BLUMEA 43 (1998) 121-127 Thatelm again! Ulmus at Pea Bullok, North Sumatra, and regional comparisons B.K.Maloney PalaeoecologyCentre,Queen'sUniversity, Belfast,Northern Ireland Summary Details ofapalynologicalrecord ofUlmusinNorth Sumatra extendingfrom c. 21,250B.P.are presentedand comparedwith recent findingsfromJava and Sulawesi (Table 1). Thereappearto benorecords ofUlmuspre-dating thePleistocene inSoutheastAsia (Muller, 1981;Caratini&Tissot, 1985;Watanasak, 1990).Four-pored Ulmuspollen wasfirstreportedby Maloney (1984) fromtheradiocarbondatedsitesofPeaSimsim andTao Sipinggan andthe thenundatedPeaSijajap record.Itwassubsequently also foundatSibisaSwamp (Maloney, 1985).Morerecently, fossilUlmuspollen was dis- coveredatsites inWest Java(Stuijts, 1993;VanderKaars &Dam, 1995).Two cores fromPeaBullok, NorthSumatra,havenowbeenanalysed andUlmusoccurredintwo samples,onesamplefromeach core.With 18radiocarbondates,thePeaBullokcores are nowthebest dated deposits fromIndonesia(Maloney & McCormac, 1996)and theolder ofthetwo cores, CoreA, fromthe edge ofthe site, datesback to about 30,000B.P. atitsbase,while thesectionofthecore fromthecentre (Core B) isabout 20,000yearsoldat3.50m depthandthereisanotherhalfmetre intactwhichremains to beanalysed andradiocarbondatedatsome futuretime. FourradiocarbondateshavenowbeenobtainedfromtheshortPeaSijajap core.Its base isabout4000yearsoldandthesingle occurrence ofUlmuspollendatestoaround 2135 B.P. Insufficientorganic materialis availableto date Sibisa. Torecap briefly on the earlierfindings, all theNorthSumatran sitesreported upon, including PeaBullok, are on thehigh Toba Plateau.Sibisa Swamp is nearParapat, northofthelake,buttheothersites aresouthofLakeToba.PeaSim-sim,TaoSipinggan and Pea Bullok are all atc. 1400m altitude.Pea Sijajap is at about one hundred metres lowerinthedownfaultedSimamoravalleytothewestofPeaSim-simandTao Sipinggan whicharenearLintongnihutaPardolaan(the newvillageofLintongnihuta). SibisaSwamp isalso atabout 1300maltitude. PeaBullokislocatedapproximately 2km northofSiborongborong ontheeastside oftheroadtoBalige. Thesiteappearsto beanextinct volcaniccrateranditisinfilled totherimwithpeats. Unfortunately,becauseoftheamountofwoodinthestratigraphy, itwas impossible toobtainacomplete core tothebase ofthe depositeitherfrom the 122 BLUMEA—VoI.43, No. 1, 1998 Fig. 1.Locationofpollensitesmentioned inthetextandmajorareasofseasonal drought(hatched) and drypockets (dots).Base map adaptedfrom Van Steenis (1979: 107,fig. 5). centreor theedge butsincethereis approximately 30,000yearsofpeataccumulation attheedge, it is likely that thecraterformed duringthelast majoreruption ofToba whichhasbeendated(Chesneretal„ 1990)atc. 74,000B.P. Onespecies ofelm, UlmuslanceifoliaRoxb.ex Wall.(Touw &Van Steenis, 1968) hasbeenreported fromtheTobaareabutnoUlmushasbeenfoundinJava(Backer & Bakhuizen van den Brink, 1965), although it does occur in Flores and Sulawesi (Soepadmo, 1977).VanSteenis (1979: 145) statedthatwhere Ulmus was presentin theLesser SundaIslandsitwasinlocalisedwetpockets andmay bea chancerelictof aformermuchricherandmoreextensiverainforestfloraratherthan anewinvader. Therecord fromPeaSim-sim,theolderofthepreviously analysed sitesfromNorth Sumatra,showedthatUlmuspollen wascontributing sporadically