Rev. Biol. Trop., 41 (1): 47-56,1993

Recovery following clearing of an upper montane Quercus forest in Costa Rica

Maarten Kappelle H. de Vries Laboratory, University of Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands.

(Rec. 25-V1-1992. Acep. 25-IX-1992)

Abstrad: Pattems in recovery following clearing of upper montane Quercusforests (2900 - 3000m alt.) in the Costa Rican Cordillera de Talamanca have been studied and four different successional forest phases (pioneer, ear1y succes­ sional, rnid-successional, mature) have been distinguished. Arboreal species richness increases during succession being largest in lhe mid-successional forest phase. Woody Asteraceae dominate lhe ear1y secondary phases, while Araliaceae, Lauraceae and to a lesser extent Myrsinaceae become prominent in later phases including lhe mature sta­ ge. Quercusrecovers largely, being the dominant genus in mid-successional and mature foresto Young secondary pha­ ses are rich in rapid-growing light-demanding canopy species, while more developed multi-layered phases are domi­ nated by a large number of shade-tolerant subcanopy species. In general, secondary succession may lead (within a pe­ riod of approximately 35 years after clearing and abandonment) to an amoreal recovery ofabout 70 % of the original tree species composition in mature f orest.

Key words: Costa Rica, disturbance, montane, Quercus, recovery, seccondary succession, tropical foresto

