMountPinatubo,
Philippines.USGSFactSheet11397.Availableat:pubs.usgs.gov/fs/1997/fs11397/(updated
28/02/05)
USGS.2011.VolcanoHazardsProgram.Availableat:volcanoes.usgs.gov(Accessed08/05/11)
Usbeck,T.,Wohlgemuth,T.,Dobbertin,M.,Pfister,C.,Bürgi,A.&Rebetez,M.2010.Increasing
stormdamagetoforestsinSwizerlandfrom1858to2007.AgriculturalandForestMeteorology,150:
47–55.
42
vanMantgem,P.J.,Stephenson,N.L.,Byrne,J.C.,Daniels,L.D.,Franklin,J.F.,Fulé,P.Z.,Harmon,
M.E.,Larson,A.J.,Smith,J.M.,Taylor,A.H.&Veblen,T.T.2009.Widespreadincreaseoftree
mortalityratesinthewesternUnitedStates.Science,323:521–524.
Vittoz,P.,Stewart,G.H.&Duncan,R.P.2001.EarthquakeimpactsinoldgrowthNothofagusforests
inNewZealand.JournalofVegetationScience,12:417–426.
Whittaker,R.J.,Bush,M.B.&Richards,K.1989.Plantrecolonizationandvegetationsuccessionon
theKrakatauIslands,Indonesia.EcologicalMonographs,59:59–123.
Williams,J.,Albright,D.,Hoffmann,A.A.,Eritsov,A.,Moore,P.F.,CarlosMendesDeMorais,J.,
Leonard,M.,SanMiguelAyanz,J.,Xanthopoulos,G.&VanLierop.,P.2011.Findingsand
implicationsfromacoarsescaleglobalassessmentofrecentselectedmegafires.Paperpresentedat
the5thInternationalWildlandFireConference,SunCity,SouthAfrica,9–13May2011.
WorldMeteorologicalOrganization(WMO).2011.WMOWebsite.Availableat:www.wmo.int
(accessed06/03/11)
Xu,W.,Wang,X.,Ouyang,Z.,Zhang,J.,Li,Z.,Xiao,Y.&Zheng,H.2009.Conservationofgiantpanda
habitatinSouthMinshan,China,aftertheMay2008earthquake.FrontiersinEcologyandthe
Environment,7(7):353–358.
ZabkaM.&NentwigW.2002.TheKrakatauislands(Indonesia)asamodelareaforzoogeographical
study,aSalticidae(Arachnida:Araneae)perspective.AnnalsZoologici(Warszawa),52:465–474.
Zhao,M.&Running,S.W.2010.Droughtinducedreductioninglobalterrestrialnetprimary
productionfrom2000through2009.Science,329(5994):940–943.
43
44