tothefossilpollen record fromabout 16,100B.P. (this is arevisionofthe 15,700B.P.estimate forthe 6.75m depth given in Maloney, 1984)andto theTaoSipinggan record fromthebe- ginning ofdeposition slightly over 12,000years ago. AtPeaBullokonepollengrainwas presentinasamplewhichisabout21,250years old from CoreA and anotherfrom alevel dating to approximately 17,850B.P. in B.K.Maloney: Ulmus atPea Bullok,North Sumatra 123 CoreB sample. Vander Kaars& Dam(1995: 69) dismisslong-distance transportof pollen in theirexplanation ofthe findings from Lake Bandung but a sample from CoreB containedapollen grainofAbies(identification confirmedbyDr.V.A.Hall). This is extremely unlikely to bea contaminantas no samples containing firpollen wereprepared inour laboratoryaroundthetimeatwhichthismaterialwaspretreated andsampletubes arerigorously cleanedafteruse. Thepollengrainmust,presumably, havebeen transported out ofmainlandAsia by theNE monsoon and demonstrates thattherehasbeensomelong-distance transportofpollen. Schmidt(1974: 187)stated that Abies is only foundabove 22° N in Vietnam (it is present at altitudesofover 2000 mintheFan Si Pan massif). Turning to the Javanesereports, Stuijts(1993) found Ulmuspollen attwo of her sites: RancaUpas (c. 1750m), whichhasa 10,000yearoldpollenrecord, andKawah Putih(2200 m),whichis undatable.Ulmus was presentinfive samples fromRanca Upasincluding oneofprobableveryrecent ageandintwo samples fromKawahPutih. However,intheseinstancesthepollengrains hadbetweenfourandsixpores,notjust fourpores as inthecaseofall the Sumatranelm pollen grains, so thepossibility of laboratory contaminationbypollen grainsfromaEuropean sourcecannotbeexcluded1, butRancaUpas is locatedonly 55km southwestofBandung whileKawahPutih is situatedabout 10km northeastofGunung Pangrango. As faras long-distance trans- port is concerned,Stuijts (1993: 32) foundelmpollen inamodernsample fromthe topofGunung Pangrango ata heightof3020m,i.e. whereitcouldhavebeentrans- portedeitherfrommainlandAsiaor,perhaps, Floresor Sulawesi.Interestingly, Ulmus (pollen morphology undescribed) has only been reported once (Gremmen, 1990: fig.2)fromSulawesi(ithasa0.1%representation inspectrum27,whichpost-dates a radiocarbondateof2610±50B.P. atRawaLampulung). Itwas not foundin any of the20 surfacesamples analysed fromhighland NorthSumatrabutoccurred attrace levels(Beuning, 1996:16)in two lakes fromEast Java.Thiswriteris inclinedto sug- gestthathereweareprobably dealing withlong-distance transportofpollen, andthis is analternativeexplanation foralltheNorthSumatranfinds. Beuning lists thispos- sibilityas oneofthreeforherfinds.Theothertwo are thatelmdoesgrowinEastJava andcontaminationwithNorthAmericanUlmusduringchemicalpre-treatmentofsam- ples. She discountsthelatterbecauseofStuijts' finds. Thesamecannotbesaidconcerning thereportbyVanderKaars& Dam(1995)from theBandung area. They triedtomaketotal tree pollen counts ofapproximately 300, but sometimes it was not possible to count beyond 100.Where Ulmusoccurred, it ranged upto5-10% oftotaltree pollen incoresDPDR-I andDPDR-II,andupto20% insamples froma quarrysection (Van derKaars&Dam, 1995:69). Herethelikeli- hoodoflong-distance transportisremote. 