During the last few decades tropical monta­ Cordillera de Talamanca. They have been se­ ne forests have been cleared and degraded on a lected for the present study since different stu­ broad seale (Budowski 1968, Monasterio et al. dies on their botany and ecology have become 1987). Recovery after clearing of these forests available during the last five years (e.g. Blaser is eonsiderably sIowed down by low tempera­ 1987, Jiménez et al. 1988, Van Velzen and tures due to the diurnal climate prevailing in Wijtzes 1990, Kappelle 1992, Kappelle el al. the montane tropies. At present there is little 1989, 1991, 1992). On this occasion the preli­ knowledge about this proeess in the pluvial ne­ mínary results of this study are presented, thus otropieal upper montane forest belt. Indeed, offering a first outline of forest recovery in the most studies on neotropical forest sueeession Costa Rican upper montane vegetation belt. following clearing and abandonment have been eonducted in lowland rain forest (e.g. Ewel 1980, Gómez-Pompa and Del Amo 1985, MATERIAL AND MET HODS Purata 1986, Saldarriaga 1988, Toro and Saldarriaga 1990, Brown and Lugo 1990) or in The study area is situated in the Cordillera mid-elevation eloud forests (e.g. Byer and de Talamanca, which is formed of intrusive, Weaver 1977, Sugden et al. 1985). and Tertiary volcanic roeks, alternated with To fill this gap, a study of the patterns in re­ marine sediments (WeyI 1980, Castillo 1984, covery after clearing of neotropieal upper mon­ Kappelle et al. 1989). Pleistoeene glaciations tane forest has reeently been initiated in pri­ have left its traces such as fossil periglacial mary (mature) and seeondary (reeovering) phenomena on the Cerro de la Muerte (3491 m Quercus forests. These high-elevation forests alt.) at the nearby Buenavista massif blanket large parts of the Atlantíc and Paeific (Hastenrath 1973). Soils sustaining montane slopes of the western part of the Costa Rican Quercus forests are developed from volcanic 48 REVISTADE BIOLOGIAmOPICAL ashes, medium-textured, moderately fertile, oscillated between 9.8 and 11.2 oC, a range very acid and excessively drained (Vásquez verysimilar to thevalue at, the above-mentioned 1983, Van Uffelen 1991). Average annual tem­ Villa Mills station. Before abandonment and re­ peratureat the nearbytown of VillaMills (3000 covery, all secondary forest patches selected o m as.l.) is 10.9 C, while average rainfall is had been used for dairy cattle grazing during a 2812 mm (Instituto Meteorológico Nacional period of 5 to 10 yr following clearing and bur­ 1988). Diurnal mist during the aftemoons is ning. In order 10 avoid significant differences in considerable (cloud forest), especially during propagule input (primaryspecies invasion) from the rainyseason (Mayto November). nearby matureforest. sites sustaining secondary Sample sites are located in the highly defo­ forest were selected within a range of 200 to rested 62,000 ha Los Santos Forest Reserve in 400m distanceto primary foresto the westem partof theCordillera de Talamanca D 0 Three subsequent recovering forest phases (9 35'40"N, 83 44'30''W). This protected area of different ages since abandonment as well as created in 1975 (Meza and Bonilla 1990) ser­ a mature forest phase for reference purposes ves since 1982 as a buffer rone to the612,570 were examined. Sixteen 0.05 ha forest plots ha UNESCO-declared Amistad Biosphere were distributed over a. primary (mature) fo­ Reserve (Reserva de la Biósfera de la Amistad rest, and secondary (recovering) forests of ap­ 1990). Clearing of upper montane oak forest proximately b. 8-12 yr (pioneer), c. 20-22 yr stands occured frequently during the last five (earIy successional), andd. 30-35 yr (mid-suc­ decades generatinga híghly heterogeneous pat­ cessional) since abandonment. Late successio­ tero of vegetation types. Today, within the bor­ nal forest (40-80 yr of recovery following clea­ ders of the Los Santos Forest Reserve between ring) could not be sampled, because it was ab­ elevations of 2400 and 3200m tracts of pristine sent in fuestudy area: deforestation started only upper montane Chusquea - Quercus forests in the 1950's after the construction of the form a mosaic with patchesof secondary vege­ Intermerican Highway to San Isidro del tation of different ages, including grasslands, General. In eachpresent forestphase four plots shrublands and forests (Kappelle et al. 1989, were established andmarked on recent and past Van Velzen and Wijtzes 1990). Thebest exam­ aerial photographs in order to check former pIe of such a vegetational mosaic is found in land cover and use. Personal observations on the upper part of the Río Savegre watershed in land use his10ry were confmned by oral infor­ the vicinity of Jaboncillos and San Gerardo de mationfrom localfarmers (E. Ceciliano and M. Dota (Copey District, Dota Canton, San José Navarro, pers. com.). Province). In eachplot trees ? 3 cm dbh weresampled, Recovery following clearing of upper mon­ recorded, identified, and when necessary plant tane Quercus Iorest was studied here. materialwas collectedand subsequently exami­ Therefore, forest patcheswith similar topograp­ ned and deposited at the Costa Rican National hic, geomorphologic, edaphic, climatic and Herbarium (CR). Aerial crown cover values anthropogenic characteristics were selected. were estimated for all tree species separately, Patches were randomly coosen on south-facing following basic phytosociological procedures Pacificslopes of 20 10 35 degrees al about 2900 (Mueller-Dombois and Ellenberg 1974, Braun­ to 3000 maltitude. They had topsoils (0-25 cm) Blanquet 1979). For each species crown cover mainly containing darkbrown organic matter values estimated in four plots belonging to one with dispersed charcoal fragments giving rise phase were avemged and used for a preliminary to a very high root density, and subsoils (25- phytosociological analysis (Table 1). 100 cm) showing (pale) yellowish-brown clay Considering dominance - based on average ae­ material with orange-brown mottling caused by rial crown cover percentages - an ecological small weathered stone fragments (2-5 cm optimum at a certain moment in the successio­ diam.), sometimes layered in an iron pan hed. nal sere couId be distinguished for every spe­ the dry Here, during one wk in earIy season of cies. Thus, tree species could be divided. into 1991 - 1992 minimum temperatures fluctuated o four main ecological species groups: I. pioneer between 5 and 7 C and maximum temperato­ trees, n. early secondary trees, m. late secon­ res between 15 and 23 OC. The average annual dary trees, and IV. primary trees. According to temperature as measured at 60 cm soil depth the vegetation layer preference of each species KAPPELLE: Recovery of QIIBn:1IS forest 49

TABLEl

.List0150 tree species present inlOUTsuccessional lorest phoses 01 tM CostaRica" uppermontane QuerciJslorest ecosystem