1) Data onthe distribution ofelm and onthe pollenmorphologyofAsian-Southeast Asianelm speciesisnotplentiful, soitis notpossibleto statedefinitivelythat 5-or6-pored pollengrains areabsent.However,Nair (1965:39,pi. XIV,fig. 177)states thatUlmuswallichiana Planch, is (4-)5-porateandHuang(1972:235,pi. 154:25-30)showsthatUlmusparvifloraJacq.has4or 5 pores. 124 BLUMEA Vol.43, No. 1,1998 Table 1a.Finds offossil Ulmus from SoutheastAsiaand theirestimated ages. LLooccaattiioonn AAllttiittuuddee DDeepptthh PPeerrcceennttaaggeeooff NNuummbbeerr EEssttiimmaatteedd aaggee ((mm)) ((ccmm)) ppoolllleennssuumm ooffggrraaiinnss ((yyeeaarrssBB..PP..)) SSUuMmAaTtRraA PPeeaaBBuullllookkCCoorreeAA 11440000 446655 00..1188 1 2211225500 PPeeaaBBuullllookkCCoorreeBB 11440000 223355 00..2277 1 1177885599 PPeeaaSSiimm--ssiimm 11440000 667755 00..2299 1 1155770000 447755 11..0022 1 1122220044 226600 00..6655 1 88558888 111100 00..1133 1 33990000 TTaaooSSiippiinnggggaann 11440000 992200 00..4499 1 1122113300 447700 11..0033 1 33550000 225555 00..8833 1 11550000 PPeeaaSSiijjaajjaapp 11330000 6655 00..2200 11 22113355 SSiibbiissaa cc.. 11330000 114455 00..1188 22 uunnddaatteedd JJAaVvAa SSiittuuGGuunnuunngg:: UUllmmaacceeaaee cc.. 11005500 662255 00..7700 33 66557744 552255 00..2200 11 55666655 551100 00..4400 11 55552288 225500 00..6600 22 44665500 115500 00..1100 11 22779900 110000 00..2200 11 11886600 TTeellaaggaaSSaaaatt 11445500 UUllmmuuss 2211(01 11..9900 22 22222211 SSiittuuBBaayyoonnggbboonngg 11330000 UUllmmuuss 552255 00..2200 11 1111880066 UUllmmaacceeaaee 773300 00..3300 11 1155882299 RRaannccaa UUppaassIIII cc.. 11775500 UUllmmaacceeaaee 667755 00..5500 11 88667722 662255 00..3300 11 88334455 33S8O0 00..3300 11 55991177 222200 00..3300 11 44226622 RRaannccaa UUppaassddiiaaggrraamm UUllmmuuss 7755 994400 117700 33664477 338800 55991177 662255 88334455 880000 99449900 884400 99889955 997755 1100116622 11002255 1100336600 11007700 11112200 11116600 11220000 11227755 1100338800 11330000 TTeellaaggaaPPaatteennggaannII 11557755 UUllmmaacceeaaee 334400 00..3300 11 11992222 333300 11..0000 66 11886644 B.K.Maloney: Ulmus atPea Bullok,North Sumatra 125 (Tablelacontinued) LLooccaattiioonn AAllttiittuuddee DDeepptthh PPeerrcceennttaaggeeooff NNuummbbeerr EEssttiimmaatteeddaaggee ((mm)) ((ccmm)) ppoolllleennssuumm ooffggrraaiinnss ((yyeeaarrssBB..PP..)) TTeellaaggaaPPaatteennggaannIIII::aabbsseenntt TTeellaaggaaPPaatteennggaannIIIIII UUllmmaacceeaaee 11007755 00..3300 1 44881144 UUltmmuuss 11006600 00..3300 1 44773366 UUllmmaacceeaaee 11004400 00..3300 1 44663300 UUllmmuuss 669900 00..2200 1 22774411 UUllmmaacceeaaee 772200 00..3300 1 33000000 UUllmmuuss 221100 00..4400 1 11005500 UUllmmaacceeaaee 116600 00..2200 1 880000 KKaawwaahhPPuuttiihn 22220000 UUllmmuuss 225500 ttrraaccee 115500 ttrraaccee ((SShhoowwnnoonnddiiaaggrraamm,,nnoottttaabbuullaatteedd)) SSiittuuCCiihhaarruuss II 11552255 UUllmmuuss 11550000 00..1100 11((7?)) 99004411 SSiittuuCCiihhaarruuss IIII UUllmmuuss 337700 00..1100 11((7?)) 11339911 UUllmmaacceeaaee 335500 00..1100 11((7?)) 11228899 UUllmmuuss 330000 00..1100 11((7?)) 11003366 SSUuLlaAwWeEsSiI RRaawwaaLLaammppuulluunngg UUllmmuuss 554400 00..1100 11((7?)) 