Aerial Layer crown cover(%) Preter. Families (N=29) Species (N=50) PF ES MS MF

PIoneer treespecles (9) ASTERACEAE SeMcío cope,ewGreenm. C PAPAVERACEAE BocconiafrutesceM1.; 1 C ASTERACEAE SeMeío mullivelliusBenlh. <1 <1 C SAURAUlACEAE SllIITIlIIÍa 1Iertl&_W Scemann <1 <1 C GARRYACEAE Garrya laurifoUa Hartwegex Benth. sap. quiclNMis(Smith) Dahl. <1 d C ASTERACEAE AgeraJilltl8llbconlata (Benth.)R. King &:H. RomnlOl1 6 1 <1 C ASTERACEAE Verf>uilltloe1'8tedimta Benth. 10 3 1 C POLYGALACEAE Mo1lllÍlfa1Ullap;msis Kunth 2 1 <1 C FLACOUR11ACEAE AbaJüJ par11ifloraPavón RuízL6pez&: S 4 <1 C

Early secondary tree spec:les (18) SYMPLOCACEAE SymplocosirazueMis Cuí. <1 C LOGANlACEAE BwJJkja rritida Benth. 22 <1 C ESCAU.ONlACEAE &caUonia myrli//oiJu Li. varo palllM (Ruiz &: Pavon) S1eumer 3 <1 C MELASTOMATACEAE Miconia scltM/U WU1d. <1 s. , 1 ONAGRACEAE FucltsiaarboresceM Sims. 1 4 2 C CHLORANTHACEAE Hedyosmum _xk_ Cordemoy <1 1 <1 S SYMPLOCACEAE Symplocosserrulola Kunth <1 <1 <1 S AQUIFOUACEAE l/ex disc% r Standley var./omproph,//a (Standley) Edwin <1 <1 S CORNACEAE ContUSdisciflora Mociño &:Sessé 1 13 3 <1 C ARAUACEAE OnopaMXm/ape_ (Kunth)Decne. &:P1anehon 2 7 1 1 C

Late secondary tree spec:les (9) LAURACEAE Ocollla calophy//aMez <1 S MYRSINACEAE Anlisia afr.rrigropwu;tata <1 S LAURACEAE Pe1'8eaveslicula Standley &:S teyenn. <1 S MYRSlNACEAE Anlisiaglalldu/oso margillata Oetsted 1 S RUfACEAE Za1&thoxylum _laMslictumSchldl &: Cham. <1 1 S ERlCACEAE Comarostaphy/is arbutoidesLindley sap.arbutoiJulindley <1 <1 1 S MYKfACEAE MyrcÍOlll/tesfrtl&raM varo hispidu/aMcVaugh <1 <1 1 S CAPRIFOUACEAE V"WUI'IUUIIC08taric_ (Oetsted)Hema1ey <1 S 3 4 S MYRSINACEAE MyrsilU coriacea (Sw.) R Br. ex Roemer&: Schultes <1 2 3 1 S

PrImar)" treespedes (22) MELASTOMATACEAE Miconia ronduzii Cogn. 2 S ARAUACEAE OreopaNJ1t 1IUbigellUSStandley 2 S ROSACEAE PnutuS tlIIIIIiIaris KoeIme 2 S CLUSIACEAE C/usíapalmmra Standley <1 S CWSIACEAE C /usía rotundata Standley . <1 S SYMPLOCACEAE S,mp/ocosausliMmithii Standley <1 S MYRSlNACEAE Anlisiac08taricew Lunde1l <1 7 S ARAUACEAE Schefflerapittun (Marchal)Frodin <1 2 C LAURACEAE NectaNlrasalicilltl A11c:n <1 <1 S LAURACEAE Ocollla pittien (Mez)Van derWerlf <1 <1 S RHAMNACEAE RhamIIUS OTtlodendrollL.O. Williams <1 <1 S WINTERACEAE Drimysg1'allalÚllSÍs Li. <1 <1 S FAGACEAE Quen:uscopeyew Com. Mueller 1 44 80 C FAGACEAE Quen:usC08taricensis Liebm. 1 4 26 C STYRACACEAE Slyrax arge1llllusPresl <1 <1 3 15 S CUNONlACEAE Weillmannia piMata1.; <1 13 4 15 C TIIEACEAE CleyeratheaeoiJu (Sw.) Choisy 3 3 6 11 S ERlCACEAE VaccwumcOllSQlJgUÜleum Klotzsch <1 1 1 11 S AQUIFOUACEAE ¡In:paZ/ida Standley <1 <1 <1 3 S MYRSINACEAE MyrSÜ18 pe/lucitlopuN:tata Oersted <1 <1 1 2 S ARALÍACEAE OnopaMX capitatus (lacq.)Decne. &:P1anchon <1 <1 <1 1 S RUfACEAE ZaIIthoxylumscheryi Lunde11 <1 <1 1 1 S

Note: Each speciea is assigned10 one ofout foureco1ogical groups speciea (bold), according10 their dominance basedon aerisl crown cover. Averagespecies cover percentages forestin 0.05ha plata arepxesentcd far each succesaional phase(PF pioneer,ES early successionaJ., MS mid-successional,mature). MF C overpercentsgea leaath an 1 % arexepresented by a '<1' signo Data. on layer preferenceeaeh of spe- cíes is given (C canopy,S subcanopy). so REVISTADE BIOLOGIATROPICAL they could be subdivided into: A. canopy trees; the process of recovery. A schematic vege­ and B. subcanopy trees.Diagrams showing dis­ tation profile representing thissuccessional tribution patteros of species groups could be sere on basis of its principal tree species is made for aH four forest phases, and for the shown in Fig. 1. Below, a briefdescription Quercus forest ecosystem as a whole. The fo­ of each phase is given on basis of its tree restphases - each witha differentset of charac­ composition. teristic tree species - could be described and compared in order to discover general trends in Tbe pioneer torest pbase: The pioneer fo-. uppermontane Quercusforest recovery. rest phase. which has been recovering after abandonment about 10 yrs ago, is made up of RESULTS AND DISCUSSION 29 tree species, half of which are canopy spe­ cies. This phase is characterized by rapid-gro­ Fifty tree species in 29 families with indivi­ wing. large-leaved pioneertrees with a low wo­ duals 2: 3 cm dbh have been recorded in four od density, such as Senecio copeyensis and different successional phases (pioneer, Bocconia frutescens. Four out of fine pioneer earlyanó mid-successional, anómature) of trees belong to the composite family: Costa Rican uppermontane Quercus forest Ageratina subcordata. Senecio copeyensis. S. (TabIe 1). Each phase is characterizedby a multivenius and Verbesina oerstediana. These different set of pioneer, secondary and pri­ species dominate this phase, together with mary, canopy and subcanopy tree species, Abatia parviflora. Cleyera theaeoides, wruch appear at different moments during Monnina xalapensis and Oreopanaxxalap ense.

Height (m)

Legend to Ihe principal tree species

mllillTIl Quercus copeyensis 111 Quercus costaricansis l1li Styrax argenteus � Vaccinium consanguineum W1] Weinmannia pinnata mili Cleyera theaeoides 11m] Oreopanax xaJapense � Comus discif/ora EJ 6uddleja ni/ida D Abatia parviflora O Ageratina subcordata

Verbesina oarstadiana O...

pioneer fores! phase early suecessional mid-successional malure fores! phase lores! phase loresl phase

Fig. 1. SchemalÍc vegetation profile representing Ihe successional sere in a Costa Rican upper montane Quercus forest ecosystem. KAPPELLE: Recovery of Quercus forest 51