11990000 Table 1b. FindsofmodernUlmuspollenfrom SoutheastAsia. Location Altitude Percentageof Number (m) pollensum ofgrains GunungPangrango 3010 1.00 1 RancaUpas c. 1750 0.40 1 Waduk Wlingi,southofGunungKelud 110 trace RanuLading,southwestsideofGunungLamongan 350 trace Thepollensumusedtocalculatethe Sumatranfigureswastotaldrylandpollenplus Cyatheaceae whilethatusedfor the Javanand Sulawesi sampleswastotalarboreal pollen.Ulmus mayhave beenexcludedfromthe SituCiharuspollensumbecauserecalculationusingStuijts' published arborealpollentotals givespercentageshigherthan 0.10. The number ofpollengrainsfoundis solow thatthe differenceinmethodofcalculatingtheresults is notvery important.Raw data fromVan derKaars&Dam's diagramshave notbeenpublishedand accuratepercentagescould notbe derived from Stuijts' Ranca Upaspublisheddiagram so tabulationwas not possible. Estimatedages werecalculatedusingthe depthofthe centre ofthe sampleand disregarding the errorofthe determination. 126 BLUMEA—V01.43, No. 1, 1998 Ulmus mainly occurs in thelowlandandsubmontaneforests of seasonally dryareas between200-1450maltitude(Soepadmo, 1977),although, according toVanderKaars & Dam(1995)itispresentinriparianforestinThailand(no source given, elmhasnot yetbeenconsideredinFloraofThailand).FourvernacularnamesforUlmuslanceifolia Roxb.are listed by Smitinand(1980), andall ofthem northern.Santisuk (1988: 29) hasreported itfromthe middletree layerofseasonalforest and(I.e.: 33) thecanopy layer oflowermontane forest.It is amongtaxareplacing fagaceous trees in shady ravinesofthelowermontaneforestarea(1.c.:34) althoughitisnot statedtoberiverine, butitdoesgrowonvalleyslopes. Smitinand(1966: 115)foundwhatmaybeU. lancei- foliaatc. 1800maltitudeonanopenlimestoneridge atDoiChiengdao. Stuijts(1993: 32)recordsapersonal communicationfromthelateProfessor vanSteeniswhichstated that Ulmus grows in regions subject to some extent to a seasonal climate: Flores, Sulawesi and northern Sumatra. Nevertheless, Van Steenis (1979: 145) notedthat Ulmuswas amongrainforesttaxa whichoccurred inlocalwet pockets intheLesser SundaIslands andthatthesewere probably chancerelictsofaoncemuchricher and moreextensiverainforestfloraratherthannewinvaders. NorthSumatra,exceptthe rainshadowarea atc.900maltitudearoundLakeToba,cannotberegarded as season- ally dry. A pollen indicator forseasonal dryness in island Southeast Asia wouldgreatly aid palaeoclimatic reconstruction. Ulmushasrelatively highpercentagesintheBandung area betweenabout81,000-74,000B.P., a drierperiod, but it is also frequent in a humidperiod pre-dating 81,000B.P.Thehighpercentagessuggestlocaloccurrence, but, becauseofpossible overlapping dryland-riparian ecologies, theelm onitsown cannot be regarded as areliableindicatorofseasonal dryness while itspresence at background frequencies during theperiod ofLatePleistocene coolerconditionsin NorthSumatradonotjustifyarguingacase forincreasedseasonality ofclimatethere, especially as Pea Bullok must have been in the cloud forest belt (Maloney & McCormac, 1996)for atleast partofthistime.Indeed, ifVan Steenis(1979) is cor- rect, itmay beabetterindicatorfortheoccurrence oflocalisedwetter areas. REFERENCES Backer,C.A. &R.C. Bakhuizen vanden Brinkf. 1965.FloraofJava2.Groningen. Beuning,K.R.M. 1996.Modempollenrain,vegetationandclimate inlowland EastJava,Indone- sia. Modern QuaternaryResearch in Southeast Asia 14: 1-51. 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