The latter, an araliaceous species with short-li­ dopunctata.Oreopanax capilatus.Quer cus co­ . ved compound palmate leaves looks very simi­ peyensis. Q. costaricensis. Styrax argenteus, lar 10 species of the .genus Cecropia, aoondant Symplocos serrulata, Vaccinium consangui­ in lowland successional forest, and may occupy neum. Viburnum costaricanum and Zantho­ i18 niche in high-altitude environments. Other, xylum scheryi. less common canopy species inelude Cornus disciflora,Fuchsia arborescens.Garrya lauri­ The mid-successional forest pbase: The foUa ssp. quichensis - a species weU-known third distinguished phase comprioos secondary from above-situated subalpine dwarf fores18 -, forest of 30 to 35 yrs oId. The association of Saurauia veraguasensis, and occasionally many pioneerand secondarytrees together with Quercus copeyensis, Q. costaricensis and a large arcay of primary species makesit by far Weinmannia pinnata. Doring this phasemany the most tree species-riehstage: 38 tree species latesecondary and primary subcanopy trees are (76 % of the totalnumber of species found) in­ already present in low numbers but do not re­ habit the four0.05 ha plo18 of mid-successional ach their mature state. Among them are forest. This phase is dominated almost exelusi­ Comarostaphylis arbutoides ssp. arbutoides, vely by 10 10 15 m tallQuercus copeyensis tre­ Hedyosmum mexicanum. Ilex discolor var. es, accompanied by the less-dominant canopy lamprophylla.l. pallida.Myrci anthesfrag rans species Q. costaricensis and Weinmannia pin­ varo hispidula.Myrsine coriacea. M. pelluci­ nata. Subcanopy trees andtreele18 belonging lO dopunctata. Oreopanax capitatus. Styrax ar­ the speciesMyrsine coriacea. Viburnum costa­ genteus. Symplocos serrulata. Vaccinium con­ ricanum.Comarostaphylis arbutoides varo a r­ sanguineum. Viburnum costaricanum and butoides.Myrcianthes fragrans varo hispidula Zanthoxylum scheryi. and Zanthoxylum melanostictum seem to have their ecological optimum in this phase. Howe­ Tbe early successional forest pbase: The ver, it is believed, that C. arbutoides.M. fra­ successional phase repreoonting earIy secon­ grans, and Z. melanostictum get their maximum dary forest of about 20 yr oId since abandon­ aerial crown cover in mature forest, although ment contains 32 tree species andis dominated theyhave not beenrecorded in the primary forest by Buddleja nítida. Cornus disciflora. plots. In the relatively darker parts of the subca­ Weinmannia pinnata and Oreopanax xalapen­ nopy - belowrather dense boles of Quercus trees se canopy trees. Large-leaved pioneering - many 4 to 8 m high individuals are fOWld be­ Senecio copeyensis has disappeared totally. longing to Cleyera theaeoides. llex pallida. Abatía parviflora and Verbesina oerstediana Myrsine pellucidopuctata.Oreopanax capitatus, individuals are still numerous, bot 10000 some Styrax argenteus.Vaccinium consanguineum and of the vigor they had in the former phase. Too Zanthoxylum scheryi. Several species fOWld in same may be true for Bocconia frutescens, this phase occur for the frrst time during sueces­ Garrya laurifolia ssp. quichensis. Saurauia sion, but still with low aerial crown cover per­ veraguasensis, and Senecio multivenius. centages. They belong mainly to either the Canopy treeslikeFuchsia arborescens, en lOO Myrsmaceae (Ardisia costaricensis, A. glandu­ contrary, gel prominent. Several other species, losomarginata and A. aff. nigropunctata) or the such as Escallonia myrtillioides varo patens, Lauraceae (Nectandra salicina. Ocotea ca­ Miconia schnellii, Symplocos irazuensis and lophylla. O. piuieri and Persea vesticula). Other Zanthoxylum melanostictum occur for lOO ftrst newly appearing trees inelude Drimys grana­ time. Many other speciesthat were alreadypre­ densis. Rhamnus oreodendron. and Schefflera oont in the pioneer forest phase contmue their piuieri. Although present with less 'individuals life-cycle, although they display low aerial and lower aerial ClOwn cover values numerous ClOwncover percentages, as doAgeratina sub­ pioneer and early-secondary species are still oc­ cordata. Comarostaphylis arbutoides ssp. a r­ cupying small relatively open areas. Among butoides.Hedyosmum mexicanum.lIex palli­ them most prominent are Cornus disciflora. da,Monnina xalapensis. Myrc ianthesfragrans Fuchsia arborescens. Verbesina oerstediana and varo hispidula, Myrsine coriacea. M. pelluci- Oreopanaxxalapense. 52 REVISTA DE BIOLOGIATROPICAL

Tbe mature rorest pbase: The mature or 40,..------, primary forest phase of the upper montane Quercus forest ecosystem is indeed dominated o PloneerforAst Ill] Ear1y sucr.essíona! forest by Quercus spp. lt resembles the Quercus cos­ !El M!d-successional fores! taricensis - Quercus copeyensis forest commu­ 11 Maturetorest nity earlier described by KappeUe el al. (1989) and consists of mature forest characterized by 30 to 40 m tan Quercus treesand dense stands Pig. 2. Total numbers of tree speciesin fourdíff erent suc­ of 5 m high Chusquea spp. bamboos. In four cessional pbases of tbe Costa Rican upper montane 0.05 ha plots together onIy 26 species were re­ Quercusfores! ecosystem. corded, which is about a two-third of the num­ ber of tree speciespresent in the late-secondary ecosystems (West el al. 1981, G6mez-Pompa phase. This might be explained by the lack of a and Del Amo 1985. Sugden et al, 1985, Brown dozen of secondary species. Most conspicuous and Lugo 1990). However, it is quite remarka­ is therather uniform canopylayer in comparison ble, that the lowest tree speciesrichness is found with the highly diverse subcanopy layer. About in the mature fores! phase. Other studies on fo­ 60 to 95 % of the canopy aerial crown cover is rest recovery in both neotropical lowland and made up of Quercus spp. with only few canopy montane forest present it as the most species­ individuals belonging to Schefflera pittíeri and rich phase (Purata 1986, Saldarriaga 1988, Weinmanniapinnata. In the 8 10 15 (20) m tan González-Espinosa et al. 1991). In the Mexican subcanopy, on the contrary, a series of shade­ ChiapashighIands, for example,40 yr old secon­ tolerant trees find their place. Species such as dary Pinus-Quercus forests recovered just a 85 Styrax argenteus, Cleyera theaeoides, % of the 8peciesrichness found in matureforest, Vaccinium consanguineum and Ardisia costa­ including all vascular terrestrial plants ricensis domínate this vegetation layer. Other (González-Espinosael al. 199 1). Thereare seve­ less-abundant trees like llex pallida, Myrsine ral possible causes that might explain why mid­ pellucidopunctata and Oreopanax capitatus - successional forest in montane Costa Rica is ri­ present from the beginning of succession - get cher in tree species than the mature foresto First, their greatest dominance in this 'final' sueces­ many primary tree species are already appearing sional phase. Primary subcanopy species like in theshrub layer of pioneerand earIy successio­ Ocotea pittieri and Rhamnus oreodendron alre­ nal forest (e.g. Quercus spp., Styrax argenteus, ady present in late secondary forest become Weinmannia pínnata, Cleyera theaeoídes, more plOminent. In relatively recent tree faIl Vaccinium consanguineum), whereas numerous gaps one may encounter Oreopanax xalapense pioneer and earIy secondary species are absent and Cornus disciflora, two successional species in fue mature forest phase (e.g. Senecio spp., well-known from the canopy of early and mid­ Bocconia frutescens. Verbesina oerstediana, successional forest phases. Al the border of Ageratina subcordata, Monnina xalapensis, such gaps Viburnum costaricanum and Abatía parviflora). Secondly, the area of mature Myrsine coriacea arecommon. Six species ha­ fores! sampled might be too small to inelude ve been found only in mature forest, two of many 'late secondary specíes' (e.g. Ardisa spp., them belonging to the primary forest genus Ocotea calophylla, Persea vesticula. Clusía. The species Prunus annularis, which Comarostaphylis arbutoides), which are belie­ has an average 2 % aerial ClOwn cover in the ved to be primary species, according to earlier mature foresí phase, might be considered as an studies (Kappelleet al. 1989). Third, it might be indicator for undisturbed upper montane pri­ just a maller of chance, that many other primary mary Quercus foresto species weU-known from upper montane Quercus forests in the study area, such as Myrsine pittieri, Magnolia spp., and Podo­ General patterns in arboreal recovery: carpaceae (Kappelle el al. 1989, 1991), havenot Comparing the fourforest phases one notes im­ been found in the mature forest studied. Finally, mediately the initial íncrease in the number of physical characteristics (light availabílity, $Oí! tree species during succession (Fig. 2), a phe­ plOperties) may differ over short topographíc nomenon well-known from other tropical ranges locally favouring Quercus species. KAPPELLH: RecoveryQuercus of forest 53

Comparing the most species-rich families as coslaricanum andMyrsine coriacea, which are occurring in the four different successional present throughout succession, including the phases, the declineof Asteraceae species as se­ mature phase. On the whole, almost halfof aU concJary succession advances is evident (pig. recorded species (45 %) are primary species, 3), an eveot also known from Mexican high­ while the other half is more or less equaUy dis­ elevation pine-oak forest (González-Espinosa trlbu100 over the pioneer, early and late secon­ el al. 1991). Composite trees recorded resolt to dary species groups. be large-leaved, light-demanding pioneer and early-secondary species, which do not bear the 100 -,------, 50 shady conditions prevailing under large • Pioneer species 80 • EarIy secondaryspecies Quercus canopy sttuctures in mid-successional 1: 40 � • Late secondary species and mature forest phases. Myrsinaceae, "!i j¡ 60 !l'I Primsry species Araliaceae, and Lauraceae, on theother band. !i :¡ " 0 !l ! get more prominent as secondary forests grow 40 3 :s 20 older, and numbers stabilize atthe end of the l " ! � successional pathway. ti 20 1 OC 0

o o • Asteraceae Early suc>- Mid-suc Montan�8 PIoneer cesslonal cesslonal 5 • Myrsinaceae Mature Ouercus torest torest forest • Araliaceae forest forest (N=26) (N=29) (N=32) (N=38) (N=50)

Fig. 4. Piooeer, early and late 1CCOIldary, andprimary tn::e species in relative numben lor each of four erentdiff suc­ cessional phases ol me Costa Rican upper montane Qwrcus forestecosystem, andin absolute numben fortbe ecosystem as a whole.

o FinaUy, a distinction can be made between EarIy suc- Mid-suc- canopy and subcanopy species sets. In each fo­ Pioneer cessional cessional Malure rest phase a differe�t canopy species subca­ lorest lores! lorest lores! I nopy species - ratio is displayed, showing a de­ Fig. 3. Most species-rich tn::e families in absolute nmnben crease in canopy species, and an increase in for each of four different sucx:essiooalphases of tbe Costa subcanopy species along the successional gra­ Rican uppermon_tane Quercu.rforest ecosystem. dieot (pig. 5). Pioneer forest has equal numbers of canopy andsubcanopy species,bol maturefo­ When we have a look at the relative num­ rest has about 20 % canopy species and almost bers of pioneer, early and late secondary, and 80 % subcanopy species. This might be explai­ primary species as distrlbu100 over the four fo­ ned by the fact that canopy species diversity de­ rest phases (pig. 4), one observes an expec100 creases largely during succession. Inlaterforest decrease in pioneer species and an increase in phases the canopy gets monogenericaUy domi­ primary species during succession. It is interes­ na1OO: two species of Quercus reduce the light ting to note, however, that not more than about and space available to other species, which are 30 % of aU tree species recorded in pioneer fo­ finaUy outcompe1OO. Only Schefflera piltieri and rest are ttue pioneer trees, while over 80% of Weinmannia pinnata may reach canopy heights the trees found in primary forest are ttue pri­ and sharethe upperforest suatumwith Quercus mary trees. Thus, pioneer forest - although do­ spp. Thesubcanopy, onthe contrary, becomes minated by pioneer trees, wheo considering ae­ better developed during succession, in laterpha­ rial ClOwn cover projections - is made up of a ses harboliring a targe range of small trees and mixture of pioneer, secondary and primary spe� treelets with different ecological demands. Most cies. The mature forest phase instead is almost of these subcanopy species appear lO be primary entirely made up of primary species. Excep­ species (pig. 6), thus having their ecological op­ tions are the secondary tree species Cornus timum, i.e. their highest aerial crown cover per­ disciflora, Oreopanax xalapense, Viburnum centages, in the mature f�tphase (Table 1). 54 REVISTADE BIOLOGIATROPICAL

80 species. Although primary forest was expected 0 Canopy species lO berichest in tree species, later secondary fo­ 1m Subcanopy species rest phases were more diverse, combining spe­ � 60 cies from different stages. Overall, compositio­ .,� nal recovery tends 10 develop al a faster rate .o lE than earlier authors expected. Ewel (1980), for "" ¡: instance, found very littIe forestrecovery in me ..,., 40 '<:; frrst yr following clearing of an oak-dominated '" O-,,", forestat nearby Ojo de Agua (2900 m alt.). He o> > stated that the regrowth of such a high-eleva­ �,., 20 non tropical forest is so slow that it may never o: reestablish after clearing. The present study, on the otherhand, shows mat a complete recovery

o Early suc- Mid-suc- of the arboreal compostion in Costa Rican montane oakforests may be possible. However, Pioneer cessional cessional Mature the vertical forest structure may reslOre itself at lores! lorest lores! lores! a much slower pace than the mere tree species (N=29) (N=32) (N=38) (N=26) composition treated here (Kappelle et al. in Fig.5. Canopyand subcanopyrree species in relative num­ prep.). ben for each of fOUT dit'ferent successional phases oí me Costarucan upper montane Qu.ercus forest ecosystem. ACKNOWLEDGMENTS

20�------�------� 1 am very grateful lo Antoine M. Cleef � Canopy species (University of Amsterdam. ASD), Pablo Sánchez (Herbario Nacional, Museo Nacional, I11III Subcanopy species CR) and Adelaida Chaverri (Universidad Nacional, Heredia) for logistic support. Marjolein Alkemade, Marta Juárez, Peer Kennis, Miguel Leal and Rob de Vries helped with fieldwork. Two anonymous reviewers commented on the manuscript. This study was supported by grant W 84-331 of lile Netherlands Foundation for the Advancement of TropicalResearch (WOTRO). Early Late Pioneer secondary secondary Primary species specíes species species RESUMEN

Pig. 6. Canopy snd subcanopytree species in absolute Se han estudiado los patrones de la recupe­ numbendistributed eady and late secondary, ayer pioneer, ración después de la de los bosques monta­ snd primary speciesof me Costa rucan upper montane tala Quercusforest econsystem. no-altos de Quercus en la Cordillera de Talamanca, Costa Rica, distinguiéndose cuatro Results of tile recovery after clearing of fases sucesionales (pionera, sucesional tempra­ Costa Rican upper montane Quercus forests na, sucesional intermedia, madura). La riqueza show a hopeful successional process, where it de especies arbóreas aumenta durante la suce­ concems compositional recovery. Arborea! re­ sión siendo más grande en la fase intermedia. cuperation in forests, which developed afterha­ Las asteráceasleñosas dominan las fases secun­ ving been c1eared and abandoned 30 10 35 yr darias tempranas. mientras que las araliáceas, ago, reaches a 70 % of the primary treespecies las lauráceas y en menor parte las mirsináceas composition in mature foresto By that time a suelen ser importantes en las fases tardías, in­ dozen of pioneer and early secondary canopy cluyendo la fase madura. El género Querc u s trees are almost completely replaced by pri­ (roble. encino) se recupera muy bien, dominan­ mary Quercus trees, offering shade to nome­ do el bosque secundario tardío y maduro. Las mus subcanopy elements, such as lauraceous fasesjóvenes son ricasen especies heliófitas de KAPPELLE:Recove¡y of Q/le1T:1IS fores! 55 crecimiento rápido en el dosel, mientras que las Jiménez, W., A. Chaverri, R. Miranda &; I. Rojas. 1988. fases más desarrolladas están dominadas porun Aproximaciones silviculturales .al manejo de un roble­ dal (Q/le1T:1IS spp. ) en San Gerardo deDota, CostaRica. gran número de especies del subdosel toleran­ ThrriaJba 38(3): 208-214. tes a la sombra. En general, la sucesión secun­ daria puede llegar - dentto de un período de Kappelle, M. 1992. Distribución altitudinal de la vegeta­ aproximadamente 35 afios después de la tala y ci6n del Parque Nacional Chirrip6, Costa Rica. Brenesia 36 (IDpress). el abandono - a una recuperaciónarbórea de un 70 % de la composición originalde especies de Kappelle, M. , A.M. Cleef' &; A. Chaverri. 1989. árbolesen el bosque maduro. Phytosociology of montaneClallSq/lea-QwlT:lIS forests, Cordillera de Talamanca, Costa Rica. Brenesia 32: 73- lOS.

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